Run test suite on wa-serde-derive

Compile serde_derive to wasm
2026-04-24 01:48:00 +00:00 · 2022-07-01 17:56:18 -07:00 · 2022-07-01 17:55:51 -07:00
231 changed files with 17374 additions and 15606 deletions
@@ -0,0 +1 @@
+test_suite/tests/expand/*.expanded.rs linguist-generated
@@ -1 +0,0 @@
-github: dtolnay
@@ -3,12 +3,8 @@ name: CI
 on:
  push:
  pull_request:
-  workflow_dispatch:
  schedule: [cron: "40 1 * * *"]

-permissions:
-  contents: read
-
 env:
  RUSTFLAGS: -Dwarnings

@@ -16,24 +12,20 @@ jobs:
  test:
    name: Test suite
    runs-on: ubuntu-latest
-    timeout-minutes: 45
    steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v3
      - uses: dtolnay/rust-toolchain@nightly
      - run: cd test_suite && cargo test --features unstable
-      - uses: actions/upload-artifact@v6
-        if: always()
-        with:
-          name: Cargo.lock
-          path: Cargo.lock
-        continue-on-error: true
+      - uses: dtolnay/install@cargo-expand
+        if: github.event_name != 'pull_request'
+      - run: cd test_suite && cargo test --features expandtest --test expandtest -- --include-ignored
+        if: github.event_name != 'pull_request'

  windows:
    name: Test suite (windows)
    runs-on: windows-latest
-    timeout-minutes: 45
    steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v3
      - uses: dtolnay/rust-toolchain@nightly
      - run: cd test_suite && cargo test --features unstable -- --skip ui --exact

@@ -44,33 +36,31 @@ jobs:
      fail-fast: false
      matrix:
        rust: [stable, beta]
-    timeout-minutes: 45
    steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v3
      - uses: dtolnay/rust-toolchain@master
        with:
          toolchain: ${{matrix.rust}}
      - run: cd serde && cargo build --features rc
      - run: cd serde && cargo build --no-default-features
-      - run: cd test_suite/no_std && cargo build
+      - run: cd serde_test && cargo build
+      - run: cd serde_test && cargo test --features serde/derive,serde/rc

  nightly:
-    name: Rust nightly${{matrix.os == 'windows' && ' (windows)' || ''}}
+    name: Rust nightly ${{matrix.os == 'windows' && '(windows)' || ''}}
    runs-on: ${{matrix.os}}-latest
    strategy:
      fail-fast: false
      matrix:
        os: [ubuntu, windows]
-    timeout-minutes: 45
    steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v3
      - uses: dtolnay/rust-toolchain@nightly
      - run: cd serde && cargo build
      - run: cd serde && cargo build --no-default-features
      - run: cd serde && cargo build --no-default-features --features alloc
      - run: cd serde && cargo build --no-default-features --features rc,alloc
-      - run: cd serde && cargo build --no-default-features --features unstable
-      - run: cd serde_core && cargo test --features rc,unstable
+      - run: cd serde && cargo test --features derive,rc,unstable
      - run: cd test_suite/no_std && cargo build
        if: matrix.os != 'windows'
      - run: cd serde_derive && cargo check --tests
@@ -78,91 +68,116 @@ jobs:
          RUSTFLAGS: --cfg exhaustive ${{env.RUSTFLAGS}}
        if: matrix.os != 'windows'

+  msrv:
+    name: Rust 1.13.0
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - uses: dtolnay/rust-toolchain@1.13.0
+      - name: Get timestamp for cache
+        id: date
+        run: echo ::set-output name=yearmo::$(date +%Y%m)
+      - uses: actions/cache@v1
+        with:
+          path: ~/.cargo/registry/index
+          key: cargo-registry-index-${{steps.date.outputs.yearmo}}
+      - run: cd serde && cargo build --features rc
+      - run: cd serde && cargo build --no-default-features
+      - run: cd serde_test && cargo build
+
  build:
    name: Rust ${{matrix.rust}}
    runs-on: ubuntu-latest
    strategy:
      fail-fast: false
      matrix:
-        rust: [1.56.0, 1.60.0]
-    timeout-minutes: 45
+        rust: [1.19.0, 1.20.0, 1.21.0, 1.25.0, 1.26.0, 1.34.0]
    steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v3
      - uses: dtolnay/rust-toolchain@master
        with:
          toolchain: ${{matrix.rust}}
-      - run: sed -i '/"test_suite"/d' Cargo.toml
-      - run: cd serde && cargo build --features rc
      - run: cd serde && cargo build --no-default-features
-      - run: cd serde && cargo build --no-default-features --features alloc
+      - run: cd serde && cargo build
+
+  more:
+    name: Rust ${{matrix.rust}}
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        rust: [1.27.0, 1.28.0]
+    steps:
+      - uses: actions/checkout@v3
+      - uses: dtolnay/rust-toolchain@master
+        with:
+          toolchain: ${{matrix.rust}}
+        # Work around failing to parse manifest because editions are unstable.
+      - run: sed -i /test_suite/d Cargo.toml
+      - run: cd serde && cargo build --no-default-features
      - run: cd serde && cargo build

  derive:
-    name: Rust 1.68.0
+    name: Rust 1.31.0
    runs-on: ubuntu-latest
-    timeout-minutes: 45
    steps:
-      - uses: actions/checkout@v6
-      - uses: dtolnay/rust-toolchain@1.68.0
-      - run: |
-          sed -i 's/proc-macro2 = { workspace = true/proc-macro2 = { version = "1"/' serde_derive*/Cargo.toml
-          sed -i 's/quote = { workspace = true/quote = { version = "1"/' serde_derive*/Cargo.toml
-          sed -i 's/syn = { workspace = true/syn = { version = "2"/' serde_derive*/Cargo.toml
+      - uses: actions/checkout@v3
+      - uses: dtolnay/rust-toolchain@1.31.0
      - run: cd serde && cargo check --no-default-features
      - run: cd serde && cargo check
      - run: cd serde_derive && cargo check

-  minimal:
-    name: Minimal versions
+  alloc:
+    name: Rust 1.36.0
    runs-on: ubuntu-latest
-    timeout-minutes: 45
    steps:
-      - uses: actions/checkout@v6
-      - uses: dtolnay/rust-toolchain@nightly
-      - run: cargo generate-lockfile -Z minimal-versions
-      - run: cargo check --locked --workspace
+      - uses: actions/checkout@v3
+      - uses: dtolnay/rust-toolchain@1.36.0
+      - run: cd serde && cargo build --no-default-features --features alloc

-  doc:
-    name: Documentation
+  emscripten:
+    name: Emscripten
    runs-on: ubuntu-latest
-    timeout-minutes: 45
-    env:
-      RUSTDOCFLAGS: -Dwarnings
    steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v3
      - uses: dtolnay/rust-toolchain@nightly
-      - uses: dtolnay/install@cargo-docs-rs
-      - run: cargo docs-rs -p serde
-      - run: cargo docs-rs -p serde_core
-      - run: cargo docs-rs -p serde_derive
-      - run: cargo docs-rs -p serde_derive_internals
+      - uses: actions/setup-node@v1
+        with:
+          node-version: 9
+      - name: Install cargo-web
+        run: |
+          CARGO_WEB_RELEASE=$(curl -L -s -H Accept:application/json https://github.com/koute/cargo-web/releases/latest)
+          CARGO_WEB_VERSION=$(echo "${CARGO_WEB_RELEASE}" | jq -r .tag_name)
+          CARGO_WEB_URL="https://github.com/koute/cargo-web/releases/download/${CARGO_WEB_VERSION}/cargo-web-x86_64-unknown-linux-gnu.gz"
+          mkdir -p ~/.cargo/bin
+          curl -L "${CARGO_WEB_URL}" | gzip -d > ~/.cargo/bin/cargo-web
+          chmod +x ~/.cargo/bin/cargo-web
+      - run: cd test_suite && cargo web test --target=asmjs-unknown-emscripten --nodejs
+        continue-on-error: true
+      - run: cd test_suite && cargo web test --target=wasm32-unknown-emscripten --nodejs
+        continue-on-error: true

  clippy:
    name: Clippy
    runs-on: ubuntu-latest
    if: github.event_name != 'pull_request'
-    timeout-minutes: 45
    steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v3
      - uses: dtolnay/rust-toolchain@clippy
      - run: cd serde && cargo clippy --features rc,unstable -- -Dclippy::all -Dclippy::pedantic
-      - run: cd serde_core && cargo clippy --features rc,unstable -- -Dclippy::all -Dclippy::pedantic
      - run: cd serde_derive && cargo clippy -- -Dclippy::all -Dclippy::pedantic
      - run: cd serde_derive_internals && cargo clippy -- -Dclippy::all -Dclippy::pedantic
+      - run: cd serde_test && cargo clippy -- -Dclippy::all -Dclippy::pedantic
      - run: cd test_suite && cargo clippy --tests --features unstable -- -Dclippy::all -Dclippy::pedantic
      - run: cd test_suite/no_std && cargo clippy -- -Dclippy::all -Dclippy::pedantic

  miri:
    name: Miri
    runs-on: ubuntu-latest
-    timeout-minutes: 45
    steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v3
      - uses: dtolnay/rust-toolchain@miri
-        with:
-          toolchain: nightly-2025-05-16  # https://github.com/rust-lang/miri/issues/4323
-      - run: cargo miri setup
-      - run: cd serde_core && cargo miri test --features rc,unstable
+      - run: cd serde && cargo miri test --features derive,rc,unstable
        env:
          MIRIFLAGS: -Zmiri-strict-provenance
      - run: cd test_suite && cargo miri test --features unstable
@@ -173,9 +188,7 @@ jobs:
    name: Outdated
    runs-on: ubuntu-latest
    if: github.event_name != 'pull_request'
-    timeout-minutes: 45
    steps:
-      - uses: actions/checkout@v6
-      - uses: dtolnay/rust-toolchain@stable
+      - uses: actions/checkout@v3
      - uses: dtolnay/install@cargo-outdated
-      - run: cargo outdated --workspace --exit-code 1
+      - run: cargo outdated --workspace --exclude macrotest,prettyplease --exit-code 1
@@ -1,2 +1,4 @@
-/target/
-/Cargo.lock
+target/
+**/*.rs.bk
+*.sw[po]
+Cargo.lock
@@ -27,11 +27,11 @@ pull request with your changes. If anything does not pass, typically it will be
 easier to iterate and fix it locally than waiting for the CI servers to run
 tests for you.

-##### In the [`serde_core`] directory
+##### In the [`serde`] directory

 ```sh
 # Test all the example code in Serde documentation
-cargo test
+cargo test --features derive
 ```

 ##### In the [`test_suite`] directory
@@ -43,7 +43,7 @@ cargo +nightly test --features unstable

 Note that this test suite currently only supports running on a nightly compiler.

-[`serde_core`]: https://github.com/serde-rs/serde/tree/master/serde_core
+[`serde`]: https://github.com/serde-rs/serde/tree/master/serde
 [`test_suite`]: https://github.com/serde-rs/serde/tree/master/test_suite

 ## Conduct
@@ -1,19 +1,7 @@
 [workspace]
 members = [
    "serde",
-    "serde_core",
-    "serde_derive",
    "serde_derive_internals",
+    "serde_test",
    "test_suite",
 ]
-resolver = "2"
-
-[patch.crates-io]
-serde = { path = "serde" }
-serde_core = { path = "serde_core" }
-serde_derive = { path = "serde_derive" }
-
-[workspace.dependencies]
-proc-macro2 = { version = "1.0.74", default-features = false }
-quote = { version = "1.0.35", default-features = false }
-syn = { version = "2.0.81", default-features = false }
@@ -174,3 +174,28 @@ TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
   of your accepting any such warranty or additional liability.

 END OF TERMS AND CONDITIONS
+
+APPENDIX: How to apply the Apache License to your work.
+
+   To apply the Apache License to your work, attach the following
+   boilerplate notice, with the fields enclosed by brackets "[]"
+   replaced with your own identifying information. (Don't include
+   the brackets!)  The text should be enclosed in the appropriate
+   comment syntax for the file format. We also recommend that a
+   file or class name and description of purpose be included on the
+   same "printed page" as the copyright notice for easier
+   identification within third-party archives.
+
+Copyright [yyyy] [name of copyright owner]
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+	http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
@@ -1,13 +1,13 @@
-# Serde &emsp; [![Build Status]][actions] [![Latest Version]][crates.io] [![serde msrv]][Rust 1.56] [![serde_derive msrv]][Rust 1.68]
+# Serde &emsp; [![Build Status]][actions] [![Latest Version]][crates.io] [![serde: rustc 1.13+]][Rust 1.13] [![serde_derive: rustc 1.31+]][Rust 1.31]

-[Build Status]: https://img.shields.io/github/actions/workflow/status/serde-rs/serde/ci.yml?branch=master
+[Build Status]: https://img.shields.io/github/workflow/status/serde-rs/serde/CI/master
 [actions]: https://github.com/serde-rs/serde/actions?query=branch%3Amaster
 [Latest Version]: https://img.shields.io/crates/v/serde.svg
 [crates.io]: https://crates.io/crates/serde
-[serde msrv]: https://img.shields.io/crates/msrv/serde.svg?label=serde%20msrv&color=lightgray
-[serde_derive msrv]: https://img.shields.io/crates/msrv/serde_derive.svg?label=serde_derive%20msrv&color=lightgray
-[Rust 1.56]: https://blog.rust-lang.org/2021/10/21/Rust-1.56.0/
-[Rust 1.68]: https://blog.rust-lang.org/2023/03/09/Rust-1.68.0/
+[serde: rustc 1.13+]: https://img.shields.io/badge/serde-rustc_1.13+-lightgray.svg
+[serde_derive: rustc 1.31+]: https://img.shields.io/badge/serde_derive-rustc_1.31+-lightgray.svg
+[Rust 1.13]: https://blog.rust-lang.org/2016/11/10/Rust-1.13.html
+[Rust 1.31]: https://blog.rust-lang.org/2018/12/06/Rust-1.31-and-rust-2018.html

 **Serde is a framework for *ser*ializing and *de*serializing Rust data structures efficiently and generically.**

@@ -15,11 +15,11 @@

 You may be looking for:

- [An overview of Serde](https://serde.rs)
+- [An overview of Serde](https://serde.rs/)
 - [Data formats supported by Serde](https://serde.rs/#data-formats)
 - [Setting up `#[derive(Serialize, Deserialize)]`](https://serde.rs/derive.html)
 - [Examples](https://serde.rs/examples.html)
- [API documentation](https://docs.rs/serde)
+- [API documentation](https://docs.serde.rs/serde/)
 - [Release notes](https://github.com/serde-rs/serde/releases)

 ## Serde in action
@@ -27,7 +27,7 @@ You may be looking for:
 <details>
 <summary>
 Click to show Cargo.toml.
-<a href="https://play.rust-lang.org/?edition=2021&gist=72755f28f99afc95e01d63174b28c1f5" target="_blank">Run this code in the playground.</a>
+<a href="https://play.rust-lang.org/?edition=2018&gist=72755f28f99afc95e01d63174b28c1f5" target="_blank">Run this code in the playground.</a>
 </summary>

 ```toml
@@ -48,7 +48,7 @@ serde_json = "1.0"
 <p></p>

 ```rust
-use serde::{Deserialize, Serialize};
+use serde::{Serialize, Deserialize};

 #[derive(Serialize, Deserialize, Debug)]
 struct Point {
@@ -6,17 +6,17 @@

 You may be looking for:

- [An overview of Serde](https://serde.rs)
+- [An overview of Serde](https://serde.rs/)
 - [Data formats supported by Serde](https://serde.rs/#data-formats)
 - [Setting up `#[derive(Serialize, Deserialize)]`](https://serde.rs/derive.html)
 - [Examples](https://serde.rs/examples.html)
- [API documentation](https://docs.rs/serde)
+- [API documentation](https://docs.serde.rs/serde/)
 - [Release notes](https://github.com/serde-rs/serde/releases)

 ## Serde in action

 ```rust
-use serde::{Deserialize, Serialize};
+use serde::{Serialize, Deserialize};

 #[derive(Serialize, Deserialize, Debug)]
 struct Point {
@@ -46,8 +46,8 @@ fn main() {
 Serde is one of the most widely used Rust libraries so any place that Rustaceans
 congregate will be able to help you out. For chat, consider trying the
 [#rust-questions] or [#rust-beginners] channels of the unofficial community
-Discord (invite: <https://discord.gg/rust-lang-community>), the [#rust-usage]
-or [#beginners] channels of the official Rust Project Discord (invite:
+Discord (invite: <https://discord.gg/rust-lang-community>, the [#rust-usage] or
+[#beginners] channels of the official Rust Project Discord (invite:
 <https://discord.gg/rust-lang>), or the [#general][zulip] stream in Zulip. For
 asynchronous, consider the [\[rust\] tag on StackOverflow][stackoverflow], the
 [/r/rust] subreddit which has a pinned weekly easy questions post, or the Rust
@@ -0,0 +1 @@
+msrv = "1.13.0"
@@ -1,36 +1,30 @@
 [package]
 name = "serde"
-version = "1.0.228"
+version = "1.0.137" # remember to update html_root_url and serde_derive dependency
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>", "David Tolnay <dtolnay@gmail.com>"]
-build = "build.rs"
-categories = ["encoding", "no-std", "no-std::no-alloc"]
-description = "A generic serialization/deserialization framework"
-documentation = "https://docs.rs/serde"
-edition = "2021"
-homepage = "https://serde.rs"
-keywords = ["serde", "serialization", "no_std"]
+rust-version = "1.13"
 license = "MIT OR Apache-2.0"
-readme = "crates-io.md"
+description = "A generic serialization/deserialization framework"
+homepage = "https://serde.rs"
 repository = "https://github.com/serde-rs/serde"
-rust-version = "1.56"
+documentation = "https://docs.serde.rs/serde/"
+keywords = ["serde", "serialization", "no_std"]
+categories = ["encoding"]
+readme = "crates-io.md"
+include = ["build.rs", "src/**/*.rs", "crates-io.md", "README.md", "LICENSE-APACHE", "LICENSE-MIT"]
+build = "build.rs"

 [dependencies]
-serde_core = { version = "=1.0.228", path = "../serde_core", default-features = false, features = ["result"] }
-serde_derive = { version = "1", optional = true, path = "../serde_derive" }
+serde_derive = { version = "=1.0.137", optional = true, path = "../serde_derive" }
+
+[dev-dependencies]
+serde_derive = { version = "1.0", path = "../serde_derive" }

 [package.metadata.playground]
 features = ["derive", "rc"]

 [package.metadata.docs.rs]
-features = ["derive", "rc", "unstable"]
 targets = ["x86_64-unknown-linux-gnu"]
-rustdoc-args = [
-    "--generate-link-to-definition",
-    "--generate-macro-expansion",
-    "--extern-html-root-url=core=https://doc.rust-lang.org",
-    "--extern-html-root-url=alloc=https://doc.rust-lang.org",
-    "--extern-html-root-url=std=https://doc.rust-lang.org",
-]


 ### FEATURES #################################################################
@@ -43,20 +37,20 @@ derive = ["serde_derive"]

 # Provide impls for common standard library types like Vec<T> and HashMap<K, V>.
 # Requires a dependency on the Rust standard library.
-std = ["serde_core/std"]
+std = []

 # Provide impls for types that require unstable functionality. For tracking and
 # discussion of unstable functionality please refer to this issue:
 #
 #    https://github.com/serde-rs/serde/issues/812
-unstable = ["serde_core/unstable"]
+unstable = []

 # Provide impls for types in the Rust core allocation and collections library
 # including String, Box<T>, Vec<T>, and Cow<T>. This is a subset of std but may
 # be enabled without depending on all of std.
-alloc = ["serde_core/alloc"]
+alloc = []

 # Opt into impls for Rc<T> and Arc<T>. Serializing and deserializing these types
 # does not preserve identity and may result in multiple copies of the same data.
 # Be sure that this is what you want before enabling this feature.
-rc = ["serde_core/rc"]
+rc = []
@@ -1,69 +1,140 @@
 use std::env;
-use std::fs;
-use std::path::PathBuf;
 use std::process::Command;
-use std::str;
-
-const PRIVATE: &str = "\
-#[doc(hidden)]
-pub mod __private$$ {
-    #[doc(hidden)]
-    pub use crate::private::*;
-}
-use serde_core::__private$$ as serde_core_private;
-";
+use std::str::{self, FromStr};

 // The rustc-cfg strings below are *not* public API. Please let us know by
 // opening a GitHub issue if your build environment requires some way to enable
 // these cfgs other than by executing our build script.
 fn main() {
-    println!("cargo:rerun-if-changed=build.rs");
-
-    println!("cargo:rustc-cfg=if_docsrs_then_no_serde_core");
-
-    let out_dir = PathBuf::from(env::var_os("OUT_DIR").unwrap());
-    let patch_version = env::var("CARGO_PKG_VERSION_PATCH").unwrap();
-    let module = PRIVATE.replace("$$", &patch_version);
-    fs::write(out_dir.join("private.rs"), module).unwrap();
-
    let minor = match rustc_minor_version() {
        Some(minor) => minor,
        None => return,
    };

-    if minor >= 77 {
-        println!("cargo:rustc-check-cfg=cfg(feature, values(\"result\"))");
-        println!("cargo:rustc-check-cfg=cfg(if_docsrs_then_no_serde_core)");
-        println!("cargo:rustc-check-cfg=cfg(no_core_cstr)");
-        println!("cargo:rustc-check-cfg=cfg(no_core_error)");
-        println!("cargo:rustc-check-cfg=cfg(no_core_net)");
-        println!("cargo:rustc-check-cfg=cfg(no_core_num_saturating)");
-        println!("cargo:rustc-check-cfg=cfg(no_diagnostic_namespace)");
-        println!("cargo:rustc-check-cfg=cfg(no_serde_derive)");
-        println!("cargo:rustc-check-cfg=cfg(no_std_atomic)");
-        println!("cargo:rustc-check-cfg=cfg(no_std_atomic64)");
-        println!("cargo:rustc-check-cfg=cfg(no_target_has_atomic)");
+    let target = env::var("TARGET").unwrap();
+    let emscripten = target == "asmjs-unknown-emscripten" || target == "wasm32-unknown-emscripten";
+
+    // std::collections::Bound was stabilized in Rust 1.17
+    // but it was moved to core::ops later in Rust 1.26:
+    // https://doc.rust-lang.org/core/ops/enum.Bound.html
+    if minor < 26 {
+        println!("cargo:rustc-cfg=no_ops_bound");
+        if minor < 17 {
+            println!("cargo:rustc-cfg=no_collections_bound");
+        }
    }

-    // Current minimum supported version of serde_derive crate is Rust 1.68.
-    if minor < 68 {
+    // core::cmp::Reverse stabilized in Rust 1.19:
+    // https://doc.rust-lang.org/stable/core/cmp/struct.Reverse.html
+    if minor < 19 {
+        println!("cargo:rustc-cfg=no_core_reverse");
+    }
+
+    // CString::into_boxed_c_str and PathBuf::into_boxed_path stabilized in Rust 1.20:
+    // https://doc.rust-lang.org/std/ffi/struct.CString.html#method.into_boxed_c_str
+    // https://doc.rust-lang.org/std/path/struct.PathBuf.html#method.into_boxed_path
+    if minor < 20 {
+        println!("cargo:rustc-cfg=no_de_boxed_c_str");
+        println!("cargo:rustc-cfg=no_de_boxed_path");
+    }
+
+    // From<Box<T>> for Rc<T> / Arc<T> stabilized in Rust 1.21:
+    // https://doc.rust-lang.org/std/rc/struct.Rc.html#impl-From<Box<T>>
+    // https://doc.rust-lang.org/std/sync/struct.Arc.html#impl-From<Box<T>>
+    if minor < 21 {
+        println!("cargo:rustc-cfg=no_de_rc_dst");
+    }
+
+    // Duration available in core since Rust 1.25:
+    // https://blog.rust-lang.org/2018/03/29/Rust-1.25.html#library-stabilizations
+    if minor < 25 {
+        println!("cargo:rustc-cfg=no_core_duration");
+    }
+
+    // 128-bit integers stabilized in Rust 1.26:
+    // https://blog.rust-lang.org/2018/05/10/Rust-1.26.html
+    //
+    // Disabled on Emscripten targets before Rust 1.40 since
+    // Emscripten did not support 128-bit integers until Rust 1.40
+    // (https://github.com/rust-lang/rust/pull/65251)
+    if minor < 26 || emscripten && minor < 40 {
+        println!("cargo:rustc-cfg=no_integer128");
+    }
+
+    // Inclusive ranges methods stabilized in Rust 1.27:
+    // https://github.com/rust-lang/rust/pull/50758
+    // Also Iterator::try_for_each:
+    // https://blog.rust-lang.org/2018/06/21/Rust-1.27.html#library-stabilizations
+    if minor < 27 {
+        println!("cargo:rustc-cfg=no_range_inclusive");
+        println!("cargo:rustc-cfg=no_iterator_try_fold");
+    }
+
+    // Non-zero integers stabilized in Rust 1.28:
+    // https://blog.rust-lang.org/2018/08/02/Rust-1.28.html#library-stabilizations
+    if minor < 28 {
+        println!("cargo:rustc-cfg=no_num_nonzero");
+    }
+
+    // Current minimum supported version of serde_derive crate is Rust 1.31.
+    if minor < 31 {
        println!("cargo:rustc-cfg=no_serde_derive");
    }

-    // Support for the `#[diagnostic]` tool attribute namespace
-    // https://blog.rust-lang.org/2024/05/02/Rust-1.78.0.html#diagnostic-attributes
-    if minor < 78 {
-        println!("cargo:rustc-cfg=no_diagnostic_namespace");
+    // TryFrom, Atomic types, non-zero signed integers, and SystemTime::checked_add
+    // stabilized in Rust 1.34:
+    // https://blog.rust-lang.org/2019/04/11/Rust-1.34.0.html#tryfrom-and-tryinto
+    // https://blog.rust-lang.org/2019/04/11/Rust-1.34.0.html#library-stabilizations
+    if minor < 34 {
+        println!("cargo:rustc-cfg=no_core_try_from");
+        println!("cargo:rustc-cfg=no_num_nonzero_signed");
+        println!("cargo:rustc-cfg=no_systemtime_checked_add");
+    }
+
+    // Whitelist of archs that support std::sync::atomic module. Ideally we
+    // would use #[cfg(target_has_atomic = "...")] but it is not stable yet.
+    // Instead this is based on rustc's compiler/rustc_target/src/spec/*.rs.
+    let has_atomic64 = target.starts_with("x86_64")
+        || target.starts_with("i686")
+        || target.starts_with("aarch64")
+        || target.starts_with("powerpc64")
+        || target.starts_with("sparc64")
+        || target.starts_with("mips64el")
+        || target.starts_with("riscv64");
+    let has_atomic32 = has_atomic64 || emscripten;
+    if minor < 34 || !has_atomic64 {
+        println!("cargo:rustc-cfg=no_std_atomic64");
+    }
+    if minor < 34 || !has_atomic32 {
+        println!("cargo:rustc-cfg=no_std_atomic");
    }
 }

 fn rustc_minor_version() -> Option<u32> {
-    let rustc = env::var_os("RUSTC")?;
-    let output = Command::new(rustc).arg("--version").output().ok()?;
-    let version = str::from_utf8(&output.stdout).ok()?;
+    let rustc = match env::var_os("RUSTC") {
+        Some(rustc) => rustc,
+        None => return None,
+    };
+
+    let output = match Command::new(rustc).arg("--version").output() {
+        Ok(output) => output,
+        Err(_) => return None,
+    };
+
+    let version = match str::from_utf8(&output.stdout) {
+        Ok(version) => version,
+        Err(_) => return None,
+    };
+
    let mut pieces = version.split('.');
    if pieces.next() != Some("rustc 1") {
        return None;
    }
-    pieces.next()?.parse().ok()
+
+    let next = match pieces.next() {
+        Some(next) => next,
+        None => return None,
+    };
+
+    u32::from_str(next).ok()
 }
@@ -1 +0,0 @@
-../../serde_core/src
@@ -1,7 +1,7 @@
-use crate::lib::fmt::{self, Write};
-use crate::lib::str;
+use lib::fmt::{self, Write};
+use lib::str;

-pub(super) struct Buf<'a> {
+pub struct Buf<'a> {
    bytes: &'a mut [u8],
    offset: usize,
 }
@@ -1,6 +1,6 @@
-use crate::lib::*;
+use lib::*;

-use crate::de::{
+use de::{
    Deserialize, Deserializer, EnumAccess, Error, MapAccess, SeqAccess, VariantAccess, Visitor,
 };

@@ -10,12 +10,13 @@ use crate::de::{
 /// any type, except that it does not store any information about the data that
 /// gets deserialized.
 ///
-/// ```edition2021
+/// ```edition2018
+/// use std::fmt;
+/// use std::marker::PhantomData;
+///
 /// use serde::de::{
 ///     self, Deserialize, DeserializeSeed, Deserializer, IgnoredAny, SeqAccess, Visitor,
 /// };
-/// use std::fmt;
-/// use std::marker::PhantomData;
 ///
 /// /// A seed that can be used to deserialize only the `n`th element of a sequence
 /// /// while efficiently discarding elements of any type before or after index `n`.
@@ -107,7 +108,7 @@ use crate::de::{
 /// #     Ok(())
 /// # }
 /// ```
-#[derive(Copy, Clone, Debug, Default, PartialEq)]
+#[derive(Copy, Clone, Debug, Default)]
 pub struct IgnoredAny;

 impl<'de> Visitor<'de> for IgnoredAny {
@@ -129,10 +130,12 @@ impl<'de> Visitor<'de> for IgnoredAny {
        Ok(IgnoredAny)
    }

-    #[inline]
-    fn visit_i128<E>(self, x: i128) -> Result<Self::Value, E> {
-        let _ = x;
-        Ok(IgnoredAny)
+    serde_if_integer128! {
+        #[inline]
+        fn visit_i128<E>(self, x: i128) -> Result<Self::Value, E> {
+            let _ = x;
+            Ok(IgnoredAny)
+        }
    }

    #[inline]
@@ -141,10 +144,12 @@ impl<'de> Visitor<'de> for IgnoredAny {
        Ok(IgnoredAny)
    }

-    #[inline]
-    fn visit_u128<E>(self, x: u128) -> Result<Self::Value, E> {
-        let _ = x;
-        Ok(IgnoredAny)
+    serde_if_integer128! {
+        #[inline]
+        fn visit_u128<E>(self, x: u128) -> Result<Self::Value, E> {
+            let _ = x;
+            Ok(IgnoredAny)
+        }
    }

    #[inline]
@@ -193,7 +198,7 @@ impl<'de> Visitor<'de> for IgnoredAny {
    where
        A: SeqAccess<'de>,
    {
-        while let Some(IgnoredAny) = tri!(seq.next_element()) {
+        while let Some(IgnoredAny) = try!(seq.next_element()) {
            // Gobble
        }
        Ok(IgnoredAny)
@@ -204,7 +209,7 @@ impl<'de> Visitor<'de> for IgnoredAny {
    where
        A: MapAccess<'de>,
    {
-        while let Some((IgnoredAny, IgnoredAny)) = tri!(map.next_entry()) {
+        while let Some((IgnoredAny, IgnoredAny)) = try!(map.next_entry()) {
            // Gobble
        }
        Ok(IgnoredAny)
@@ -223,7 +228,7 @@ impl<'de> Visitor<'de> for IgnoredAny {
    where
        A: EnumAccess<'de>,
    {
-        tri!(data.variant::<IgnoredAny>()).1.newtype_variant()
+        data.variant::<IgnoredAny>()?.1.newtype_variant()
    }
 }

@@ -30,7 +30,7 @@
 //! # The Deserializer trait
 //!
 //! [`Deserializer`] implementations are provided by third-party crates, for
-//! example [`serde_json`], [`serde_yaml`] and [`postcard`].
+//! example [`serde_json`], [`serde_yaml`] and [`bincode`].
 //!
 //! A partial list of well-maintained formats is given on the [Serde
 //! website][data formats].
@@ -64,8 +64,8 @@
 //!    - RefCell\<T\>
 //!    - Mutex\<T\>
 //!    - RwLock\<T\>
-//!    - Rc\<T\>&emsp;*(if* features = \["rc"\] *is enabled)*
-//!    - Arc\<T\>&emsp;*(if* features = \["rc"\] *is enabled)*
+//!    - Rc\<T\>&emsp;*(if* features = ["rc"] *is enabled)*
+//!    - Arc\<T\>&emsp;*(if* features = ["rc"] *is enabled)*
 //!  - **Collection types**:
 //!    - BTreeMap\<K, V\>
 //!    - BTreeSet\<T\>
@@ -101,10 +101,10 @@
 //!    - SocketAddrV6
 //!
 //! [Implementing `Deserialize`]: https://serde.rs/impl-deserialize.html
-//! [`Deserialize`]: crate::Deserialize
-//! [`Deserializer`]: crate::Deserializer
+//! [`Deserialize`]: ../trait.Deserialize.html
+//! [`Deserializer`]: ../trait.Deserializer.html
 //! [`LinkedHashMap<K, V>`]: https://docs.rs/linked-hash-map/*/linked_hash_map/struct.LinkedHashMap.html
-//! [`postcard`]: https://github.com/jamesmunns/postcard
+//! [`bincode`]: https://github.com/bincode-org/bincode
 //! [`linked-hash-map`]: https://crates.io/crates/linked-hash-map
 //! [`serde_derive`]: https://crates.io/crates/serde_derive
 //! [`serde_json`]: https://github.com/serde-rs/json
@@ -112,25 +112,26 @@
 //! [derive section of the manual]: https://serde.rs/derive.html
 //! [data formats]: https://serde.rs/#data-formats

-use crate::lib::*;
+use lib::*;

 ////////////////////////////////////////////////////////////////////////////////

 pub mod value;

+#[cfg(not(no_integer128))]
+mod format;
 mod ignored_any;
 mod impls;
+mod utf8;

 pub use self::ignored_any::IgnoredAny;
-#[cfg(all(any(not(feature = "std"), target_os = "none"), no_core_error))]
-#[doc(no_inline)]
-pub use crate::std_error::Error as StdError;
-#[cfg(all(any(not(feature = "std"), target_os = "none"), not(no_core_error)))]
-#[doc(no_inline)]
-pub use core::error::Error as StdError;
-#[cfg(all(feature = "std", not(target_os = "none")))]
+
+#[cfg(feature = "std")]
 #[doc(no_inline)]
 pub use std::error::Error as StdError;
+#[cfg(not(feature = "std"))]
+#[doc(no_inline)]
+pub use std_error::Error as StdError;

 ////////////////////////////////////////////////////////////////////////////////

@@ -156,18 +157,12 @@ macro_rules! declare_error_trait {
        /// type appropriate for a basic JSON data format.
        ///
        /// [example data format]: https://serde.rs/data-format.html
-        #[cfg_attr(
-            not(no_diagnostic_namespace),
-            diagnostic::on_unimplemented(
-                message = "the trait bound `{Self}: serde::de::Error` is not satisfied",
-            )
-        )]
        pub trait Error: Sized $(+ $($supertrait)::+)* {
            /// Raised when there is general error when deserializing a type.
            ///
            /// The message should not be capitalized and should not end with a period.
            ///
-            /// ```edition2021
+            /// ```edition2018
            /// # use std::str::FromStr;
            /// #
            /// # struct IpAddr;
@@ -210,7 +205,7 @@ macro_rules! declare_error_trait {
            /// containing an integer, the unexpected type is the integer and the
            /// expected type is the string.
            #[cold]
-            fn invalid_type(unexp: Unexpected, exp: &dyn Expected) -> Self {
+            fn invalid_type(unexp: Unexpected, exp: &Expected) -> Self {
                Error::custom(format_args!("invalid type: {}, expected {}", unexp, exp))
            }

@@ -228,7 +223,7 @@ macro_rules! declare_error_trait {
            /// that is not valid UTF-8, the unexpected value is the bytes and the
            /// expected value is a string.
            #[cold]
-            fn invalid_value(unexp: Unexpected, exp: &dyn Expected) -> Self {
+            fn invalid_value(unexp: Unexpected, exp: &Expected) -> Self {
                Error::custom(format_args!("invalid value: {}, expected {}", unexp, exp))
            }

@@ -242,7 +237,7 @@ macro_rules! declare_error_trait {
            /// expected. For example `exp` might say that a tuple of size 6 was
            /// expected.
            #[cold]
-            fn invalid_length(len: usize, exp: &dyn Expected) -> Self {
+            fn invalid_length(len: usize, exp: &Expected) -> Self {
                Error::custom(format_args!("invalid length {}, expected {}", len, exp))
            }

@@ -300,10 +295,10 @@ macro_rules! declare_error_trait {
    }
 }

-#[cfg(all(feature = "std", not(target_os = "none")))]
+#[cfg(feature = "std")]
 declare_error_trait!(Error: Sized + StdError);

-#[cfg(any(not(feature = "std"), target_os = "none"))]
+#[cfg(not(feature = "std"))]
 declare_error_trait!(Error: Sized + Debug + Display);

 /// `Unexpected` represents an unexpected invocation of any one of the `Visitor`
@@ -312,7 +307,7 @@ declare_error_trait!(Error: Sized + Debug + Display);
 /// This is used as an argument to the `invalid_type`, `invalid_value`, and
 /// `invalid_length` methods of the `Error` trait to build error messages.
 ///
-/// ```edition2021
+/// ```edition2018
 /// # use std::fmt;
 /// #
 /// # use serde::de::{self, Unexpected, Visitor};
@@ -405,20 +400,20 @@ impl<'a> fmt::Display for Unexpected<'a> {
            Bool(b) => write!(formatter, "boolean `{}`", b),
            Unsigned(i) => write!(formatter, "integer `{}`", i),
            Signed(i) => write!(formatter, "integer `{}`", i),
-            Float(f) => write!(formatter, "floating point `{}`", WithDecimalPoint(f)),
+            Float(f) => write!(formatter, "floating point `{}`", f),
            Char(c) => write!(formatter, "character `{}`", c),
            Str(s) => write!(formatter, "string {:?}", s),
-            Bytes(_) => formatter.write_str("byte array"),
-            Unit => formatter.write_str("unit value"),
-            Option => formatter.write_str("Option value"),
-            NewtypeStruct => formatter.write_str("newtype struct"),
-            Seq => formatter.write_str("sequence"),
-            Map => formatter.write_str("map"),
-            Enum => formatter.write_str("enum"),
-            UnitVariant => formatter.write_str("unit variant"),
-            NewtypeVariant => formatter.write_str("newtype variant"),
-            TupleVariant => formatter.write_str("tuple variant"),
-            StructVariant => formatter.write_str("struct variant"),
+            Bytes(_) => write!(formatter, "byte array"),
+            Unit => write!(formatter, "unit value"),
+            Option => write!(formatter, "Option value"),
+            NewtypeStruct => write!(formatter, "newtype struct"),
+            Seq => write!(formatter, "sequence"),
+            Map => write!(formatter, "map"),
+            Enum => write!(formatter, "enum"),
+            UnitVariant => write!(formatter, "unit variant"),
+            NewtypeVariant => write!(formatter, "newtype variant"),
+            TupleVariant => write!(formatter, "tuple variant"),
+            StructVariant => write!(formatter, "struct variant"),
            Other(other) => formatter.write_str(other),
        }
    }
@@ -437,10 +432,11 @@ impl<'a> fmt::Display for Unexpected<'a> {
 /// Within the context of a `Visitor` implementation, the `Visitor` itself
 /// (`&self`) is an implementation of this trait.
 ///
-/// ```edition2021
-/// # use serde::de::{self, Unexpected, Visitor};
+/// ```edition2018
 /// # use std::fmt;
 /// #
+/// # use serde::de::{self, Unexpected, Visitor};
+/// #
 /// # struct Example;
 /// #
 /// # impl<'de> Visitor<'de> for Example {
@@ -461,7 +457,7 @@ impl<'a> fmt::Display for Unexpected<'a> {
 ///
 /// Outside of a `Visitor`, `&"..."` can be used.
 ///
-/// ```edition2021
+/// ```edition2018
 /// # use serde::de::{self, Unexpected};
 /// #
 /// # fn example<E>() -> Result<(), E>
@@ -469,18 +465,9 @@ impl<'a> fmt::Display for Unexpected<'a> {
 /// #     E: de::Error,
 /// # {
 /// #     let v = true;
-/// return Err(de::Error::invalid_type(
-///     Unexpected::Bool(v),
-///     &"a negative integer",
-/// ));
+/// return Err(de::Error::invalid_type(Unexpected::Bool(v), &"a negative integer"));
 /// # }
 /// ```
-#[cfg_attr(
-    not(no_diagnostic_namespace),
-    diagnostic::on_unimplemented(
-        message = "the trait bound `{Self}: serde::de::Expected` is not satisfied",
-    )
-)]
 pub trait Expected {
    /// Format an explanation of what data was being expected. Same signature as
    /// the `Display` and `Debug` traits.
@@ -496,13 +483,13 @@ where
    }
 }

-impl Expected for &str {
+impl<'a> Expected for &'a str {
    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
        formatter.write_str(self)
    }
 }

-impl Display for dyn Expected + '_ {
+impl<'a> Display for Expected + 'a {
    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
        Expected::fmt(self, formatter)
    }
@@ -514,8 +501,8 @@ impl Display for dyn Expected + '_ {
 /// by Serde.
 ///
 /// Serde provides `Deserialize` implementations for many Rust primitive and
-/// standard library types. The complete list is [here][crate::de]. All of these
-/// can be deserialized using Serde out of the box.
+/// standard library types. The complete list is [here][de]. All of these can
+/// be deserialized using Serde out of the box.
 ///
 /// Additionally, Serde provides a procedural macro called `serde_derive` to
 /// automatically generate `Deserialize` implementations for structs and enums
@@ -531,6 +518,7 @@ impl Display for dyn Expected + '_ {
 /// `LinkedHashMap<K, V>` type that is deserializable by Serde because the crate
 /// provides an implementation of `Deserialize` for it.
 ///
+/// [de]: https://docs.serde.rs/serde/de/index.html
 /// [derive]: https://serde.rs/derive.html
 /// [impl-deserialize]: https://serde.rs/impl-deserialize.html
 ///
@@ -541,16 +529,6 @@ impl Display for dyn Expected + '_ {
 /// deserializer lifetimes] for a more detailed explanation of these lifetimes.
 ///
 /// [Understanding deserializer lifetimes]: https://serde.rs/lifetimes.html
-#[cfg_attr(
-    not(no_diagnostic_namespace),
-    diagnostic::on_unimplemented(
-        // Prevents `serde_core::de::Deserialize` appearing in the error message
-        // in projects with no direct dependency on serde_core.
-        message = "the trait bound `{Self}: serde::Deserialize<'de>` is not satisfied",
-        note = "for local types consider adding `#[derive(serde::Deserialize)]` to your `{Self}` type",
-        note = "for types from other crates check whether the crate offers a `serde` feature flag",
-    )
-)]
 pub trait Deserialize<'de>: Sized {
    /// Deserialize this value from the given Serde deserializer.
    ///
@@ -587,7 +565,7 @@ pub trait Deserialize<'de>: Sized {
        D: Deserializer<'de>,
    {
        // Default implementation just delegates to `deserialize` impl.
-        *place = tri!(Deserialize::deserialize(deserializer));
+        *place = Deserialize::deserialize(deserializer)?;
        Ok(())
    }
 }
@@ -600,7 +578,7 @@ pub trait Deserialize<'de>: Sized {
 /// from the input string, but a `from_reader` function may only deserialize
 /// owned data.
 ///
-/// ```edition2021
+/// ```edition2018
 /// # use serde::de::{Deserialize, DeserializeOwned};
 /// # use std::io::{Read, Result};
 /// #
@@ -623,12 +601,6 @@ pub trait Deserialize<'de>: Sized {
 /// lifetimes].
 ///
 /// [Understanding deserializer lifetimes]: https://serde.rs/lifetimes.html
-#[cfg_attr(
-    not(no_diagnostic_namespace),
-    diagnostic::on_unimplemented(
-        message = "the trait bound `{Self}: serde::de::DeserializeOwned` is not satisfied",
-    )
-)]
 pub trait DeserializeOwned: for<'de> Deserialize<'de> {}
 impl<T> DeserializeOwned for T where T: for<'de> Deserialize<'de> {}

@@ -645,7 +617,7 @@ impl<T> DeserializeOwned for T where T: for<'de> Deserialize<'de> {}
 ///
 /// The canonical API for stateless deserialization looks like this:
 ///
-/// ```edition2021
+/// ```edition2018
 /// # use serde::Deserialize;
 /// #
 /// # enum Error {}
@@ -659,7 +631,7 @@ impl<T> DeserializeOwned for T where T: for<'de> Deserialize<'de> {}
 /// Adjusting an API like this to support stateful deserialization is a matter
 /// of accepting a seed as input:
 ///
-/// ```edition2021
+/// ```edition2018
 /// # use serde::de::DeserializeSeed;
 /// #
 /// # enum Error {}
@@ -692,11 +664,12 @@ impl<T> DeserializeOwned for T where T: for<'de> Deserialize<'de> {}
 /// into it. This requires stateful deserialization using the `DeserializeSeed`
 /// trait.
 ///
-/// ```edition2021
-/// use serde::de::{Deserialize, DeserializeSeed, Deserializer, SeqAccess, Visitor};
+/// ```edition2018
 /// use std::fmt;
 /// use std::marker::PhantomData;
 ///
+/// use serde::de::{Deserialize, DeserializeSeed, Deserializer, SeqAccess, Visitor};
+///
 /// // A DeserializeSeed implementation that uses stateful deserialization to
 /// // append array elements onto the end of an existing vector. The preexisting
 /// // state ("seed") in this case is the Vec<T>. The `deserialize` method of
@@ -735,11 +708,6 @@ impl<T> DeserializeOwned for T where T: for<'de> Deserialize<'de> {}
 ///             where
 ///                 A: SeqAccess<'de>,
 ///             {
-///                 // Decrease the number of reallocations if there are many elements
-///                 if let Some(size_hint) = seq.size_hint() {
-///                     self.0.reserve(size_hint);
-///                 }
-///
 ///                 // Visit each element in the inner array and push it onto
 ///                 // the existing vector.
 ///                 while let Some(elem) = seq.next_element()? {
@@ -794,12 +762,6 @@ impl<T> DeserializeOwned for T where T: for<'de> Deserialize<'de> {}
 /// #     Ok(())
 /// # }
 /// ```
-#[cfg_attr(
-    not(no_diagnostic_namespace),
-    diagnostic::on_unimplemented(
-        message = "the trait bound `{Self}: serde::de::DeserializeSeed<'de>` is not satisfied",
-    )
-)]
 pub trait DeserializeSeed<'de>: Sized {
    /// The type produced by using this seed.
    type Value;
@@ -895,10 +857,10 @@ where
 /// The `Deserializer` trait supports two entry point styles which enables
 /// different kinds of deserialization.
 ///
-/// 1. The `deserialize_any` method. Self-describing data formats like JSON are
-///    able to look at the serialized data and tell what it represents. For
-///    example the JSON deserializer may see an opening curly brace (`{`) and
-///    know that it is seeing a map. If the data format supports
+/// 1. The `deserialize` method. Self-describing data formats like JSON are able
+///    to look at the serialized data and tell what it represents. For example
+///    the JSON deserializer may see an opening curly brace (`{`) and know that
+///    it is seeing a map. If the data format supports
 ///    `Deserializer::deserialize_any`, it will drive the Visitor using whatever
 ///    type it sees in the input. JSON uses this approach when deserializing
 ///    `serde_json::Value` which is an enum that can represent any JSON
@@ -907,7 +869,7 @@ where
 ///    `Deserializer::deserialize_any`.
 ///
 /// 2. The various `deserialize_*` methods. Non-self-describing formats like
-///    Postcard need to be told what is in the input in order to deserialize it.
+///    Bincode need to be told what is in the input in order to deserialize it.
 ///    The `deserialize_*` methods are hints to the deserializer for how to
 ///    interpret the next piece of input. Non-self-describing formats are not
 ///    able to deserialize something like `serde_json::Value` which relies on
@@ -917,7 +879,7 @@ where
 /// `Deserializer::deserialize_any` unless you need to be told by the
 /// Deserializer what type is in the input. Know that relying on
 /// `Deserializer::deserialize_any` means your data type will be able to
-/// deserialize from self-describing formats only, ruling out Postcard and many
+/// deserialize from self-describing formats only, ruling out Bincode and many
 /// others.
 ///
 /// [Serde data model]: https://serde.rs/data-model.html
@@ -936,12 +898,6 @@ where
 /// a basic JSON `Deserializer`.
 ///
 /// [example data format]: https://serde.rs/data-format.html
-#[cfg_attr(
-    not(no_diagnostic_namespace),
-    diagnostic::on_unimplemented(
-        message = "the trait bound `{Self}: serde::de::Deserializer<'de>` is not satisfied",
-    )
-)]
 pub trait Deserializer<'de>: Sized {
    /// The error type that can be returned if some error occurs during
    /// deserialization.
@@ -954,7 +910,7 @@ pub trait Deserializer<'de>: Sized {
    /// `Deserializer::deserialize_any` unless you need to be told by the
    /// Deserializer what type is in the input. Know that relying on
    /// `Deserializer::deserialize_any` means your data type will be able to
-    /// deserialize from self-describing formats only, ruling out Postcard and
+    /// deserialize from self-describing formats only, ruling out Bincode and
    /// many others.
    fn deserialize_any<V>(self, visitor: V) -> Result<V::Value, Self::Error>
    where
@@ -985,15 +941,18 @@ pub trait Deserializer<'de>: Sized {
    where
        V: Visitor<'de>;

-    /// Hint that the `Deserialize` type is expecting an `i128` value.
-    ///
-    /// The default behavior unconditionally returns an error.
-    fn deserialize_i128<V>(self, visitor: V) -> Result<V::Value, Self::Error>
-    where
-        V: Visitor<'de>,
-    {
-        let _ = visitor;
-        Err(Error::custom("i128 is not supported"))
+    serde_if_integer128! {
+        /// Hint that the `Deserialize` type is expecting an `i128` value.
+        ///
+        /// This method is available only on Rust compiler versions >=1.26. The
+        /// default behavior unconditionally returns an error.
+        fn deserialize_i128<V>(self, visitor: V) -> Result<V::Value, Self::Error>
+        where
+            V: Visitor<'de>
+        {
+            let _ = visitor;
+            Err(Error::custom("i128 is not supported"))
+        }
    }

    /// Hint that the `Deserialize` type is expecting a `u8` value.
@@ -1016,15 +975,18 @@ pub trait Deserializer<'de>: Sized {
    where
        V: Visitor<'de>;

-    /// Hint that the `Deserialize` type is expecting an `u128` value.
-    ///
-    /// The default behavior unconditionally returns an error.
-    fn deserialize_u128<V>(self, visitor: V) -> Result<V::Value, Self::Error>
-    where
-        V: Visitor<'de>,
-    {
-        let _ = visitor;
-        Err(Error::custom("u128 is not supported"))
+    serde_if_integer128! {
+        /// Hint that the `Deserialize` type is expecting an `u128` value.
+        ///
+        /// This method is available only on Rust compiler versions >=1.26. The
+        /// default behavior unconditionally returns an error.
+        fn deserialize_u128<V>(self, visitor: V) -> Result<V::Value, Self::Error>
+        where
+            V: Visitor<'de>
+        {
+            let _ = visitor;
+            Err(Error::custom("u128 is not supported"))
+        }
    }

    /// Hint that the `Deserialize` type is expecting a `f32` value.
@@ -1189,10 +1151,10 @@ pub trait Deserializer<'de>: Sized {
    /// Some types have a human-readable form that may be somewhat expensive to
    /// construct, as well as a binary form that is compact and efficient.
    /// Generally text-based formats like JSON and YAML will prefer to use the
-    /// human-readable one and binary formats like Postcard will prefer the
+    /// human-readable one and binary formats like Bincode will prefer the
    /// compact one.
    ///
-    /// ```edition2021
+    /// ```edition2018
    /// # use std::ops::Add;
    /// # use std::str::FromStr;
    /// #
@@ -1257,9 +1219,13 @@ pub trait Deserializer<'de>: Sized {
    // Not public API.
    #[cfg(all(not(no_serde_derive), any(feature = "std", feature = "alloc")))]
    #[doc(hidden)]
-    fn __deserialize_content_v1<V>(self, visitor: V) -> Result<V::Value, Self::Error>
+    fn __deserialize_content<V>(
+        self,
+        _: ::actually_private::T,
+        visitor: V,
+    ) -> Result<::private::de::Content<'de>, Self::Error>
    where
-        V: Visitor<'de, Value = crate::private::Content<'de>>,
+        V: Visitor<'de, Value = ::private::de::Content<'de>>,
    {
        self.deserialize_any(visitor)
    }
@@ -1279,10 +1245,11 @@ pub trait Deserializer<'de>: Sized {
 ///
 /// # Example
 ///
-/// ```edition2021
-/// # use serde::de::{self, Unexpected, Visitor};
+/// ```edition2018
 /// # use std::fmt;
 /// #
+/// # use serde::de::{self, Unexpected, Visitor};
+/// #
 /// /// A visitor that deserializes a long string - a string containing at least
 /// /// some minimum number of bytes.
 /// struct LongString {
@@ -1308,12 +1275,6 @@ pub trait Deserializer<'de>: Sized {
 ///     }
 /// }
 /// ```
-#[cfg_attr(
-    not(no_diagnostic_namespace),
-    diagnostic::on_unimplemented(
-        message = "the trait bound `{Self}: serde::de::Visitor<'de>` is not satisfied",
-    )
-)]
 pub trait Visitor<'de>: Sized {
    /// The value produced by this visitor.
    type Value;
@@ -1325,7 +1286,7 @@ pub trait Visitor<'de>: Sized {
    /// "an integer between 0 and 64". The message should not be capitalized and
    /// should not end with a period.
    ///
-    /// ```edition2021
+    /// ```edition2018
    /// # use std::fmt;
    /// #
    /// # struct S {
@@ -1398,20 +1359,20 @@ pub trait Visitor<'de>: Sized {
        Err(Error::invalid_type(Unexpected::Signed(v), &self))
    }

-    /// The input contains a `i128`.
-    ///
-    /// The default implementation fails with a type error.
-    fn visit_i128<E>(self, v: i128) -> Result<Self::Value, E>
-    where
-        E: Error,
-    {
-        let mut buf = [0u8; 58];
-        let mut writer = crate::format::Buf::new(&mut buf);
-        fmt::Write::write_fmt(&mut writer, format_args!("integer `{}` as i128", v)).unwrap();
-        Err(Error::invalid_type(
-            Unexpected::Other(writer.as_str()),
-            &self,
-        ))
+    serde_if_integer128! {
+        /// The input contains a `i128`.
+        ///
+        /// This method is available only on Rust compiler versions >=1.26. The
+        /// default implementation fails with a type error.
+        fn visit_i128<E>(self, v: i128) -> Result<Self::Value, E>
+        where
+            E: Error,
+        {
+            let mut buf = [0u8; 58];
+            let mut writer = format::Buf::new(&mut buf);
+            fmt::Write::write_fmt(&mut writer, format_args!("integer `{}` as i128", v)).unwrap();
+            Err(Error::invalid_type(Unexpected::Other(writer.as_str()), &self))
+        }
    }

    /// The input contains a `u8`.
@@ -1460,20 +1421,20 @@ pub trait Visitor<'de>: Sized {
        Err(Error::invalid_type(Unexpected::Unsigned(v), &self))
    }

-    /// The input contains a `u128`.
-    ///
-    /// The default implementation fails with a type error.
-    fn visit_u128<E>(self, v: u128) -> Result<Self::Value, E>
-    where
-        E: Error,
-    {
-        let mut buf = [0u8; 57];
-        let mut writer = crate::format::Buf::new(&mut buf);
-        fmt::Write::write_fmt(&mut writer, format_args!("integer `{}` as u128", v)).unwrap();
-        Err(Error::invalid_type(
-            Unexpected::Other(writer.as_str()),
-            &self,
-        ))
+    serde_if_integer128! {
+        /// The input contains a `u128`.
+        ///
+        /// This method is available only on Rust compiler versions >=1.26. The
+        /// default implementation fails with a type error.
+        fn visit_u128<E>(self, v: u128) -> Result<Self::Value, E>
+        where
+            E: Error,
+        {
+            let mut buf = [0u8; 57];
+            let mut writer = format::Buf::new(&mut buf);
+            fmt::Write::write_fmt(&mut writer, format_args!("integer `{}` as u128", v)).unwrap();
+            Err(Error::invalid_type(Unexpected::Other(writer.as_str()), &self))
+        }
    }

    /// The input contains an `f32`.
@@ -1509,7 +1470,7 @@ pub trait Visitor<'de>: Sized {
    where
        E: Error,
    {
-        self.visit_str(v.encode_utf8(&mut [0u8; 4]))
+        self.visit_str(utf8::encode(v).as_str())
    }

    /// The input contains a string. The lifetime of the string is ephemeral and
@@ -1564,7 +1525,6 @@ pub trait Visitor<'de>: Sized {
    /// `String`.
    #[inline]
    #[cfg(any(feature = "std", feature = "alloc"))]
-    #[cfg_attr(docsrs, doc(cfg(any(feature = "std", feature = "alloc"))))]
    fn visit_string<E>(self, v: String) -> Result<Self::Value, E>
    where
        E: Error,
@@ -1587,6 +1547,7 @@ pub trait Visitor<'de>: Sized {
    where
        E: Error,
    {
+        let _ = v;
        Err(Error::invalid_type(Unexpected::Bytes(v), &self))
    }

@@ -1594,7 +1555,7 @@ pub trait Visitor<'de>: Sized {
    /// `Deserializer`.
    ///
    /// This enables zero-copy deserialization of bytes in some formats. For
-    /// example Postcard data containing bytes can be deserialized with zero
+    /// example Bincode data containing bytes can be deserialized with zero
    /// copying into a `&'a [u8]` as long as the input data outlives `'a`.
    ///
    /// The default implementation forwards to `visit_bytes`.
@@ -1623,7 +1584,6 @@ pub trait Visitor<'de>: Sized {
    /// The default implementation forwards to `visit_bytes` and then drops the
    /// `Vec<u8>`.
    #[cfg(any(feature = "std", feature = "alloc"))]
-    #[cfg_attr(docsrs, doc(cfg(any(feature = "std", feature = "alloc"))))]
    fn visit_byte_buf<E>(self, v: Vec<u8>) -> Result<Self::Value, E>
    where
        E: Error,
@@ -1740,12 +1700,6 @@ pub trait Visitor<'de>: Sized {
 /// implementation of `SeqAccess` for a basic JSON data format.
 ///
 /// [example data format]: https://serde.rs/data-format.html
-#[cfg_attr(
-    not(no_diagnostic_namespace),
-    diagnostic::on_unimplemented(
-        message = "the trait bound `{Self}: serde::de::SeqAccess<'de>` is not satisfied",
-    )
-)]
 pub trait SeqAccess<'de> {
    /// The error type that can be returned if some error occurs during
    /// deserialization.
@@ -1780,9 +1734,9 @@ pub trait SeqAccess<'de> {
    }
 }

-impl<'de, A> SeqAccess<'de> for &mut A
+impl<'de, 'a, A: ?Sized> SeqAccess<'de> for &'a mut A
 where
-    A: ?Sized + SeqAccess<'de>,
+    A: SeqAccess<'de>,
 {
    type Error = A::Error;

@@ -1828,12 +1782,6 @@ where
 /// implementation of `MapAccess` for a basic JSON data format.
 ///
 /// [example data format]: https://serde.rs/data-format.html
-#[cfg_attr(
-    not(no_diagnostic_namespace),
-    diagnostic::on_unimplemented(
-        message = "the trait bound `{Self}: serde::de::MapAccess<'de>` is not satisfied",
-    )
-)]
 pub trait MapAccess<'de> {
    /// The error type that can be returned if some error occurs during
    /// deserialization.
@@ -1879,9 +1827,9 @@ pub trait MapAccess<'de> {
        K: DeserializeSeed<'de>,
        V: DeserializeSeed<'de>,
    {
-        match tri!(self.next_key_seed(kseed)) {
+        match try!(self.next_key_seed(kseed)) {
            Some(key) => {
-                let value = tri!(self.next_value_seed(vseed));
+                let value = try!(self.next_value_seed(vseed));
                Ok(Some((key, value)))
            }
            None => Ok(None),
@@ -1939,9 +1887,9 @@ pub trait MapAccess<'de> {
    }
 }

-impl<'de, A> MapAccess<'de> for &mut A
+impl<'de, 'a, A: ?Sized> MapAccess<'de> for &'a mut A
 where
-    A: ?Sized + MapAccess<'de>,
+    A: MapAccess<'de>,
 {
    type Error = A::Error;

@@ -2026,12 +1974,6 @@ where
 /// implementation of `EnumAccess` for a basic JSON data format.
 ///
 /// [example data format]: https://serde.rs/data-format.html
-#[cfg_attr(
-    not(no_diagnostic_namespace),
-    diagnostic::on_unimplemented(
-        message = "the trait bound `{Self}: serde::de::EnumAccess<'de>` is not satisfied",
-    )
-)]
 pub trait EnumAccess<'de>: Sized {
    /// The error type that can be returned if some error occurs during
    /// deserialization.
@@ -2079,12 +2021,6 @@ pub trait EnumAccess<'de>: Sized {
 /// implementation of `VariantAccess` for a basic JSON data format.
 ///
 /// [example data format]: https://serde.rs/data-format.html
-#[cfg_attr(
-    not(no_diagnostic_namespace),
-    diagnostic::on_unimplemented(
-        message = "the trait bound `{Self}: serde::de::VariantAccess<'de>` is not satisfied",
-    )
-)]
 pub trait VariantAccess<'de>: Sized {
    /// The error type that can be returned if some error occurs during
    /// deserialization. Must match the error type of our `EnumAccess`.
@@ -2095,7 +2031,7 @@ pub trait VariantAccess<'de>: Sized {
    /// If the data contains a different type of variant, the following
    /// `invalid_type` error should be constructed:
    ///
-    /// ```edition2021
+    /// ```edition2018
    /// # use serde::de::{self, value, DeserializeSeed, Visitor, VariantAccess, Unexpected};
    /// #
    /// # struct X;
@@ -2135,7 +2071,7 @@ pub trait VariantAccess<'de>: Sized {
    /// If the data contains a different type of variant, the following
    /// `invalid_type` error should be constructed:
    ///
-    /// ```edition2021
+    /// ```edition2018
    /// # use serde::de::{self, value, DeserializeSeed, Visitor, VariantAccess, Unexpected};
    /// #
    /// # struct X;
@@ -2191,7 +2127,7 @@ pub trait VariantAccess<'de>: Sized {
    /// If the data contains a different type of variant, the following
    /// `invalid_type` error should be constructed:
    ///
-    /// ```edition2021
+    /// ```edition2018
    /// # use serde::de::{self, value, DeserializeSeed, Visitor, VariantAccess, Unexpected};
    /// #
    /// # struct X;
@@ -2208,7 +2144,11 @@ pub trait VariantAccess<'de>: Sized {
    /// #         T: DeserializeSeed<'de>,
    /// #     { unimplemented!() }
    /// #
-    /// fn tuple_variant<V>(self, _len: usize, _visitor: V) -> Result<V::Value, Self::Error>
+    /// fn tuple_variant<V>(
+    ///     self,
+    ///     _len: usize,
+    ///     _visitor: V,
+    /// ) -> Result<V::Value, Self::Error>
    /// where
    ///     V: Visitor<'de>,
    /// {
@@ -2234,7 +2174,7 @@ pub trait VariantAccess<'de>: Sized {
    /// If the data contains a different type of variant, the following
    /// `invalid_type` error should be constructed:
    ///
-    /// ```edition2021
+    /// ```edition2018
    /// # use serde::de::{self, value, DeserializeSeed, Visitor, VariantAccess, Unexpected};
    /// #
    /// # struct X;
@@ -2294,10 +2234,10 @@ pub trait VariantAccess<'de>: Sized {
 ///
 /// # Example
 ///
-/// ```edition2021
-/// use serde::de::{value, Deserialize, IntoDeserializer};
-/// use serde_derive::Deserialize;
+/// ```edition2018
 /// use std::str::FromStr;
+/// use serde::Deserialize;
+/// use serde::de::{value, IntoDeserializer};
 ///
 /// #[derive(Deserialize)]
 /// enum Setting {
@@ -2341,52 +2281,15 @@ impl Display for OneOf {
            1 => write!(formatter, "`{}`", self.names[0]),
            2 => write!(formatter, "`{}` or `{}`", self.names[0], self.names[1]),
            _ => {
-                tri!(formatter.write_str("one of "));
+                try!(write!(formatter, "one of "));
                for (i, alt) in self.names.iter().enumerate() {
                    if i > 0 {
-                        tri!(formatter.write_str(", "));
+                        try!(write!(formatter, ", "));
                    }
-                    tri!(write!(formatter, "`{}`", alt));
+                    try!(write!(formatter, "`{}`", alt));
                }
                Ok(())
            }
        }
    }
 }
-
-struct WithDecimalPoint(f64);
-
-impl Display for WithDecimalPoint {
-    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
-        struct LookForDecimalPoint<'f, 'a> {
-            formatter: &'f mut fmt::Formatter<'a>,
-            has_decimal_point: bool,
-        }
-
-        impl<'f, 'a> fmt::Write for LookForDecimalPoint<'f, 'a> {
-            fn write_str(&mut self, fragment: &str) -> fmt::Result {
-                self.has_decimal_point |= fragment.contains('.');
-                self.formatter.write_str(fragment)
-            }
-
-            fn write_char(&mut self, ch: char) -> fmt::Result {
-                self.has_decimal_point |= ch == '.';
-                self.formatter.write_char(ch)
-            }
-        }
-
-        if self.0.is_finite() {
-            let mut writer = LookForDecimalPoint {
-                formatter,
-                has_decimal_point: false,
-            };
-            tri!(write!(writer, "{}", self.0));
-            if !writer.has_decimal_point {
-                tri!(formatter.write_str(".0"));
-            }
-        } else {
-            tri!(write!(formatter, "{}", self.0));
-        }
-        Ok(())
-    }
-}
@@ -1,11 +1,10 @@
-use crate::de::{Deserialize, DeserializeSeed, Deserializer};
+use de::{Deserialize, DeserializeSeed, Deserializer};

 /// A DeserializeSeed helper for implementing deserialize_in_place Visitors.
 ///
 /// Wraps a mutable reference and calls deserialize_in_place on it.
 pub struct InPlaceSeed<'a, T: 'a>(pub &'a mut T);

-#[cfg_attr(not(no_diagnostic_namespace), diagnostic::do_not_recommend)]
 impl<'a, 'de, T> DeserializeSeed<'de> for InPlaceSeed<'a, T>
 where
    T: Deserialize<'de>,
@@ -0,0 +1,46 @@
+use lib::*;
+
+const TAG_CONT: u8 = 0b1000_0000;
+const TAG_TWO_B: u8 = 0b1100_0000;
+const TAG_THREE_B: u8 = 0b1110_0000;
+const TAG_FOUR_B: u8 = 0b1111_0000;
+const MAX_ONE_B: u32 = 0x80;
+const MAX_TWO_B: u32 = 0x800;
+const MAX_THREE_B: u32 = 0x10000;
+
+#[inline]
+pub fn encode(c: char) -> Encode {
+    let code = c as u32;
+    let mut buf = [0; 4];
+    let pos = if code < MAX_ONE_B {
+        buf[3] = code as u8;
+        3
+    } else if code < MAX_TWO_B {
+        buf[2] = (code >> 6 & 0x1F) as u8 | TAG_TWO_B;
+        buf[3] = (code & 0x3F) as u8 | TAG_CONT;
+        2
+    } else if code < MAX_THREE_B {
+        buf[1] = (code >> 12 & 0x0F) as u8 | TAG_THREE_B;
+        buf[2] = (code >> 6 & 0x3F) as u8 | TAG_CONT;
+        buf[3] = (code & 0x3F) as u8 | TAG_CONT;
+        1
+    } else {
+        buf[0] = (code >> 18 & 0x07) as u8 | TAG_FOUR_B;
+        buf[1] = (code >> 12 & 0x3F) as u8 | TAG_CONT;
+        buf[2] = (code >> 6 & 0x3F) as u8 | TAG_CONT;
+        buf[3] = (code & 0x3F) as u8 | TAG_CONT;
+        0
+    };
+    Encode { buf: buf, pos: pos }
+}
+
+pub struct Encode {
+    buf: [u8; 4],
+    pos: usize,
+}
+
+impl Encode {
+    pub fn as_str(&self) -> &str {
+        str::from_utf8(&self.buf[self.pos..]).unwrap()
+    }
+}
@@ -1,10 +1,10 @@
 //! Building blocks for deserializing basic values using the `IntoDeserializer`
 //! trait.
 //!
-//! ```edition2021
-//! use serde::de::{value, Deserialize, IntoDeserializer};
-//! use serde_derive::Deserialize;
+//! ```edition2018
 //! use std::str::FromStr;
+//! use serde::Deserialize;
+//! use serde::de::{value, IntoDeserializer};
 //!
 //! #[derive(Deserialize)]
 //! enum Setting {
@@ -21,12 +21,12 @@
 //! }
 //! ```

-use crate::lib::*;
+use lib::*;

 use self::private::{First, Second};
-use crate::de::{self, Deserializer, Expected, IntoDeserializer, SeqAccess, Visitor};
-use crate::private::size_hint;
-use crate::ser;
+use __private::size_hint;
+use de::{self, Deserializer, Expected, IntoDeserializer, SeqAccess, Visitor};
+use ser;

 ////////////////////////////////////////////////////////////////////////////////

@@ -112,8 +112,7 @@ impl Debug for Error {
    }
 }

-#[cfg(all(feature = "std", not(target_os = "none")))]
-#[cfg_attr(docsrs, doc(cfg(feature = "std")))]
+#[cfg(feature = "std")]
 impl error::Error for Error {
    fn description(&self) -> &str {
        &self.err
@@ -129,7 +128,9 @@ where
    type Deserializer = UnitDeserializer<E>;

    fn into_deserializer(self) -> UnitDeserializer<E> {
-        UnitDeserializer::new()
+        UnitDeserializer {
+            marker: PhantomData,
+        }
    }
 }

@@ -140,15 +141,6 @@ pub struct UnitDeserializer<E> {

 impl_copy_clone!(UnitDeserializer);

-impl<E> UnitDeserializer<E> {
-    #[allow(missing_docs)]
-    pub fn new() -> Self {
-        UnitDeserializer {
-            marker: PhantomData,
-        }
-    }
-}
-
 impl<'de, E> de::Deserializer<'de> for UnitDeserializer<E>
 where
    E: de::Error,
@@ -176,17 +168,6 @@ where
    }
 }

-impl<'de, E> IntoDeserializer<'de, E> for UnitDeserializer<E>
-where
-    E: de::Error,
-{
-    type Deserializer = Self;
-
-    fn into_deserializer(self) -> Self {
-        self
-    }
-}
-
 impl<E> Debug for UnitDeserializer<E> {
    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
        formatter.debug_struct("UnitDeserializer").finish()
@@ -197,14 +178,12 @@ impl<E> Debug for UnitDeserializer<E> {

 /// A deserializer that cannot be instantiated.
 #[cfg(feature = "unstable")]
-#[cfg_attr(docsrs, doc(cfg(feature = "unstable")))]
 pub struct NeverDeserializer<E> {
    never: !,
    marker: PhantomData<E>,
 }

 #[cfg(feature = "unstable")]
-#[cfg_attr(docsrs, doc(cfg(feature = "unstable")))]
 impl<'de, E> IntoDeserializer<'de, E> for !
 where
    E: de::Error,
@@ -237,18 +216,6 @@ where
    }
 }

-#[cfg(feature = "unstable")]
-impl<'de, E> IntoDeserializer<'de, E> for NeverDeserializer<E>
-where
-    E: de::Error,
-{
-    type Deserializer = Self;
-
-    fn into_deserializer(self) -> Self {
-        self
-    }
-}
-
 ////////////////////////////////////////////////////////////////////////////////

 macro_rules! primitive_deserializer {
@@ -269,15 +236,8 @@ macro_rules! primitive_deserializer {
            type Deserializer = $name<E>;

            fn into_deserializer(self) -> $name<E> {
-                $name::new(self)
-            }
-        }
-
-        impl<E> $name<E> {
-            #[allow(missing_docs)]
-            pub fn new(value: $ty) -> Self {
                $name {
-                    value,
+                    value: self,
                    marker: PhantomData,
                }
            }
@@ -303,17 +263,6 @@ macro_rules! primitive_deserializer {
            }
        }

-        impl<'de, E> IntoDeserializer<'de, E> for $name<E>
-        where
-            E: de::Error,
-        {
-            type Deserializer = Self;
-
-            fn into_deserializer(self) -> Self {
-                self
-            }
-        }
-
        impl<E> Debug for $name<E> {
            fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
                formatter
@@ -330,17 +279,20 @@ primitive_deserializer!(i8, "an `i8`.", I8Deserializer, visit_i8);
 primitive_deserializer!(i16, "an `i16`.", I16Deserializer, visit_i16);
 primitive_deserializer!(i32, "an `i32`.", I32Deserializer, visit_i32);
 primitive_deserializer!(i64, "an `i64`.", I64Deserializer, visit_i64);
-primitive_deserializer!(i128, "an `i128`.", I128Deserializer, visit_i128);
 primitive_deserializer!(isize, "an `isize`.", IsizeDeserializer, visit_i64 as i64);
 primitive_deserializer!(u8, "a `u8`.", U8Deserializer, visit_u8);
 primitive_deserializer!(u16, "a `u16`.", U16Deserializer, visit_u16);
 primitive_deserializer!(u64, "a `u64`.", U64Deserializer, visit_u64);
-primitive_deserializer!(u128, "a `u128`.", U128Deserializer, visit_u128);
 primitive_deserializer!(usize, "a `usize`.", UsizeDeserializer, visit_u64 as u64);
 primitive_deserializer!(f32, "an `f32`.", F32Deserializer, visit_f32);
 primitive_deserializer!(f64, "an `f64`.", F64Deserializer, visit_f64);
 primitive_deserializer!(char, "a `char`.", CharDeserializer, visit_char);

+serde_if_integer128! {
+    primitive_deserializer!(i128, "an `i128`.", I128Deserializer, visit_i128);
+    primitive_deserializer!(u128, "a `u128`.", U128Deserializer, visit_u128);
+}
+
 /// A deserializer holding a `u32`.
 pub struct U32Deserializer<E> {
    value: u32,
@@ -356,15 +308,8 @@ where
    type Deserializer = U32Deserializer<E>;

    fn into_deserializer(self) -> U32Deserializer<E> {
-        U32Deserializer::new(self)
-    }
-}
-
-impl<E> U32Deserializer<E> {
-    #[allow(missing_docs)]
-    pub fn new(value: u32) -> Self {
        U32Deserializer {
-            value,
+            value: self,
            marker: PhantomData,
        }
    }
@@ -404,17 +349,6 @@ where
    }
 }

-impl<'de, E> IntoDeserializer<'de, E> for U32Deserializer<E>
-where
-    E: de::Error,
-{
-    type Deserializer = Self;
-
-    fn into_deserializer(self) -> Self {
-        self
-    }
-}
-
 impl<'de, E> de::EnumAccess<'de> for U32Deserializer<E>
 where
    E: de::Error,
@@ -456,15 +390,8 @@ where
    type Deserializer = StrDeserializer<'a, E>;

    fn into_deserializer(self) -> StrDeserializer<'a, E> {
-        StrDeserializer::new(self)
-    }
-}
-
-impl<'a, E> StrDeserializer<'a, E> {
-    #[allow(missing_docs)]
-    pub fn new(value: &'a str) -> Self {
        StrDeserializer {
-            value,
+            value: self,
            marker: PhantomData,
        }
    }
@@ -504,17 +431,6 @@ where
    }
 }

-impl<'de, 'a, E> IntoDeserializer<'de, E> for StrDeserializer<'a, E>
-where
-    E: de::Error,
-{
-    type Deserializer = Self;
-
-    fn into_deserializer(self) -> Self {
-        self
-    }
-}
-
 impl<'de, 'a, E> de::EnumAccess<'de> for StrDeserializer<'a, E>
 where
    E: de::Error,
@@ -554,7 +470,7 @@ impl<'de, E> BorrowedStrDeserializer<'de, E> {
    /// Create a new borrowed deserializer from the given string.
    pub fn new(value: &'de str) -> BorrowedStrDeserializer<'de, E> {
        BorrowedStrDeserializer {
-            value,
+            value: value,
            marker: PhantomData,
        }
    }
@@ -594,17 +510,6 @@ where
    }
 }

-impl<'de, E> IntoDeserializer<'de, E> for BorrowedStrDeserializer<'de, E>
-where
-    E: de::Error,
-{
-    type Deserializer = Self;
-
-    fn into_deserializer(self) -> Self {
-        self
-    }
-}
-
 impl<'de, E> de::EnumAccess<'de> for BorrowedStrDeserializer<'de, E>
 where
    E: de::Error,
@@ -633,7 +538,6 @@ impl<'de, E> Debug for BorrowedStrDeserializer<'de, E> {

 /// A deserializer holding a `String`.
 #[cfg(any(feature = "std", feature = "alloc"))]
-#[cfg_attr(docsrs, doc(cfg(any(feature = "std", feature = "alloc"))))]
 pub struct StringDeserializer<E> {
    value: String,
    marker: PhantomData<E>,
@@ -650,7 +554,6 @@ impl<E> Clone for StringDeserializer<E> {
 }

 #[cfg(any(feature = "std", feature = "alloc"))]
-#[cfg_attr(docsrs, doc(cfg(any(feature = "std", feature = "alloc"))))]
 impl<'de, E> IntoDeserializer<'de, E> for String
 where
    E: de::Error,
@@ -658,16 +561,8 @@ where
    type Deserializer = StringDeserializer<E>;

    fn into_deserializer(self) -> StringDeserializer<E> {
-        StringDeserializer::new(self)
-    }
-}
-
-#[cfg(any(feature = "std", feature = "alloc"))]
-impl<E> StringDeserializer<E> {
-    #[allow(missing_docs)]
-    pub fn new(value: String) -> Self {
        StringDeserializer {
-            value,
+            value: self,
            marker: PhantomData,
        }
    }
@@ -708,18 +603,6 @@ where
    }
 }

-#[cfg(any(feature = "std", feature = "alloc"))]
-impl<'de, E> IntoDeserializer<'de, E> for StringDeserializer<E>
-where
-    E: de::Error,
-{
-    type Deserializer = Self;
-
-    fn into_deserializer(self) -> Self {
-        self
-    }
-}
-
 #[cfg(any(feature = "std", feature = "alloc"))]
 impl<'de, E> de::EnumAccess<'de> for StringDeserializer<E>
 where
@@ -750,7 +633,6 @@ impl<E> Debug for StringDeserializer<E> {

 /// A deserializer holding a `Cow<str>`.
 #[cfg(any(feature = "std", feature = "alloc"))]
-#[cfg_attr(docsrs, doc(cfg(any(feature = "std", feature = "alloc"))))]
 pub struct CowStrDeserializer<'a, E> {
    value: Cow<'a, str>,
    marker: PhantomData<E>,
@@ -767,7 +649,6 @@ impl<'a, E> Clone for CowStrDeserializer<'a, E> {
 }

 #[cfg(any(feature = "std", feature = "alloc"))]
-#[cfg_attr(docsrs, doc(cfg(any(feature = "std", feature = "alloc"))))]
 impl<'de, 'a, E> IntoDeserializer<'de, E> for Cow<'a, str>
 where
    E: de::Error,
@@ -775,16 +656,8 @@ where
    type Deserializer = CowStrDeserializer<'a, E>;

    fn into_deserializer(self) -> CowStrDeserializer<'a, E> {
-        CowStrDeserializer::new(self)
-    }
-}
-
-#[cfg(any(feature = "std", feature = "alloc"))]
-impl<'a, E> CowStrDeserializer<'a, E> {
-    #[allow(missing_docs)]
-    pub fn new(value: Cow<'a, str>) -> Self {
        CowStrDeserializer {
-            value,
+            value: self,
            marker: PhantomData,
        }
    }
@@ -828,18 +701,6 @@ where
    }
 }

-#[cfg(any(feature = "std", feature = "alloc"))]
-impl<'de, 'a, E> IntoDeserializer<'de, E> for CowStrDeserializer<'a, E>
-where
-    E: de::Error,
-{
-    type Deserializer = Self;
-
-    fn into_deserializer(self) -> Self {
-        self
-    }
-}
-
 #[cfg(any(feature = "std", feature = "alloc"))]
 impl<'de, 'a, E> de::EnumAccess<'de> for CowStrDeserializer<'a, E>
 where
@@ -878,7 +739,7 @@ impl<'a, E> BytesDeserializer<'a, E> {
    /// Create a new deserializer from the given bytes.
    pub fn new(value: &'a [u8]) -> Self {
        BytesDeserializer {
-            value,
+            value: value,
            marker: PhantomData,
        }
    }
@@ -917,17 +778,6 @@ where
    }
 }

-impl<'de, 'a, E> IntoDeserializer<'de, E> for BytesDeserializer<'a, E>
-where
-    E: de::Error,
-{
-    type Deserializer = Self;
-
-    fn into_deserializer(self) -> Self {
-        self
-    }
-}
-
 impl<'a, E> Debug for BytesDeserializer<'a, E> {
    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
        formatter
@@ -948,7 +798,7 @@ impl<'de, E> BorrowedBytesDeserializer<'de, E> {
    /// Create a new borrowed deserializer from the given borrowed bytes.
    pub fn new(value: &'de [u8]) -> Self {
        BorrowedBytesDeserializer {
-            value,
+            value: value,
            marker: PhantomData,
        }
    }
@@ -976,17 +826,6 @@ where
    }
 }

-impl<'de, E> IntoDeserializer<'de, E> for BorrowedBytesDeserializer<'de, E>
-where
-    E: de::Error,
-{
-    type Deserializer = Self;
-
-    fn into_deserializer(self) -> Self {
-        self
-    }
-}
-
 impl<'de, E> Debug for BorrowedBytesDeserializer<'de, E> {
    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
        formatter
@@ -1054,8 +893,8 @@ where
    where
        V: de::Visitor<'de>,
    {
-        let v = tri!(visitor.visit_seq(&mut self));
-        tri!(self.end());
+        let v = try!(visitor.visit_seq(&mut self));
+        try!(self.end());
        Ok(v)
    }

@@ -1066,19 +905,6 @@ where
    }
 }

-impl<'de, I, T, E> IntoDeserializer<'de, E> for SeqDeserializer<I, E>
-where
-    I: Iterator<Item = T>,
-    T: IntoDeserializer<'de, E>,
-    E: de::Error,
-{
-    type Deserializer = Self;
-
-    fn into_deserializer(self) -> Self {
-        self
-    }
-}
-
 impl<'de, I, T, E> de::SeqAccess<'de> for SeqDeserializer<I, E>
 where
    I: Iterator<Item = T>,
@@ -1110,7 +936,7 @@ struct ExpectedInSeq(usize);
 impl Expected for ExpectedInSeq {
    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
        if self.0 == 1 {
-            formatter.write_str("1 element in sequence")
+            write!(formatter, "1 element in sequence")
        } else {
            write!(formatter, "{} elements in sequence", self.0)
        }
@@ -1133,7 +959,6 @@ where
 ////////////////////////////////////////////////////////////////////////////////

 #[cfg(any(feature = "std", feature = "alloc"))]
-#[cfg_attr(docsrs, doc(cfg(any(feature = "std", feature = "alloc"))))]
 impl<'de, T, E> IntoDeserializer<'de, E> for Vec<T>
 where
    T: IntoDeserializer<'de, E>,
@@ -1147,7 +972,6 @@ where
 }

 #[cfg(any(feature = "std", feature = "alloc"))]
-#[cfg_attr(docsrs, doc(cfg(any(feature = "std", feature = "alloc"))))]
 impl<'de, T, E> IntoDeserializer<'de, E> for BTreeSet<T>
 where
    T: IntoDeserializer<'de, E> + Eq + Ord,
@@ -1160,8 +984,7 @@ where
    }
 }

-#[cfg(all(feature = "std", not(target_os = "none")))]
-#[cfg_attr(docsrs, doc(cfg(feature = "std")))]
+#[cfg(feature = "std")]
 impl<'de, T, S, E> IntoDeserializer<'de, E> for HashSet<T, S>
 where
    T: IntoDeserializer<'de, E> + Eq + Hash,
@@ -1186,7 +1009,7 @@ pub struct SeqAccessDeserializer<A> {
 impl<A> SeqAccessDeserializer<A> {
    /// Construct a new `SeqAccessDeserializer<A>`.
    pub fn new(seq: A) -> Self {
-        SeqAccessDeserializer { seq }
+        SeqAccessDeserializer { seq: seq }
    }
 }

@@ -1210,17 +1033,6 @@ where
    }
 }

-impl<'de, A> IntoDeserializer<'de, A::Error> for SeqAccessDeserializer<A>
-where
-    A: de::SeqAccess<'de>,
-{
-    type Deserializer = Self;
-
-    fn into_deserializer(self) -> Self {
-        self
-    }
-}
-
 ////////////////////////////////////////////////////////////////////////////////

 /// A deserializer that iterates over a map.
@@ -1306,8 +1118,8 @@ where
    where
        V: de::Visitor<'de>,
    {
-        let value = tri!(visitor.visit_map(&mut self));
-        tri!(self.end());
+        let value = try!(visitor.visit_map(&mut self));
+        try!(self.end());
        Ok(value)
    }

@@ -1315,8 +1127,8 @@ where
    where
        V: de::Visitor<'de>,
    {
-        let value = tri!(visitor.visit_seq(&mut self));
-        tri!(self.end());
+        let value = try!(visitor.visit_seq(&mut self));
+        try!(self.end());
        Ok(value)
    }

@@ -1335,21 +1147,6 @@ where
    }
 }

-impl<'de, I, E> IntoDeserializer<'de, E> for MapDeserializer<'de, I, E>
-where
-    I: Iterator,
-    I::Item: private::Pair,
-    First<I::Item>: IntoDeserializer<'de, E>,
-    Second<I::Item>: IntoDeserializer<'de, E>,
-    E: de::Error,
-{
-    type Deserializer = Self;
-
-    fn into_deserializer(self) -> Self {
-        self
-    }
-}
-
 impl<'de, I, E> de::MapAccess<'de> for MapDeserializer<'de, I, E>
 where
    I: Iterator,
@@ -1395,8 +1192,8 @@ where
    {
        match self.next_pair() {
            Some((key, value)) => {
-                let key = tri!(kseed.deserialize(key.into_deserializer()));
-                let value = tri!(vseed.deserialize(value.into_deserializer()));
+                let key = try!(kseed.deserialize(key.into_deserializer()));
+                let value = try!(vseed.deserialize(value.into_deserializer()));
                Ok(Some((key, value)))
            }
            None => Ok(None),
@@ -1500,7 +1297,7 @@ where
        V: de::Visitor<'de>,
    {
        let mut pair_visitor = PairVisitor(Some(self.0), Some(self.1), PhantomData);
-        let pair = tri!(visitor.visit_seq(&mut pair_visitor));
+        let pair = try!(visitor.visit_seq(&mut pair_visitor));
        if pair_visitor.1.is_none() {
            Ok(pair)
        } else {
@@ -1564,7 +1361,7 @@ struct ExpectedInMap(usize);
 impl Expected for ExpectedInMap {
    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
        if self.0 == 1 {
-            formatter.write_str("1 element in map")
+            write!(formatter, "1 element in map")
        } else {
            write!(formatter, "{} elements in map", self.0)
        }
@@ -1574,7 +1371,6 @@ impl Expected for ExpectedInMap {
 ////////////////////////////////////////////////////////////////////////////////

 #[cfg(any(feature = "std", feature = "alloc"))]
-#[cfg_attr(docsrs, doc(cfg(any(feature = "std", feature = "alloc"))))]
 impl<'de, K, V, E> IntoDeserializer<'de, E> for BTreeMap<K, V>
 where
    K: IntoDeserializer<'de, E> + Eq + Ord,
@@ -1588,8 +1384,7 @@ where
    }
 }

-#[cfg(all(feature = "std", not(target_os = "none")))]
-#[cfg_attr(docsrs, doc(cfg(feature = "std")))]
+#[cfg(feature = "std")]
 impl<'de, K, V, S, E> IntoDeserializer<'de, E> for HashMap<K, V, S>
 where
    K: IntoDeserializer<'de, E> + Eq + Hash,
@@ -1615,7 +1410,7 @@ pub struct MapAccessDeserializer<A> {
 impl<A> MapAccessDeserializer<A> {
    /// Construct a new `MapAccessDeserializer<A>`.
    pub fn new(map: A) -> Self {
-        MapAccessDeserializer { map }
+        MapAccessDeserializer { map: map }
    }
 }

@@ -1651,17 +1446,6 @@ where
    }
 }

-impl<'de, A> IntoDeserializer<'de, A::Error> for MapAccessDeserializer<A>
-where
-    A: de::MapAccess<'de>,
-{
-    type Deserializer = Self;
-
-    fn into_deserializer(self) -> Self {
-        self
-    }
-}
-
 impl<'de, A> de::EnumAccess<'de> for MapAccessDeserializer<A>
 where
    A: de::MapAccess<'de>,
@@ -1673,7 +1457,7 @@ where
    where
        T: de::DeserializeSeed<'de>,
    {
-        match tri!(self.map.next_key_seed(seed)) {
+        match self.map.next_key_seed(seed)? {
            Some(key) => Ok((key, private::map_as_enum(self.map))),
            None => Err(de::Error::invalid_type(de::Unexpected::Map, &"enum")),
        }
@@ -1682,58 +1466,10 @@ where

 ////////////////////////////////////////////////////////////////////////////////

-/// A deserializer holding an `EnumAccess`.
-#[derive(Clone, Debug)]
-pub struct EnumAccessDeserializer<A> {
-    access: A,
-}
-
-impl<A> EnumAccessDeserializer<A> {
-    /// Construct a new `EnumAccessDeserializer<A>`.
-    pub fn new(access: A) -> Self {
-        EnumAccessDeserializer { access }
-    }
-}
-
-impl<'de, A> de::Deserializer<'de> for EnumAccessDeserializer<A>
-where
-    A: de::EnumAccess<'de>,
-{
-    type Error = A::Error;
-
-    fn deserialize_any<V>(self, visitor: V) -> Result<V::Value, Self::Error>
-    where
-        V: de::Visitor<'de>,
-    {
-        visitor.visit_enum(self.access)
-    }
-
-    forward_to_deserialize_any! {
-        bool i8 i16 i32 i64 i128 u8 u16 u32 u64 u128 f32 f64 char str string
-        bytes byte_buf option unit unit_struct newtype_struct seq tuple
-        tuple_struct map struct enum identifier ignored_any
-    }
-}
-
-impl<'de, A> IntoDeserializer<'de, A::Error> for EnumAccessDeserializer<A>
-where
-    A: de::EnumAccess<'de>,
-{
-    type Deserializer = Self;
-
-    fn into_deserializer(self) -> Self {
-        self
-    }
-}
-
-////////////////////////////////////////////////////////////////////////////////
-
 mod private {
-    use crate::lib::*;
+    use lib::*;

-    use crate::de::{
-        self, DeserializeSeed, Deserializer, MapAccess, Unexpected, VariantAccess, Visitor,
-    };
+    use de::{self, DeserializeSeed, Deserializer, MapAccess, Unexpected, VariantAccess, Visitor};

    pub struct UnitOnly<E> {
        marker: PhantomData<E>,
@@ -1798,7 +1534,7 @@ mod private {
    }

    pub fn map_as_enum<A>(map: A) -> MapAsEnum<A> {
-        MapAsEnum { map }
+        MapAsEnum { map: map }
    }

    impl<'de, A> VariantAccess<'de> for MapAsEnum<A>
@@ -1822,7 +1558,10 @@ mod private {
        where
            V: Visitor<'de>,
        {
-            self.map.next_value_seed(SeedTupleVariant { len, visitor })
+            self.map.next_value_seed(SeedTupleVariant {
+                len: len,
+                visitor: visitor,
+            })
        }

        fn struct_variant<V>(
@@ -1833,7 +1572,8 @@ mod private {
        where
            V: Visitor<'de>,
        {
-            self.map.next_value_seed(SeedStructVariant { visitor })
+            self.map
+                .next_value_seed(SeedStructVariant { visitor: visitor })
        }
    }

@@ -1,14 +1,82 @@
+/// Conditional compilation depending on whether Serde is built with support for
+/// 128-bit integers.
+///
+/// Data formats that wish to support Rust compiler versions older than 1.26
+/// (or targets that lack 128-bit integers) may place the i128 / u128 methods
+/// of their Serializer and Deserializer behind this macro.
+///
+/// Data formats that require a minimum Rust compiler version of at least 1.26,
+/// or do not target platforms that lack 128-bit integers, do not need to
+/// bother with this macro and may assume support for 128-bit integers.
+///
+/// ```edition2018
+/// # use serde::__private::doc::Error;
+/// #
+/// # struct MySerializer;
+/// #
+/// use serde::{serde_if_integer128, Serializer};
+///
+/// impl Serializer for MySerializer {
+///     type Ok = ();
+///     type Error = Error;
+///
+///     fn serialize_i64(self, v: i64) -> Result<Self::Ok, Self::Error> {
+///         /* ... */
+/// #         unimplemented!()
+///     }
+///
+///     /* ... */
+///
+///     serde_if_integer128! {
+///         fn serialize_i128(self, v: i128) -> Result<Self::Ok, Self::Error> {
+///             /* ... */
+/// #             unimplemented!()
+///         }
+///
+///         fn serialize_u128(self, v: u128) -> Result<Self::Ok, Self::Error> {
+///             /* ... */
+/// #             unimplemented!()
+///         }
+///     }
+/// #
+/// #     serde::__serialize_unimplemented! {
+/// #         bool i8 i16 i32 u8 u16 u32 u64 f32 f64 char str bytes none some
+/// #         unit unit_struct unit_variant newtype_struct newtype_variant seq
+/// #         tuple tuple_struct tuple_variant map struct struct_variant
+/// #     }
+/// }
+/// ```
+///
+/// When Serde is built with support for 128-bit integers, this macro expands
+/// transparently into just the input tokens.
+///
+/// ```edition2018
+/// macro_rules! serde_if_integer128 {
+///     ($($tt:tt)*) => {
+///         $($tt)*
+///     };
+/// }
+/// ```
+///
+/// When built without support for 128-bit integers, this macro expands to
+/// nothing.
+///
+/// ```edition2018
+/// macro_rules! serde_if_integer128 {
+///     ($($tt:tt)*) => {};
+/// }
+/// ```
+#[cfg(not(no_integer128))]
 #[macro_export]
-#[deprecated = "
-This macro has no effect on any version of Serde released in the past 2 years.
-It was used long ago in crates that needed to support Rustc older than 1.26.0,
-or Emscripten targets older than 1.40.0, which did not yet have 128-bit integer
-support. These days Serde requires a Rust compiler newer than that so 128-bit
-integers are always supported.
-"]
-#[doc(hidden)]
 macro_rules! serde_if_integer128 {
    ($($tt:tt)*) => {
        $($tt)*
    };
 }
+
+#[cfg(no_integer128)]
+#[macro_export]
+#[doc(hidden)]
+macro_rules! serde_if_integer128 {
+    ($($tt:tt)*) => {};
+}
@@ -9,7 +9,7 @@
 //! these two groups interact with each other, allowing any supported data
 //! structure to be serialized and deserialized using any supported data format.
 //!
-//! See the Serde website <https://serde.rs> for additional documentation and
+//! See the Serde website <https://serde.rs/> for additional documentation and
 //! usage examples.
 //!
 //! ## Design
@@ -31,7 +31,8 @@
 //! for Serde by the community.
 //!
 //! - [JSON], the ubiquitous JavaScript Object Notation used by many HTTP APIs.
-//! - [Postcard], a no\_std and embedded-systems friendly compact binary format.
+//! - [Bincode], a compact binary format
+//!   used for IPC within the Servo rendering engine.
 //! - [CBOR], a Concise Binary Object Representation designed for small message
 //!   size without the need for version negotiation.
 //! - [YAML], a self-proclaimed human-friendly configuration language that ain't
@@ -44,9 +45,8 @@
 //! - [Avro], a binary format used within Apache Hadoop, with support for schema
 //!   definition.
 //! - [JSON5], a superset of JSON including some productions from ES5.
+//! - [Postcard], a no\_std and embedded-systems friendly compact binary format.
 //! - [URL] query strings, in the x-www-form-urlencoded format.
-//! - [Starlark], the format used for describing build targets by the Bazel and
-//!   Buck build systems. *(serialization only)*
 //! - [Envy], a way to deserialize environment variables into Rust structs.
 //!   *(deserialization only)*
 //! - [Envy Store], a way to deserialize [AWS Parameter Store] parameters into
@@ -54,30 +54,23 @@
 //! - [S-expressions], the textual representation of code and data used by the
 //!   Lisp language family.
 //! - [D-Bus]'s binary wire format.
-//! - [FlexBuffers], the schemaless cousin of Google's FlatBuffers zero-copy
-//!   serialization format.
-//! - [Bencode], a simple binary format used in the BitTorrent protocol.
-//! - [Token streams], for processing Rust procedural macro input.
-//!   *(deserialization only)*
+//! - [FlexBuffers], the schemaless cousin of Google's FlatBuffers zero-copy serialization format.
 //! - [DynamoDB Items], the format used by [rusoto_dynamodb] to transfer data to
 //!   and from DynamoDB.
-//! - [Hjson], a syntax extension to JSON designed around human reading and
-//!   editing. *(deserialization only)*
-//! - [CSV], Comma-separated values is a tabular text file format.
 //!
 //! [JSON]: https://github.com/serde-rs/json
-//! [Postcard]: https://github.com/jamesmunns/postcard
+//! [Bincode]: https://github.com/bincode-org/bincode
 //! [CBOR]: https://github.com/enarx/ciborium
 //! [YAML]: https://github.com/dtolnay/serde-yaml
 //! [MessagePack]: https://github.com/3Hren/msgpack-rust
-//! [TOML]: https://docs.rs/toml
+//! [TOML]: https://github.com/alexcrichton/toml-rs
 //! [Pickle]: https://github.com/birkenfeld/serde-pickle
 //! [RON]: https://github.com/ron-rs/ron
 //! [BSON]: https://github.com/mongodb/bson-rust
-//! [Avro]: https://docs.rs/apache-avro
+//! [Avro]: https://github.com/flavray/avro-rs
 //! [JSON5]: https://github.com/callum-oakley/json5-rs
+//! [Postcard]: https://github.com/jamesmunns/postcard
 //! [URL]: https://docs.rs/serde_qs
-//! [Starlark]: https://github.com/dtolnay/serde-starlark
 //! [Envy]: https://github.com/softprops/envy
 //! [Envy Store]: https://github.com/softprops/envy-store
 //! [Cargo]: https://doc.rust-lang.org/cargo/reference/manifest.html
@@ -85,83 +78,66 @@
 //! [S-expressions]: https://github.com/rotty/lexpr-rs
 //! [D-Bus]: https://docs.rs/zvariant
 //! [FlexBuffers]: https://github.com/google/flatbuffers/tree/master/rust/flexbuffers
-//! [Bencode]: https://github.com/P3KI/bendy
-//! [Token streams]: https://github.com/oxidecomputer/serde_tokenstream
 //! [DynamoDB Items]: https://docs.rs/serde_dynamo
 //! [rusoto_dynamodb]: https://docs.rs/rusoto_dynamodb
-//! [Hjson]: https://github.com/Canop/deser-hjson
-//! [CSV]: https://docs.rs/csv

 ////////////////////////////////////////////////////////////////////////////////

 // Serde types in rustdoc of other crates get linked to here.
-#![doc(html_root_url = "https://docs.rs/serde/1.0.228")]
+#![doc(html_root_url = "https://docs.rs/serde/1.0.137")]
 // Support using Serde without the standard library!
-// Also force no_std on target_os = "none" (wasm32v1-none) even if std feature is enabled
-// This handles Cargo feature unification where std gets enabled for no_std targets
-#![cfg_attr(any(not(feature = "std"), target_os = "none"), no_std)]
-// Show which crate feature enables conditionally compiled APIs in documentation.
-#![cfg_attr(docsrs, feature(doc_cfg, rustdoc_internals))]
-#![cfg_attr(docsrs, allow(internal_features))]
+#![cfg_attr(not(feature = "std"), no_std)]
 // Unstable functionality only if the user asks for it. For tracking and
 // discussion of these features please refer to this issue:
 //
 //    https://github.com/serde-rs/serde/issues/812
 #![cfg_attr(feature = "unstable", feature(never_type))]
-#![allow(
-    unknown_lints,
-    bare_trait_objects,
-    deprecated,
-    mismatched_lifetime_syntaxes
-)]
+#![allow(unknown_lints, bare_trait_objects, deprecated)]
+#![cfg_attr(feature = "cargo-clippy", allow(renamed_and_removed_lints))]
 // Ignored clippy and clippy_pedantic lints
-#![allow(
-    // clippy bug: https://github.com/rust-lang/rust-clippy/issues/5704
-    clippy::unnested_or_patterns,
-    // clippy bug: https://github.com/rust-lang/rust-clippy/issues/7768
-    clippy::semicolon_if_nothing_returned,
-    // not available in our oldest supported compiler
-    clippy::empty_enums,
-    clippy::type_repetition_in_bounds, // https://github.com/rust-lang/rust-clippy/issues/8772
-    // integer and float ser/de requires these sorts of casts
-    clippy::cast_possible_truncation,
-    clippy::cast_possible_wrap,
-    clippy::cast_precision_loss,
-    clippy::cast_sign_loss,
-    // things are often more readable this way
-    clippy::cast_lossless,
-    clippy::module_name_repetitions,
-    clippy::single_match_else,
-    clippy::type_complexity,
-    clippy::use_self,
-    clippy::zero_prefixed_literal,
-    // correctly used
-    clippy::derive_partial_eq_without_eq,
-    clippy::enum_glob_use,
-    clippy::explicit_auto_deref,
-    clippy::incompatible_msrv,
-    clippy::let_underscore_untyped,
-    clippy::map_err_ignore,
-    clippy::new_without_default,
-    clippy::result_unit_err,
-    clippy::wildcard_imports,
-    // not practical
-    clippy::needless_pass_by_value,
-    clippy::similar_names,
-    clippy::too_many_lines,
-    // preference
-    clippy::doc_markdown,
-    clippy::elidable_lifetime_names,
-    clippy::needless_lifetimes,
-    clippy::unseparated_literal_suffix,
-    // false positive
-    clippy::needless_doctest_main,
-    // noisy
-    clippy::missing_errors_doc,
-    clippy::must_use_candidate,
+#![cfg_attr(
+    feature = "cargo-clippy",
+    allow(
+        // clippy bug: https://github.com/rust-lang/rust-clippy/issues/5704
+        unnested_or_patterns,
+        // clippy bug: https://github.com/rust-lang/rust-clippy/issues/7768
+        semicolon_if_nothing_returned,
+        // not available in our oldest supported compiler
+        empty_enum,
+        type_repetition_in_bounds, // https://github.com/rust-lang/rust-clippy/issues/8772
+        // integer and float ser/de requires these sorts of casts
+        cast_possible_truncation,
+        cast_possible_wrap,
+        cast_sign_loss,
+        // things are often more readable this way
+        cast_lossless,
+        module_name_repetitions,
+        option_if_let_else,
+        single_match_else,
+        type_complexity,
+        use_self,
+        zero_prefixed_literal,
+        // correctly used
+        derive_partial_eq_without_eq,
+        enum_glob_use,
+        let_underscore_drop,
+        map_err_ignore,
+        result_unit_err,
+        wildcard_imports,
+        // not practical
+        needless_pass_by_value,
+        similar_names,
+        too_many_lines,
+        // preference
+        doc_markdown,
+        unseparated_literal_suffix,
+        // false positive
+        needless_doctest_main,
+        // noisy
+        missing_errors_doc,
+        must_use_candidate,
+    )
 )]
-// Restrictions
-#![deny(clippy::question_mark_used)]
 // Rustc lints.
 #![deny(missing_docs, unused_imports)]

@@ -170,142 +146,156 @@
 #[cfg(feature = "alloc")]
 extern crate alloc;

-// Explicitly import core crate for no_std targets (especially wasm32v1-none)
-#[cfg(any(not(feature = "std"), target_os = "none"))]
-extern crate core;
+/// A facade around all the types we need from the `std`, `core`, and `alloc`
+/// crates. This avoids elaborate import wrangling having to happen in every
+/// module.
+mod lib {
+    mod core {
+        #[cfg(not(feature = "std"))]
+        pub use core::*;
+        #[cfg(feature = "std")]
+        pub use std::*;
+    }

-// Rustdoc has a lot of shortcomings related to cross-crate re-exports that make
-// the rendered documentation of serde_core traits in serde more challenging to
-// understand than the equivalent documentation of the same items in serde_core.
-// https://github.com/rust-lang/rust/labels/A-cross-crate-reexports
-// So, just for the purpose of docs.rs documentation, we inline the contents of
-// serde_core into serde. This sidesteps all the cross-crate rustdoc bugs.
-#[cfg(docsrs)]
-#[macro_use]
-#[path = "core/crate_root.rs"]
-mod crate_root;
+    pub use self::core::{cmp, iter, mem, num, ptr, slice, str};
+    pub use self::core::{f32, f64};
+    pub use self::core::{i16, i32, i64, i8, isize};
+    pub use self::core::{u16, u32, u64, u8, usize};

-#[cfg(docsrs)]
-#[macro_use]
-#[path = "core/macros.rs"]
-mod macros;
+    pub use self::core::cell::{Cell, RefCell};
+    pub use self::core::clone::{self, Clone};
+    pub use self::core::convert::{self, From, Into};
+    pub use self::core::default::{self, Default};
+    pub use self::core::fmt::{self, Debug, Display};
+    pub use self::core::marker::{self, PhantomData};
+    pub use self::core::num::Wrapping;
+    pub use self::core::ops::Range;
+    pub use self::core::option::{self, Option};
+    pub use self::core::result::{self, Result};

-#[cfg(not(docsrs))]
-macro_rules! crate_root {
-    () => {
-        /// A facade around all the types we need from the `std`, `core`, and `alloc`
-        /// crates. This avoids elaborate import wrangling having to happen in every
-        /// module.
-        ///
-        /// NOTE: On targets where std is not available (target_os = "none", e.g. wasm32v1-none),
-        /// we always use core/alloc even if the "std" feature is enabled due to Cargo feature
-        /// unification.
-        mod lib {
-            mod core {
-                #[cfg(any(not(feature = "std"), target_os = "none"))]
-                pub use ::core::*;
-                #[cfg(all(feature = "std", not(target_os = "none")))]
-                pub use ::std::*;
-            }
+    #[cfg(all(feature = "alloc", not(feature = "std")))]
+    pub use alloc::borrow::{Cow, ToOwned};
+    #[cfg(feature = "std")]
+    pub use std::borrow::{Cow, ToOwned};

-            // Re-export the full prelude for wasm32v1-none and other no_std targets
-            #[cfg(any(not(feature = "std"), target_os = "none"))]
-            pub use ::core::prelude::rust_2021::*;
-            #[cfg(all(feature = "std", not(target_os = "none")))]
-            pub use ::std::prelude::rust_2021::*;
+    #[cfg(all(feature = "alloc", not(feature = "std")))]
+    pub use alloc::string::{String, ToString};
+    #[cfg(feature = "std")]
+    pub use std::string::{String, ToString};

-            // Prelude items that may not be re-exported by glob import
-            #[cfg(any(not(feature = "std"), target_os = "none"))]
-            pub use ::core::option::Option::{self, None, Some};
-            #[cfg(any(not(feature = "std"), target_os = "none"))]
-            pub use ::core::result::Result::{self, Err, Ok};
-            #[cfg(all(feature = "std", not(target_os = "none")))]
-            pub use ::std::option::Option::{self, None, Some};
-            #[cfg(all(feature = "std", not(target_os = "none")))]
-            pub use ::std::result::Result::{self, Err, Ok};
+    #[cfg(all(feature = "alloc", not(feature = "std")))]
+    pub use alloc::vec::Vec;
+    #[cfg(feature = "std")]
+    pub use std::vec::Vec;

-            pub use self::core::{f32, f64};
-            pub use self::core::{ptr, str};
+    #[cfg(all(feature = "alloc", not(feature = "std")))]
+    pub use alloc::boxed::Box;
+    #[cfg(feature = "std")]
+    pub use std::boxed::Box;

-            #[cfg(any(feature = "std", feature = "alloc"))]
-            pub use self::core::slice;
+    #[cfg(all(feature = "rc", feature = "alloc", not(feature = "std")))]
+    pub use alloc::rc::{Rc, Weak as RcWeak};
+    #[cfg(all(feature = "rc", feature = "std"))]
+    pub use std::rc::{Rc, Weak as RcWeak};

-            pub use self::core::clone;
-            pub use self::core::convert;
-            pub use self::core::default;
-            pub use self::core::fmt::{self, Debug, Display, Write as FmtWrite};
-            pub use self::core::marker::{self, PhantomData};
-            pub use self::core::option;
-            pub use self::core::result;
+    #[cfg(all(feature = "rc", feature = "alloc", not(feature = "std")))]
+    pub use alloc::sync::{Arc, Weak as ArcWeak};
+    #[cfg(all(feature = "rc", feature = "std"))]
+    pub use std::sync::{Arc, Weak as ArcWeak};

-            #[cfg(all(feature = "alloc", any(not(feature = "std"), target_os = "none")))]
-            pub use alloc::borrow::{Cow, ToOwned};
-            #[cfg(all(feature = "std", not(target_os = "none")))]
-            pub use std::borrow::{Cow, ToOwned};
+    #[cfg(all(feature = "alloc", not(feature = "std")))]
+    pub use alloc::collections::{BTreeMap, BTreeSet, BinaryHeap, LinkedList, VecDeque};
+    #[cfg(feature = "std")]
+    pub use std::collections::{BTreeMap, BTreeSet, BinaryHeap, LinkedList, VecDeque};

-            #[cfg(all(feature = "alloc", any(not(feature = "std"), target_os = "none")))]
-            pub use alloc::string::{String, ToString};
-            #[cfg(all(feature = "std", not(target_os = "none")))]
-            pub use std::string::{String, ToString};
+    #[cfg(feature = "std")]
+    pub use std::{error, net};

-            #[cfg(all(feature = "alloc", any(not(feature = "std"), target_os = "none")))]
-            pub use alloc::vec::Vec;
-            #[cfg(all(feature = "std", not(target_os = "none")))]
-            pub use std::vec::Vec;
+    #[cfg(feature = "std")]
+    pub use std::collections::{HashMap, HashSet};
+    #[cfg(feature = "std")]
+    pub use std::ffi::{CStr, CString, OsStr, OsString};
+    #[cfg(feature = "std")]
+    pub use std::hash::{BuildHasher, Hash};
+    #[cfg(feature = "std")]
+    pub use std::io::Write;
+    #[cfg(feature = "std")]
+    pub use std::path::{Path, PathBuf};
+    #[cfg(feature = "std")]
+    pub use std::sync::{Mutex, RwLock};
+    #[cfg(feature = "std")]
+    pub use std::time::{SystemTime, UNIX_EPOCH};

-            #[cfg(all(feature = "alloc", any(not(feature = "std"), target_os = "none")))]
-            pub use alloc::boxed::Box;
-            #[cfg(all(feature = "std", not(target_os = "none")))]
-            pub use std::boxed::Box;
-        }
+    #[cfg(all(feature = "std", not(no_collections_bound), no_ops_bound))]
+    pub use std::collections::Bound;

-        // None of this crate's error handling needs the `From::from` error conversion
-        // performed implicitly by the `?` operator or the standard library's `try!`
-        // macro. This simplified macro gives a 5.5% improvement in compile time
-        // compared to standard `try!`, and 9% improvement compared to `?`.
-        #[cfg(not(no_serde_derive))]
-        macro_rules! tri {
-            ($expr:expr) => {
-                match $expr {
-                    Ok(val) => val,
-                    Err(err) => return Err(err),
-                }
-            };
-        }
+    #[cfg(not(no_core_reverse))]
+    pub use self::core::cmp::Reverse;

-        ////////////////////////////////////////////////////////////////////////////////
+    #[cfg(not(no_ops_bound))]
+    pub use self::core::ops::Bound;

-        pub use serde_core::{
-            de, forward_to_deserialize_any, ser, Deserialize, Deserializer, Serialize, Serializer,
-        };
+    #[cfg(not(no_range_inclusive))]
+    pub use self::core::ops::RangeInclusive;

-        // Used by generated code and doc tests. Not public API.
-        #[doc(hidden)]
-        mod private;
-
-        include!(concat!(env!("OUT_DIR"), "/private.rs"));
+    #[cfg(all(feature = "std", not(no_std_atomic)))]
+    pub use std::sync::atomic::{
+        AtomicBool, AtomicI16, AtomicI32, AtomicI8, AtomicIsize, AtomicU16, AtomicU32, AtomicU8,
+        AtomicUsize, Ordering,
    };
+    #[cfg(all(feature = "std", not(no_std_atomic64)))]
+    pub use std::sync::atomic::{AtomicI64, AtomicU64};
+
+    #[cfg(any(feature = "std", not(no_core_duration)))]
+    pub use self::core::time::Duration;
 }

-crate_root!();
+////////////////////////////////////////////////////////////////////////////////

+#[macro_use]
+mod macros;
+
+#[macro_use]
 mod integer128;

+pub mod de;
+pub mod ser;
+
+#[doc(inline)]
+pub use de::{Deserialize, Deserializer};
+#[doc(inline)]
+pub use ser::{Serialize, Serializer};
+
+// Used by generated code and doc tests. Not public API.
+#[doc(hidden)]
+#[path = "private/mod.rs"]
+pub mod __private;
+
+#[allow(unused_imports)]
+use self::__private as export;
+#[allow(unused_imports)]
+use self::__private as private;
+
+#[path = "de/seed.rs"]
+mod seed;
+
+#[cfg(not(feature = "std"))]
+mod std_error;
+
 // Re-export #[derive(Serialize, Deserialize)].
 //
 // The reason re-exporting is not enabled by default is that disabling it would
 // be annoying for crates that provide handwritten impls or data formats. They
 // would need to disable default features and then explicitly re-enable std.
 #[cfg(feature = "serde_derive")]
+#[allow(unused_imports)]
+#[macro_use]
 extern crate serde_derive;
-
-/// Derive macro available if serde is built with `features = ["derive"]`.
 #[cfg(feature = "serde_derive")]
-#[cfg_attr(docsrs, doc(cfg(feature = "derive")))]
-pub use serde_derive::{Deserialize, Serialize};
-
-#[macro_export]
 #[doc(hidden)]
-macro_rules! __require_serde_not_serde_core {
-    () => {};
+pub use serde_derive::*;
+
+#[cfg(all(not(no_serde_derive), any(feature = "std", feature = "alloc")))]
+mod actually_private {
+    pub struct T;
 }
@@ -1,6 +1,7 @@
 // Super explicit first paragraph because this shows up at the top level and
 // trips up people who are just looking for basic Serialize / Deserialize
 // documentation.
+//
 /// Helper macro when implementing the `Deserializer` part of a new data format
 /// for Serde.
 ///
@@ -10,7 +11,7 @@
 /// input. This requires repetitive implementations of all the [`Deserializer`]
 /// trait methods.
 ///
-/// ```edition2021
+/// ```edition2018
 /// # use serde::forward_to_deserialize_any;
 /// # use serde::de::{value, Deserializer, Visitor};
 /// #
@@ -46,7 +47,7 @@
 /// methods so that they forward directly to [`Deserializer::deserialize_any`].
 /// You can choose which methods to forward.
 ///
-/// ```edition2021
+/// ```edition2018
 /// # use serde::forward_to_deserialize_any;
 /// # use serde::de::{value, Deserializer, Visitor};
 /// #
@@ -77,10 +78,11 @@
 /// called `V`. A different type parameter and a different lifetime can be
 /// specified explicitly if necessary.
 ///
-/// ```edition2021
+/// ```edition2018
+/// # use std::marker::PhantomData;
+/// #
 /// # use serde::forward_to_deserialize_any;
 /// # use serde::de::{value, Deserializer, Visitor};
-/// # use std::marker::PhantomData;
 /// #
 /// # struct MyDeserializer<V>(PhantomData<V>);
 /// #
@@ -103,9 +105,9 @@
 /// # }
 /// ```
 ///
-/// [`Deserializer`]: crate::Deserializer
-/// [`Visitor`]: crate::de::Visitor
-/// [`Deserializer::deserialize_any`]: crate::Deserializer::deserialize_any
+/// [`Deserializer`]: trait.Deserializer.html
+/// [`Visitor`]: de/trait.Visitor.html
+/// [`Deserializer::deserialize_any`]: trait.Deserializer.html#tymethod.deserialize_any
 #[macro_export(local_inner_macros)]
 macro_rules! forward_to_deserialize_any {
    (<$visitor:ident: Visitor<$lifetime:tt>> $($func:ident)*) => {
@@ -122,7 +124,7 @@ macro_rules! forward_to_deserialize_any {
 macro_rules! forward_to_deserialize_any_method {
    ($func:ident<$l:tt, $v:ident>($($arg:ident : $ty:ty),*)) => {
        #[inline]
-        fn $func<$v>(self, $($arg: $ty,)* visitor: $v) -> $crate::__private::Result<$v::Value, <Self as $crate::de::Deserializer<$l>>::Error>
+        fn $func<$v>(self, $($arg: $ty,)* visitor: $v) -> $crate::__private::Result<$v::Value, Self::Error>
        where
            $v: $crate::de::Visitor<$l>,
        {
@@ -153,7 +155,9 @@ macro_rules! forward_to_deserialize_any_helper {
        forward_to_deserialize_any_method!{deserialize_i64<$l, $v>()}
    };
    (i128<$l:tt, $v:ident>) => {
-        forward_to_deserialize_any_method!{deserialize_i128<$l, $v>()}
+        serde_if_integer128! {
+            forward_to_deserialize_any_method!{deserialize_i128<$l, $v>()}
+        }
    };
    (u8<$l:tt, $v:ident>) => {
        forward_to_deserialize_any_method!{deserialize_u8<$l, $v>()}
@@ -168,7 +172,9 @@ macro_rules! forward_to_deserialize_any_helper {
        forward_to_deserialize_any_method!{deserialize_u64<$l, $v>()}
    };
    (u128<$l:tt, $v:ident>) => {
-        forward_to_deserialize_any_method!{deserialize_u128<$l, $v>()}
+        serde_if_integer128! {
+            forward_to_deserialize_any_method!{deserialize_u128<$l, $v>()}
+        }
    };
    (f32<$l:tt, $v:ident>) => {
        forward_to_deserialize_any_method!{deserialize_f32<$l, $v>()}
@@ -1,14 +1,13 @@
 // Used only by Serde doc tests. Not public API.

-use crate::lib::*;
+use lib::*;

-use crate::ser;
+use ser;

 #[doc(hidden)]
 #[derive(Debug)]
 pub struct Error;

-#[cfg_attr(not(no_diagnostic_namespace), diagnostic::do_not_recommend)]
 impl ser::Error for Error {
    fn custom<T>(_: T) -> Self
    where
@@ -18,15 +17,13 @@ impl ser::Error for Error {
    }
 }

-#[cfg(all(feature = "std", not(target_os = "none")))]
-#[cfg_attr(not(no_diagnostic_namespace), diagnostic::do_not_recommend)]
+#[cfg(feature = "std")]
 impl error::Error for Error {
    fn description(&self) -> &str {
        unimplemented!()
    }
 }

-#[cfg_attr(not(no_diagnostic_namespace), diagnostic::do_not_recommend)]
 impl Display for Error {
    fn fmt(&self, _: &mut fmt::Formatter) -> fmt::Result {
        unimplemented!()
@@ -59,10 +56,7 @@ macro_rules! __serialize_unimplemented {
 #[macro_export]
 macro_rules! __serialize_unimplemented_method {
    ($func:ident $(<$t:ident>)* ($($arg:ty),*) -> $ret:ident) => {
-        fn $func $(<$t>)* (self $(, _: $arg)*) -> $crate::__private::Result<Self::$ret, Self::Error>
-        where
-            $($t: ?Sized + $crate::Serialize,)*
-        {
+        fn $func $(<$t: ?Sized + $crate::Serialize>)* (self $(, _: $arg)*) -> $crate::__private::Result<Self::$ret, Self::Error> {
            unimplemented!()
        }
    };
@@ -3,16 +3,48 @@ pub mod de;
 #[cfg(not(no_serde_derive))]
 pub mod ser;

-pub use crate::lib::clone::Clone;
-pub use crate::lib::convert::{From, Into, TryFrom};
-pub use crate::lib::default::Default;
-pub use crate::lib::fmt::{self, Formatter};
-pub use crate::lib::marker::PhantomData;
-pub use crate::lib::option::Option::{self, None, Some};
-pub use crate::lib::ptr;
-pub use crate::lib::result::Result::{self, Err, Ok};
+pub mod size_hint;

-pub use crate::serde_core_private::string::from_utf8_lossy;
+// FIXME: #[cfg(doctest)] once https://github.com/rust-lang/rust/issues/67295 is fixed.
+pub mod doc;
+
+pub use lib::clone::Clone;
+pub use lib::convert::{From, Into};
+pub use lib::default::Default;
+pub use lib::fmt::{self, Formatter};
+pub use lib::marker::PhantomData;
+pub use lib::option::Option::{self, None, Some};
+pub use lib::ptr;
+pub use lib::result::Result::{self, Err, Ok};
+
+pub use self::string::from_utf8_lossy;

 #[cfg(any(feature = "alloc", feature = "std"))]
-pub use crate::lib::{ToString, Vec};
+pub use lib::{ToString, Vec};
+
+#[cfg(not(no_core_try_from))]
+pub use lib::convert::TryFrom;
+
+mod string {
+    use lib::*;
+
+    #[cfg(any(feature = "std", feature = "alloc"))]
+    pub fn from_utf8_lossy(bytes: &[u8]) -> Cow<str> {
+        String::from_utf8_lossy(bytes)
+    }
+
+    // The generated code calls this like:
+    //
+    //     let value = &_serde::__private::from_utf8_lossy(bytes);
+    //     Err(_serde::de::Error::unknown_variant(value, VARIANTS))
+    //
+    // so it is okay for the return type to be different from the std case as long
+    // as the above works.
+    #[cfg(not(any(feature = "std", feature = "alloc")))]
+    pub fn from_utf8_lossy(bytes: &[u8]) -> &str {
+        // Three unicode replacement characters if it fails. They look like a
+        // white-on-black question mark. The user will recognize it as invalid
+        // UTF-8.
+        str::from_utf8(bytes).unwrap_or("\u{fffd}\u{fffd}\u{fffd}")
+    }
+}
@@ -1,12 +1,6 @@
-use crate::lib::*;
+use lib::*;

-// Explicit prelude import for wasm32v1-none and other no_std targets
-#[allow(unused_imports)]
-use ::core::prelude::rust_2021::*;
-#[allow(unused_imports)]
-use ::core::write;
-
-use crate::ser::{self, Impossible, Serialize, SerializeMap, SerializeStruct, Serializer};
+use ser::{self, Impossible, Serialize, SerializeMap, SerializeStruct, Serializer};

 #[cfg(any(feature = "std", feature = "alloc"))]
 use self::content::{
@@ -33,10 +27,10 @@ where
    T: Serialize,
 {
    value.serialize(TaggedSerializer {
-        type_ident,
-        variant_ident,
-        tag,
-        variant_name,
+        type_ident: type_ident,
+        variant_ident: variant_ident,
+        tag: tag,
+        variant_name: variant_name,
        delegate: serializer,
    })
 }
@@ -57,14 +51,15 @@ enum Unsupported {
    String,
    ByteArray,
    Optional,
+    Unit,
+    #[cfg(any(feature = "std", feature = "alloc"))]
+    UnitStruct,
    Sequence,
    Tuple,
    TupleStruct,
-    #[cfg(not(any(feature = "std", feature = "alloc")))]
    Enum,
 }

-#[cfg_attr(not(no_diagnostic_namespace), diagnostic::do_not_recommend)]
 impl Display for Unsupported {
    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
        match *self {
@@ -75,10 +70,12 @@ impl Display for Unsupported {
            Unsupported::String => formatter.write_str("a string"),
            Unsupported::ByteArray => formatter.write_str("a byte array"),
            Unsupported::Optional => formatter.write_str("an optional"),
+            Unsupported::Unit => formatter.write_str("unit"),
+            #[cfg(any(feature = "std", feature = "alloc"))]
+            Unsupported::UnitStruct => formatter.write_str("unit struct"),
            Unsupported::Sequence => formatter.write_str("a sequence"),
            Unsupported::Tuple => formatter.write_str("a tuple"),
            Unsupported::TupleStruct => formatter.write_str("a tuple struct"),
-            #[cfg(not(any(feature = "std", feature = "alloc")))]
            Unsupported::Enum => formatter.write_str("an enum"),
        }
    }
@@ -96,7 +93,6 @@ where
    }
 }

-#[cfg_attr(not(no_diagnostic_namespace), diagnostic::do_not_recommend)]
 impl<S> Serializer for TaggedSerializer<S>
 where
    S: Serializer,
@@ -180,22 +176,20 @@ where
        Err(self.bad_type(Unsupported::Optional))
    }

-    fn serialize_some<T>(self, _: &T) -> Result<Self::Ok, Self::Error>
+    fn serialize_some<T: ?Sized>(self, _: &T) -> Result<Self::Ok, Self::Error>
    where
-        T: ?Sized + Serialize,
+        T: Serialize,
    {
        Err(self.bad_type(Unsupported::Optional))
    }

    fn serialize_unit(self) -> Result<Self::Ok, Self::Error> {
-        let mut map = tri!(self.delegate.serialize_map(Some(1)));
-        tri!(map.serialize_entry(self.tag, self.variant_name));
-        map.end()
+        Err(self.bad_type(Unsupported::Unit))
    }

    fn serialize_unit_struct(self, _: &'static str) -> Result<Self::Ok, Self::Error> {
-        let mut map = tri!(self.delegate.serialize_map(Some(1)));
-        tri!(map.serialize_entry(self.tag, self.variant_name));
+        let mut map = try!(self.delegate.serialize_map(Some(1)));
+        try!(map.serialize_entry(self.tag, self.variant_name));
        map.end()
    }

@@ -205,24 +199,24 @@ where
        _: u32,
        inner_variant: &'static str,
    ) -> Result<Self::Ok, Self::Error> {
-        let mut map = tri!(self.delegate.serialize_map(Some(2)));
-        tri!(map.serialize_entry(self.tag, self.variant_name));
-        tri!(map.serialize_entry(inner_variant, &()));
+        let mut map = try!(self.delegate.serialize_map(Some(2)));
+        try!(map.serialize_entry(self.tag, self.variant_name));
+        try!(map.serialize_entry(inner_variant, &()));
        map.end()
    }

-    fn serialize_newtype_struct<T>(
+    fn serialize_newtype_struct<T: ?Sized>(
        self,
        _: &'static str,
        value: &T,
    ) -> Result<Self::Ok, Self::Error>
    where
-        T: ?Sized + Serialize,
+        T: Serialize,
    {
        value.serialize(self)
    }

-    fn serialize_newtype_variant<T>(
+    fn serialize_newtype_variant<T: ?Sized>(
        self,
        _: &'static str,
        _: u32,
@@ -230,11 +224,11 @@ where
        inner_value: &T,
    ) -> Result<Self::Ok, Self::Error>
    where
-        T: ?Sized + Serialize,
+        T: Serialize,
    {
-        let mut map = tri!(self.delegate.serialize_map(Some(2)));
-        tri!(map.serialize_entry(self.tag, self.variant_name));
-        tri!(map.serialize_entry(inner_variant, inner_value));
+        let mut map = try!(self.delegate.serialize_map(Some(2)));
+        try!(map.serialize_entry(self.tag, self.variant_name));
+        try!(map.serialize_entry(inner_variant, inner_value));
        map.end()
    }

@@ -275,9 +269,9 @@ where
        inner_variant: &'static str,
        len: usize,
    ) -> Result<Self::SerializeTupleVariant, Self::Error> {
-        let mut map = tri!(self.delegate.serialize_map(Some(2)));
-        tri!(map.serialize_entry(self.tag, self.variant_name));
-        tri!(map.serialize_key(inner_variant));
+        let mut map = try!(self.delegate.serialize_map(Some(2)));
+        try!(map.serialize_entry(self.tag, self.variant_name));
+        try!(map.serialize_key(inner_variant));
        Ok(SerializeTupleVariantAsMapValue::new(
            map,
            inner_variant,
@@ -286,8 +280,8 @@ where
    }

    fn serialize_map(self, len: Option<usize>) -> Result<Self::SerializeMap, Self::Error> {
-        let mut map = tri!(self.delegate.serialize_map(len.map(|len| len + 1)));
-        tri!(map.serialize_entry(self.tag, self.variant_name));
+        let mut map = try!(self.delegate.serialize_map(len.map(|len| len + 1)));
+        try!(map.serialize_entry(self.tag, self.variant_name));
        Ok(map)
    }

@@ -296,8 +290,8 @@ where
        name: &'static str,
        len: usize,
    ) -> Result<Self::SerializeStruct, Self::Error> {
-        let mut state = tri!(self.delegate.serialize_struct(name, len + 1));
-        tri!(state.serialize_field(self.tag, self.variant_name));
+        let mut state = try!(self.delegate.serialize_struct(name, len + 1));
+        try!(state.serialize_field(self.tag, self.variant_name));
        Ok(state)
    }

@@ -322,9 +316,9 @@ where
        inner_variant: &'static str,
        len: usize,
    ) -> Result<Self::SerializeStructVariant, Self::Error> {
-        let mut map = tri!(self.delegate.serialize_map(Some(2)));
-        tri!(map.serialize_entry(self.tag, self.variant_name));
-        tri!(map.serialize_key(inner_variant));
+        let mut map = try!(self.delegate.serialize_map(Some(2)));
+        try!(map.serialize_entry(self.tag, self.variant_name));
+        try!(map.serialize_key(inner_variant));
        Ok(SerializeStructVariantAsMapValue::new(
            map,
            inner_variant,
@@ -333,9 +327,9 @@ where
    }

    #[cfg(not(any(feature = "std", feature = "alloc")))]
-    fn collect_str<T>(self, _: &T) -> Result<Self::Ok, Self::Error>
+    fn collect_str<T: ?Sized>(self, _: &T) -> Result<Self::Ok, Self::Error>
    where
-        T: ?Sized + Display,
+        T: Display,
    {
        Err(self.bad_type(Unsupported::String))
    }
@@ -343,13 +337,9 @@ where

 #[cfg(any(feature = "std", feature = "alloc"))]
 mod content {
-    use crate::lib::*;
+    use lib::*;

-    // Explicit prelude import for wasm32v1-none and other no_std targets
-    #[allow(unused_imports)]
-    use ::core::prelude::rust_2021::*;
-
-    use crate::ser::{self, Serialize, Serializer};
+    use ser::{self, Serialize, Serializer};

    pub struct SerializeTupleVariantAsMapValue<M> {
        map: M,
@@ -360,14 +350,13 @@ mod content {
    impl<M> SerializeTupleVariantAsMapValue<M> {
        pub fn new(map: M, name: &'static str, len: usize) -> Self {
            SerializeTupleVariantAsMapValue {
-                map,
-                name,
+                map: map,
+                name: name,
                fields: Vec::with_capacity(len),
            }
        }
    }

-    #[cfg_attr(not(no_diagnostic_namespace), diagnostic::do_not_recommend)]
    impl<M> ser::SerializeTupleVariant for SerializeTupleVariantAsMapValue<M>
    where
        M: ser::SerializeMap,
@@ -375,17 +364,17 @@ mod content {
        type Ok = M::Ok;
        type Error = M::Error;

-        fn serialize_field<T>(&mut self, value: &T) -> Result<(), M::Error>
+        fn serialize_field<T: ?Sized>(&mut self, value: &T) -> Result<(), M::Error>
        where
-            T: ?Sized + Serialize,
+            T: Serialize,
        {
-            let value = tri!(value.serialize(ContentSerializer::<M::Error>::new()));
+            let value = try!(value.serialize(ContentSerializer::<M::Error>::new()));
            self.fields.push(value);
            Ok(())
        }

        fn end(mut self) -> Result<M::Ok, M::Error> {
-            tri!(self
+            try!(self
                .map
                .serialize_value(&Content::TupleStruct(self.name, self.fields)));
            self.map.end()
@@ -401,14 +390,13 @@ mod content {
    impl<M> SerializeStructVariantAsMapValue<M> {
        pub fn new(map: M, name: &'static str, len: usize) -> Self {
            SerializeStructVariantAsMapValue {
-                map,
-                name,
+                map: map,
+                name: name,
                fields: Vec::with_capacity(len),
            }
        }
    }

-    #[cfg_attr(not(no_diagnostic_namespace), diagnostic::do_not_recommend)]
    impl<M> ser::SerializeStructVariant for SerializeStructVariantAsMapValue<M>
    where
        M: ser::SerializeMap,
@@ -416,17 +404,21 @@ mod content {
        type Ok = M::Ok;
        type Error = M::Error;

-        fn serialize_field<T>(&mut self, key: &'static str, value: &T) -> Result<(), M::Error>
+        fn serialize_field<T: ?Sized>(
+            &mut self,
+            key: &'static str,
+            value: &T,
+        ) -> Result<(), M::Error>
        where
-            T: ?Sized + Serialize,
+            T: Serialize,
        {
-            let value = tri!(value.serialize(ContentSerializer::<M::Error>::new()));
+            let value = try!(value.serialize(ContentSerializer::<M::Error>::new()));
            self.fields.push((key, value));
            Ok(())
        }

        fn end(mut self) -> Result<M::Ok, M::Error> {
-            tri!(self
+            try!(self
                .map
                .serialize_value(&Content::Struct(self.name, self.fields)));
            self.map.end()
@@ -476,7 +468,6 @@ mod content {
        ),
    }

-    #[cfg_attr(not(no_diagnostic_namespace), diagnostic::do_not_recommend)]
    impl Serialize for Content {
        fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
        where
@@ -508,50 +499,50 @@ mod content {
                }
                Content::Seq(ref elements) => elements.serialize(serializer),
                Content::Tuple(ref elements) => {
-                    use crate::ser::SerializeTuple;
-                    let mut tuple = tri!(serializer.serialize_tuple(elements.len()));
+                    use ser::SerializeTuple;
+                    let mut tuple = try!(serializer.serialize_tuple(elements.len()));
                    for e in elements {
-                        tri!(tuple.serialize_element(e));
+                        try!(tuple.serialize_element(e));
                    }
                    tuple.end()
                }
                Content::TupleStruct(n, ref fields) => {
-                    use crate::ser::SerializeTupleStruct;
-                    let mut ts = tri!(serializer.serialize_tuple_struct(n, fields.len()));
+                    use ser::SerializeTupleStruct;
+                    let mut ts = try!(serializer.serialize_tuple_struct(n, fields.len()));
                    for f in fields {
-                        tri!(ts.serialize_field(f));
+                        try!(ts.serialize_field(f));
                    }
                    ts.end()
                }
                Content::TupleVariant(n, i, v, ref fields) => {
-                    use crate::ser::SerializeTupleVariant;
-                    let mut tv = tri!(serializer.serialize_tuple_variant(n, i, v, fields.len()));
+                    use ser::SerializeTupleVariant;
+                    let mut tv = try!(serializer.serialize_tuple_variant(n, i, v, fields.len()));
                    for f in fields {
-                        tri!(tv.serialize_field(f));
+                        try!(tv.serialize_field(f));
                    }
                    tv.end()
                }
                Content::Map(ref entries) => {
-                    use crate::ser::SerializeMap;
-                    let mut map = tri!(serializer.serialize_map(Some(entries.len())));
-                    for (k, v) in entries {
-                        tri!(map.serialize_entry(k, v));
+                    use ser::SerializeMap;
+                    let mut map = try!(serializer.serialize_map(Some(entries.len())));
+                    for &(ref k, ref v) in entries {
+                        try!(map.serialize_entry(k, v));
                    }
                    map.end()
                }
                Content::Struct(n, ref fields) => {
-                    use crate::ser::SerializeStruct;
-                    let mut s = tri!(serializer.serialize_struct(n, fields.len()));
+                    use ser::SerializeStruct;
+                    let mut s = try!(serializer.serialize_struct(n, fields.len()));
                    for &(k, ref v) in fields {
-                        tri!(s.serialize_field(k, v));
+                        try!(s.serialize_field(k, v));
                    }
                    s.end()
                }
                Content::StructVariant(n, i, v, ref fields) => {
-                    use crate::ser::SerializeStructVariant;
-                    let mut sv = tri!(serializer.serialize_struct_variant(n, i, v, fields.len()));
+                    use ser::SerializeStructVariant;
+                    let mut sv = try!(serializer.serialize_struct_variant(n, i, v, fields.len()));
                    for &(k, ref v) in fields {
-                        tri!(sv.serialize_field(k, v));
+                        try!(sv.serialize_field(k, v));
                    }
                    sv.end()
                }
@@ -569,7 +560,6 @@ mod content {
        }
    }

-    #[cfg_attr(not(no_diagnostic_namespace), diagnostic::do_not_recommend)]
    impl<E> Serializer for ContentSerializer<E>
    where
        E: ser::Error,
@@ -645,11 +635,11 @@ mod content {
            Ok(Content::None)
        }

-        fn serialize_some<T>(self, value: &T) -> Result<Content, E>
+        fn serialize_some<T: ?Sized>(self, value: &T) -> Result<Content, E>
        where
-            T: ?Sized + Serialize,
+            T: Serialize,
        {
-            Ok(Content::Some(Box::new(tri!(value.serialize(self)))))
+            Ok(Content::Some(Box::new(try!(value.serialize(self)))))
        }

        fn serialize_unit(self) -> Result<Content, E> {
@@ -669,17 +659,21 @@ mod content {
            Ok(Content::UnitVariant(name, variant_index, variant))
        }

-        fn serialize_newtype_struct<T>(self, name: &'static str, value: &T) -> Result<Content, E>
+        fn serialize_newtype_struct<T: ?Sized>(
+            self,
+            name: &'static str,
+            value: &T,
+        ) -> Result<Content, E>
        where
-            T: ?Sized + Serialize,
+            T: Serialize,
        {
            Ok(Content::NewtypeStruct(
                name,
-                Box::new(tri!(value.serialize(self))),
+                Box::new(try!(value.serialize(self))),
            ))
        }

-        fn serialize_newtype_variant<T>(
+        fn serialize_newtype_variant<T: ?Sized>(
            self,
            name: &'static str,
            variant_index: u32,
@@ -687,13 +681,13 @@ mod content {
            value: &T,
        ) -> Result<Content, E>
        where
-            T: ?Sized + Serialize,
+            T: Serialize,
        {
            Ok(Content::NewtypeVariant(
                name,
                variant_index,
                variant,
-                Box::new(tri!(value.serialize(self))),
+                Box::new(try!(value.serialize(self))),
            ))
        }

@@ -717,7 +711,7 @@ mod content {
            len: usize,
        ) -> Result<Self::SerializeTupleStruct, E> {
            Ok(SerializeTupleStruct {
-                name,
+                name: name,
                fields: Vec::with_capacity(len),
                error: PhantomData,
            })
@@ -731,9 +725,9 @@ mod content {
            len: usize,
        ) -> Result<Self::SerializeTupleVariant, E> {
            Ok(SerializeTupleVariant {
-                name,
-                variant_index,
-                variant,
+                name: name,
+                variant_index: variant_index,
+                variant: variant,
                fields: Vec::with_capacity(len),
                error: PhantomData,
            })
@@ -753,7 +747,7 @@ mod content {
            len: usize,
        ) -> Result<Self::SerializeStruct, E> {
            Ok(SerializeStruct {
-                name,
+                name: name,
                fields: Vec::with_capacity(len),
                error: PhantomData,
            })
@@ -767,9 +761,9 @@ mod content {
            len: usize,
        ) -> Result<Self::SerializeStructVariant, E> {
            Ok(SerializeStructVariant {
-                name,
-                variant_index,
-                variant,
+                name: name,
+                variant_index: variant_index,
+                variant: variant,
                fields: Vec::with_capacity(len),
                error: PhantomData,
            })
@@ -781,7 +775,6 @@ mod content {
        error: PhantomData<E>,
    }

-    #[cfg_attr(not(no_diagnostic_namespace), diagnostic::do_not_recommend)]
    impl<E> ser::SerializeSeq for SerializeSeq<E>
    where
        E: ser::Error,
@@ -789,11 +782,11 @@ mod content {
        type Ok = Content;
        type Error = E;

-        fn serialize_element<T>(&mut self, value: &T) -> Result<(), E>
+        fn serialize_element<T: ?Sized>(&mut self, value: &T) -> Result<(), E>
        where
-            T: ?Sized + Serialize,
+            T: Serialize,
        {
-            let value = tri!(value.serialize(ContentSerializer::<E>::new()));
+            let value = try!(value.serialize(ContentSerializer::<E>::new()));
            self.elements.push(value);
            Ok(())
        }
@@ -808,7 +801,6 @@ mod content {
        error: PhantomData<E>,
    }

-    #[cfg_attr(not(no_diagnostic_namespace), diagnostic::do_not_recommend)]
    impl<E> ser::SerializeTuple for SerializeTuple<E>
    where
        E: ser::Error,
@@ -816,11 +808,11 @@ mod content {
        type Ok = Content;
        type Error = E;

-        fn serialize_element<T>(&mut self, value: &T) -> Result<(), E>
+        fn serialize_element<T: ?Sized>(&mut self, value: &T) -> Result<(), E>
        where
-            T: ?Sized + Serialize,
+            T: Serialize,
        {
-            let value = tri!(value.serialize(ContentSerializer::<E>::new()));
+            let value = try!(value.serialize(ContentSerializer::<E>::new()));
            self.elements.push(value);
            Ok(())
        }
@@ -836,7 +828,6 @@ mod content {
        error: PhantomData<E>,
    }

-    #[cfg_attr(not(no_diagnostic_namespace), diagnostic::do_not_recommend)]
    impl<E> ser::SerializeTupleStruct for SerializeTupleStruct<E>
    where
        E: ser::Error,
@@ -844,11 +835,11 @@ mod content {
        type Ok = Content;
        type Error = E;

-        fn serialize_field<T>(&mut self, value: &T) -> Result<(), E>
+        fn serialize_field<T: ?Sized>(&mut self, value: &T) -> Result<(), E>
        where
-            T: ?Sized + Serialize,
+            T: Serialize,
        {
-            let value = tri!(value.serialize(ContentSerializer::<E>::new()));
+            let value = try!(value.serialize(ContentSerializer::<E>::new()));
            self.fields.push(value);
            Ok(())
        }
@@ -866,7 +857,6 @@ mod content {
        error: PhantomData<E>,
    }

-    #[cfg_attr(not(no_diagnostic_namespace), diagnostic::do_not_recommend)]
    impl<E> ser::SerializeTupleVariant for SerializeTupleVariant<E>
    where
        E: ser::Error,
@@ -874,11 +864,11 @@ mod content {
        type Ok = Content;
        type Error = E;

-        fn serialize_field<T>(&mut self, value: &T) -> Result<(), E>
+        fn serialize_field<T: ?Sized>(&mut self, value: &T) -> Result<(), E>
        where
-            T: ?Sized + Serialize,
+            T: Serialize,
        {
-            let value = tri!(value.serialize(ContentSerializer::<E>::new()));
+            let value = try!(value.serialize(ContentSerializer::<E>::new()));
            self.fields.push(value);
            Ok(())
        }
@@ -899,7 +889,6 @@ mod content {
        error: PhantomData<E>,
    }

-    #[cfg_attr(not(no_diagnostic_namespace), diagnostic::do_not_recommend)]
    impl<E> ser::SerializeMap for SerializeMap<E>
    where
        E: ser::Error,
@@ -907,24 +896,24 @@ mod content {
        type Ok = Content;
        type Error = E;

-        fn serialize_key<T>(&mut self, key: &T) -> Result<(), E>
+        fn serialize_key<T: ?Sized>(&mut self, key: &T) -> Result<(), E>
        where
-            T: ?Sized + Serialize,
+            T: Serialize,
        {
-            let key = tri!(key.serialize(ContentSerializer::<E>::new()));
+            let key = try!(key.serialize(ContentSerializer::<E>::new()));
            self.key = Some(key);
            Ok(())
        }

-        fn serialize_value<T>(&mut self, value: &T) -> Result<(), E>
+        fn serialize_value<T: ?Sized>(&mut self, value: &T) -> Result<(), E>
        where
-            T: ?Sized + Serialize,
+            T: Serialize,
        {
            let key = self
                .key
                .take()
                .expect("serialize_value called before serialize_key");
-            let value = tri!(value.serialize(ContentSerializer::<E>::new()));
+            let value = try!(value.serialize(ContentSerializer::<E>::new()));
            self.entries.push((key, value));
            Ok(())
        }
@@ -933,13 +922,13 @@ mod content {
            Ok(Content::Map(self.entries))
        }

-        fn serialize_entry<K, V>(&mut self, key: &K, value: &V) -> Result<(), E>
+        fn serialize_entry<K: ?Sized, V: ?Sized>(&mut self, key: &K, value: &V) -> Result<(), E>
        where
-            K: ?Sized + Serialize,
-            V: ?Sized + Serialize,
+            K: Serialize,
+            V: Serialize,
        {
-            let key = tri!(key.serialize(ContentSerializer::<E>::new()));
-            let value = tri!(value.serialize(ContentSerializer::<E>::new()));
+            let key = try!(key.serialize(ContentSerializer::<E>::new()));
+            let value = try!(value.serialize(ContentSerializer::<E>::new()));
            self.entries.push((key, value));
            Ok(())
        }
@@ -951,7 +940,6 @@ mod content {
        error: PhantomData<E>,
    }

-    #[cfg_attr(not(no_diagnostic_namespace), diagnostic::do_not_recommend)]
    impl<E> ser::SerializeStruct for SerializeStruct<E>
    where
        E: ser::Error,
@@ -959,11 +947,11 @@ mod content {
        type Ok = Content;
        type Error = E;

-        fn serialize_field<T>(&mut self, key: &'static str, value: &T) -> Result<(), E>
+        fn serialize_field<T: ?Sized>(&mut self, key: &'static str, value: &T) -> Result<(), E>
        where
-            T: ?Sized + Serialize,
+            T: Serialize,
        {
-            let value = tri!(value.serialize(ContentSerializer::<E>::new()));
+            let value = try!(value.serialize(ContentSerializer::<E>::new()));
            self.fields.push((key, value));
            Ok(())
        }
@@ -981,7 +969,6 @@ mod content {
        error: PhantomData<E>,
    }

-    #[cfg_attr(not(no_diagnostic_namespace), diagnostic::do_not_recommend)]
    impl<E> ser::SerializeStructVariant for SerializeStructVariant<E>
    where
        E: ser::Error,
@@ -989,11 +976,11 @@ mod content {
        type Ok = Content;
        type Error = E;

-        fn serialize_field<T>(&mut self, key: &'static str, value: &T) -> Result<(), E>
+        fn serialize_field<T: ?Sized>(&mut self, key: &'static str, value: &T) -> Result<(), E>
        where
-            T: ?Sized + Serialize,
+            T: Serialize,
        {
-            let value = tri!(value.serialize(ContentSerializer::<E>::new()));
+            let value = try!(value.serialize(ContentSerializer::<E>::new()));
            self.fields.push((key, value));
            Ok(())
        }
@@ -1026,7 +1013,6 @@ where
 }

 #[cfg(any(feature = "std", feature = "alloc"))]
-#[cfg_attr(not(no_diagnostic_namespace), diagnostic::do_not_recommend)]
 impl<'a, M> Serializer for FlatMapSerializer<'a, M>
 where
    M: SerializeMap + 'a,
@@ -1039,7 +1025,7 @@ where
    type SerializeTupleStruct = Impossible<Self::Ok, M::Error>;
    type SerializeMap = FlatMapSerializeMap<'a, M>;
    type SerializeStruct = FlatMapSerializeStruct<'a, M>;
-    type SerializeTupleVariant = FlatMapSerializeTupleVariantAsMapValue<'a, M>;
+    type SerializeTupleVariant = Impossible<Self::Ok, M::Error>;
    type SerializeStructVariant = FlatMapSerializeStructVariantAsMapValue<'a, M>;

    fn serialize_bool(self, _: bool) -> Result<Self::Ok, Self::Error> {
@@ -1102,9 +1088,9 @@ where
        Ok(())
    }

-    fn serialize_some<T>(self, value: &T) -> Result<Self::Ok, Self::Error>
+    fn serialize_some<T: ?Sized>(self, value: &T) -> Result<Self::Ok, Self::Error>
    where
-        T: ?Sized + Serialize,
+        T: Serialize,
    {
        value.serialize(self)
    }
@@ -1114,30 +1100,30 @@ where
    }

    fn serialize_unit_struct(self, _: &'static str) -> Result<Self::Ok, Self::Error> {
-        Ok(())
+        Err(Self::bad_type(Unsupported::UnitStruct))
    }

    fn serialize_unit_variant(
        self,
        _: &'static str,
        _: u32,
-        variant: &'static str,
+        _: &'static str,
    ) -> Result<Self::Ok, Self::Error> {
-        self.0.serialize_entry(variant, &())
+        Err(Self::bad_type(Unsupported::Enum))
    }

-    fn serialize_newtype_struct<T>(
+    fn serialize_newtype_struct<T: ?Sized>(
        self,
        _: &'static str,
        value: &T,
    ) -> Result<Self::Ok, Self::Error>
    where
-        T: ?Sized + Serialize,
+        T: Serialize,
    {
        value.serialize(self)
    }

-    fn serialize_newtype_variant<T>(
+    fn serialize_newtype_variant<T: ?Sized>(
        self,
        _: &'static str,
        _: u32,
@@ -1145,9 +1131,10 @@ where
        value: &T,
    ) -> Result<Self::Ok, Self::Error>
    where
-        T: ?Sized + Serialize,
+        T: Serialize,
    {
-        self.0.serialize_entry(variant, value)
+        try!(self.0.serialize_key(variant));
+        self.0.serialize_value(value)
    }

    fn serialize_seq(self, _: Option<usize>) -> Result<Self::SerializeSeq, Self::Error> {
@@ -1170,11 +1157,10 @@ where
        self,
        _: &'static str,
        _: u32,
-        variant: &'static str,
+        _: &'static str,
        _: usize,
    ) -> Result<Self::SerializeTupleVariant, Self::Error> {
-        tri!(self.0.serialize_key(variant));
-        Ok(FlatMapSerializeTupleVariantAsMapValue::new(self.0))
+        Err(Self::bad_type(Unsupported::Enum))
    }

    fn serialize_map(self, _: Option<usize>) -> Result<Self::SerializeMap, Self::Error> {
@@ -1196,7 +1182,7 @@ where
        inner_variant: &'static str,
        _: usize,
    ) -> Result<Self::SerializeStructVariant, Self::Error> {
-        tri!(self.0.serialize_key(inner_variant));
+        try!(self.0.serialize_key(inner_variant));
        Ok(FlatMapSerializeStructVariantAsMapValue::new(
            self.0,
            inner_variant,
@@ -1208,7 +1194,6 @@ where
 pub struct FlatMapSerializeMap<'a, M: 'a>(&'a mut M);

 #[cfg(any(feature = "std", feature = "alloc"))]
-#[cfg_attr(not(no_diagnostic_namespace), diagnostic::do_not_recommend)]
 impl<'a, M> ser::SerializeMap for FlatMapSerializeMap<'a, M>
 where
    M: SerializeMap + 'a,
@@ -1216,24 +1201,28 @@ where
    type Ok = ();
    type Error = M::Error;

-    fn serialize_key<T>(&mut self, key: &T) -> Result<(), Self::Error>
+    fn serialize_key<T: ?Sized>(&mut self, key: &T) -> Result<(), Self::Error>
    where
-        T: ?Sized + Serialize,
+        T: Serialize,
    {
        self.0.serialize_key(key)
    }

-    fn serialize_value<T>(&mut self, value: &T) -> Result<(), Self::Error>
+    fn serialize_value<T: ?Sized>(&mut self, value: &T) -> Result<(), Self::Error>
    where
-        T: ?Sized + Serialize,
+        T: Serialize,
    {
        self.0.serialize_value(value)
    }

-    fn serialize_entry<K, V>(&mut self, key: &K, value: &V) -> Result<(), Self::Error>
+    fn serialize_entry<K: ?Sized, V: ?Sized>(
+        &mut self,
+        key: &K,
+        value: &V,
+    ) -> Result<(), Self::Error>
    where
-        K: ?Sized + Serialize,
-        V: ?Sized + Serialize,
+        K: Serialize,
+        V: Serialize,
    {
        self.0.serialize_entry(key, value)
    }
@@ -1247,7 +1236,6 @@ where
 pub struct FlatMapSerializeStruct<'a, M: 'a>(&'a mut M);

 #[cfg(any(feature = "std", feature = "alloc"))]
-#[cfg_attr(not(no_diagnostic_namespace), diagnostic::do_not_recommend)]
 impl<'a, M> ser::SerializeStruct for FlatMapSerializeStruct<'a, M>
 where
    M: SerializeMap + 'a,
@@ -1255,9 +1243,13 @@ where
    type Ok = ();
    type Error = M::Error;

-    fn serialize_field<T>(&mut self, key: &'static str, value: &T) -> Result<(), Self::Error>
+    fn serialize_field<T: ?Sized>(
+        &mut self,
+        key: &'static str,
+        value: &T,
+    ) -> Result<(), Self::Error>
    where
-        T: ?Sized + Serialize,
+        T: Serialize,
    {
        self.0.serialize_entry(key, value)
    }
@@ -1267,53 +1259,6 @@ where
    }
 }

-////////////////////////////////////////////////////////////////////////////////////////////////////
-
-#[cfg(any(feature = "std", feature = "alloc"))]
-pub struct FlatMapSerializeTupleVariantAsMapValue<'a, M: 'a> {
-    map: &'a mut M,
-    fields: Vec<Content>,
-}
-
-#[cfg(any(feature = "std", feature = "alloc"))]
-impl<'a, M> FlatMapSerializeTupleVariantAsMapValue<'a, M>
-where
-    M: SerializeMap + 'a,
-{
-    fn new(map: &'a mut M) -> Self {
-        FlatMapSerializeTupleVariantAsMapValue {
-            map,
-            fields: Vec::new(),
-        }
-    }
-}
-
-#[cfg(any(feature = "std", feature = "alloc"))]
-#[cfg_attr(not(no_diagnostic_namespace), diagnostic::do_not_recommend)]
-impl<'a, M> ser::SerializeTupleVariant for FlatMapSerializeTupleVariantAsMapValue<'a, M>
-where
-    M: SerializeMap + 'a,
-{
-    type Ok = ();
-    type Error = M::Error;
-
-    fn serialize_field<T>(&mut self, value: &T) -> Result<(), Self::Error>
-    where
-        T: ?Sized + Serialize,
-    {
-        let value = tri!(value.serialize(ContentSerializer::<M::Error>::new()));
-        self.fields.push(value);
-        Ok(())
-    }
-
-    fn end(self) -> Result<(), Self::Error> {
-        tri!(self.map.serialize_value(&Content::Seq(self.fields)));
-        Ok(())
-    }
-}
-
-////////////////////////////////////////////////////////////////////////////////////////////////////
-
 #[cfg(any(feature = "std", feature = "alloc"))]
 pub struct FlatMapSerializeStructVariantAsMapValue<'a, M: 'a> {
    map: &'a mut M,
@@ -1328,15 +1273,14 @@ where
 {
    fn new(map: &'a mut M, name: &'static str) -> FlatMapSerializeStructVariantAsMapValue<'a, M> {
        FlatMapSerializeStructVariantAsMapValue {
-            map,
-            name,
+            map: map,
+            name: name,
            fields: Vec::new(),
        }
    }
 }

 #[cfg(any(feature = "std", feature = "alloc"))]
-#[cfg_attr(not(no_diagnostic_namespace), diagnostic::do_not_recommend)]
 impl<'a, M> ser::SerializeStructVariant for FlatMapSerializeStructVariantAsMapValue<'a, M>
 where
    M: SerializeMap + 'a,
@@ -1344,49 +1288,23 @@ where
    type Ok = ();
    type Error = M::Error;

-    fn serialize_field<T>(&mut self, key: &'static str, value: &T) -> Result<(), Self::Error>
+    fn serialize_field<T: ?Sized>(
+        &mut self,
+        key: &'static str,
+        value: &T,
+    ) -> Result<(), Self::Error>
    where
-        T: ?Sized + Serialize,
+        T: Serialize,
    {
-        let value = tri!(value.serialize(ContentSerializer::<M::Error>::new()));
+        let value = try!(value.serialize(ContentSerializer::<M::Error>::new()));
        self.fields.push((key, value));
        Ok(())
    }

    fn end(self) -> Result<(), Self::Error> {
-        tri!(self
+        try!(self
            .map
            .serialize_value(&Content::Struct(self.name, self.fields)));
        Ok(())
    }
 }
-
-pub struct AdjacentlyTaggedEnumVariant {
-    pub enum_name: &'static str,
-    pub variant_index: u32,
-    pub variant_name: &'static str,
-}
-
-#[cfg_attr(not(no_diagnostic_namespace), diagnostic::do_not_recommend)]
-impl Serialize for AdjacentlyTaggedEnumVariant {
-    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
-    where
-        S: Serializer,
-    {
-        serializer.serialize_unit_variant(self.enum_name, self.variant_index, self.variant_name)
-    }
-}
-
-// Error when Serialize for a non_exhaustive remote enum encounters a variant
-// that is not recognized.
-pub struct CannotSerializeVariant<T>(pub T);
-
-#[cfg_attr(not(no_diagnostic_namespace), diagnostic::do_not_recommend)]
-impl<T> Display for CannotSerializeVariant<T>
-where
-    T: Debug,
-{
-    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
-        write!(formatter, "enum variant cannot be serialized: {:?}", self.0)
-    }
-}
@@ -0,0 +1,21 @@
+use lib::*;
+
+pub fn from_bounds<I>(iter: &I) -> Option<usize>
+where
+    I: Iterator,
+{
+    helper(iter.size_hint())
+}
+
+#[cfg(any(feature = "std", feature = "alloc"))]
+#[inline]
+pub fn cautious(hint: Option<usize>) -> usize {
+    cmp::min(hint.unwrap_or(0), 4096)
+}
+
+fn helper(bounds: (usize, Option<usize>)) -> Option<usize> {
+    match bounds {
+        (lower, Some(upper)) if lower == upper => Some(upper),
+        _ => None,
+    }
+}
@@ -1,6 +1,5 @@
-use crate::lib::*;
-
-use crate::ser::{Error, Impossible, Serialize, Serializer};
+use lib::*;
+use ser::{Error, Impossible, Serialize, Serializer};

 impl Error for fmt::Error {
    fn custom<T: Display>(_msg: T) -> Self {
@@ -18,9 +17,8 @@ macro_rules! fmt_primitives {
    };
 }

-/// ```edition2021
-/// use serde::ser::Serialize;
-/// use serde_derive::Serialize;
+/// ```edition2018
+/// use serde::Serialize;
 /// use std::fmt::{self, Display};
 ///
 /// #[derive(Serialize)]
@@ -36,7 +34,7 @@ macro_rules! fmt_primitives {
 ///     }
 /// }
 /// ```
-impl<'a> Serializer for &mut fmt::Formatter<'a> {
+impl<'a, 'b> Serializer for &'a mut fmt::Formatter<'b> {
    type Ok = ();
    type Error = fmt::Error;
    type SerializeSeq = Impossible<(), fmt::Error>;
@@ -53,12 +51,10 @@ impl<'a> Serializer for &mut fmt::Formatter<'a> {
        serialize_i16: i16,
        serialize_i32: i32,
        serialize_i64: i64,
-        serialize_i128: i128,
        serialize_u8: u8,
        serialize_u16: u16,
        serialize_u32: u32,
        serialize_u64: u64,
-        serialize_u128: u128,
        serialize_f32: f32,
        serialize_f64: f64,
        serialize_char: char,
@@ -66,6 +62,13 @@ impl<'a> Serializer for &mut fmt::Formatter<'a> {
        serialize_unit_struct: &'static str,
    }

+    serde_if_integer128! {
+        fmt_primitives! {
+            serialize_i128: i128,
+            serialize_u128: u128,
+        }
+    }
+
    fn serialize_unit_variant(
        self,
        _name: &'static str,
@@ -75,9 +78,9 @@ impl<'a> Serializer for &mut fmt::Formatter<'a> {
        Display::fmt(variant, self)
    }

-    fn serialize_newtype_struct<T>(self, _name: &'static str, value: &T) -> fmt::Result
+    fn serialize_newtype_struct<T: ?Sized>(self, _name: &'static str, value: &T) -> fmt::Result
    where
-        T: ?Sized + Serialize,
+        T: Serialize,
    {
        Serialize::serialize(value, self)
    }
@@ -90,9 +93,9 @@ impl<'a> Serializer for &mut fmt::Formatter<'a> {
        Err(fmt::Error)
    }

-    fn serialize_some<T>(self, _value: &T) -> fmt::Result
+    fn serialize_some<T: ?Sized>(self, _value: &T) -> fmt::Result
    where
-        T: ?Sized + Serialize,
+        T: Serialize,
    {
        Err(fmt::Error)
    }
@@ -101,7 +104,7 @@ impl<'a> Serializer for &mut fmt::Formatter<'a> {
        Err(fmt::Error)
    }

-    fn serialize_newtype_variant<T>(
+    fn serialize_newtype_variant<T: ?Sized>(
        self,
        _name: &'static str,
        _variant_index: u32,
@@ -109,7 +112,7 @@ impl<'a> Serializer for &mut fmt::Formatter<'a> {
        _value: &T,
    ) -> fmt::Result
    where
-        T: ?Sized + Serialize,
+        T: Serialize,
    {
        Err(fmt::Error)
    }
@@ -162,9 +165,9 @@ impl<'a> Serializer for &mut fmt::Formatter<'a> {
        Err(fmt::Error)
    }

-    fn collect_str<T>(self, value: &T) -> fmt::Result
+    fn collect_str<T: ?Sized>(self, value: &T) -> fmt::Result
    where
-        T: ?Sized + Display,
+        T: Display,
    {
        Display::fmt(value, self)
    }
@@ -1,6 +1,6 @@
-use crate::lib::*;
+use lib::*;

-use crate::ser::{Error, Serialize, SerializeTuple, Serializer};
+use ser::{Error, Serialize, SerializeTuple, Serializer};

 ////////////////////////////////////////////////////////////////////////////////

@@ -24,17 +24,20 @@ primitive_impl!(i8, serialize_i8);
 primitive_impl!(i16, serialize_i16);
 primitive_impl!(i32, serialize_i32);
 primitive_impl!(i64, serialize_i64);
-primitive_impl!(i128, serialize_i128);
 primitive_impl!(usize, serialize_u64 as u64);
 primitive_impl!(u8, serialize_u8);
 primitive_impl!(u16, serialize_u16);
 primitive_impl!(u32, serialize_u32);
 primitive_impl!(u64, serialize_u64);
-primitive_impl!(u128, serialize_u128);
 primitive_impl!(f32, serialize_f32);
 primitive_impl!(f64, serialize_f64);
 primitive_impl!(char, serialize_char);

+serde_if_integer128! {
+    primitive_impl!(i128, serialize_i128);
+    primitive_impl!(u128, serialize_u128);
+}
+
 ////////////////////////////////////////////////////////////////////////////////

 impl Serialize for str {
@@ -48,7 +51,6 @@ impl Serialize for str {
 }

 #[cfg(any(feature = "std", feature = "alloc"))]
-#[cfg_attr(docsrs, doc(cfg(any(feature = "std", feature = "alloc"))))]
 impl Serialize for String {
    #[inline]
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
@@ -70,8 +72,7 @@ impl<'a> Serialize for fmt::Arguments<'a> {

 ////////////////////////////////////////////////////////////////////////////////

-#[cfg(any(feature = "std", not(no_core_cstr)))]
-#[cfg_attr(docsrs, doc(cfg(feature = "std")))]
+#[cfg(feature = "std")]
 impl Serialize for CStr {
    #[inline]
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
@@ -82,8 +83,7 @@ impl Serialize for CStr {
    }
 }

-#[cfg(any(feature = "std", all(not(no_core_cstr), feature = "alloc")))]
-#[cfg_attr(docsrs, doc(cfg(any(feature = "std", feature = "alloc"))))]
+#[cfg(feature = "std")]
 impl Serialize for CString {
    #[inline]
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
@@ -114,10 +114,7 @@ where

 ////////////////////////////////////////////////////////////////////////////////

-impl<T> Serialize for PhantomData<T>
-where
-    T: ?Sized,
-{
+impl<T: ?Sized> Serialize for PhantomData<T> {
    #[inline]
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
    where
@@ -136,7 +133,7 @@ impl<T> Serialize for [T; 0] {
    where
        S: Serializer,
    {
-        tri!(serializer.serialize_tuple(0)).end()
+        try!(serializer.serialize_tuple(0)).end()
    }
 }

@@ -152,9 +149,9 @@ macro_rules! array_impls {
                where
                    S: Serializer,
                {
-                    let mut seq = tri!(serializer.serialize_tuple($len));
+                    let mut seq = try!(serializer.serialize_tuple($len));
                    for e in self {
-                        tri!(seq.serialize_element(e));
+                        try!(seq.serialize_element(e));
                    }
                    seq.end()
                }
@@ -185,15 +182,13 @@ where
    }
 }

+#[cfg(any(feature = "std", feature = "alloc"))]
 macro_rules! seq_impl {
-    (
-        $(#[$attr:meta])*
-        $ty:ident <T $(, $typaram:ident : $bound:ident)*>
-    ) => {
-        $(#[$attr])*
+    ($ty:ident < T $(: $tbound1:ident $(+ $tbound2:ident)*)* $(, $typaram:ident : $bound:ident)* >) => {
        impl<T $(, $typaram)*> Serialize for $ty<T $(, $typaram)*>
        where
-            T: Serialize,
+            T: Serialize $(+ $tbound1 $(+ $tbound2)*)*,
+            $($typaram: $bound,)*
        {
            #[inline]
            fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
@@ -206,41 +201,23 @@ macro_rules! seq_impl {
    }
 }

-seq_impl! {
-    #[cfg(any(feature = "std", feature = "alloc"))]
-    #[cfg_attr(docsrs, doc(cfg(any(feature = "std", feature = "alloc"))))]
-    BinaryHeap<T>
-}
+#[cfg(any(feature = "std", feature = "alloc"))]
+seq_impl!(BinaryHeap<T: Ord>);

-seq_impl! {
-    #[cfg(any(feature = "std", feature = "alloc"))]
-    #[cfg_attr(docsrs, doc(cfg(any(feature = "std", feature = "alloc"))))]
-    BTreeSet<T>
-}
+#[cfg(any(feature = "std", feature = "alloc"))]
+seq_impl!(BTreeSet<T: Ord>);

-seq_impl! {
-    #[cfg(all(feature = "std", not(target_os = "none")))]
-    #[cfg_attr(docsrs, doc(cfg(feature = "std")))]
-    HashSet<T, H: BuildHasher>
-}
+#[cfg(feature = "std")]
+seq_impl!(HashSet<T: Eq + Hash, H: BuildHasher>);

-seq_impl! {
-    #[cfg(any(feature = "std", feature = "alloc"))]
-    #[cfg_attr(docsrs, doc(cfg(any(feature = "std", feature = "alloc"))))]
-    LinkedList<T>
-}
+#[cfg(any(feature = "std", feature = "alloc"))]
+seq_impl!(LinkedList<T>);

-seq_impl! {
-    #[cfg(any(feature = "std", feature = "alloc"))]
-    #[cfg_attr(docsrs, doc(cfg(any(feature = "std", feature = "alloc"))))]
-    Vec<T>
-}
+#[cfg(any(feature = "std", feature = "alloc"))]
+seq_impl!(Vec<T>);

-seq_impl! {
-    #[cfg(any(feature = "std", feature = "alloc"))]
-    #[cfg_attr(docsrs, doc(cfg(any(feature = "std", feature = "alloc"))))]
-    VecDeque<T>
-}
+#[cfg(any(feature = "std", feature = "alloc"))]
+seq_impl!(VecDeque<T>);

 ////////////////////////////////////////////////////////////////////////////////

@@ -253,32 +230,16 @@ where
        S: Serializer,
    {
        use super::SerializeStruct;
-        let mut state = tri!(serializer.serialize_struct("Range", 2));
-        tri!(state.serialize_field("start", &self.start));
-        tri!(state.serialize_field("end", &self.end));
-        state.end()
-    }
-}
-
-////////////////////////////////////////////////////////////////////////////////
-
-impl<Idx> Serialize for RangeFrom<Idx>
-where
-    Idx: Serialize,
-{
-    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
-    where
-        S: Serializer,
-    {
-        use super::SerializeStruct;
-        let mut state = tri!(serializer.serialize_struct("RangeFrom", 1));
-        tri!(state.serialize_field("start", &self.start));
+        let mut state = try!(serializer.serialize_struct("Range", 2));
+        try!(state.serialize_field("start", &self.start));
+        try!(state.serialize_field("end", &self.end));
        state.end()
    }
 }

 ////////////////////////////////////////////////////////////////////////////////

+#[cfg(not(no_range_inclusive))]
 impl<Idx> Serialize for RangeInclusive<Idx>
 where
    Idx: Serialize,
@@ -288,32 +249,16 @@ where
        S: Serializer,
    {
        use super::SerializeStruct;
-        let mut state = tri!(serializer.serialize_struct("RangeInclusive", 2));
-        tri!(state.serialize_field("start", &self.start()));
-        tri!(state.serialize_field("end", &self.end()));
-        state.end()
-    }
-}
-
-////////////////////////////////////////////////////////////////////////////////
-
-impl<Idx> Serialize for RangeTo<Idx>
-where
-    Idx: Serialize,
-{
-    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
-    where
-        S: Serializer,
-    {
-        use super::SerializeStruct;
-        let mut state = tri!(serializer.serialize_struct("RangeTo", 1));
-        tri!(state.serialize_field("end", &self.end));
+        let mut state = try!(serializer.serialize_struct("RangeInclusive", 2));
+        try!(state.serialize_field("start", &self.start()));
+        try!(state.serialize_field("end", &self.end()));
        state.end()
    }
 }

 ////////////////////////////////////////////////////////////////////////////////

+#[cfg(any(not(no_ops_bound), all(feature = "std", not(no_collections_bound))))]
 impl<T> Serialize for Bound<T>
 where
    T: Serialize,
@@ -347,7 +292,6 @@ impl Serialize for () {
 }

 #[cfg(feature = "unstable")]
-#[cfg_attr(docsrs, doc(cfg(feature = "unstable")))]
 impl Serialize for ! {
    fn serialize<S>(&self, _serializer: S) -> Result<S::Ok, S::Error>
    where
@@ -362,46 +306,28 @@ impl Serialize for ! {
 macro_rules! tuple_impls {
    ($($len:expr => ($($n:tt $name:ident)+))+) => {
        $(
-            #[cfg_attr(docsrs, doc(hidden))]
            impl<$($name),+> Serialize for ($($name,)+)
            where
                $($name: Serialize,)+
            {
-                tuple_impl_body!($len => ($($n)+));
+                #[inline]
+                fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+                where
+                    S: Serializer,
+                {
+                    let mut tuple = try!(serializer.serialize_tuple($len));
+                    $(
+                        try!(tuple.serialize_element(&self.$n));
+                    )+
+                    tuple.end()
+                }
            }
        )+
-    };
-}
-
-macro_rules! tuple_impl_body {
-    ($len:expr => ($($n:tt)+)) => {
-        #[inline]
-        fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
-        where
-            S: Serializer,
-        {
-            let mut tuple = tri!(serializer.serialize_tuple($len));
-            $(
-                tri!(tuple.serialize_element(&self.$n));
-            )+
-            tuple.end()
-        }
-    };
-}
-
-#[cfg_attr(docsrs, doc(fake_variadic))]
-#[cfg_attr(
-    docsrs,
-    doc = "This trait is implemented for tuples up to 16 items long."
-)]
-impl<T> Serialize for (T,)
-where
-    T: Serialize,
-{
-    tuple_impl_body!(1 => (0));
+    }
 }

 tuple_impls! {
+    1 => (0 T0)
    2 => (0 T0 1 T1)
    3 => (0 T0 1 T1 2 T2)
    4 => (0 T0 1 T1 2 T2 3 T3)
@@ -421,16 +347,14 @@ tuple_impls! {

 ////////////////////////////////////////////////////////////////////////////////

+#[cfg(any(feature = "std", feature = "alloc"))]
 macro_rules! map_impl {
-    (
-        $(#[$attr:meta])*
-        $ty:ident <K $(: $kbound1:ident $(+ $kbound2:ident)*)*, V $(, $typaram:ident : $bound:ident)*>
-    ) => {
-        $(#[$attr])*
+    ($ty:ident < K $(: $kbound1:ident $(+ $kbound2:ident)*)*, V $(, $typaram:ident : $bound:ident)* >) => {
        impl<K, V $(, $typaram)*> Serialize for $ty<K, V $(, $typaram)*>
        where
-            K: Serialize,
+            K: Serialize $(+ $kbound1 $(+ $kbound2)*)*,
            V: Serialize,
+            $($typaram: $bound,)*
        {
            #[inline]
            fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
@@ -443,26 +367,20 @@ macro_rules! map_impl {
    }
 }

-map_impl! {
-    #[cfg(any(feature = "std", feature = "alloc"))]
-    #[cfg_attr(docsrs, doc(cfg(any(feature = "std", feature = "alloc"))))]
-    BTreeMap<K: Ord, V>
-}
+#[cfg(any(feature = "std", feature = "alloc"))]
+map_impl!(BTreeMap<K: Ord, V>);

-map_impl! {
-    #[cfg(all(feature = "std", not(target_os = "none")))]
-    #[cfg_attr(docsrs, doc(cfg(feature = "std")))]
-    HashMap<K: Eq + Hash, V, H: BuildHasher>
-}
+#[cfg(feature = "std")]
+map_impl!(HashMap<K: Eq + Hash, V, H: BuildHasher>);

 ////////////////////////////////////////////////////////////////////////////////

 macro_rules! deref_impl {
    (
-        $(#[$attr:meta])*
+        $(#[doc = $doc:tt])*
        <$($desc:tt)+
    ) => {
-        $(#[$attr])*
+        $(#[doc = $doc])*
        impl <$($desc)+ {
            #[inline]
            fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
@@ -475,20 +393,13 @@ macro_rules! deref_impl {
    };
 }

-deref_impl! {
-    <'a, T> Serialize for &'a T where T: ?Sized + Serialize
-}
+deref_impl!(<'a, T: ?Sized> Serialize for &'a T where T: Serialize);
+deref_impl!(<'a, T: ?Sized> Serialize for &'a mut T where T: Serialize);

-deref_impl! {
-    <'a, T> Serialize for &'a mut T where T: ?Sized + Serialize
-}
-
-deref_impl! {
-    #[cfg(any(feature = "std", feature = "alloc"))]
-    #[cfg_attr(docsrs, doc(cfg(any(feature = "std", feature = "alloc"))))]
-    <T> Serialize for Box<T> where T: ?Sized + Serialize
-}
+#[cfg(any(feature = "std", feature = "alloc"))]
+deref_impl!(<T: ?Sized> Serialize for Box<T> where T: Serialize);

+#[cfg(all(feature = "rc", any(feature = "std", feature = "alloc")))]
 deref_impl! {
    /// This impl requires the [`"rc"`] Cargo feature of Serde.
    ///
@@ -498,11 +409,10 @@ deref_impl! {
    /// repeated data.
    ///
    /// [`"rc"`]: https://serde.rs/feature-flags.html#-features-rc
-    #[cfg(all(feature = "rc", any(feature = "std", feature = "alloc")))]
-    #[cfg_attr(docsrs, doc(cfg(all(feature = "rc", any(feature = "std", feature = "alloc")))))]
-    <T> Serialize for Rc<T> where T: ?Sized + Serialize
+    <T: ?Sized> Serialize for Rc<T> where T: Serialize
 }

+#[cfg(all(feature = "rc", any(feature = "std", feature = "alloc")))]
 deref_impl! {
    /// This impl requires the [`"rc"`] Cargo feature of Serde.
    ///
@@ -512,16 +422,11 @@ deref_impl! {
    /// repeated data.
    ///
    /// [`"rc"`]: https://serde.rs/feature-flags.html#-features-rc
-    #[cfg(all(feature = "rc", any(feature = "std", feature = "alloc")))]
-    #[cfg_attr(docsrs, doc(cfg(all(feature = "rc", any(feature = "std", feature = "alloc")))))]
-    <T> Serialize for Arc<T> where T: ?Sized + Serialize
+    <T: ?Sized> Serialize for Arc<T> where T: Serialize
 }

-deref_impl! {
-    #[cfg(any(feature = "std", feature = "alloc"))]
-    #[cfg_attr(docsrs, doc(cfg(any(feature = "std", feature = "alloc"))))]
-    <'a, T> Serialize for Cow<'a, T> where T: ?Sized + Serialize + ToOwned
-}
+#[cfg(any(feature = "std", feature = "alloc"))]
+deref_impl!(<'a, T: ?Sized> Serialize for Cow<'a, T> where T: Serialize + ToOwned);

 ////////////////////////////////////////////////////////////////////////////////

@@ -529,13 +434,9 @@ deref_impl! {
 ///
 /// [`"rc"`]: https://serde.rs/feature-flags.html#-features-rc
 #[cfg(all(feature = "rc", any(feature = "std", feature = "alloc")))]
-#[cfg_attr(
-    docsrs,
-    doc(cfg(all(feature = "rc", any(feature = "std", feature = "alloc"))))
-)]
-impl<T> Serialize for RcWeak<T>
+impl<T: ?Sized> Serialize for RcWeak<T>
 where
-    T: ?Sized + Serialize,
+    T: Serialize,
 {
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
    where
@@ -549,13 +450,9 @@ where
 ///
 /// [`"rc"`]: https://serde.rs/feature-flags.html#-features-rc
 #[cfg(all(feature = "rc", any(feature = "std", feature = "alloc")))]
-#[cfg_attr(
-    docsrs,
-    doc(cfg(all(feature = "rc", any(feature = "std", feature = "alloc"))))
-)]
-impl<T> Serialize for ArcWeak<T>
+impl<T: ?Sized> Serialize for ArcWeak<T>
 where
-    T: ?Sized + Serialize,
+    T: Serialize,
 {
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
    where
@@ -568,8 +465,9 @@ where
 ////////////////////////////////////////////////////////////////////////////////

 macro_rules! nonzero_integers {
-    ($($T:ident,)+) => {
+    ( $( $T: ident, )+ ) => {
        $(
+            #[cfg(not(no_num_nonzero))]
            impl Serialize for num::$T {
                fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
                where
@@ -583,20 +481,35 @@ macro_rules! nonzero_integers {
 }

 nonzero_integers! {
-    NonZeroI8,
-    NonZeroI16,
-    NonZeroI32,
-    NonZeroI64,
-    NonZeroI128,
-    NonZeroIsize,
    NonZeroU8,
    NonZeroU16,
    NonZeroU32,
    NonZeroU64,
-    NonZeroU128,
    NonZeroUsize,
 }

+#[cfg(not(no_num_nonzero_signed))]
+nonzero_integers! {
+    NonZeroI8,
+    NonZeroI16,
+    NonZeroI32,
+    NonZeroI64,
+    NonZeroIsize,
+}
+
+// Currently 128-bit integers do not work on Emscripten targets so we need an
+// additional `#[cfg]`
+serde_if_integer128! {
+    nonzero_integers! {
+        NonZeroU128,
+    }
+
+    #[cfg(not(no_num_nonzero_signed))]
+    nonzero_integers! {
+        NonZeroI128,
+    }
+}
+
 impl<T> Serialize for Cell<T>
 where
    T: Serialize + Copy,
@@ -611,7 +524,7 @@ where

 impl<T> Serialize for RefCell<T>
 where
-    T: ?Sized + Serialize,
+    T: Serialize,
 {
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
    where
@@ -624,11 +537,10 @@ where
    }
 }

-#[cfg(all(feature = "std", not(target_os = "none")))]
-#[cfg_attr(docsrs, doc(cfg(feature = "std")))]
+#[cfg(feature = "std")]
 impl<T> Serialize for Mutex<T>
 where
-    T: ?Sized + Serialize,
+    T: Serialize,
 {
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
    where
@@ -641,11 +553,10 @@ where
    }
 }

-#[cfg(all(feature = "std", not(target_os = "none")))]
-#[cfg_attr(docsrs, doc(cfg(feature = "std")))]
+#[cfg(feature = "std")]
 impl<T> Serialize for RwLock<T>
 where
-    T: ?Sized + Serialize,
+    T: Serialize,
 {
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
    where
@@ -660,8 +571,6 @@ where

 ////////////////////////////////////////////////////////////////////////////////

-#[cfg(feature = "result")]
-#[cfg_attr(docsrs, doc(cfg(feature = "result")))]
 impl<T, E> Serialize for Result<T, E>
 where
    T: Serialize,
@@ -682,36 +591,35 @@ where

 ////////////////////////////////////////////////////////////////////////////////

+#[cfg(any(feature = "std", not(no_core_duration)))]
 impl Serialize for Duration {
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
    where
        S: Serializer,
    {
        use super::SerializeStruct;
-        let mut state = tri!(serializer.serialize_struct("Duration", 2));
-        tri!(state.serialize_field("secs", &self.as_secs()));
-        tri!(state.serialize_field("nanos", &self.subsec_nanos()));
+        let mut state = try!(serializer.serialize_struct("Duration", 2));
+        try!(state.serialize_field("secs", &self.as_secs()));
+        try!(state.serialize_field("nanos", &self.subsec_nanos()));
        state.end()
    }
 }

 ////////////////////////////////////////////////////////////////////////////////

-#[cfg(all(feature = "std", not(target_os = "none")))]
-#[cfg_attr(docsrs, doc(cfg(feature = "std")))]
+#[cfg(feature = "std")]
 impl Serialize for SystemTime {
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
    where
        S: Serializer,
    {
        use super::SerializeStruct;
-        let duration_since_epoch = match self.duration_since(UNIX_EPOCH) {
-            Ok(duration_since_epoch) => duration_since_epoch,
-            Err(_) => return Err(S::Error::custom("SystemTime must be later than UNIX_EPOCH")),
-        };
-        let mut state = tri!(serializer.serialize_struct("SystemTime", 2));
-        tri!(state.serialize_field("secs_since_epoch", &duration_since_epoch.as_secs()));
-        tri!(state.serialize_field("nanos_since_epoch", &duration_since_epoch.subsec_nanos()));
+        let duration_since_epoch = self
+            .duration_since(UNIX_EPOCH)
+            .map_err(|_| S::Error::custom("SystemTime must be later than UNIX_EPOCH"))?;
+        let mut state = try!(serializer.serialize_struct("SystemTime", 2));
+        try!(state.serialize_field("secs_since_epoch", &duration_since_epoch.as_secs()));
+        try!(state.serialize_field("nanos_since_epoch", &duration_since_epoch.subsec_nanos()));
        state.end()
    }
 }
@@ -722,17 +630,27 @@ impl Serialize for SystemTime {
 /// statically known to never have more than a constant `MAX_LEN` bytes.
 ///
 /// Panics if the `Display` impl tries to write more than `MAX_LEN` bytes.
-#[cfg(any(feature = "std", not(no_core_net)))]
+#[cfg(feature = "std")]
 macro_rules! serialize_display_bounded_length {
    ($value:expr, $max:expr, $serializer:expr) => {{
        let mut buffer = [0u8; $max];
-        let mut writer = crate::format::Buf::new(&mut buffer);
-        write!(&mut writer, "{}", $value).unwrap();
-        $serializer.serialize_str(writer.as_str())
+        let remaining_len = {
+            let mut remaining = &mut buffer[..];
+            write!(remaining, "{}", $value).unwrap();
+            remaining.len()
+        };
+        let written_len = buffer.len() - remaining_len;
+        let written = &buffer[..written_len];
+
+        // write! only provides fmt::Formatter to Display implementations, which
+        // has methods write_str and write_char but no method to write arbitrary
+        // bytes. Therefore `written` must be valid UTF-8.
+        let written_str = str::from_utf8(written).expect("must be valid UTF-8");
+        $serializer.serialize_str(written_str)
    }};
 }

-#[cfg(any(feature = "std", not(no_core_net)))]
+#[cfg(feature = "std")]
 impl Serialize for net::IpAddr {
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
    where
@@ -756,15 +674,15 @@ impl Serialize for net::IpAddr {
    }
 }

-#[cfg(any(feature = "std", not(no_core_net)))]
-const DEC_DIGITS_LUT: &[u8] = b"\
+#[cfg(feature = "std")]
+const DEC_DIGITS_LUT: &'static [u8] = b"\
      0001020304050607080910111213141516171819\
      2021222324252627282930313233343536373839\
      4041424344454647484950515253545556575859\
      6061626364656667686970717273747576777879\
      8081828384858687888990919293949596979899";

-#[cfg(any(feature = "std", not(no_core_net)))]
+#[cfg(feature = "std")]
 #[inline]
 fn format_u8(mut n: u8, out: &mut [u8]) -> usize {
    if n >= 100 {
@@ -785,7 +703,7 @@ fn format_u8(mut n: u8, out: &mut [u8]) -> usize {
    }
 }

-#[cfg(any(feature = "std", not(no_core_net)))]
+#[cfg(feature = "std")]
 #[test]
 fn test_format_u8() {
    let mut i = 0u8;
@@ -802,7 +720,7 @@ fn test_format_u8() {
    }
 }

-#[cfg(any(feature = "std", not(no_core_net)))]
+#[cfg(feature = "std")]
 impl Serialize for net::Ipv4Addr {
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
    where
@@ -817,16 +735,15 @@ impl Serialize for net::Ipv4Addr {
                // Skip over delimiters that we initialized buf with
                written += format_u8(*oct, &mut buf[written + 1..]) + 1;
            }
-            // Safety: We've only written ASCII bytes to the buffer, so it is valid UTF-8
-            let buf = unsafe { str::from_utf8_unchecked(&buf[..written]) };
-            serializer.serialize_str(buf)
+            // We've only written ASCII bytes to the buffer, so it is valid UTF-8
+            serializer.serialize_str(unsafe { str::from_utf8_unchecked(&buf[..written]) })
        } else {
            self.octets().serialize(serializer)
        }
    }
 }

-#[cfg(any(feature = "std", not(no_core_net)))]
+#[cfg(feature = "std")]
 impl Serialize for net::Ipv6Addr {
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
    where
@@ -842,7 +759,7 @@ impl Serialize for net::Ipv6Addr {
    }
 }

-#[cfg(any(feature = "std", not(no_core_net)))]
+#[cfg(feature = "std")]
 impl Serialize for net::SocketAddr {
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
    where
@@ -866,7 +783,7 @@ impl Serialize for net::SocketAddr {
    }
 }

-#[cfg(any(feature = "std", not(no_core_net)))]
+#[cfg(feature = "std")]
 impl Serialize for net::SocketAddrV4 {
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
    where
@@ -882,7 +799,7 @@ impl Serialize for net::SocketAddrV4 {
    }
 }

-#[cfg(any(feature = "std", not(no_core_net)))]
+#[cfg(feature = "std")]
 impl Serialize for net::SocketAddrV6 {
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
    where
@@ -903,8 +820,7 @@ impl Serialize for net::SocketAddrV6 {

 ////////////////////////////////////////////////////////////////////////////////

-#[cfg(all(feature = "std", not(target_os = "none")))]
-#[cfg_attr(docsrs, doc(cfg(feature = "std")))]
+#[cfg(feature = "std")]
 impl Serialize for Path {
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
    where
@@ -917,8 +833,7 @@ impl Serialize for Path {
    }
 }

-#[cfg(all(feature = "std", not(target_os = "none")))]
-#[cfg_attr(docsrs, doc(cfg(feature = "std")))]
+#[cfg(feature = "std")]
 impl Serialize for PathBuf {
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
    where
@@ -928,8 +843,7 @@ impl Serialize for PathBuf {
    }
 }

-#[cfg(all(feature = "std", not(target_os = "none"), any(unix, windows)))]
-#[cfg_attr(docsrs, doc(cfg(all(feature = "std", any(unix, windows)))))]
+#[cfg(all(feature = "std", any(unix, windows)))]
 impl Serialize for OsStr {
    #[cfg(unix)]
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
@@ -951,8 +865,7 @@ impl Serialize for OsStr {
    }
 }

-#[cfg(all(feature = "std", not(target_os = "none"), any(unix, windows)))]
-#[cfg_attr(docsrs, doc(cfg(all(feature = "std", any(unix, windows)))))]
+#[cfg(all(feature = "std", any(unix, windows)))]
 impl Serialize for OsString {
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
    where
@@ -977,20 +890,7 @@ where
    }
 }

-#[cfg(not(no_core_num_saturating))]
-impl<T> Serialize for Saturating<T>
-where
-    T: Serialize,
-{
-    #[inline]
-    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
-    where
-        S: Serializer,
-    {
-        self.0.serialize(serializer)
-    }
-}
-
+#[cfg(not(no_core_reverse))]
 impl<T> Serialize for Reverse<T>
 where
    T: Serialize,
@@ -1006,40 +906,31 @@ where

 ////////////////////////////////////////////////////////////////////////////////

-#[cfg(all(feature = "std", not(target_os = "none"), not(no_std_atomic)))]
+#[cfg(all(feature = "std", not(no_std_atomic)))]
 macro_rules! atomic_impl {
-    ($($ty:ident $size:expr)*) => {
+    ($($ty:ident)*) => {
        $(
-            #[cfg(any(no_target_has_atomic, target_has_atomic = $size))]
-            #[cfg_attr(docsrs, doc(cfg(all(feature = "std", target_has_atomic = $size))))]
            impl Serialize for $ty {
                fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
                where
                    S: Serializer,
                {
                    // Matches the atomic ordering used in libcore for the Debug impl
-                    self.load(Ordering::Relaxed).serialize(serializer)
+                    self.load(Ordering::SeqCst).serialize(serializer)
                }
            }
        )*
    }
 }

-#[cfg(all(feature = "std", not(target_os = "none"), not(no_std_atomic)))]
+#[cfg(all(feature = "std", not(no_std_atomic)))]
 atomic_impl! {
-    AtomicBool "8"
-    AtomicI8 "8"
-    AtomicI16 "16"
-    AtomicI32 "32"
-    AtomicIsize "ptr"
-    AtomicU8 "8"
-    AtomicU16 "16"
-    AtomicU32 "32"
-    AtomicUsize "ptr"
+    AtomicBool
+    AtomicI8 AtomicI16 AtomicI32 AtomicIsize
+    AtomicU8 AtomicU16 AtomicU32 AtomicUsize
 }

-#[cfg(all(feature = "std", not(target_os = "none"), not(no_std_atomic64)))]
+#[cfg(all(feature = "std", not(no_std_atomic64)))]
 atomic_impl! {
-    AtomicI64 "64"
-    AtomicU64 "64"
+    AtomicI64 AtomicU64
 }
@@ -1,8 +1,8 @@
 //! This module contains `Impossible` serializer and its implementations.

-use crate::lib::*;
+use lib::*;

-use crate::ser::{
+use ser::{
    self, Serialize, SerializeMap, SerializeSeq, SerializeStruct, SerializeStructVariant,
    SerializeTuple, SerializeTupleStruct, SerializeTupleVariant,
 };
@@ -15,9 +15,9 @@ use crate::ser::{
 /// [`SerializeTuple`], [`SerializeTupleStruct`], [`SerializeTupleVariant`],
 /// [`SerializeMap`], [`SerializeStruct`], and [`SerializeStructVariant`].
 ///
-/// ```edition2021
+/// ```edition2018
 /// # use serde::ser::{Serializer, Impossible};
-/// # use serde_core::__private::doc::Error;
+/// # use serde::__private::doc::Error;
 /// #
 /// # struct MySerializer;
 /// #
@@ -41,7 +41,7 @@ use crate::ser::{
 ///     }
 ///
 ///     /* other Serializer methods */
-/// #     serde_core::__serialize_unimplemented! {
+/// #     serde::__serialize_unimplemented! {
 /// #         bool i8 i16 i32 i64 u8 u16 u32 u64 f32 f64 char str bytes none some
 /// #         unit unit_struct unit_variant newtype_struct newtype_variant
 /// #         tuple tuple_struct tuple_variant map struct struct_variant
@@ -49,14 +49,14 @@ use crate::ser::{
 /// }
 /// ```
 ///
-/// [`Serializer`]: crate::Serializer
-/// [`SerializeSeq`]: crate::ser::SerializeSeq
-/// [`SerializeTuple`]: crate::ser::SerializeTuple
-/// [`SerializeTupleStruct`]: crate::ser::SerializeTupleStruct
-/// [`SerializeTupleVariant`]: crate::ser::SerializeTupleVariant
-/// [`SerializeMap`]: crate::ser::SerializeMap
-/// [`SerializeStruct`]: crate::ser::SerializeStruct
-/// [`SerializeStructVariant`]: crate::ser::SerializeStructVariant
+/// [`Serializer`]: trait.Serializer.html
+/// [`SerializeSeq`]: trait.SerializeSeq.html
+/// [`SerializeTuple`]: trait.SerializeTuple.html
+/// [`SerializeTupleStruct`]: trait.SerializeTupleStruct.html
+/// [`SerializeTupleVariant`]: trait.SerializeTupleVariant.html
+/// [`SerializeMap`]: trait.SerializeMap.html
+/// [`SerializeStruct`]: trait.SerializeStruct.html
+/// [`SerializeStructVariant`]: trait.SerializeStructVariant.html
 pub struct Impossible<Ok, Error> {
    void: Void,
    ok: PhantomData<Ok>,
@@ -72,9 +72,9 @@ where
    type Ok = Ok;
    type Error = Error;

-    fn serialize_element<T>(&mut self, value: &T) -> Result<(), Error>
+    fn serialize_element<T: ?Sized>(&mut self, value: &T) -> Result<(), Error>
    where
-        T: ?Sized + Serialize,
+        T: Serialize,
    {
        let _ = value;
        match self.void {}
@@ -92,9 +92,9 @@ where
    type Ok = Ok;
    type Error = Error;

-    fn serialize_element<T>(&mut self, value: &T) -> Result<(), Error>
+    fn serialize_element<T: ?Sized>(&mut self, value: &T) -> Result<(), Error>
    where
-        T: ?Sized + Serialize,
+        T: Serialize,
    {
        let _ = value;
        match self.void {}
@@ -112,9 +112,9 @@ where
    type Ok = Ok;
    type Error = Error;

-    fn serialize_field<T>(&mut self, value: &T) -> Result<(), Error>
+    fn serialize_field<T: ?Sized>(&mut self, value: &T) -> Result<(), Error>
    where
-        T: ?Sized + Serialize,
+        T: Serialize,
    {
        let _ = value;
        match self.void {}
@@ -132,9 +132,9 @@ where
    type Ok = Ok;
    type Error = Error;

-    fn serialize_field<T>(&mut self, value: &T) -> Result<(), Error>
+    fn serialize_field<T: ?Sized>(&mut self, value: &T) -> Result<(), Error>
    where
-        T: ?Sized + Serialize,
+        T: Serialize,
    {
        let _ = value;
        match self.void {}
@@ -152,17 +152,17 @@ where
    type Ok = Ok;
    type Error = Error;

-    fn serialize_key<T>(&mut self, key: &T) -> Result<(), Error>
+    fn serialize_key<T: ?Sized>(&mut self, key: &T) -> Result<(), Error>
    where
-        T: ?Sized + Serialize,
+        T: Serialize,
    {
        let _ = key;
        match self.void {}
    }

-    fn serialize_value<T>(&mut self, value: &T) -> Result<(), Error>
+    fn serialize_value<T: ?Sized>(&mut self, value: &T) -> Result<(), Error>
    where
-        T: ?Sized + Serialize,
+        T: Serialize,
    {
        let _ = value;
        match self.void {}
@@ -180,9 +180,9 @@ where
    type Ok = Ok;
    type Error = Error;

-    fn serialize_field<T>(&mut self, key: &'static str, value: &T) -> Result<(), Error>
+    fn serialize_field<T: ?Sized>(&mut self, key: &'static str, value: &T) -> Result<(), Error>
    where
-        T: ?Sized + Serialize,
+        T: Serialize,
    {
        let _ = key;
        let _ = value;
@@ -201,9 +201,9 @@ where
    type Ok = Ok;
    type Error = Error;

-    fn serialize_field<T>(&mut self, key: &'static str, value: &T) -> Result<(), Error>
+    fn serialize_field<T: ?Sized>(&mut self, key: &'static str, value: &T) -> Result<(), Error>
    where
-        T: ?Sized + Serialize,
+        T: Serialize,
    {
        let _ = key;
        let _ = value;
@@ -1,4 +1,4 @@
-use crate::lib::{Debug, Display};
+use lib::{Debug, Display};

 /// Either a re-export of std::error::Error or a new identical trait, depending
 /// on whether Serde's "std" feature is enabled.
@@ -9,7 +9,7 @@ use crate::lib::{Debug, Display};
 /// generally provide their error types with a `std::error::Error` impl
 /// directly:
 ///
-/// ```edition2021
+/// ```edition2018
 /// #[derive(Debug)]
 /// struct MySerError {...}
 ///
@@ -29,7 +29,7 @@ use crate::lib::{Debug, Display};
 /// std = ["serde/std"]
 /// ```
 ///
-/// ```edition2021
+/// ```edition2018
 /// #[cfg(feature = "std")]
 /// impl std::error::Error for MySerError {}
 /// ```
@@ -37,12 +37,12 @@ use crate::lib::{Debug, Display};
 /// ... or else provide the std Error impl unconditionally via Serde's
 /// re-export:
 ///
-/// ```edition2021
+/// ```edition2018
 /// impl serde::ser::StdError for MySerError {}
 /// ```
 pub trait Error: Debug + Display {
    /// The underlying cause of this error, if any.
-    fn source(&self) -> Option<&(dyn Error + 'static)> {
+    fn source(&self) -> Option<&(Error + 'static)> {
        None
    }
 }
@@ -1,70 +0,0 @@
-[package]
-name = "serde_core"
-version = "1.0.228"
-authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>", "David Tolnay <dtolnay@gmail.com>"]
-build = "build.rs"
-categories = ["encoding", "no-std", "no-std::no-alloc"]
-description = "Serde traits only, with no support for derive -- use the `serde` crate instead"
-documentation = "https://docs.rs/serde_core"
-edition = "2021"
-homepage = "https://serde.rs"
-keywords = ["serde", "serialization", "no_std"]
-license = "MIT OR Apache-2.0"
-repository = "https://github.com/serde-rs/serde"
-rust-version = "1.56"
-
-[dev-dependencies]
-serde = { version = "1", path = "../serde" }
-serde_derive = { version = "1", path = "../serde_derive" }
-
-[package.metadata.playground]
-features = ["rc", "result"]
-
-[package.metadata.docs.rs]
-features = ["rc", "result", "unstable"]
-targets = ["x86_64-unknown-linux-gnu"]
-rustdoc-args = [
-    "--generate-link-to-definition",
-    "--generate-macro-expansion",
-    "--extern-html-root-url=core=https://doc.rust-lang.org",
-    "--extern-html-root-url=alloc=https://doc.rust-lang.org",
-    "--extern-html-root-url=std=https://doc.rust-lang.org",
-]
-
-# This cfg cannot be enabled, but it still forces Cargo to keep serde_derive's
-# version in lockstep with serde's, even if someone depends on the two crates
-# separately with serde's "derive" feature disabled. Every serde_derive release
-# is compatible with exactly one serde release because the generated code
-# involves nonpublic APIs which are not bound by semver.
-[target.'cfg(any())'.dependencies]
-serde_derive = { version = "=1.0.228", path = "../serde_derive" }
-
-
-### FEATURES #################################################################
-
-[features]
-default = ["std", "result"]
-
-# Provide impls for common standard library types like Vec<T> and HashMap<K, V>.
-# Requires a dependency on the Rust standard library.
-std = []
-
-# Provide impls for types that require unstable functionality. For tracking and
-# discussion of unstable functionality please refer to this issue:
-#
-#    https://github.com/serde-rs/serde/issues/812
-unstable = []
-
-# Provide impls for types in the Rust core allocation and collections library
-# including String, Box<T>, Vec<T>, and Cow<T>. This is a subset of std but may
-# be enabled without depending on all of std.
-alloc = []
-
-# Opt into impls for Rc<T> and Arc<T>. Serializing and deserializing these types
-# does not preserve identity and may result in multiple copies of the same data.
-# Be sure that this is what you want before enabling this feature.
-rc = []
-
-# Provide impls for Result<T, E>. Convenient in some contexts but can lead to
-# confusion if ? or unwrap are used incautiously.
-result = []
@@ -1,28 +0,0 @@
-The `serde_core` crate contains Serde's trait definitions with **no support for
-#\[derive()\]**.
-
-In crates that derive an implementation of `Serialize` or `Deserialize`, you
-must depend on the [`serde`] crate, not `serde_core`.
-
-[`serde`]: https://crates.io/crates/serde
-
-In crates that handwrite implementations of Serde traits, or only use them as
-trait bounds, depending on `serde_core` is permitted. But `serde` re-exports all
-of these traits and can be used for this use case too. If in doubt, disregard
-`serde_core` and always use `serde`.
-
-Crates that depend on `serde_core` instead of `serde` are able to compile in
-parallel with `serde_derive` even when `serde`'s "derive" feature is turned on,
-as shown in the following build timings.
-
-<br>
-
-| When `serde_json` depends on `serde` |
-|---|
-| <img src="https://github.com/user-attachments/assets/78dc179c-6ab1-4059-928c-1474b0d9d0bb"> |
-
-<br>
-
-| When `serde_json` depends on `serde_core` |
-|---|
-| <img src="https://github.com/user-attachments/assets/6b6cff5e-3e45-4ac7-9db1-d99ee8b9f5f7"> |
@@ -1,113 +0,0 @@
-use std::env;
-use std::fs;
-use std::path::PathBuf;
-use std::process::Command;
-use std::str;
-
-const PRIVATE: &str = "\
-#[doc(hidden)]
-pub mod __private$$ {
-    #[doc(hidden)]
-    pub use crate::private::*;
-}
-";
-
-// The rustc-cfg strings below are *not* public API. Please let us know by
-// opening a GitHub issue if your build environment requires some way to enable
-// these cfgs other than by executing our build script.
-fn main() {
-    println!("cargo:rerun-if-changed=build.rs");
-
-    let out_dir = PathBuf::from(env::var_os("OUT_DIR").unwrap());
-    let patch_version = env::var("CARGO_PKG_VERSION_PATCH").unwrap();
-    let module = PRIVATE.replace("$$", &patch_version);
-    fs::write(out_dir.join("private.rs"), module).unwrap();
-
-    let minor = match rustc_minor_version() {
-        Some(minor) => minor,
-        None => return,
-    };
-
-    if minor >= 77 {
-        println!("cargo:rustc-check-cfg=cfg(if_docsrs_then_no_serde_core)");
-        println!("cargo:rustc-check-cfg=cfg(no_core_cstr)");
-        println!("cargo:rustc-check-cfg=cfg(no_core_error)");
-        println!("cargo:rustc-check-cfg=cfg(no_core_net)");
-        println!("cargo:rustc-check-cfg=cfg(no_core_num_saturating)");
-        println!("cargo:rustc-check-cfg=cfg(no_diagnostic_namespace)");
-        println!("cargo:rustc-check-cfg=cfg(no_serde_derive)");
-        println!("cargo:rustc-check-cfg=cfg(no_std_atomic)");
-        println!("cargo:rustc-check-cfg=cfg(no_std_atomic64)");
-        println!("cargo:rustc-check-cfg=cfg(no_target_has_atomic)");
-    }
-
-    let target = env::var("TARGET").unwrap();
-    let emscripten = target == "asmjs-unknown-emscripten" || target == "wasm32-unknown-emscripten";
-
-    // Support for #[cfg(target_has_atomic = "...")] stabilized in Rust 1.60.
-    if minor < 60 {
-        println!("cargo:rustc-cfg=no_target_has_atomic");
-        // Allowlist of archs that support std::sync::atomic module. This is
-        // based on rustc's compiler/rustc_target/src/spec/*.rs.
-        let has_atomic64 = target.starts_with("x86_64")
-            || target.starts_with("i686")
-            || target.starts_with("aarch64")
-            || target.starts_with("powerpc64")
-            || target.starts_with("sparc64")
-            || target.starts_with("mips64el")
-            || target.starts_with("riscv64");
-        let has_atomic32 = has_atomic64 || emscripten;
-        if minor < 34 || !has_atomic64 {
-            println!("cargo:rustc-cfg=no_std_atomic64");
-        }
-        if minor < 34 || !has_atomic32 {
-            println!("cargo:rustc-cfg=no_std_atomic");
-        }
-    }
-
-    // Support for core::ffi::CStr and alloc::ffi::CString stabilized in Rust 1.64.
-    // https://blog.rust-lang.org/2022/09/22/Rust-1.64.0.html#c-compatible-ffi-types-in-core-and-alloc
-    if minor < 64 {
-        println!("cargo:rustc-cfg=no_core_cstr");
-    }
-
-    // Current minimum supported version of serde_derive crate is Rust 1.68.
-    if minor < 68 {
-        println!("cargo:rustc-cfg=no_serde_derive");
-    }
-
-    // Support for core::num::Saturating and std::num::Saturating stabilized in Rust 1.74
-    // https://blog.rust-lang.org/2023/11/16/Rust-1.74.0.html#stabilized-apis
-    if minor < 74 {
-        println!("cargo:rustc-cfg=no_core_num_saturating");
-    }
-
-    // Support for core::net stabilized in Rust 1.77.
-    // https://blog.rust-lang.org/2024/03/21/Rust-1.77.0.html
-    if minor < 77 {
-        println!("cargo:rustc-cfg=no_core_net");
-    }
-
-    // Support for the `#[diagnostic]` tool attribute namespace
-    // https://blog.rust-lang.org/2024/05/02/Rust-1.78.0.html#diagnostic-attributes
-    if minor < 78 {
-        println!("cargo:rustc-cfg=no_diagnostic_namespace");
-    }
-
-    // The Error trait became available in core in 1.81.
-    // https://blog.rust-lang.org/2024/09/05/Rust-1.81.0.html#coreerrorerror
-    if minor < 81 {
-        println!("cargo:rustc-cfg=no_core_error");
-    }
-}
-
-fn rustc_minor_version() -> Option<u32> {
-    let rustc = env::var_os("RUSTC")?;
-    let output = Command::new(rustc).arg("--version").output().ok()?;
-    let version = str::from_utf8(&output.stdout).ok()?;
-    let mut pieces = version.split('.');
-    if pieces.next() != Some("rustc 1") {
-        return None;
-    }
-    pieces.next()?.parse().ok()
-}
@@ -1,205 +0,0 @@
-macro_rules! crate_root {
-    () => {
-        /// A facade around all the types we need from the `std`, `core`, and `alloc`
-        /// crates. This avoids elaborate import wrangling having to happen in every
-        /// module.
-        ///
-        /// NOTE: On targets where std is not available (target_os = "none", e.g. wasm32v1-none),
-        /// we always use core/alloc even if the "std" feature is enabled due to Cargo feature
-        /// unification. This is handled by checking `target_os = "none"` in all cfg conditions.
-        mod lib {
-            mod core {
-                // On wasm32v1-none (target_os = "none"), always use ::core even if std feature is enabled
-                // This handles Cargo feature unification where std gets enabled for no_std targets
-                #[cfg(any(not(feature = "std"), target_os = "none"))]
-                pub use ::core::*;
-                #[cfg(all(feature = "std", not(target_os = "none")))]
-                pub use ::std::*;
-            }
-
-            // Re-export the full prelude for wasm32v1-none and other no_std targets
-            // On target_os = "none", always use ::core::prelude even with std feature
-            #[cfg(any(not(feature = "std"), target_os = "none"))]
-            pub use ::core::prelude::rust_2021::*;
-            #[cfg(all(feature = "std", not(target_os = "none")))]
-            pub use ::std::prelude::rust_2021::*;
-
-            // Prelude items that may not be re-exported by glob import
-            #[cfg(any(not(feature = "std"), target_os = "none"))]
-            pub use ::core::option::Option::{self, None, Some};
-            #[cfg(any(not(feature = "std"), target_os = "none"))]
-            pub use ::core::result::Result::{self, Err, Ok};
-            #[cfg(all(feature = "std", not(target_os = "none")))]
-            pub use ::std::option::Option::{self, None, Some};
-            #[cfg(all(feature = "std", not(target_os = "none")))]
-            pub use ::std::result::Result::{self, Err, Ok};
-
-            pub use self::core::{f32, f64};
-            pub use self::core::{iter, num, str};
-
-            #[cfg(any(feature = "std", feature = "alloc"))]
-            pub use self::core::{cmp, mem};
-
-            pub use self::core::cell::{Cell, RefCell};
-            pub use self::core::cmp::Reverse;
-            pub use self::core::fmt::{self, Debug, Display, Write as FmtWrite};
-            pub use self::core::marker::{PhantomData, Sized};
-            pub use self::core::clone::Clone;
-            pub use self::core::marker::{Copy, Send, Sync, Unpin};
-            pub use self::core::default::Default;
-            pub use self::core::cmp::{Eq, Ord, PartialEq, PartialOrd};
-            pub use self::core::convert::{AsMut, AsRef, From, Into};
-            pub use self::core::iter::{
-                DoubleEndedIterator, ExactSizeIterator, Extend, IntoIterator, Iterator,
-            };
-            pub use self::core::ops::{Drop, Fn, FnMut, FnOnce};
-            pub use self::core::num::Wrapping;
-            pub use self::core::ops::{Bound, Range, RangeFrom, RangeInclusive, RangeTo};
-            pub use self::core::result;
-            pub use self::core::time::Duration;
-
-            // For alloc types: use alloc when std is not available OR on target_os = "none"
-            #[cfg(all(feature = "alloc", any(not(feature = "std"), target_os = "none")))]
-            pub use alloc::borrow::{Cow, ToOwned};
-            #[cfg(all(feature = "std", not(target_os = "none")))]
-            pub use std::borrow::{Cow, ToOwned};
-
-            #[cfg(all(feature = "alloc", any(not(feature = "std"), target_os = "none")))]
-            pub use alloc::string::{String, ToString};
-            #[cfg(all(feature = "std", not(target_os = "none")))]
-            pub use std::string::{String, ToString};
-
-            #[cfg(all(feature = "alloc", any(not(feature = "std"), target_os = "none")))]
-            pub use alloc::vec::Vec;
-            #[cfg(all(feature = "std", not(target_os = "none")))]
-            pub use std::vec::Vec;
-
-            #[cfg(all(feature = "alloc", any(not(feature = "std"), target_os = "none")))]
-            pub use alloc::boxed::Box;
-            #[cfg(all(feature = "std", not(target_os = "none")))]
-            pub use std::boxed::Box;
-
-            #[cfg(all(feature = "rc", feature = "alloc", any(not(feature = "std"), target_os = "none")))]
-            pub use alloc::rc::{Rc, Weak as RcWeak};
-            #[cfg(all(feature = "rc", feature = "std", not(target_os = "none")))]
-            pub use std::rc::{Rc, Weak as RcWeak};
-
-            #[cfg(all(feature = "rc", feature = "alloc", any(not(feature = "std"), target_os = "none")))]
-            pub use alloc::sync::{Arc, Weak as ArcWeak};
-            #[cfg(all(feature = "rc", feature = "std", not(target_os = "none")))]
-            pub use std::sync::{Arc, Weak as ArcWeak};
-
-            #[cfg(all(feature = "alloc", any(not(feature = "std"), target_os = "none")))]
-            pub use alloc::collections::{BTreeMap, BTreeSet, BinaryHeap, LinkedList, VecDeque};
-            #[cfg(all(feature = "std", not(target_os = "none")))]
-            pub use std::collections::{BTreeMap, BTreeSet, BinaryHeap, LinkedList, VecDeque};
-
-            #[cfg(all(not(no_core_cstr), any(not(feature = "std"), target_os = "none")))]
-            pub use self::core::ffi::CStr;
-            #[cfg(all(feature = "std", not(target_os = "none")))]
-            pub use std::ffi::CStr;
-
-            #[cfg(all(not(no_core_cstr), feature = "alloc", any(not(feature = "std"), target_os = "none")))]
-            pub use alloc::ffi::CString;
-            #[cfg(all(feature = "std", not(target_os = "none")))]
-            pub use std::ffi::CString;
-
-            #[cfg(all(not(no_core_net), any(not(feature = "std"), target_os = "none")))]
-            pub use self::core::net;
-            #[cfg(all(feature = "std", not(target_os = "none")))]
-            pub use std::net;
-
-            // std-only types - not available on target_os = "none"
-            #[cfg(all(feature = "std", not(target_os = "none")))]
-            pub use std::error;
-
-            #[cfg(all(feature = "std", not(target_os = "none")))]
-            pub use std::collections::{HashMap, HashSet};
-            #[cfg(all(feature = "std", not(target_os = "none")))]
-            pub use std::ffi::{OsStr, OsString};
-            #[cfg(all(feature = "std", not(target_os = "none")))]
-            pub use std::hash::{BuildHasher, Hash};
-            #[cfg(all(feature = "std", not(target_os = "none")))]
-            pub use std::io::Write;
-            #[cfg(all(feature = "std", not(target_os = "none")))]
-            pub use std::path::{Path, PathBuf};
-            #[cfg(all(feature = "std", not(target_os = "none")))]
-            pub use std::sync::{Mutex, RwLock};
-            #[cfg(all(feature = "std", not(target_os = "none")))]
-            pub use std::time::{SystemTime, UNIX_EPOCH};
-
-            #[cfg(all(feature = "std", not(target_os = "none"), no_target_has_atomic, not(no_std_atomic)))]
-            pub use std::sync::atomic::{
-                AtomicBool, AtomicI16, AtomicI32, AtomicI8, AtomicIsize, AtomicU16, AtomicU32,
-                AtomicU8, AtomicUsize, Ordering,
-            };
-            #[cfg(all(feature = "std", not(target_os = "none"), no_target_has_atomic, not(no_std_atomic64)))]
-            pub use std::sync::atomic::{AtomicI64, AtomicU64};
-
-            #[cfg(all(feature = "std", not(target_os = "none"), not(no_target_has_atomic)))]
-            pub use std::sync::atomic::Ordering;
-            #[cfg(all(feature = "std", not(target_os = "none"), not(no_target_has_atomic), target_has_atomic = "8"))]
-            pub use std::sync::atomic::{AtomicBool, AtomicI8, AtomicU8};
-            #[cfg(all(feature = "std", not(target_os = "none"), not(no_target_has_atomic), target_has_atomic = "16"))]
-            pub use std::sync::atomic::{AtomicI16, AtomicU16};
-            #[cfg(all(feature = "std", not(target_os = "none"), not(no_target_has_atomic), target_has_atomic = "32"))]
-            pub use std::sync::atomic::{AtomicI32, AtomicU32};
-            #[cfg(all(feature = "std", not(target_os = "none"), not(no_target_has_atomic), target_has_atomic = "64"))]
-            pub use std::sync::atomic::{AtomicI64, AtomicU64};
-            #[cfg(all(feature = "std", not(target_os = "none"), not(no_target_has_atomic), target_has_atomic = "ptr"))]
-            pub use std::sync::atomic::{AtomicIsize, AtomicUsize};
-
-            #[cfg(not(no_core_num_saturating))]
-            pub use self::core::num::Saturating;
-        }
-
-        // None of this crate's error handling needs the `From::from` error conversion
-        // performed implicitly by the `?` operator or the standard library's `try!`
-        // macro. This simplified macro gives a 5.5% improvement in compile time
-        // compared to standard `try!`, and 9% improvement compared to `?`.
-        macro_rules! tri {
-            ($expr:expr) => {
-                match $expr {
-                    Ok(val) => val,
-                    Err(err) => return Err(err),
-                }
-            };
-        }
-
-        #[cfg_attr(all(docsrs, if_docsrs_then_no_serde_core), path = "core/de/mod.rs")]
-        pub mod de;
-        #[cfg_attr(all(docsrs, if_docsrs_then_no_serde_core), path = "core/ser/mod.rs")]
-        pub mod ser;
-
-        #[cfg_attr(all(docsrs, if_docsrs_then_no_serde_core), path = "core/format.rs")]
-        mod format;
-
-        #[doc(inline)]
-        pub use crate::de::{Deserialize, Deserializer};
-        #[doc(inline)]
-        pub use crate::ser::{Serialize, Serializer};
-
-        // Used by generated code. Not public API.
-        #[doc(hidden)]
-        #[cfg_attr(
-            all(docsrs, if_docsrs_then_no_serde_core),
-            path = "core/private/mod.rs"
-        )]
-        mod private;
-
-        // Used by declarative macro generated code. Not public API.
-        #[doc(hidden)]
-        pub mod __private {
-            #[doc(hidden)]
-            pub use crate::private::doc;
-            #[doc(hidden)]
-            pub use core::result::Result;
-        }
-
-        include!(concat!(env!("OUT_DIR"), "/private.rs"));
-
-        #[cfg(all(any(not(feature = "std"), target_os = "none"), no_core_error))]
-        #[cfg_attr(all(docsrs, if_docsrs_then_no_serde_core), path = "core/std_error.rs")]
-        mod std_error;
-    };
-}
@@ -1,127 +0,0 @@
-//! Serde is a framework for ***ser***ializing and ***de***serializing Rust data
-//! structures efficiently and generically.
-//!
-//! The `serde_core` crate contains Serde's trait definitions with **no support
-//! for #\[derive()\]**.
-//!
-//! In crates that derive an implementation of `Serialize` or `Deserialize`, you
-//! must depend on the [`serde`] crate, not `serde_core`.
-//!
-//! [`serde`]: https://crates.io/crates/serde
-//!
-//! In crates that handwrite implementations of Serde traits, or only use them
-//! as trait bounds, depending on `serde_core` is permitted. But `serde`
-//! re-exports all of these traits and can be used for this use case too. If in
-//! doubt, disregard `serde_core` and always use `serde`.
-//!
-//! Crates that depend on `serde_core` instead of `serde` are able to compile in
-//! parallel with `serde_derive` even when `serde`'s "derive" feature is turned on,
-//! as shown in the following build timings.
-//!
-//! <br>
-//!
-//! <table>
-//! <tr><td align="center">When <code>serde_json</code> depends on <code>serde</code></td></tr>
-//! <tr><td><img src="https://github.com/user-attachments/assets/78dc179c-6ab1-4059-928c-1474b0d9d0bb"></td></tr>
-//! </table>
-//!
-//! <br>
-//!
-//! <table>
-//! <tr><td align="center">When <code>serde_json</code> depends on <code>serde_core</code></td></tr>
-//! <tr><td><img src="https://github.com/user-attachments/assets/6b6cff5e-3e45-4ac7-9db1-d99ee8b9f5f7"></td></tr>
-//! </table>
-
-////////////////////////////////////////////////////////////////////////////////
-
-// Serde types in rustdoc of other crates get linked to here.
-#![doc(html_root_url = "https://docs.rs/serde_core/1.0.228")]
-// Support using Serde without the standard library!
-// Also force no_std on target_os = "none" (wasm32v1-none) even if std feature is enabled
-// This handles Cargo feature unification where std gets enabled for no_std targets
-#![cfg_attr(any(not(feature = "std"), target_os = "none"), no_std)]
-// Show which crate feature enables conditionally compiled APIs in documentation.
-#![cfg_attr(docsrs, feature(doc_cfg, rustdoc_internals))]
-#![cfg_attr(docsrs, allow(internal_features))]
-// Unstable functionality only if the user asks for it. For tracking and
-// discussion of these features please refer to this issue:
-//
-//    https://github.com/serde-rs/serde/issues/812
-#![cfg_attr(feature = "unstable", feature(never_type))]
-#![allow(unknown_lints, bare_trait_objects, deprecated)]
-// Ignored clippy and clippy_pedantic lints
-#![allow(
-    // clippy bug: https://github.com/rust-lang/rust-clippy/issues/5704
-    clippy::unnested_or_patterns,
-    // clippy bug: https://github.com/rust-lang/rust-clippy/issues/7768
-    clippy::semicolon_if_nothing_returned,
-    // not available in our oldest supported compiler
-    clippy::empty_enums,
-    clippy::type_repetition_in_bounds, // https://github.com/rust-lang/rust-clippy/issues/8772
-    // integer and float ser/de requires these sorts of casts
-    clippy::cast_possible_truncation,
-    clippy::cast_possible_wrap,
-    clippy::cast_precision_loss,
-    clippy::cast_sign_loss,
-    // things are often more readable this way
-    clippy::cast_lossless,
-    clippy::module_name_repetitions,
-    clippy::single_match_else,
-    clippy::type_complexity,
-    clippy::use_self,
-    clippy::zero_prefixed_literal,
-    // correctly used
-    clippy::derive_partial_eq_without_eq,
-    clippy::enum_glob_use,
-    clippy::explicit_auto_deref,
-    clippy::incompatible_msrv,
-    clippy::let_underscore_untyped,
-    clippy::map_err_ignore,
-    clippy::new_without_default,
-    clippy::result_unit_err,
-    clippy::wildcard_imports,
-    // not practical
-    clippy::needless_pass_by_value,
-    clippy::similar_names,
-    clippy::too_many_lines,
-    // preference
-    clippy::doc_markdown,
-    clippy::elidable_lifetime_names,
-    clippy::needless_lifetimes,
-    clippy::unseparated_literal_suffix,
-    // false positive
-    clippy::needless_doctest_main,
-    // noisy
-    clippy::missing_errors_doc,
-    clippy::must_use_candidate,
-)]
-// Restrictions
-#![deny(clippy::question_mark_used)]
-// Rustc lints.
-#![deny(missing_docs, unused_imports)]
-
-////////////////////////////////////////////////////////////////////////////////
-
-#[cfg(all(feature = "alloc", any(not(feature = "std"), target_os = "none")))]
-extern crate alloc;
-
-// Explicitly import core crate for no_std targets (especially wasm32v1-none)
-#[cfg(not(feature = "std"))]
-extern crate core;
-
-#[macro_use]
-mod crate_root;
-#[macro_use]
-mod macros;
-
-crate_root!();
-
-#[macro_export]
-#[doc(hidden)]
-macro_rules! __require_serde_not_serde_core {
-    () => {
-        ::core::compile_error!(
-            "Serde derive requires a dependency on the serde crate, not serde_core"
-        );
-    };
-}
@@ -1,39 +0,0 @@
-use crate::lib::*;
-
-// Used from generated code to buffer the contents of the Deserializer when
-// deserializing untagged enums and internally tagged enums.
-//
-// Not public API. Use serde-value instead.
-//
-// Obsoleted by format-specific buffer types (https://github.com/serde-rs/serde/pull/2912).
-#[doc(hidden)]
-pub enum Content<'de> {
-    Bool(bool),
-
-    U8(u8),
-    U16(u16),
-    U32(u32),
-    U64(u64),
-
-    I8(i8),
-    I16(i16),
-    I32(i32),
-    I64(i64),
-
-    F32(f32),
-    F64(f64),
-
-    Char(char),
-    String(String),
-    Str(&'de str),
-    ByteBuf(Vec<u8>),
-    Bytes(&'de [u8]),
-
-    None,
-    Some(Box<Content<'de>>),
-
-    Unit,
-    Newtype(Box<Content<'de>>),
-    Seq(Vec<Content<'de>>),
-    Map(Vec<(Content<'de>, Content<'de>)>),
-}
@@ -1,21 +0,0 @@
-#[cfg(all(not(no_serde_derive), any(feature = "std", feature = "alloc")))]
-mod content;
-mod seed;
-
-// FIXME: #[cfg(doctest)] once https://github.com/rust-lang/rust/issues/67295 is fixed.
-#[doc(hidden)]
-pub mod doc;
-
-#[doc(hidden)]
-pub mod size_hint;
-
-#[doc(hidden)]
-pub mod string;
-
-#[cfg(all(not(no_serde_derive), any(feature = "std", feature = "alloc")))]
-#[doc(hidden)]
-pub use self::content::Content;
-#[doc(hidden)]
-pub use self::seed::InPlaceSeed;
-#[doc(hidden)]
-pub use crate::lib::result::Result;
@@ -1,30 +0,0 @@
-#[cfg(any(feature = "std", feature = "alloc"))]
-use crate::lib::*;
-
-pub fn from_bounds<I>(iter: &I) -> Option<usize>
-where
-    I: Iterator,
-{
-    helper(iter.size_hint())
-}
-
-#[cfg(any(feature = "std", feature = "alloc"))]
-pub fn cautious<Element>(hint: Option<usize>) -> usize {
-    const MAX_PREALLOC_BYTES: usize = 1024 * 1024;
-
-    if mem::size_of::<Element>() == 0 {
-        0
-    } else {
-        cmp::min(
-            hint.unwrap_or(0),
-            MAX_PREALLOC_BYTES / mem::size_of::<Element>(),
-        )
-    }
-}
-
-fn helper(bounds: (usize, Option<usize>)) -> Option<usize> {
-    match bounds {
-        (lower, Some(upper)) if lower == upper => Some(upper),
-        _ => None,
-    }
-}
@@ -1,23 +0,0 @@
-use crate::lib::*;
-
-#[cfg(any(feature = "std", feature = "alloc"))]
-#[doc(hidden)]
-pub fn from_utf8_lossy(bytes: &[u8]) -> Cow<'_, str> {
-    String::from_utf8_lossy(bytes)
-}
-
-// The generated code calls this like:
-//
-//     let value = &_serde::__private::from_utf8_lossy(bytes);
-//     Err(_serde::de::Error::unknown_variant(value, VARIANTS))
-//
-// so it is okay for the return type to be different from the std case as long
-// as the above works.
-#[cfg(not(any(feature = "std", feature = "alloc")))]
-#[doc(hidden)]
-pub fn from_utf8_lossy(bytes: &[u8]) -> &str {
-    // Three unicode replacement characters if it fails. They look like a
-    // white-on-black question mark. The user will recognize it as invalid
-    // UTF-8.
-    str::from_utf8(bytes).unwrap_or("\u{fffd}\u{fffd}\u{fffd}")
-}
@@ -0,0 +1 @@
+msrv = "1.31.0"
@@ -1,42 +1,36 @@
 [package]
 name = "serde_derive"
-version = "1.0.228"
+version = "1.0.137" # remember to update html_root_url
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>", "David Tolnay <dtolnay@gmail.com>"]
-categories = ["no-std", "no-std::no-alloc"]
-description = "Macros 1.1 implementation of #[derive(Serialize, Deserialize)]"
-documentation = "https://serde.rs/derive.html"
-edition = "2021"
-exclude = ["build.rs"]
-homepage = "https://serde.rs"
-keywords = ["serde", "serialization", "no_std", "derive"]
+rust-version = "1.31"
 license = "MIT OR Apache-2.0"
-readme = "crates-io.md"
+description = "Macros 1.1 implementation of #[derive(Serialize, Deserialize)]"
+homepage = "https://serde.rs"
 repository = "https://github.com/serde-rs/serde"
-rust-version = "1.68"
+documentation = "https://serde.rs/derive.html"
+keywords = ["serde", "serialization", "no_std"]
+readme = "crates-io.md"
+include = ["build.rs", "src/**/*.rs", "crates-io.md", "README.md", "LICENSE-APACHE", "LICENSE-MIT"]

 [features]
 default = []
 deserialize_in_place = []

 [lib]
-name = "serde_derive"
-proc-macro = true
+crate-type = ["cdylib"]

 [dependencies]
-proc-macro2 = { workspace = true, features = ["proc-macro"] }
-quote = { workspace = true, features = ["proc-macro"] }
-syn = { workspace = true, features = ["clone-impls", "derive", "parsing", "printing", "proc-macro"] }
+proc-macro2 = "1.0"
+quote = "1.0"
+syn = "1.0.90"

 [dev-dependencies]
-serde = { version = "1", path = "../serde" }
+serde = { version = "1.0", path = "../serde" }

 [package.metadata.docs.rs]
 targets = ["x86_64-unknown-linux-gnu"]
-rustdoc-args = [
-    "--generate-link-to-definition",
-    "--generate-macro-expansion",
-    "--extern-html-root-url=core=https://doc.rust-lang.org",
-    "--extern-html-root-url=alloc=https://doc.rust-lang.org",
-    "--extern-html-root-url=std=https://doc.rust-lang.org",
-    "--extern-html-root-url=proc_macro=https://doc.rust-lang.org",
-]
+
+[workspace]
+
+[patch.crates-io]
+proc-macro2 = { git = "https://github.com/dtolnay/watt" }
@@ -1,8 +1,36 @@
-fn main() {
-    // Warning: build.rs is not published to crates.io.
+use std::env;
+use std::process::Command;
+use std::str;

-    println!("cargo:rerun-if-changed=build.rs");
-    println!("cargo:rustc-cfg=check_cfg");
-    println!("cargo:rustc-check-cfg=cfg(check_cfg)");
-    println!("cargo:rustc-check-cfg=cfg(exhaustive)");
+// The rustc-cfg strings below are *not* public API. Please let us know by
+// opening a GitHub issue if your build environment requires some way to enable
+// these cfgs other than by executing our build script.
+fn main() {
+    let minor = match rustc_minor_version() {
+        Some(minor) => minor,
+        None => return,
+    };
+
+    // Underscore const names stabilized in Rust 1.37:
+    // https://blog.rust-lang.org/2019/08/15/Rust-1.37.0.html#using-unnamed-const-items-for-macros
+    if minor >= 37 {
+        println!("cargo:rustc-cfg=underscore_consts");
+    }
+
+    // The ptr::addr_of! macro stabilized in Rust 1.51:
+    // https://blog.rust-lang.org/2021/03/25/Rust-1.51.0.html#stabilized-apis
+    if minor >= 51 {
+        println!("cargo:rustc-cfg=ptr_addr_of");
+    }
+}
+
+fn rustc_minor_version() -> Option<u32> {
+    let rustc = env::var_os("RUSTC")?;
+    let output = Command::new(rustc).arg("--version").output().ok()?;
+    let version = str::from_utf8(&output.stdout).ok()?;
+    let mut pieces = version.split('.');
+    if pieces.next() != Some("rustc 1") {
+        return None;
+    }
+    pieces.next()?.parse().ok()
 }
@@ -1,9 +1,12 @@
-use crate::internals::ast::{Container, Data};
-use crate::internals::{attr, ungroup};
-use proc_macro2::Span;
 use std::collections::HashSet;
+
+use syn;
 use syn::punctuated::{Pair, Punctuated};
-use syn::Token;
+
+use internals::ast::{Container, Data};
+use internals::{attr, ungroup};
+
+use proc_macro2::Span;

 // Remove the default from every type parameter because in the generated impls
 // they look like associated types: "error: associated type bindings are not
@@ -144,7 +147,6 @@ pub fn with_bound(

        fn visit_type(&mut self, ty: &'ast syn::Type) {
            match ty {
-                #![cfg_attr(all(test, exhaustive), deny(non_exhaustive_omitted_patterns))]
                syn::Type::Array(ty) => self.visit_type(&ty.elem),
                syn::Type::BareFn(ty) => {
                    for arg in &ty.inputs {
@@ -182,6 +184,7 @@ pub fn with_bound(

                syn::Type::Infer(_) | syn::Type::Never(_) | syn::Type::Verbatim(_) => {}

+                #[cfg_attr(all(test, exhaustive), deny(non_exhaustive_omitted_patterns))]
                _ => {}
            }
        }
@@ -196,14 +199,11 @@ pub fn with_bound(
                syn::PathArguments::AngleBracketed(arguments) => {
                    for arg in &arguments.args {
                        match arg {
-                            #![cfg_attr(all(test, exhaustive), deny(non_exhaustive_omitted_patterns))]
                            syn::GenericArgument::Type(arg) => self.visit_type(arg),
-                            syn::GenericArgument::AssocType(arg) => self.visit_type(&arg.ty),
+                            syn::GenericArgument::Binding(arg) => self.visit_type(&arg.ty),
                            syn::GenericArgument::Lifetime(_)
-                            | syn::GenericArgument::Const(_)
-                            | syn::GenericArgument::AssocConst(_)
-                            | syn::GenericArgument::Constraint(_) => {}
-                            _ => {}
+                            | syn::GenericArgument::Constraint(_)
+                            | syn::GenericArgument::Const(_) => {}
                        }
                    }
                }
@@ -225,12 +225,8 @@ pub fn with_bound(

        fn visit_type_param_bound(&mut self, bound: &'ast syn::TypeParamBound) {
            match bound {
-                #![cfg_attr(all(test, exhaustive), deny(non_exhaustive_omitted_patterns))]
                syn::TypeParamBound::Trait(bound) => self.visit_path(&bound.path),
-                syn::TypeParamBound::Lifetime(_)
-                | syn::TypeParamBound::PreciseCapture(_)
-                | syn::TypeParamBound::Verbatim(_) => {}
-                _ => {}
+                syn::TypeParamBound::Lifetime(_) => {}
            }
        }

@@ -255,7 +251,7 @@ pub fn with_bound(
    };
    match &cont.data {
        Data::Enum(variants) => {
-            for variant in variants {
+            for variant in variants.iter() {
                let relevant_fields = variant
                    .fields
                    .iter()
@@ -338,7 +334,7 @@ pub fn with_self_bound(

 pub fn with_lifetime_bound(generics: &syn::Generics, lifetime: &str) -> syn::Generics {
    let bound = syn::Lifetime::new(lifetime, Span::call_site());
-    let def = syn::LifetimeParam {
+    let def = syn::LifetimeDef {
        attrs: Vec::new(),
        lifetime: bound.clone(),
        colon_token: None,
@@ -1,96 +0,0 @@
-use crate::de::enum_adjacently;
-use crate::de::enum_externally;
-use crate::de::enum_internally;
-use crate::de::enum_untagged;
-use crate::de::identifier;
-use crate::de::{field_i, FieldWithAliases, Parameters};
-use crate::fragment::{Expr, Fragment, Stmts};
-use crate::internals::ast::Variant;
-use crate::internals::attr;
-use crate::private;
-use proc_macro2::TokenStream;
-use quote::quote;
-
-/// Generates `Deserialize::deserialize` body for an `enum Enum {...}`
-pub(super) fn deserialize(
-    params: &Parameters,
-    variants: &[Variant],
-    cattrs: &attr::Container,
-) -> Fragment {
-    // The variants have already been checked (in ast.rs) that all untagged variants appear at the end
-    match variants.iter().position(|var| var.attrs.untagged()) {
-        Some(variant_idx) => {
-            let (tagged, untagged) = variants.split_at(variant_idx);
-            let tagged_frag = Expr(deserialize_homogeneous_enum(params, tagged, cattrs));
-            // Ignore any error associated with non-untagged deserialization so that we
-            // can fall through to the untagged variants. This may be infallible so we
-            // need to provide the error type.
-            let first_attempt = quote! {
-                if let _serde::#private::Result::<_, __D::Error>::Ok(__ok) = (|| #tagged_frag)() {
-                    return _serde::#private::Ok(__ok);
-                }
-            };
-            enum_untagged::deserialize(params, untagged, cattrs, Some(first_attempt))
-        }
-        None => deserialize_homogeneous_enum(params, variants, cattrs),
-    }
-}
-
-fn deserialize_homogeneous_enum(
-    params: &Parameters,
-    variants: &[Variant],
-    cattrs: &attr::Container,
-) -> Fragment {
-    match cattrs.tag() {
-        attr::TagType::External => enum_externally::deserialize(params, variants, cattrs),
-        attr::TagType::Internal { tag } => {
-            enum_internally::deserialize(params, variants, cattrs, tag)
-        }
-        attr::TagType::Adjacent { tag, content } => {
-            enum_adjacently::deserialize(params, variants, cattrs, tag, content)
-        }
-        attr::TagType::None => enum_untagged::deserialize(params, variants, cattrs, None),
-    }
-}
-
-pub fn prepare_enum_variant_enum(variants: &[Variant]) -> (TokenStream, Stmts) {
-    let deserialized_variants = variants
-        .iter()
-        .enumerate()
-        .filter(|&(_i, variant)| !variant.attrs.skip_deserializing());
-
-    let fallthrough = deserialized_variants
-        .clone()
-        .find(|(_i, variant)| variant.attrs.other())
-        .map(|(i, _variant)| {
-            let ignore_variant = field_i(i);
-            quote!(_serde::#private::Ok(__Field::#ignore_variant))
-        });
-
-    let variants_stmt = {
-        let variant_names = deserialized_variants
-            .clone()
-            .flat_map(|(_i, variant)| variant.attrs.aliases());
-        quote! {
-            #[doc(hidden)]
-            const VARIANTS: &'static [&'static str] = &[ #(#variant_names),* ];
-        }
-    };
-
-    let deserialized_variants: Vec<_> = deserialized_variants
-        .map(|(i, variant)| FieldWithAliases {
-            ident: field_i(i),
-            aliases: variant.attrs.aliases(),
-        })
-        .collect();
-
-    let variant_visitor = Stmts(identifier::deserialize_generated(
-        &deserialized_variants,
-        false, // variant identifiers do not depend on the presence of flatten fields
-        true,
-        None,
-        fallthrough,
-    ));
-
-    (variants_stmt, variant_visitor)
-}
@@ -1,325 +0,0 @@
-//! Deserialization for adjacently tagged enums:
-//!
-//! ```ignore
-//! #[serde(tag = "...", content = "...")]
-//! enum Enum {}
-//! ```
-
-use crate::de::enum_;
-use crate::de::enum_untagged;
-use crate::de::{field_i, Parameters};
-use crate::fragment::{Fragment, Match};
-use crate::internals::ast::{Style, Variant};
-use crate::internals::attr;
-use crate::private;
-use quote::{quote, quote_spanned};
-use syn::spanned::Spanned;
-
-/// Generates `Deserialize::deserialize` body for an `enum Enum {...}` with `#[serde(tag, content)]` attributes
-pub(super) fn deserialize(
-    params: &Parameters,
-    variants: &[Variant],
-    cattrs: &attr::Container,
-    tag: &str,
-    content: &str,
-) -> Fragment {
-    let this_type = &params.this_type;
-    let this_value = &params.this_value;
-    let (de_impl_generics, de_ty_generics, ty_generics, where_clause) =
-        params.generics_with_de_lifetime();
-    let delife = params.borrowed.de_lifetime();
-
-    let (variants_stmt, variant_visitor) = enum_::prepare_enum_variant_enum(variants);
-
-    let variant_arms: &Vec<_> = &variants
-        .iter()
-        .enumerate()
-        .filter(|&(_, variant)| !variant.attrs.skip_deserializing())
-        .map(|(i, variant)| {
-            let variant_index = field_i(i);
-
-            let block = Match(enum_untagged::deserialize_variant(params, variant, cattrs));
-
-            quote! {
-                __Field::#variant_index => #block
-            }
-        })
-        .collect();
-
-    let rust_name = params.type_name();
-    let expecting = format!("adjacently tagged enum {}", rust_name);
-    let expecting = cattrs.expecting().unwrap_or(&expecting);
-    let type_name = cattrs.name().deserialize_name();
-    let deny_unknown_fields = cattrs.deny_unknown_fields();
-
-    // If unknown fields are allowed, we pick the visitor that can step over
-    // those. Otherwise we pick the visitor that fails on unknown keys.
-    let field_visitor_ty = if deny_unknown_fields {
-        quote! { _serde::#private::de::TagOrContentFieldVisitor }
-    } else {
-        quote! { _serde::#private::de::TagContentOtherFieldVisitor }
-    };
-
-    let mut missing_content = quote! {
-        _serde::#private::Err(<__A::Error as _serde::de::Error>::missing_field(#content))
-    };
-    let mut missing_content_fallthrough = quote!();
-    let missing_content_arms = variants
-        .iter()
-        .enumerate()
-        .filter(|&(_, variant)| !variant.attrs.skip_deserializing())
-        .filter_map(|(i, variant)| {
-            let variant_index = field_i(i);
-            let variant_ident = &variant.ident;
-
-            let arm = match variant.style {
-                Style::Unit => quote! {
-                    _serde::#private::Ok(#this_value::#variant_ident)
-                },
-                Style::Newtype if variant.attrs.deserialize_with().is_none() => {
-                    let span = variant.original.span();
-                    let func = quote_spanned!(span=> _serde::#private::de::missing_field);
-                    quote! {
-                        #func(#content).map(#this_value::#variant_ident)
-                    }
-                }
-                _ => {
-                    missing_content_fallthrough = quote!(_ => #missing_content);
-                    return None;
-                }
-            };
-            Some(quote! {
-                __Field::#variant_index => #arm,
-            })
-        })
-        .collect::<Vec<_>>();
-    if !missing_content_arms.is_empty() {
-        missing_content = quote! {
-            match __field {
-                #(#missing_content_arms)*
-                #missing_content_fallthrough
-            }
-        };
-    }
-
-    // Advance the map by one key, returning early in case of error.
-    let next_key = quote! {
-        _serde::de::MapAccess::next_key_seed(&mut __map, #field_visitor_ty {
-            tag: #tag,
-            content: #content,
-        })?
-    };
-
-    let variant_from_map = quote! {
-        _serde::de::MapAccess::next_value_seed(&mut __map, _serde::#private::de::AdjacentlyTaggedEnumVariantSeed::<__Field> {
-            enum_name: #rust_name,
-            variants: VARIANTS,
-            fields_enum: _serde::#private::PhantomData
-        })?
-    };
-
-    // When allowing unknown fields, we want to transparently step through keys
-    // we don't care about until we find `tag`, `content`, or run out of keys.
-    let next_relevant_key = if deny_unknown_fields {
-        next_key
-    } else {
-        quote!({
-            let mut __rk : _serde::#private::Option<_serde::#private::de::TagOrContentField> = _serde::#private::None;
-            while let _serde::#private::Some(__k) = #next_key {
-                match __k {
-                    _serde::#private::de::TagContentOtherField::Other => {
-                        let _ = _serde::de::MapAccess::next_value::<_serde::de::IgnoredAny>(&mut __map)?;
-                        continue;
-                    },
-                    _serde::#private::de::TagContentOtherField::Tag => {
-                        __rk = _serde::#private::Some(_serde::#private::de::TagOrContentField::Tag);
-                        break;
-                    }
-                    _serde::#private::de::TagContentOtherField::Content => {
-                        __rk = _serde::#private::Some(_serde::#private::de::TagOrContentField::Content);
-                        break;
-                    }
-                }
-            }
-
-            __rk
-        })
-    };
-
-    // Step through remaining keys, looking for duplicates of previously-seen
-    // keys. When unknown fields are denied, any key that isn't a duplicate will
-    // at this point immediately produce an error.
-    let visit_remaining_keys = quote! {
-        match #next_relevant_key {
-            _serde::#private::Some(_serde::#private::de::TagOrContentField::Tag) => {
-                _serde::#private::Err(<__A::Error as _serde::de::Error>::duplicate_field(#tag))
-            }
-            _serde::#private::Some(_serde::#private::de::TagOrContentField::Content) => {
-                _serde::#private::Err(<__A::Error as _serde::de::Error>::duplicate_field(#content))
-            }
-            _serde::#private::None => _serde::#private::Ok(__ret),
-        }
-    };
-
-    let finish_content_then_tag = if variant_arms.is_empty() {
-        quote! {
-            match #variant_from_map {}
-        }
-    } else {
-        quote! {
-            let __seed = __Seed {
-                variant: #variant_from_map,
-                marker: _serde::#private::PhantomData,
-                lifetime: _serde::#private::PhantomData,
-            };
-            let __deserializer = _serde::#private::de::ContentDeserializer::<__A::Error>::new(__content);
-            let __ret = _serde::de::DeserializeSeed::deserialize(__seed, __deserializer)?;
-            // Visit remaining keys, looking for duplicates.
-            #visit_remaining_keys
-        }
-    };
-
-    quote_block! {
-        #variant_visitor
-
-        #variants_stmt
-
-        #[doc(hidden)]
-        struct __Seed #de_impl_generics #where_clause {
-            variant: __Field,
-            marker: _serde::#private::PhantomData<#this_type #ty_generics>,
-            lifetime: _serde::#private::PhantomData<&#delife ()>,
-        }
-
-        #[automatically_derived]
-        impl #de_impl_generics _serde::de::DeserializeSeed<#delife> for __Seed #de_ty_generics #where_clause {
-            type Value = #this_type #ty_generics;
-
-            fn deserialize<__D>(self, __deserializer: __D) -> _serde::#private::Result<Self::Value, __D::Error>
-            where
-                __D: _serde::Deserializer<#delife>,
-            {
-                match self.variant {
-                    #(#variant_arms)*
-                }
-            }
-        }
-
-        #[doc(hidden)]
-        struct __Visitor #de_impl_generics #where_clause {
-            marker: _serde::#private::PhantomData<#this_type #ty_generics>,
-            lifetime: _serde::#private::PhantomData<&#delife ()>,
-        }
-
-        #[automatically_derived]
-        impl #de_impl_generics _serde::de::Visitor<#delife> for __Visitor #de_ty_generics #where_clause {
-            type Value = #this_type #ty_generics;
-
-            fn expecting(&self, __formatter: &mut _serde::#private::Formatter) -> _serde::#private::fmt::Result {
-                _serde::#private::Formatter::write_str(__formatter, #expecting)
-            }
-
-            fn visit_map<__A>(self, mut __map: __A) -> _serde::#private::Result<Self::Value, __A::Error>
-            where
-                __A: _serde::de::MapAccess<#delife>,
-            {
-                // Visit the first relevant key.
-                match #next_relevant_key {
-                    // First key is the tag.
-                    _serde::#private::Some(_serde::#private::de::TagOrContentField::Tag) => {
-                        // Parse the tag.
-                        let __field = #variant_from_map;
-                        // Visit the second key.
-                        match #next_relevant_key {
-                            // Second key is a duplicate of the tag.
-                            _serde::#private::Some(_serde::#private::de::TagOrContentField::Tag) => {
-                                _serde::#private::Err(<__A::Error as _serde::de::Error>::duplicate_field(#tag))
-                            }
-                            // Second key is the content.
-                            _serde::#private::Some(_serde::#private::de::TagOrContentField::Content) => {
-                                let __ret = _serde::de::MapAccess::next_value_seed(&mut __map,
-                                    __Seed {
-                                        variant: __field,
-                                        marker: _serde::#private::PhantomData,
-                                        lifetime: _serde::#private::PhantomData,
-                                    })?;
-                                // Visit remaining keys, looking for duplicates.
-                                #visit_remaining_keys
-                            }
-                            // There is no second key; might be okay if the we have a unit variant.
-                            _serde::#private::None => #missing_content
-                        }
-                    }
-                    // First key is the content.
-                    _serde::#private::Some(_serde::#private::de::TagOrContentField::Content) => {
-                        // Buffer up the content.
-                        let __content = _serde::de::MapAccess::next_value_seed(&mut __map, _serde::#private::de::ContentVisitor::new())?;
-                        // Visit the second key.
-                        match #next_relevant_key {
-                            // Second key is the tag.
-                            _serde::#private::Some(_serde::#private::de::TagOrContentField::Tag) => {
-                                #finish_content_then_tag
-                            }
-                            // Second key is a duplicate of the content.
-                            _serde::#private::Some(_serde::#private::de::TagOrContentField::Content) => {
-                                _serde::#private::Err(<__A::Error as _serde::de::Error>::duplicate_field(#content))
-                            }
-                            // There is no second key.
-                            _serde::#private::None => {
-                                _serde::#private::Err(<__A::Error as _serde::de::Error>::missing_field(#tag))
-                            }
-                        }
-                    }
-                    // There is no first key.
-                    _serde::#private::None => {
-                        _serde::#private::Err(<__A::Error as _serde::de::Error>::missing_field(#tag))
-                    }
-                }
-            }
-
-            fn visit_seq<__A>(self, mut __seq: __A) -> _serde::#private::Result<Self::Value, __A::Error>
-            where
-                __A: _serde::de::SeqAccess<#delife>,
-            {
-                // Visit the first element - the tag.
-                match _serde::de::SeqAccess::next_element(&mut __seq) {
-                    _serde::#private::Ok(_serde::#private::Some(__variant)) => {
-                        // Visit the second element - the content.
-                        match _serde::de::SeqAccess::next_element_seed(
-                            &mut __seq,
-                            __Seed {
-                                variant: __variant,
-                                marker: _serde::#private::PhantomData,
-                                lifetime: _serde::#private::PhantomData,
-                            },
-                        ) {
-                            _serde::#private::Ok(_serde::#private::Some(__ret)) => _serde::#private::Ok(__ret),
-                            // There is no second element.
-                            _serde::#private::Ok(_serde::#private::None) => {
-                                _serde::#private::Err(_serde::de::Error::invalid_length(1, &self))
-                            }
-                            _serde::#private::Err(__err) => _serde::#private::Err(__err),
-                        }
-                    }
-                    // There is no first element.
-                    _serde::#private::Ok(_serde::#private::None) => {
-                        _serde::#private::Err(_serde::de::Error::invalid_length(0, &self))
-                    }
-                    _serde::#private::Err(__err) => _serde::#private::Err(__err),
-                }
-            }
-        }
-
-        #[doc(hidden)]
-        const FIELDS: &'static [&'static str] = &[#tag, #content];
-        _serde::Deserializer::deserialize_struct(
-            __deserializer,
-            #type_name,
-            FIELDS,
-            __Visitor {
-                marker: _serde::#private::PhantomData::<#this_type #ty_generics>,
-                lifetime: _serde::#private::PhantomData,
-            },
-        )
-    }
-}
@@ -1,213 +0,0 @@
-//! Deserialization for externally tagged enums:
-//!
-//! ```ignore
-//! enum Enum {}
-//! ```
-
-use crate::de::enum_;
-use crate::de::struct_;
-use crate::de::tuple;
-use crate::de::{
-    expr_is_missing, field_i, unwrap_to_variant_closure, wrap_deserialize_field_with,
-    wrap_deserialize_with, Parameters, StructForm, TupleForm,
-};
-use crate::fragment::{Expr, Fragment, Match};
-use crate::internals::ast::{Field, Style, Variant};
-use crate::internals::attr;
-use crate::private;
-use proc_macro2::TokenStream;
-use quote::{quote, quote_spanned};
-use syn::spanned::Spanned;
-
-/// Generates `Deserialize::deserialize` body for an `enum Enum {...}` without additional attributes
-pub(super) fn deserialize(
-    params: &Parameters,
-    variants: &[Variant],
-    cattrs: &attr::Container,
-) -> Fragment {
-    let this_type = &params.this_type;
-    let (de_impl_generics, de_ty_generics, ty_generics, where_clause) =
-        params.generics_with_de_lifetime();
-    let delife = params.borrowed.de_lifetime();
-
-    let type_name = cattrs.name().deserialize_name();
-    let expecting = format!("enum {}", params.type_name());
-    let expecting = cattrs.expecting().unwrap_or(&expecting);
-
-    let (variants_stmt, variant_visitor) = enum_::prepare_enum_variant_enum(variants);
-
-    // Match arms to extract a variant from a string
-    let variant_arms = variants
-        .iter()
-        .enumerate()
-        .filter(|&(_, variant)| !variant.attrs.skip_deserializing())
-        .map(|(i, variant)| {
-            let variant_name = field_i(i);
-
-            let block = Match(deserialize_externally_tagged_variant(
-                params, variant, cattrs,
-            ));
-
-            quote! {
-                _serde::#private::Ok((__Field::#variant_name, __variant)) => #block
-            }
-        });
-
-    let all_skipped = variants
-        .iter()
-        .all(|variant| variant.attrs.skip_deserializing());
-    let match_variant = if all_skipped {
-        // This is an empty enum like `enum Impossible {}` or an enum in which
-        // all variants have `#[serde(skip_deserializing)]`.
-        quote! {
-            // FIXME: Once feature(exhaustive_patterns) is stable:
-            // let _serde::#private::Err(__err) = _serde::de::EnumAccess::variant::<__Field>(__data);
-            // _serde::#private::Err(__err)
-            _serde::#private::Result::map(
-                _serde::de::EnumAccess::variant::<__Field>(__data),
-                |(__impossible, _)| match __impossible {})
-        }
-    } else {
-        quote! {
-            match _serde::de::EnumAccess::variant(__data) {
-                #(#variant_arms)*
-                _serde::#private::Err(__err) => _serde::#private::Err(__err),
-            }
-        }
-    };
-
-    quote_block! {
-        #variant_visitor
-
-        #[doc(hidden)]
-        struct __Visitor #de_impl_generics #where_clause {
-            marker: _serde::#private::PhantomData<#this_type #ty_generics>,
-            lifetime: _serde::#private::PhantomData<&#delife ()>,
-        }
-
-        #[automatically_derived]
-        impl #de_impl_generics _serde::de::Visitor<#delife> for __Visitor #de_ty_generics #where_clause {
-            type Value = #this_type #ty_generics;
-
-            fn expecting(&self, __formatter: &mut _serde::#private::Formatter) -> _serde::#private::fmt::Result {
-                _serde::#private::Formatter::write_str(__formatter, #expecting)
-            }
-
-            fn visit_enum<__A>(self, __data: __A) -> _serde::#private::Result<Self::Value, __A::Error>
-            where
-                __A: _serde::de::EnumAccess<#delife>,
-            {
-                #match_variant
-            }
-        }
-
-        #variants_stmt
-
-        _serde::Deserializer::deserialize_enum(
-            __deserializer,
-            #type_name,
-            VARIANTS,
-            __Visitor {
-                marker: _serde::#private::PhantomData::<#this_type #ty_generics>,
-                lifetime: _serde::#private::PhantomData,
-            },
-        )
-    }
-}
-
-fn deserialize_externally_tagged_variant(
-    params: &Parameters,
-    variant: &Variant,
-    cattrs: &attr::Container,
-) -> Fragment {
-    if let Some(path) = variant.attrs.deserialize_with() {
-        let (wrapper, wrapper_ty, unwrap_fn) = wrap_deserialize_variant_with(params, variant, path);
-        return quote_block! {
-            #wrapper
-            _serde::#private::Result::map(
-                _serde::de::VariantAccess::newtype_variant::<#wrapper_ty>(__variant), #unwrap_fn)
-        };
-    }
-
-    let variant_ident = &variant.ident;
-
-    match variant.style {
-        Style::Unit => {
-            let this_value = &params.this_value;
-            quote_block! {
-                _serde::de::VariantAccess::unit_variant(__variant)?;
-                _serde::#private::Ok(#this_value::#variant_ident)
-            }
-        }
-        Style::Newtype => deserialize_externally_tagged_newtype_variant(
-            variant_ident,
-            params,
-            &variant.fields[0],
-            cattrs,
-        ),
-        Style::Tuple => tuple::deserialize(
-            params,
-            &variant.fields,
-            cattrs,
-            TupleForm::ExternallyTagged(variant_ident),
-        ),
-        Style::Struct => struct_::deserialize(
-            params,
-            &variant.fields,
-            cattrs,
-            StructForm::ExternallyTagged(variant_ident),
-        ),
-    }
-}
-
-fn wrap_deserialize_variant_with(
-    params: &Parameters,
-    variant: &Variant,
-    deserialize_with: &syn::ExprPath,
-) -> (TokenStream, TokenStream, TokenStream) {
-    let field_tys = variant.fields.iter().map(|field| field.ty);
-    let (wrapper, wrapper_ty) =
-        wrap_deserialize_with(params, &quote!((#(#field_tys),*)), deserialize_with);
-
-    let unwrap_fn = unwrap_to_variant_closure(params, variant, true);
-
-    (wrapper, wrapper_ty, unwrap_fn)
-}
-
-fn deserialize_externally_tagged_newtype_variant(
-    variant_ident: &syn::Ident,
-    params: &Parameters,
-    field: &Field,
-    cattrs: &attr::Container,
-) -> Fragment {
-    let this_value = &params.this_value;
-
-    if field.attrs.skip_deserializing() {
-        let default = Expr(expr_is_missing(field, cattrs));
-        return quote_block! {
-            _serde::de::VariantAccess::unit_variant(__variant)?;
-            _serde::#private::Ok(#this_value::#variant_ident(#default))
-        };
-    }
-
-    match field.attrs.deserialize_with() {
-        None => {
-            let field_ty = field.ty;
-            let span = field.original.span();
-            let func =
-                quote_spanned!(span=> _serde::de::VariantAccess::newtype_variant::<#field_ty>);
-            quote_expr! {
-                _serde::#private::Result::map(#func(__variant), #this_value::#variant_ident)
-            }
-        }
-        Some(path) => {
-            let (wrapper, wrapper_ty) = wrap_deserialize_field_with(params, field.ty, path);
-            quote_block! {
-                #wrapper
-                _serde::#private::Result::map(
-                    _serde::de::VariantAccess::newtype_variant::<#wrapper_ty>(__variant),
-                    |__wrapper| #this_value::#variant_ident(__wrapper.value))
-            }
-        }
-    }
-}
@@ -1,106 +0,0 @@
-//! Deserialization for internally tagged enums:
-//!
-//! ```ignore
-//! #[serde(tag = "...")]
-//! enum Enum {}
-//! ```
-
-use crate::de::enum_;
-use crate::de::enum_untagged;
-use crate::de::struct_;
-use crate::de::{
-    effective_style, expr_is_missing, field_i, unwrap_to_variant_closure, Parameters, StructForm,
-};
-use crate::fragment::{Expr, Fragment, Match};
-use crate::internals::ast::{Style, Variant};
-use crate::internals::attr;
-use crate::private;
-use quote::quote;
-
-/// Generates `Deserialize::deserialize` body for an `enum Enum {...}` with `#[serde(tag)]` attribute
-pub(super) fn deserialize(
-    params: &Parameters,
-    variants: &[Variant],
-    cattrs: &attr::Container,
-    tag: &str,
-) -> Fragment {
-    let (variants_stmt, variant_visitor) = enum_::prepare_enum_variant_enum(variants);
-
-    // Match arms to extract a variant from a string
-    let variant_arms = variants
-        .iter()
-        .enumerate()
-        .filter(|&(_, variant)| !variant.attrs.skip_deserializing())
-        .map(|(i, variant)| {
-            let variant_name = field_i(i);
-
-            let block = Match(deserialize_internally_tagged_variant(
-                params, variant, cattrs,
-            ));
-
-            quote! {
-                __Field::#variant_name => #block
-            }
-        });
-
-    let expecting = format!("internally tagged enum {}", params.type_name());
-    let expecting = cattrs.expecting().unwrap_or(&expecting);
-
-    quote_block! {
-        #variant_visitor
-
-        #variants_stmt
-
-        let (__tag, __content) = _serde::Deserializer::deserialize_any(
-            __deserializer,
-            _serde::#private::de::TaggedContentVisitor::<__Field>::new(#tag, #expecting))?;
-        let __deserializer = _serde::#private::de::ContentDeserializer::<__D::Error>::new(__content);
-
-        match __tag {
-            #(#variant_arms)*
-        }
-    }
-}
-
-// Generates significant part of the visit_seq and visit_map bodies of visitors
-// for the variants of internally tagged enum.
-fn deserialize_internally_tagged_variant(
-    params: &Parameters,
-    variant: &Variant,
-    cattrs: &attr::Container,
-) -> Fragment {
-    if let Some(path) = variant.attrs.deserialize_with() {
-        let unwrap_fn = unwrap_to_variant_closure(params, variant, false);
-        return quote_block! {
-            _serde::#private::Result::map(#path(__deserializer), #unwrap_fn)
-        };
-    }
-
-    let variant_ident = &variant.ident;
-
-    match effective_style(variant) {
-        Style::Unit => {
-            let this_value = &params.this_value;
-            let type_name = params.type_name();
-            let variant_name = variant.ident.to_string();
-            let default = variant.fields.first().map(|field| {
-                let default = Expr(expr_is_missing(field, cattrs));
-                quote!((#default))
-            });
-            quote_block! {
-                _serde::Deserializer::deserialize_any(__deserializer, _serde::#private::de::InternallyTaggedUnitVisitor::new(#type_name, #variant_name))?;
-                _serde::#private::Ok(#this_value::#variant_ident #default)
-            }
-        }
-        Style::Newtype => {
-            enum_untagged::deserialize_newtype_variant(variant_ident, params, &variant.fields[0])
-        }
-        Style::Struct => struct_::deserialize(
-            params,
-            &variant.fields,
-            cattrs,
-            StructForm::InternallyTagged(variant_ident),
-        ),
-        Style::Tuple => unreachable!("checked in serde_derive_internals"),
-    }
-}
@@ -1,135 +0,0 @@
-//! Deserialization for untagged enums:
-//!
-//! ```ignore
-//! #[serde(untagged)]
-//! enum Enum {}
-//! ```
-
-use crate::de::struct_;
-use crate::de::tuple;
-use crate::de::{
-    effective_style, expr_is_missing, unwrap_to_variant_closure, Parameters, StructForm, TupleForm,
-};
-use crate::fragment::{Expr, Fragment};
-use crate::internals::ast::{Field, Style, Variant};
-use crate::internals::attr;
-use crate::private;
-use proc_macro2::TokenStream;
-use quote::{quote, quote_spanned};
-use syn::spanned::Spanned;
-
-/// Generates `Deserialize::deserialize` body for an `enum Enum {...}` with `#[serde(untagged)]` attribute
-pub(super) fn deserialize(
-    params: &Parameters,
-    variants: &[Variant],
-    cattrs: &attr::Container,
-    first_attempt: Option<TokenStream>,
-) -> Fragment {
-    let attempts = variants
-        .iter()
-        .filter(|variant| !variant.attrs.skip_deserializing())
-        .map(|variant| Expr(deserialize_variant(params, variant, cattrs)));
-    // TODO this message could be better by saving the errors from the failed
-    // attempts. The heuristic used by TOML was to count the number of fields
-    // processed before an error, and use the error that happened after the
-    // largest number of fields. I'm not sure I like that. Maybe it would be
-    // better to save all the errors and combine them into one message that
-    // explains why none of the variants matched.
-    let fallthrough_msg = format!(
-        "data did not match any variant of untagged enum {}",
-        params.type_name()
-    );
-    let fallthrough_msg = cattrs.expecting().unwrap_or(&fallthrough_msg);
-
-    let private2 = private;
-    quote_block! {
-        let __content = _serde::de::DeserializeSeed::deserialize(_serde::#private::de::ContentVisitor::new(), __deserializer)?;
-        let __deserializer = _serde::#private::de::ContentRefDeserializer::<__D::Error>::new(&__content);
-
-        #first_attempt
-
-        #(
-            if let _serde::#private2::Ok(__ok) = #attempts {
-                return _serde::#private2::Ok(__ok);
-            }
-        )*
-
-        _serde::#private::Err(_serde::de::Error::custom(#fallthrough_msg))
-    }
-}
-
-// Also used by adjacently tagged enums
-pub(super) fn deserialize_variant(
-    params: &Parameters,
-    variant: &Variant,
-    cattrs: &attr::Container,
-) -> Fragment {
-    if let Some(path) = variant.attrs.deserialize_with() {
-        let unwrap_fn = unwrap_to_variant_closure(params, variant, false);
-        return quote_block! {
-            _serde::#private::Result::map(#path(__deserializer), #unwrap_fn)
-        };
-    }
-
-    let variant_ident = &variant.ident;
-
-    match effective_style(variant) {
-        Style::Unit => {
-            let this_value = &params.this_value;
-            let type_name = params.type_name();
-            let variant_name = variant.ident.to_string();
-            let default = variant.fields.first().map(|field| {
-                let default = Expr(expr_is_missing(field, cattrs));
-                quote!((#default))
-            });
-            quote_expr! {
-                match _serde::Deserializer::deserialize_any(
-                    __deserializer,
-                    _serde::#private::de::UntaggedUnitVisitor::new(#type_name, #variant_name)
-                ) {
-                    _serde::#private::Ok(()) => _serde::#private::Ok(#this_value::#variant_ident #default),
-                    _serde::#private::Err(__err) => _serde::#private::Err(__err),
-                }
-            }
-        }
-        Style::Newtype => deserialize_newtype_variant(variant_ident, params, &variant.fields[0]),
-        Style::Tuple => tuple::deserialize(
-            params,
-            &variant.fields,
-            cattrs,
-            TupleForm::Untagged(variant_ident),
-        ),
-        Style::Struct => struct_::deserialize(
-            params,
-            &variant.fields,
-            cattrs,
-            StructForm::Untagged(variant_ident),
-        ),
-    }
-}
-
-// Also used by internally tagged enums
-// Implicitly (via `generate_variant`) used by adjacently tagged enums
-pub(super) fn deserialize_newtype_variant(
-    variant_ident: &syn::Ident,
-    params: &Parameters,
-    field: &Field,
-) -> Fragment {
-    let this_value = &params.this_value;
-    let field_ty = field.ty;
-    match field.attrs.deserialize_with() {
-        None => {
-            let span = field.original.span();
-            let func = quote_spanned!(span=> <#field_ty as _serde::Deserialize>::deserialize);
-            quote_expr! {
-                _serde::#private::Result::map(#func(__deserializer), #this_value::#variant_ident)
-            }
-        }
-        Some(path) => {
-            quote_block! {
-                let __value: _serde::#private::Result<#field_ty, _> = #path(__deserializer);
-                _serde::#private::Result::map(__value, #this_value::#variant_ident)
-            }
-        }
-    }
-}
@@ -1,477 +0,0 @@
-//! Deserialization of struct field identifiers and enum variant identifiers by
-//! way of a Rust enum.
-
-use crate::de::{FieldWithAliases, Parameters};
-use crate::fragment::{Fragment, Stmts};
-use crate::internals::ast::{Style, Variant};
-use crate::internals::attr;
-use crate::private;
-use proc_macro2::{Literal, TokenStream};
-use quote::{quote, ToTokens};
-
-// Generates `Deserialize::deserialize` body for an enum with
-// `serde(field_identifier)` or `serde(variant_identifier)` attribute.
-pub(super) fn deserialize_custom(
-    params: &Parameters,
-    variants: &[Variant],
-    cattrs: &attr::Container,
-) -> Fragment {
-    let is_variant = match cattrs.identifier() {
-        attr::Identifier::Variant => true,
-        attr::Identifier::Field => false,
-        attr::Identifier::No => unreachable!(),
-    };
-
-    let this_type = params.this_type.to_token_stream();
-    let this_value = params.this_value.to_token_stream();
-
-    let (ordinary, fallthrough, fallthrough_borrowed) = if let Some(last) = variants.last() {
-        let last_ident = &last.ident;
-        if last.attrs.other() {
-            // Process `serde(other)` attribute. It would always be found on the
-            // last variant (checked in `check_identifier`), so all preceding
-            // are ordinary variants.
-            let ordinary = &variants[..variants.len() - 1];
-            let fallthrough = quote!(_serde::#private::Ok(#this_value::#last_ident));
-            (ordinary, Some(fallthrough), None)
-        } else if let Style::Newtype = last.style {
-            let ordinary = &variants[..variants.len() - 1];
-            let fallthrough = |value| {
-                quote! {
-                    _serde::#private::Result::map(
-                        _serde::Deserialize::deserialize(
-                            _serde::#private::de::IdentifierDeserializer::from(#value)
-                        ),
-                        #this_value::#last_ident)
-                }
-            };
-            (
-                ordinary,
-                Some(fallthrough(quote!(__value))),
-                Some(fallthrough(quote!(_serde::#private::de::Borrowed(
-                    __value
-                )))),
-            )
-        } else {
-            (variants, None, None)
-        }
-    } else {
-        (variants, None, None)
-    };
-
-    let idents_aliases: Vec<_> = ordinary
-        .iter()
-        .map(|variant| FieldWithAliases {
-            ident: variant.ident.clone(),
-            aliases: variant.attrs.aliases(),
-        })
-        .collect();
-
-    let names = idents_aliases.iter().flat_map(|variant| variant.aliases);
-
-    let names_const = if fallthrough.is_some() {
-        None
-    } else if is_variant {
-        let variants = quote! {
-            #[doc(hidden)]
-            const VARIANTS: &'static [&'static str] = &[ #(#names),* ];
-        };
-        Some(variants)
-    } else {
-        let fields = quote! {
-            #[doc(hidden)]
-            const FIELDS: &'static [&'static str] = &[ #(#names),* ];
-        };
-        Some(fields)
-    };
-
-    let (de_impl_generics, de_ty_generics, ty_generics, where_clause) =
-        params.generics_with_de_lifetime();
-    let delife = params.borrowed.de_lifetime();
-    let visitor_impl = Stmts(deserialize_identifier(
-        &this_value,
-        &idents_aliases,
-        is_variant,
-        fallthrough,
-        fallthrough_borrowed,
-        false,
-        cattrs.expecting(),
-    ));
-
-    quote_block! {
-        #names_const
-
-        #[doc(hidden)]
-        struct __FieldVisitor #de_impl_generics #where_clause {
-            marker: _serde::#private::PhantomData<#this_type #ty_generics>,
-            lifetime: _serde::#private::PhantomData<&#delife ()>,
-        }
-
-        #[automatically_derived]
-        impl #de_impl_generics _serde::de::Visitor<#delife> for __FieldVisitor #de_ty_generics #where_clause {
-            type Value = #this_type #ty_generics;
-
-            #visitor_impl
-        }
-
-        let __visitor = __FieldVisitor {
-            marker: _serde::#private::PhantomData::<#this_type #ty_generics>,
-            lifetime: _serde::#private::PhantomData,
-        };
-        _serde::Deserializer::deserialize_identifier(__deserializer, __visitor)
-    }
-}
-
-pub(super) fn deserialize_generated(
-    deserialized_fields: &[FieldWithAliases],
-    has_flatten: bool,
-    is_variant: bool,
-    ignore_variant: Option<TokenStream>,
-    fallthrough: Option<TokenStream>,
-) -> Fragment {
-    let this_value = quote!(__Field);
-    let field_idents: &Vec<_> = &deserialized_fields
-        .iter()
-        .map(|field| &field.ident)
-        .collect();
-
-    let visitor_impl = Stmts(deserialize_identifier(
-        &this_value,
-        deserialized_fields,
-        is_variant,
-        fallthrough,
-        None,
-        !is_variant && has_flatten,
-        None,
-    ));
-
-    let lifetime = if !is_variant && has_flatten {
-        Some(quote!(<'de>))
-    } else {
-        None
-    };
-
-    quote_block! {
-        #[allow(non_camel_case_types)]
-        #[doc(hidden)]
-        enum __Field #lifetime {
-            #(#field_idents,)*
-            #ignore_variant
-        }
-
-        #[doc(hidden)]
-        struct __FieldVisitor;
-
-        #[automatically_derived]
-        impl<'de> _serde::de::Visitor<'de> for __FieldVisitor {
-            type Value = __Field #lifetime;
-
-            #visitor_impl
-        }
-
-        #[automatically_derived]
-        impl<'de> _serde::Deserialize<'de> for __Field #lifetime {
-            #[inline]
-            fn deserialize<__D>(__deserializer: __D) -> _serde::#private::Result<Self, __D::Error>
-            where
-                __D: _serde::Deserializer<'de>,
-            {
-                _serde::Deserializer::deserialize_identifier(__deserializer, __FieldVisitor)
-            }
-        }
-    }
-}
-
-fn deserialize_identifier(
-    this_value: &TokenStream,
-    deserialized_fields: &[FieldWithAliases],
-    is_variant: bool,
-    fallthrough: Option<TokenStream>,
-    fallthrough_borrowed: Option<TokenStream>,
-    collect_other_fields: bool,
-    expecting: Option<&str>,
-) -> Fragment {
-    let str_mapping = deserialized_fields.iter().map(|field| {
-        let ident = &field.ident;
-        let aliases = field.aliases;
-        let private2 = private;
-        // `aliases` also contains a main name
-        quote! {
-            #(
-                #aliases => _serde::#private2::Ok(#this_value::#ident),
-            )*
-        }
-    });
-    let bytes_mapping = deserialized_fields.iter().map(|field| {
-        let ident = &field.ident;
-        // `aliases` also contains a main name
-        let aliases = field
-            .aliases
-            .iter()
-            .map(|alias| Literal::byte_string(alias.value.as_bytes()));
-        let private2 = private;
-        quote! {
-            #(
-                #aliases => _serde::#private2::Ok(#this_value::#ident),
-            )*
-        }
-    });
-
-    let expecting = expecting.unwrap_or(if is_variant {
-        "variant identifier"
-    } else {
-        "field identifier"
-    });
-
-    let bytes_to_str = if fallthrough.is_some() || collect_other_fields {
-        None
-    } else {
-        Some(quote! {
-            let __value = &_serde::#private::from_utf8_lossy(__value);
-        })
-    };
-
-    let (
-        value_as_str_content,
-        value_as_borrowed_str_content,
-        value_as_bytes_content,
-        value_as_borrowed_bytes_content,
-    ) = if collect_other_fields {
-        (
-            Some(quote! {
-                let __value = _serde::#private::de::Content::String(_serde::#private::ToString::to_string(__value));
-            }),
-            Some(quote! {
-                let __value = _serde::#private::de::Content::Str(__value);
-            }),
-            Some(quote! {
-                let __value = _serde::#private::de::Content::ByteBuf(__value.to_vec());
-            }),
-            Some(quote! {
-                let __value = _serde::#private::de::Content::Bytes(__value);
-            }),
-        )
-    } else {
-        (None, None, None, None)
-    };
-
-    let fallthrough_arm_tokens;
-    let fallthrough_arm = if let Some(fallthrough) = &fallthrough {
-        fallthrough
-    } else if is_variant {
-        fallthrough_arm_tokens = quote! {
-            _serde::#private::Err(_serde::de::Error::unknown_variant(__value, VARIANTS))
-        };
-        &fallthrough_arm_tokens
-    } else {
-        fallthrough_arm_tokens = quote! {
-            _serde::#private::Err(_serde::de::Error::unknown_field(__value, FIELDS))
-        };
-        &fallthrough_arm_tokens
-    };
-
-    let visit_other = if collect_other_fields {
-        quote! {
-            fn visit_bool<__E>(self, __value: bool) -> _serde::#private::Result<Self::Value, __E>
-            where
-                __E: _serde::de::Error,
-            {
-                _serde::#private::Ok(__Field::__other(_serde::#private::de::Content::Bool(__value)))
-            }
-
-            fn visit_i8<__E>(self, __value: i8) -> _serde::#private::Result<Self::Value, __E>
-            where
-                __E: _serde::de::Error,
-            {
-                _serde::#private::Ok(__Field::__other(_serde::#private::de::Content::I8(__value)))
-            }
-
-            fn visit_i16<__E>(self, __value: i16) -> _serde::#private::Result<Self::Value, __E>
-            where
-                __E: _serde::de::Error,
-            {
-                _serde::#private::Ok(__Field::__other(_serde::#private::de::Content::I16(__value)))
-            }
-
-            fn visit_i32<__E>(self, __value: i32) -> _serde::#private::Result<Self::Value, __E>
-            where
-                __E: _serde::de::Error,
-            {
-                _serde::#private::Ok(__Field::__other(_serde::#private::de::Content::I32(__value)))
-            }
-
-            fn visit_i64<__E>(self, __value: i64) -> _serde::#private::Result<Self::Value, __E>
-            where
-                __E: _serde::de::Error,
-            {
-                _serde::#private::Ok(__Field::__other(_serde::#private::de::Content::I64(__value)))
-            }
-
-            fn visit_u8<__E>(self, __value: u8) -> _serde::#private::Result<Self::Value, __E>
-            where
-                __E: _serde::de::Error,
-            {
-                _serde::#private::Ok(__Field::__other(_serde::#private::de::Content::U8(__value)))
-            }
-
-            fn visit_u16<__E>(self, __value: u16) -> _serde::#private::Result<Self::Value, __E>
-            where
-                __E: _serde::de::Error,
-            {
-                _serde::#private::Ok(__Field::__other(_serde::#private::de::Content::U16(__value)))
-            }
-
-            fn visit_u32<__E>(self, __value: u32) -> _serde::#private::Result<Self::Value, __E>
-            where
-                __E: _serde::de::Error,
-            {
-                _serde::#private::Ok(__Field::__other(_serde::#private::de::Content::U32(__value)))
-            }
-
-            fn visit_u64<__E>(self, __value: u64) -> _serde::#private::Result<Self::Value, __E>
-            where
-                __E: _serde::de::Error,
-            {
-                _serde::#private::Ok(__Field::__other(_serde::#private::de::Content::U64(__value)))
-            }
-
-            fn visit_f32<__E>(self, __value: f32) -> _serde::#private::Result<Self::Value, __E>
-            where
-                __E: _serde::de::Error,
-            {
-                _serde::#private::Ok(__Field::__other(_serde::#private::de::Content::F32(__value)))
-            }
-
-            fn visit_f64<__E>(self, __value: f64) -> _serde::#private::Result<Self::Value, __E>
-            where
-                __E: _serde::de::Error,
-            {
-                _serde::#private::Ok(__Field::__other(_serde::#private::de::Content::F64(__value)))
-            }
-
-            fn visit_char<__E>(self, __value: char) -> _serde::#private::Result<Self::Value, __E>
-            where
-                __E: _serde::de::Error,
-            {
-                _serde::#private::Ok(__Field::__other(_serde::#private::de::Content::Char(__value)))
-            }
-
-            fn visit_unit<__E>(self) -> _serde::#private::Result<Self::Value, __E>
-            where
-                __E: _serde::de::Error,
-            {
-                _serde::#private::Ok(__Field::__other(_serde::#private::de::Content::Unit))
-            }
-        }
-    } else {
-        let u64_mapping = deserialized_fields.iter().enumerate().map(|(i, field)| {
-            let i = i as u64;
-            let ident = &field.ident;
-            quote!(#i => _serde::#private::Ok(#this_value::#ident))
-        });
-
-        let u64_fallthrough_arm_tokens;
-        let u64_fallthrough_arm = if let Some(fallthrough) = &fallthrough {
-            fallthrough
-        } else {
-            let index_expecting = if is_variant { "variant" } else { "field" };
-            let fallthrough_msg = format!(
-                "{} index 0 <= i < {}",
-                index_expecting,
-                deserialized_fields.len(),
-            );
-            u64_fallthrough_arm_tokens = quote! {
-                _serde::#private::Err(_serde::de::Error::invalid_value(
-                    _serde::de::Unexpected::Unsigned(__value),
-                    &#fallthrough_msg,
-                ))
-            };
-            &u64_fallthrough_arm_tokens
-        };
-
-        quote! {
-            fn visit_u64<__E>(self, __value: u64) -> _serde::#private::Result<Self::Value, __E>
-            where
-                __E: _serde::de::Error,
-            {
-                match __value {
-                    #(#u64_mapping,)*
-                    _ => #u64_fallthrough_arm,
-                }
-            }
-        }
-    };
-
-    let visit_borrowed = if fallthrough_borrowed.is_some() || collect_other_fields {
-        let str_mapping = str_mapping.clone();
-        let bytes_mapping = bytes_mapping.clone();
-        let fallthrough_borrowed_arm = fallthrough_borrowed.as_ref().unwrap_or(fallthrough_arm);
-        Some(quote! {
-            fn visit_borrowed_str<__E>(self, __value: &'de str) -> _serde::#private::Result<Self::Value, __E>
-            where
-                __E: _serde::de::Error,
-            {
-                match __value {
-                    #(#str_mapping)*
-                    _ => {
-                        #value_as_borrowed_str_content
-                        #fallthrough_borrowed_arm
-                    }
-                }
-            }
-
-            fn visit_borrowed_bytes<__E>(self, __value: &'de [u8]) -> _serde::#private::Result<Self::Value, __E>
-            where
-                __E: _serde::de::Error,
-            {
-                match __value {
-                    #(#bytes_mapping)*
-                    _ => {
-                        #bytes_to_str
-                        #value_as_borrowed_bytes_content
-                        #fallthrough_borrowed_arm
-                    }
-                }
-            }
-        })
-    } else {
-        None
-    };
-
-    quote_block! {
-        fn expecting(&self, __formatter: &mut _serde::#private::Formatter) -> _serde::#private::fmt::Result {
-            _serde::#private::Formatter::write_str(__formatter, #expecting)
-        }
-
-        #visit_other
-
-        fn visit_str<__E>(self, __value: &str) -> _serde::#private::Result<Self::Value, __E>
-        where
-            __E: _serde::de::Error,
-        {
-            match __value {
-                #(#str_mapping)*
-                _ => {
-                    #value_as_str_content
-                    #fallthrough_arm
-                }
-            }
-        }
-
-        fn visit_bytes<__E>(self, __value: &[u8]) -> _serde::#private::Result<Self::Value, __E>
-        where
-            __E: _serde::de::Error,
-        {
-            match __value {
-                #(#bytes_mapping)*
-                _ => {
-                    #bytes_to_str
-                    #value_as_bytes_content
-                    #fallthrough_arm
-                }
-            }
-        }
-
-        #visit_borrowed
-    }
-}
@@ -1,697 +0,0 @@
-use crate::de::identifier;
-use crate::de::{
-    deserialize_seq, expr_is_missing, field_i, has_flatten, wrap_deserialize_field_with,
-    FieldWithAliases, Parameters, StructForm,
-};
-#[cfg(feature = "deserialize_in_place")]
-use crate::de::{deserialize_seq_in_place, place_lifetime};
-use crate::fragment::{Expr, Fragment, Match, Stmts};
-use crate::internals::ast::Field;
-use crate::internals::attr;
-use crate::private;
-use proc_macro2::TokenStream;
-use quote::{quote, quote_spanned};
-use syn::spanned::Spanned;
-
-/// Generates `Deserialize::deserialize` body for a `struct Struct {...}`
-pub(super) fn deserialize(
-    params: &Parameters,
-    fields: &[Field],
-    cattrs: &attr::Container,
-    form: StructForm,
-) -> Fragment {
-    let this_type = &params.this_type;
-    let this_value = &params.this_value;
-    let (de_impl_generics, de_ty_generics, ty_generics, where_clause) =
-        params.generics_with_de_lifetime();
-    let delife = params.borrowed.de_lifetime();
-
-    // If there are getters (implying private fields), construct the local type
-    // and use an `Into` conversion to get the remote type. If there are no
-    // getters then construct the target type directly.
-    let construct = if params.has_getter {
-        let local = &params.local;
-        quote!(#local)
-    } else {
-        quote!(#this_value)
-    };
-
-    let type_path = match form {
-        StructForm::Struct => construct,
-        StructForm::ExternallyTagged(variant_ident)
-        | StructForm::InternallyTagged(variant_ident)
-        | StructForm::Untagged(variant_ident) => quote!(#construct::#variant_ident),
-    };
-    let expecting = match form {
-        StructForm::Struct => format!("struct {}", params.type_name()),
-        StructForm::ExternallyTagged(variant_ident)
-        | StructForm::InternallyTagged(variant_ident)
-        | StructForm::Untagged(variant_ident) => {
-            format!("struct variant {}::{}", params.type_name(), variant_ident)
-        }
-    };
-    let expecting = cattrs.expecting().unwrap_or(&expecting);
-
-    let deserialized_fields: Vec<_> = fields
-        .iter()
-        .enumerate()
-        // Skip fields that shouldn't be deserialized or that were flattened,
-        // so they don't appear in the storage in their literal form
-        .filter(|&(_, field)| !field.attrs.skip_deserializing() && !field.attrs.flatten())
-        .map(|(i, field)| FieldWithAliases {
-            ident: field_i(i),
-            aliases: field.attrs.aliases(),
-        })
-        .collect();
-
-    let has_flatten = has_flatten(fields);
-    let field_visitor = deserialize_field_identifier(&deserialized_fields, cattrs, has_flatten);
-
-    // untagged struct variants do not get a visit_seq method. The same applies to
-    // structs that only have a map representation.
-    let visit_seq = match form {
-        StructForm::Untagged(_) => None,
-        _ if has_flatten => None,
-        _ => {
-            let mut_seq = if deserialized_fields.is_empty() {
-                quote!(_)
-            } else {
-                quote!(mut __seq)
-            };
-
-            let visit_seq = Stmts(deserialize_seq(
-                &type_path, params, fields, true, cattrs, expecting,
-            ));
-
-            Some(quote! {
-                #[inline]
-                fn visit_seq<__A>(self, #mut_seq: __A) -> _serde::#private::Result<Self::Value, __A::Error>
-                where
-                    __A: _serde::de::SeqAccess<#delife>,
-                {
-                    #visit_seq
-                }
-            })
-        }
-    };
-    let visit_map = Stmts(deserialize_map(
-        &type_path,
-        params,
-        fields,
-        cattrs,
-        has_flatten,
-    ));
-
-    let visitor_seed = match form {
-        StructForm::ExternallyTagged(..) if has_flatten => Some(quote! {
-            #[automatically_derived]
-            impl #de_impl_generics _serde::de::DeserializeSeed<#delife> for __Visitor #de_ty_generics #where_clause {
-                type Value = #this_type #ty_generics;
-
-                fn deserialize<__D>(self, __deserializer: __D) -> _serde::#private::Result<Self::Value, __D::Error>
-                where
-                    __D: _serde::Deserializer<#delife>,
-                {
-                    _serde::Deserializer::deserialize_map(__deserializer, self)
-                }
-            }
-        }),
-        _ => None,
-    };
-
-    let fields_stmt = if has_flatten {
-        None
-    } else {
-        let field_names = deserialized_fields.iter().flat_map(|field| field.aliases);
-
-        Some(quote! {
-            #[doc(hidden)]
-            const FIELDS: &'static [&'static str] = &[ #(#field_names),* ];
-        })
-    };
-
-    let visitor_expr = quote! {
-        __Visitor {
-            marker: _serde::#private::PhantomData::<#this_type #ty_generics>,
-            lifetime: _serde::#private::PhantomData,
-        }
-    };
-    let dispatch = match form {
-        StructForm::Struct if has_flatten => quote! {
-            _serde::Deserializer::deserialize_map(__deserializer, #visitor_expr)
-        },
-        StructForm::Struct => {
-            let type_name = cattrs.name().deserialize_name();
-            quote! {
-                _serde::Deserializer::deserialize_struct(__deserializer, #type_name, FIELDS, #visitor_expr)
-            }
-        }
-        StructForm::ExternallyTagged(_) if has_flatten => quote! {
-            _serde::de::VariantAccess::newtype_variant_seed(__variant, #visitor_expr)
-        },
-        StructForm::ExternallyTagged(_) => quote! {
-            _serde::de::VariantAccess::struct_variant(__variant, FIELDS, #visitor_expr)
-        },
-        StructForm::InternallyTagged(_) => quote! {
-            _serde::Deserializer::deserialize_any(__deserializer, #visitor_expr)
-        },
-        StructForm::Untagged(_) => quote! {
-            _serde::Deserializer::deserialize_any(__deserializer, #visitor_expr)
-        },
-    };
-
-    quote_block! {
-        #field_visitor
-
-        #[doc(hidden)]
-        struct __Visitor #de_impl_generics #where_clause {
-            marker: _serde::#private::PhantomData<#this_type #ty_generics>,
-            lifetime: _serde::#private::PhantomData<&#delife ()>,
-        }
-
-        #[automatically_derived]
-        impl #de_impl_generics _serde::de::Visitor<#delife> for __Visitor #de_ty_generics #where_clause {
-            type Value = #this_type #ty_generics;
-
-            fn expecting(&self, __formatter: &mut _serde::#private::Formatter) -> _serde::#private::fmt::Result {
-                _serde::#private::Formatter::write_str(__formatter, #expecting)
-            }
-
-            #visit_seq
-
-            #[inline]
-            fn visit_map<__A>(self, mut __map: __A) -> _serde::#private::Result<Self::Value, __A::Error>
-            where
-                __A: _serde::de::MapAccess<#delife>,
-            {
-                #visit_map
-            }
-        }
-
-        #visitor_seed
-
-        #fields_stmt
-
-        #dispatch
-    }
-}
-
-fn deserialize_map(
-    struct_path: &TokenStream,
-    params: &Parameters,
-    fields: &[Field],
-    cattrs: &attr::Container,
-    has_flatten: bool,
-) -> Fragment {
-    // Create the field names for the fields.
-    let fields_names: Vec<_> = fields
-        .iter()
-        .enumerate()
-        .map(|(i, field)| (field, field_i(i)))
-        .collect();
-
-    // Declare each field that will be deserialized.
-    let let_values = fields_names
-        .iter()
-        .filter(|&&(field, _)| !field.attrs.skip_deserializing() && !field.attrs.flatten())
-        .map(|(field, name)| {
-            let field_ty = field.ty;
-            quote! {
-                let mut #name: _serde::#private::Option<#field_ty> = _serde::#private::None;
-            }
-        });
-
-    // Collect contents for flatten fields into a buffer
-    let let_collect = if has_flatten {
-        Some(quote! {
-            let mut __collect = _serde::#private::Vec::<_serde::#private::Option<(
-                _serde::#private::de::Content,
-                _serde::#private::de::Content
-            )>>::new();
-        })
-    } else {
-        None
-    };
-
-    // Match arms to extract a value for a field.
-    let value_arms = fields_names
-        .iter()
-        .filter(|&&(field, _)| !field.attrs.skip_deserializing() && !field.attrs.flatten())
-        .map(|(field, name)| {
-            let deser_name = field.attrs.name().deserialize_name();
-
-            let visit = match field.attrs.deserialize_with() {
-                None => {
-                    let field_ty = field.ty;
-                    let span = field.original.span();
-                    let func =
-                        quote_spanned!(span=> _serde::de::MapAccess::next_value::<#field_ty>);
-                    quote! {
-                        #func(&mut __map)?
-                    }
-                }
-                Some(path) => {
-                    let (wrapper, wrapper_ty) = wrap_deserialize_field_with(params, field.ty, path);
-                    quote!({
-                        #wrapper
-                        match _serde::de::MapAccess::next_value::<#wrapper_ty>(&mut __map) {
-                            _serde::#private::Ok(__wrapper) => __wrapper.value,
-                            _serde::#private::Err(__err) => {
-                                return _serde::#private::Err(__err);
-                            }
-                        }
-                    })
-                }
-            };
-            quote! {
-                __Field::#name => {
-                    if _serde::#private::Option::is_some(&#name) {
-                        return _serde::#private::Err(<__A::Error as _serde::de::Error>::duplicate_field(#deser_name));
-                    }
-                    #name = _serde::#private::Some(#visit);
-                }
-            }
-        });
-
-    // Visit ignored values to consume them
-    let ignored_arm = if has_flatten {
-        Some(quote! {
-            __Field::__other(__name) => {
-                __collect.push(_serde::#private::Some((
-                    __name,
-                    _serde::de::MapAccess::next_value_seed(&mut __map, _serde::#private::de::ContentVisitor::new())?)));
-            }
-        })
-    } else if cattrs.deny_unknown_fields() {
-        None
-    } else {
-        Some(quote! {
-            _ => { let _ = _serde::de::MapAccess::next_value::<_serde::de::IgnoredAny>(&mut __map)?; }
-        })
-    };
-
-    let all_skipped = fields.iter().all(|field| field.attrs.skip_deserializing());
-    let match_keys = if cattrs.deny_unknown_fields() && all_skipped {
-        quote! {
-            // FIXME: Once feature(exhaustive_patterns) is stable:
-            // let _serde::#private::None::<__Field> = _serde::de::MapAccess::next_key(&mut __map)?;
-            _serde::#private::Option::map(
-                _serde::de::MapAccess::next_key::<__Field>(&mut __map)?,
-                |__impossible| match __impossible {});
-        }
-    } else {
-        quote! {
-            while let _serde::#private::Some(__key) = _serde::de::MapAccess::next_key::<__Field>(&mut __map)? {
-                match __key {
-                    #(#value_arms)*
-                    #ignored_arm
-                }
-            }
-        }
-    };
-
-    let extract_values = fields_names
-        .iter()
-        .filter(|&&(field, _)| !field.attrs.skip_deserializing() && !field.attrs.flatten())
-        .map(|(field, name)| {
-            let missing_expr = Match(expr_is_missing(field, cattrs));
-
-            quote! {
-                let #name = match #name {
-                    _serde::#private::Some(#name) => #name,
-                    _serde::#private::None => #missing_expr
-                };
-            }
-        });
-
-    let extract_collected = fields_names
-        .iter()
-        .filter(|&&(field, _)| field.attrs.flatten() && !field.attrs.skip_deserializing())
-        .map(|(field, name)| {
-            let field_ty = field.ty;
-            let func = match field.attrs.deserialize_with() {
-                None => {
-                    let span = field.original.span();
-                    quote_spanned!(span=> _serde::de::Deserialize::deserialize)
-                }
-                Some(path) => quote!(#path),
-            };
-            quote! {
-                let #name: #field_ty = #func(
-                    _serde::#private::de::FlatMapDeserializer(
-                        &mut __collect,
-                        _serde::#private::PhantomData))?;
-            }
-        });
-
-    let collected_deny_unknown_fields = if has_flatten && cattrs.deny_unknown_fields() {
-        Some(quote! {
-            if let _serde::#private::Some(_serde::#private::Some((__key, _))) =
-                __collect.into_iter().filter(_serde::#private::Option::is_some).next()
-            {
-                if let _serde::#private::Some(__key) = _serde::#private::de::content_as_str(&__key) {
-                    return _serde::#private::Err(
-                        _serde::de::Error::custom(format_args!("unknown field `{}`", &__key)));
-                } else {
-                    return _serde::#private::Err(
-                        _serde::de::Error::custom(format_args!("unexpected map key")));
-                }
-            }
-        })
-    } else {
-        None
-    };
-
-    let result = fields_names.iter().map(|(field, name)| {
-        let member = &field.member;
-        if field.attrs.skip_deserializing() {
-            let value = Expr(expr_is_missing(field, cattrs));
-            quote!(#member: #value)
-        } else {
-            quote!(#member: #name)
-        }
-    });
-
-    let let_default = match cattrs.default() {
-        attr::Default::Default => Some(quote!(
-            let __default: Self::Value = _serde::#private::Default::default();
-        )),
-        // If #path returns wrong type, error will be reported here (^^^^^).
-        // We attach span of the path to the function so it will be reported
-        // on the #[serde(default = "...")]
-        //                          ^^^^^
-        attr::Default::Path(path) => Some(quote_spanned!(path.span()=>
-            let __default: Self::Value = #path();
-        )),
-        attr::Default::None => {
-            // We don't need the default value, to prevent an unused variable warning
-            // we'll leave the line empty.
-            None
-        }
-    };
-
-    let mut result = quote!(#struct_path { #(#result),* });
-    if params.has_getter {
-        let this_type = &params.this_type;
-        let (_, ty_generics, _) = params.generics.split_for_impl();
-        result = quote! {
-            _serde::#private::Into::<#this_type #ty_generics>::into(#result)
-        };
-    }
-
-    quote_block! {
-        #(#let_values)*
-
-        #let_collect
-
-        #match_keys
-
-        #let_default
-
-        #(#extract_values)*
-
-        #(#extract_collected)*
-
-        #collected_deny_unknown_fields
-
-        _serde::#private::Ok(#result)
-    }
-}
-
-/// Generates `Deserialize::deserialize_in_place` body for a `struct Struct {...}`
-#[cfg(feature = "deserialize_in_place")]
-pub(super) fn deserialize_in_place(
-    params: &Parameters,
-    fields: &[Field],
-    cattrs: &attr::Container,
-) -> Option<Fragment> {
-    // for now we do not support in_place deserialization for structs that
-    // are represented as map.
-    if has_flatten(fields) {
-        return None;
-    }
-
-    let this_type = &params.this_type;
-    let (de_impl_generics, de_ty_generics, ty_generics, where_clause) =
-        params.generics_with_de_lifetime();
-    let delife = params.borrowed.de_lifetime();
-
-    let expecting = format!("struct {}", params.type_name());
-    let expecting = cattrs.expecting().unwrap_or(&expecting);
-
-    let deserialized_fields: Vec<_> = fields
-        .iter()
-        .enumerate()
-        .filter(|&(_, field)| !field.attrs.skip_deserializing())
-        .map(|(i, field)| FieldWithAliases {
-            ident: field_i(i),
-            aliases: field.attrs.aliases(),
-        })
-        .collect();
-
-    let field_visitor = deserialize_field_identifier(&deserialized_fields, cattrs, false);
-
-    let mut_seq = if deserialized_fields.is_empty() {
-        quote!(_)
-    } else {
-        quote!(mut __seq)
-    };
-    let visit_seq = Stmts(deserialize_seq_in_place(params, fields, cattrs, expecting));
-    let visit_map = Stmts(deserialize_map_in_place(params, fields, cattrs));
-    let field_names = deserialized_fields.iter().flat_map(|field| field.aliases);
-    let type_name = cattrs.name().deserialize_name();
-
-    let in_place_impl_generics = de_impl_generics.in_place();
-    let in_place_ty_generics = de_ty_generics.in_place();
-    let place_life = place_lifetime();
-
-    Some(quote_block! {
-        #field_visitor
-
-        #[doc(hidden)]
-        struct __Visitor #in_place_impl_generics #where_clause {
-            place: &#place_life mut #this_type #ty_generics,
-            lifetime: _serde::#private::PhantomData<&#delife ()>,
-        }
-
-        #[automatically_derived]
-        impl #in_place_impl_generics _serde::de::Visitor<#delife> for __Visitor #in_place_ty_generics #where_clause {
-            type Value = ();
-
-            fn expecting(&self, __formatter: &mut _serde::#private::Formatter) -> _serde::#private::fmt::Result {
-                _serde::#private::Formatter::write_str(__formatter, #expecting)
-            }
-
-            #[inline]
-            fn visit_seq<__A>(self, #mut_seq: __A) -> _serde::#private::Result<Self::Value, __A::Error>
-            where
-                __A: _serde::de::SeqAccess<#delife>,
-            {
-                #visit_seq
-            }
-
-            #[inline]
-            fn visit_map<__A>(self, mut __map: __A) -> _serde::#private::Result<Self::Value, __A::Error>
-            where
-                __A: _serde::de::MapAccess<#delife>,
-            {
-                #visit_map
-            }
-        }
-
-        #[doc(hidden)]
-        const FIELDS: &'static [&'static str] = &[ #(#field_names),* ];
-
-        _serde::Deserializer::deserialize_struct(__deserializer, #type_name, FIELDS, __Visitor {
-            place: __place,
-            lifetime: _serde::#private::PhantomData,
-        })
-    })
-}
-
-#[cfg(feature = "deserialize_in_place")]
-fn deserialize_map_in_place(
-    params: &Parameters,
-    fields: &[Field],
-    cattrs: &attr::Container,
-) -> Fragment {
-    assert!(
-        !has_flatten(fields),
-        "inplace deserialization of maps does not support flatten fields"
-    );
-
-    // Create the field names for the fields.
-    let fields_names: Vec<_> = fields
-        .iter()
-        .enumerate()
-        .map(|(i, field)| (field, field_i(i)))
-        .collect();
-
-    // For deserialize_in_place, declare booleans for each field that will be
-    // deserialized.
-    let let_flags = fields_names
-        .iter()
-        .filter(|&&(field, _)| !field.attrs.skip_deserializing())
-        .map(|(_, name)| {
-            quote! {
-                let mut #name: bool = false;
-            }
-        });
-
-    // Match arms to extract a value for a field.
-    let value_arms_from = fields_names
-        .iter()
-        .filter(|&&(field, _)| !field.attrs.skip_deserializing())
-        .map(|(field, name)| {
-            let deser_name = field.attrs.name().deserialize_name();
-            let member = &field.member;
-
-            let visit = match field.attrs.deserialize_with() {
-                None => {
-                    quote! {
-                        _serde::de::MapAccess::next_value_seed(&mut __map, _serde::#private::de::InPlaceSeed(&mut self.place.#member))?
-                    }
-                }
-                Some(path) => {
-                    let (wrapper, wrapper_ty) = wrap_deserialize_field_with(params, field.ty, path);
-                    quote!({
-                        #wrapper
-                        self.place.#member = match _serde::de::MapAccess::next_value::<#wrapper_ty>(&mut __map) {
-                            _serde::#private::Ok(__wrapper) => __wrapper.value,
-                            _serde::#private::Err(__err) => {
-                                return _serde::#private::Err(__err);
-                            }
-                        };
-                    })
-                }
-            };
-            quote! {
-                __Field::#name => {
-                    if #name {
-                        return _serde::#private::Err(<__A::Error as _serde::de::Error>::duplicate_field(#deser_name));
-                    }
-                    #visit;
-                    #name = true;
-                }
-            }
-        });
-
-    // Visit ignored values to consume them
-    let ignored_arm = if cattrs.deny_unknown_fields() {
-        None
-    } else {
-        Some(quote! {
-            _ => { let _ = _serde::de::MapAccess::next_value::<_serde::de::IgnoredAny>(&mut __map)?; }
-        })
-    };
-
-    let all_skipped = fields.iter().all(|field| field.attrs.skip_deserializing());
-
-    let match_keys = if cattrs.deny_unknown_fields() && all_skipped {
-        quote! {
-            // FIXME: Once feature(exhaustive_patterns) is stable:
-            // let _serde::#private::None::<__Field> = _serde::de::MapAccess::next_key(&mut __map)?;
-            _serde::#private::Option::map(
-                _serde::de::MapAccess::next_key::<__Field>(&mut __map)?,
-                |__impossible| match __impossible {});
-        }
-    } else {
-        quote! {
-            while let _serde::#private::Some(__key) = _serde::de::MapAccess::next_key::<__Field>(&mut __map)? {
-                match __key {
-                    #(#value_arms_from)*
-                    #ignored_arm
-                }
-            }
-        }
-    };
-
-    let check_flags = fields_names
-        .iter()
-        .filter(|&&(field, _)| !field.attrs.skip_deserializing())
-        .map(|(field, name)| {
-            let missing_expr = expr_is_missing(field, cattrs);
-            // If missing_expr unconditionally returns an error, don't try
-            // to assign its value to self.place.
-            if field.attrs.default().is_none()
-                && cattrs.default().is_none()
-                && field.attrs.deserialize_with().is_some()
-            {
-                let missing_expr = Stmts(missing_expr);
-                quote! {
-                    if !#name {
-                        #missing_expr;
-                    }
-                }
-            } else {
-                let member = &field.member;
-                let missing_expr = Expr(missing_expr);
-                quote! {
-                    if !#name {
-                        self.place.#member = #missing_expr;
-                    };
-                }
-            }
-        });
-
-    let this_type = &params.this_type;
-    let (_, ty_generics, _) = params.generics.split_for_impl();
-
-    let let_default = match cattrs.default() {
-        attr::Default::Default => Some(quote!(
-            let __default: #this_type #ty_generics = _serde::#private::Default::default();
-        )),
-        // If #path returns wrong type, error will be reported here (^^^^^).
-        // We attach span of the path to the function so it will be reported
-        // on the #[serde(default = "...")]
-        //                          ^^^^^
-        attr::Default::Path(path) => Some(quote_spanned!(path.span()=>
-            let __default: #this_type #ty_generics = #path();
-        )),
-        attr::Default::None => {
-            // We don't need the default value, to prevent an unused variable warning
-            // we'll leave the line empty.
-            None
-        }
-    };
-
-    quote_block! {
-        #(#let_flags)*
-
-        #match_keys
-
-        #let_default
-
-        #(#check_flags)*
-
-        _serde::#private::Ok(())
-    }
-}
-
-/// Generates enum and its `Deserialize` implementation that represents each
-/// non-skipped field of the struct
-fn deserialize_field_identifier(
-    deserialized_fields: &[FieldWithAliases],
-    cattrs: &attr::Container,
-    has_flatten: bool,
-) -> Stmts {
-    let (ignore_variant, fallthrough) = if has_flatten {
-        let ignore_variant = quote!(__other(_serde::#private::de::Content<'de>),);
-        let fallthrough = quote!(_serde::#private::Ok(__Field::__other(__value)));
-        (Some(ignore_variant), Some(fallthrough))
-    } else if cattrs.deny_unknown_fields() {
-        (None, None)
-    } else {
-        let ignore_variant = quote!(__ignore,);
-        let fallthrough = quote!(_serde::#private::Ok(__Field::__ignore));
-        (Some(ignore_variant), Some(fallthrough))
-    };
-
-    Stmts(identifier::deserialize_generated(
-        deserialized_fields,
-        has_flatten,
-        false,
-        ignore_variant,
-        fallthrough,
-    ))
-}
@@ -1,283 +0,0 @@
-use crate::de::{deserialize_seq, has_flatten, Parameters, TupleForm};
-#[cfg(feature = "deserialize_in_place")]
-use crate::de::{deserialize_seq_in_place, place_lifetime};
-use crate::fragment::{Fragment, Stmts};
-use crate::internals::ast::Field;
-use crate::internals::attr;
-use crate::private;
-use proc_macro2::TokenStream;
-use quote::{quote, quote_spanned};
-use syn::spanned::Spanned;
-
-/// Generates `Deserialize::deserialize` body for a `struct Tuple(...);` including `struct Newtype(T);`
-pub(super) fn deserialize(
-    params: &Parameters,
-    fields: &[Field],
-    cattrs: &attr::Container,
-    form: TupleForm,
-) -> Fragment {
-    assert!(
-        !has_flatten(fields),
-        "tuples and tuple variants cannot have flatten fields"
-    );
-
-    let field_count = fields
-        .iter()
-        .filter(|field| !field.attrs.skip_deserializing())
-        .count();
-
-    let this_type = &params.this_type;
-    let this_value = &params.this_value;
-    let (de_impl_generics, de_ty_generics, ty_generics, where_clause) =
-        params.generics_with_de_lifetime();
-    let delife = params.borrowed.de_lifetime();
-
-    // If there are getters (implying private fields), construct the local type
-    // and use an `Into` conversion to get the remote type. If there are no
-    // getters then construct the target type directly.
-    let construct = if params.has_getter {
-        let local = &params.local;
-        quote!(#local)
-    } else {
-        quote!(#this_value)
-    };
-
-    let type_path = match form {
-        TupleForm::Tuple => construct,
-        TupleForm::ExternallyTagged(variant_ident) | TupleForm::Untagged(variant_ident) => {
-            quote!(#construct::#variant_ident)
-        }
-    };
-    let expecting = match form {
-        TupleForm::Tuple => format!("tuple struct {}", params.type_name()),
-        TupleForm::ExternallyTagged(variant_ident) | TupleForm::Untagged(variant_ident) => {
-            format!("tuple variant {}::{}", params.type_name(), variant_ident)
-        }
-    };
-    let expecting = cattrs.expecting().unwrap_or(&expecting);
-
-    let nfields = fields.len();
-
-    let visit_newtype_struct = match form {
-        TupleForm::Tuple if nfields == 1 => {
-            Some(deserialize_newtype_struct(&type_path, params, &fields[0]))
-        }
-        _ => None,
-    };
-
-    let visit_seq = Stmts(deserialize_seq(
-        &type_path, params, fields, false, cattrs, expecting,
-    ));
-
-    let visitor_expr = quote! {
-        __Visitor {
-            marker: _serde::#private::PhantomData::<#this_type #ty_generics>,
-            lifetime: _serde::#private::PhantomData,
-        }
-    };
-    let dispatch = match form {
-        TupleForm::Tuple if nfields == 1 => {
-            let type_name = cattrs.name().deserialize_name();
-            quote! {
-                _serde::Deserializer::deserialize_newtype_struct(__deserializer, #type_name, #visitor_expr)
-            }
-        }
-        TupleForm::Tuple => {
-            let type_name = cattrs.name().deserialize_name();
-            quote! {
-                _serde::Deserializer::deserialize_tuple_struct(__deserializer, #type_name, #field_count, #visitor_expr)
-            }
-        }
-        TupleForm::ExternallyTagged(_) => quote! {
-            _serde::de::VariantAccess::tuple_variant(__variant, #field_count, #visitor_expr)
-        },
-        TupleForm::Untagged(_) => quote! {
-            _serde::Deserializer::deserialize_tuple(__deserializer, #field_count, #visitor_expr)
-        },
-    };
-
-    let visitor_var = if field_count == 0 {
-        quote!(_)
-    } else {
-        quote!(mut __seq)
-    };
-
-    quote_block! {
-        #[doc(hidden)]
-        struct __Visitor #de_impl_generics #where_clause {
-            marker: _serde::#private::PhantomData<#this_type #ty_generics>,
-            lifetime: _serde::#private::PhantomData<&#delife ()>,
-        }
-
-        #[automatically_derived]
-        impl #de_impl_generics _serde::de::Visitor<#delife> for __Visitor #de_ty_generics #where_clause {
-            type Value = #this_type #ty_generics;
-
-            fn expecting(&self, __formatter: &mut _serde::#private::Formatter) -> _serde::#private::fmt::Result {
-                _serde::#private::Formatter::write_str(__formatter, #expecting)
-            }
-
-            #visit_newtype_struct
-
-            #[inline]
-            fn visit_seq<__A>(self, #visitor_var: __A) -> _serde::#private::Result<Self::Value, __A::Error>
-            where
-                __A: _serde::de::SeqAccess<#delife>,
-            {
-                #visit_seq
-            }
-        }
-
-        #dispatch
-    }
-}
-
-fn deserialize_newtype_struct(
-    type_path: &TokenStream,
-    params: &Parameters,
-    field: &Field,
-) -> TokenStream {
-    let delife = params.borrowed.de_lifetime();
-    let field_ty = field.ty;
-    let deserializer_var = quote!(__e);
-
-    let value = match field.attrs.deserialize_with() {
-        None => {
-            let span = field.original.span();
-            let func = quote_spanned!(span=> <#field_ty as _serde::Deserialize>::deserialize);
-            quote! {
-                #func(#deserializer_var)?
-            }
-        }
-        Some(path) => {
-            // If #path returns wrong type, error will be reported here (^^^^^).
-            // We attach span of the path to the function so it will be reported
-            // on the #[serde(with = "...")]
-            //                       ^^^^^
-            quote_spanned! {path.span()=>
-                #path(#deserializer_var)?
-            }
-        }
-    };
-
-    let mut result = quote!(#type_path(__field0));
-    if params.has_getter {
-        let this_type = &params.this_type;
-        let (_, ty_generics, _) = params.generics.split_for_impl();
-        result = quote! {
-            _serde::#private::Into::<#this_type #ty_generics>::into(#result)
-        };
-    }
-
-    quote! {
-        #[inline]
-        fn visit_newtype_struct<__E>(self, #deserializer_var: __E) -> _serde::#private::Result<Self::Value, __E::Error>
-        where
-            __E: _serde::Deserializer<#delife>,
-        {
-            let __field0: #field_ty = #value;
-            _serde::#private::Ok(#result)
-        }
-    }
-}
-
-/// Generates `Deserialize::deserialize_in_place` body for a `struct Tuple(...);` including `struct Newtype(T);`
-#[cfg(feature = "deserialize_in_place")]
-pub(super) fn deserialize_in_place(
-    params: &Parameters,
-    fields: &[Field],
-    cattrs: &attr::Container,
-) -> Fragment {
-    assert!(
-        !has_flatten(fields),
-        "tuples and tuple variants cannot have flatten fields"
-    );
-
-    let field_count = fields
-        .iter()
-        .filter(|field| !field.attrs.skip_deserializing())
-        .count();
-
-    let this_type = &params.this_type;
-    let (de_impl_generics, de_ty_generics, ty_generics, where_clause) =
-        params.generics_with_de_lifetime();
-    let delife = params.borrowed.de_lifetime();
-
-    let expecting = format!("tuple struct {}", params.type_name());
-    let expecting = cattrs.expecting().unwrap_or(&expecting);
-
-    let nfields = fields.len();
-
-    let visit_newtype_struct = if nfields == 1 {
-        // We do not generate deserialize_in_place if every field has a
-        // deserialize_with.
-        assert!(fields[0].attrs.deserialize_with().is_none());
-
-        Some(quote! {
-            #[inline]
-            fn visit_newtype_struct<__E>(self, __e: __E) -> _serde::#private::Result<Self::Value, __E::Error>
-            where
-                __E: _serde::Deserializer<#delife>,
-            {
-                _serde::Deserialize::deserialize_in_place(__e, &mut self.place.0)
-            }
-        })
-    } else {
-        None
-    };
-
-    let visit_seq = Stmts(deserialize_seq_in_place(params, fields, cattrs, expecting));
-
-    let visitor_expr = quote! {
-        __Visitor {
-            place: __place,
-            lifetime: _serde::#private::PhantomData,
-        }
-    };
-
-    let type_name = cattrs.name().deserialize_name();
-    let dispatch = if nfields == 1 {
-        quote!(_serde::Deserializer::deserialize_newtype_struct(__deserializer, #type_name, #visitor_expr))
-    } else {
-        quote!(_serde::Deserializer::deserialize_tuple_struct(__deserializer, #type_name, #field_count, #visitor_expr))
-    };
-
-    let visitor_var = if field_count == 0 {
-        quote!(_)
-    } else {
-        quote!(mut __seq)
-    };
-
-    let in_place_impl_generics = de_impl_generics.in_place();
-    let in_place_ty_generics = de_ty_generics.in_place();
-    let place_life = place_lifetime();
-
-    quote_block! {
-        #[doc(hidden)]
-        struct __Visitor #in_place_impl_generics #where_clause {
-            place: &#place_life mut #this_type #ty_generics,
-            lifetime: _serde::#private::PhantomData<&#delife ()>,
-        }
-
-        #[automatically_derived]
-        impl #in_place_impl_generics _serde::de::Visitor<#delife> for __Visitor #in_place_ty_generics #where_clause {
-            type Value = ();
-
-            fn expecting(&self, __formatter: &mut _serde::#private::Formatter) -> _serde::#private::fmt::Result {
-                _serde::#private::Formatter::write_str(__formatter, #expecting)
-            }
-
-            #visit_newtype_struct
-
-            #[inline]
-            fn visit_seq<__A>(self, #visitor_var: __A) -> _serde::#private::Result<Self::Value, __A::Error>
-            where
-                __A: _serde::de::SeqAccess<#delife>,
-            {
-                #visit_seq
-            }
-        }
-
-        #dispatch
-    }
-}
@@ -1,52 +0,0 @@
-use crate::de::Parameters;
-use crate::fragment::Fragment;
-use crate::internals::attr;
-use crate::private;
-use quote::quote;
-
-/// Generates `Deserialize::deserialize` body for a `struct Unit;`
-pub(super) fn deserialize(params: &Parameters, cattrs: &attr::Container) -> Fragment {
-    let this_type = &params.this_type;
-    let this_value = &params.this_value;
-    let type_name = cattrs.name().deserialize_name();
-    let (de_impl_generics, de_ty_generics, ty_generics, where_clause) =
-        params.generics_with_de_lifetime();
-    let delife = params.borrowed.de_lifetime();
-
-    let expecting = format!("unit struct {}", params.type_name());
-    let expecting = cattrs.expecting().unwrap_or(&expecting);
-
-    quote_block! {
-        #[doc(hidden)]
-        struct __Visitor #de_impl_generics #where_clause {
-            marker: _serde::#private::PhantomData<#this_type #ty_generics>,
-            lifetime: _serde::#private::PhantomData<&#delife ()>,
-        }
-
-        #[automatically_derived]
-        impl #de_impl_generics _serde::de::Visitor<#delife> for __Visitor #de_ty_generics #where_clause {
-            type Value = #this_type #ty_generics;
-
-            fn expecting(&self, __formatter: &mut _serde::#private::Formatter) -> _serde::#private::fmt::Result {
-                _serde::#private::Formatter::write_str(__formatter, #expecting)
-            }
-
-            #[inline]
-            fn visit_unit<__E>(self) -> _serde::#private::Result<Self::Value, __E>
-            where
-                __E: _serde::de::Error,
-            {
-                _serde::#private::Ok(#this_value)
-            }
-        }
-
-        _serde::Deserializer::deserialize_unit_struct(
-            __deserializer,
-            #type_name,
-            __Visitor {
-                marker: _serde::#private::PhantomData::<#this_type #ty_generics>,
-                lifetime: _serde::#private::PhantomData,
-            },
-        )
-    }
-}
@@ -1,56 +0,0 @@
-use proc_macro2::TokenStream;
-use quote::quote;
-
-pub fn allow_deprecated(input: &syn::DeriveInput) -> Option<TokenStream> {
-    if should_allow_deprecated(input) {
-        Some(quote! { #[allow(deprecated)] })
-    } else {
-        None
-    }
-}
-
-/// Determine if an `#[allow(deprecated)]` should be added to the derived impl.
-///
-/// This should happen if the derive input or an enum variant it contains has
-/// one of:
-///   - `#[deprecated]`
-///   - `#[allow(deprecated)]`
-fn should_allow_deprecated(input: &syn::DeriveInput) -> bool {
-    if contains_deprecated(&input.attrs) {
-        return true;
-    }
-    if let syn::Data::Enum(data_enum) = &input.data {
-        for variant in &data_enum.variants {
-            if contains_deprecated(&variant.attrs) {
-                return true;
-            }
-        }
-    }
-    false
-}
-
-/// Check whether the given attributes contains one of:
-///   - `#[deprecated]`
-///   - `#[allow(deprecated)]`
-fn contains_deprecated(attrs: &[syn::Attribute]) -> bool {
-    for attr in attrs {
-        if attr.path().is_ident("deprecated") {
-            return true;
-        }
-        if let syn::Meta::List(meta_list) = &attr.meta {
-            if meta_list.path.is_ident("allow") {
-                let mut allow_deprecated = false;
-                let _ = meta_list.parse_nested_meta(|meta| {
-                    if meta.path.is_ident("deprecated") {
-                        allow_deprecated = true;
-                    }
-                    Ok(())
-                });
-                if allow_deprecated {
-                    return true;
-                }
-            }
-        }
-    }
-    false
-}
@@ -1,7 +1,23 @@
-use proc_macro2::TokenStream;
-use quote::quote;
+use proc_macro2::{Ident, TokenStream};
+use quote::format_ident;
+
+use syn;
+use try;
+
+pub fn wrap_in_const(
+    serde_path: Option<&syn::Path>,
+    trait_: &str,
+    ty: &Ident,
+    code: TokenStream,
+) -> TokenStream {
+    let try_replacement = try::replacement();
+
+    let dummy_const = if cfg!(underscore_consts) {
+        format_ident!("_")
+    } else {
+        format_ident!("_IMPL_{}_FOR_{}", trait_, unraw(ty))
+    };

-pub fn wrap_in_const(serde_path: Option<&syn::Path>, code: TokenStream) -> TokenStream {
    let use_serde = match serde_path {
        Some(path) => quote! {
            use #path as _serde;
@@ -14,18 +30,19 @@ pub fn wrap_in_const(serde_path: Option<&syn::Path>, code: TokenStream) -> Token

    quote! {
        #[doc(hidden)]
-        #[allow(
-            non_upper_case_globals,
-            unused_attributes,
-            unused_qualifications,
-            clippy::absolute_paths,
-        )]
-        const _: () = {
+        #[allow(non_upper_case_globals, unused_attributes, unused_qualifications)]
+        const #dummy_const: () = {
            #use_serde
-
-            _serde::__require_serde_not_serde_core!();
-
+            #try_replacement
            #code
        };
    }
 }
+
+#[allow(deprecated)]
+fn unraw(ident: &Ident) -> String {
+    // str::trim_start_matches was added in 1.30, trim_left_matches deprecated
+    // in 1.33. We currently support rustc back to 1.15 so we need to continue
+    // to use the deprecated one.
+    ident.to_string().trim_left_matches("r#").to_owned()
+}
@@ -1,6 +1,6 @@
 use proc_macro2::TokenStream;
 use quote::ToTokens;
-use syn::{token, Token};
+use syn::token;

 pub enum Fragment {
    /// Tokens that can be used as an expression.
@@ -1,9 +1,10 @@
 //! A Serde ast, parsed from the Syn ast and ready to generate Rust code.

-use crate::internals::{attr, check, Ctxt, Derive};
-use proc_macro2::Ident;
+use internals::attr;
+use internals::check;
+use internals::{Ctxt, Derive};
+use syn;
 use syn::punctuated::Punctuated;
-use syn::Token;

 /// A source data structure annotated with `#[derive(Serialize)]` and/or `#[derive(Deserialize)]`,
 /// parsed into an internal representation.
@@ -63,17 +64,13 @@ impl<'a> Container<'a> {
        cx: &Ctxt,
        item: &'a syn::DeriveInput,
        derive: Derive,
-        private: &Ident,
    ) -> Option<Container<'a>> {
-        let attrs = attr::Container::from_ast(cx, item);
+        let mut attrs = attr::Container::from_ast(cx, item);

        let mut data = match &item.data {
-            syn::Data::Enum(data) => {
-                Data::Enum(enum_from_ast(cx, &data.variants, attrs.default(), private))
-            }
+            syn::Data::Enum(data) => Data::Enum(enum_from_ast(cx, &data.variants, attrs.default())),
            syn::Data::Struct(data) => {
-                let (style, fields) =
-                    struct_from_ast(cx, &data.fields, None, attrs.default(), private);
+                let (style, fields) = struct_from_ast(cx, &data.fields, None, attrs.default());
                Data::Struct(style, fields)
            }
            syn::Data::Union(_) => {
@@ -82,27 +79,35 @@ impl<'a> Container<'a> {
            }
        };

+        let mut has_flatten = false;
        match &mut data {
            Data::Enum(variants) => {
                for variant in variants {
                    variant.attrs.rename_by_rules(attrs.rename_all_rules());
                    for field in &mut variant.fields {
-                        field.attrs.rename_by_rules(
-                            variant
-                                .attrs
-                                .rename_all_rules()
-                                .or(attrs.rename_all_fields_rules()),
-                        );
+                        if field.attrs.flatten() {
+                            has_flatten = true;
+                        }
+                        field
+                            .attrs
+                            .rename_by_rules(variant.attrs.rename_all_rules());
                    }
                }
            }
            Data::Struct(_, fields) => {
                for field in fields {
+                    if field.attrs.flatten() {
+                        has_flatten = true;
+                    }
                    field.attrs.rename_by_rules(attrs.rename_all_rules());
                }
            }
        }

+        if has_flatten {
+            attrs.mark_has_flatten();
+        }
+
        let mut item = Container {
            ident: item.ident.clone(),
            attrs,
@@ -116,7 +121,7 @@ impl<'a> Container<'a> {
 }

 impl<'a> Data<'a> {
-    pub fn all_fields(&'a self) -> Box<dyn Iterator<Item = &'a Field<'a>> + 'a> {
+    pub fn all_fields(&'a self) -> Box<Iterator<Item = &'a Field<'a>> + 'a> {
        match self {
            Data::Enum(variants) => {
                Box::new(variants.iter().flat_map(|variant| variant.fields.iter()))
@@ -134,19 +139,13 @@ fn enum_from_ast<'a>(
    cx: &Ctxt,
    variants: &'a Punctuated<syn::Variant, Token![,]>,
    container_default: &attr::Default,
-    private: &Ident,
 ) -> Vec<Variant<'a>> {
-    let variants: Vec<Variant> = variants
+    variants
        .iter()
        .map(|variant| {
            let attrs = attr::Variant::from_ast(cx, variant);
-            let (style, fields) = struct_from_ast(
-                cx,
-                &variant.fields,
-                Some(&attrs),
-                container_default,
-                private,
-            );
+            let (style, fields) =
+                struct_from_ast(cx, &variant.fields, Some(&attrs), container_default);
            Variant {
                ident: variant.ident.clone(),
                attrs,
@@ -155,20 +154,7 @@ fn enum_from_ast<'a>(
                original: variant,
            }
        })
-        .collect();
-
-    let index_of_last_tagged_variant = variants
-        .iter()
-        .rposition(|variant| !variant.attrs.untagged());
-    if let Some(index_of_last_tagged_variant) = index_of_last_tagged_variant {
-        for variant in &variants[..index_of_last_tagged_variant] {
-            if variant.attrs.untagged() {
-                cx.error_spanned_by(&variant.ident, "all variants with the #[serde(untagged)] attribute must be placed at the end of the enum");
-            }
-        }
-    }
-
-    variants
+        .collect()
 }

 fn struct_from_ast<'a>(
@@ -176,20 +162,19 @@ fn struct_from_ast<'a>(
    fields: &'a syn::Fields,
    attrs: Option<&attr::Variant>,
    container_default: &attr::Default,
-    private: &Ident,
 ) -> (Style, Vec<Field<'a>>) {
    match fields {
        syn::Fields::Named(fields) => (
            Style::Struct,
-            fields_from_ast(cx, &fields.named, attrs, container_default, private),
+            fields_from_ast(cx, &fields.named, attrs, container_default),
        ),
        syn::Fields::Unnamed(fields) if fields.unnamed.len() == 1 => (
            Style::Newtype,
-            fields_from_ast(cx, &fields.unnamed, attrs, container_default, private),
+            fields_from_ast(cx, &fields.unnamed, attrs, container_default),
        ),
        syn::Fields::Unnamed(fields) => (
            Style::Tuple,
-            fields_from_ast(cx, &fields.unnamed, attrs, container_default, private),
+            fields_from_ast(cx, &fields.unnamed, attrs, container_default),
        ),
        syn::Fields::Unit => (Style::Unit, Vec::new()),
    }
@@ -200,7 +185,6 @@ fn fields_from_ast<'a>(
    fields: &'a Punctuated<syn::Field, Token![,]>,
    attrs: Option<&attr::Variant>,
    container_default: &attr::Default,
-    private: &Ident,
 ) -> Vec<Field<'a>> {
    fields
        .iter()
@@ -210,7 +194,7 @@ fn fields_from_ast<'a>(
                Some(ident) => syn::Member::Named(ident.clone()),
                None => syn::Member::Unnamed(i.into()),
            },
-            attrs: attr::Field::from_ast(cx, i, field, attrs, container_default, private),
+            attrs: attr::Field::from_ast(cx, i, field, attrs, container_default),
            ty: &field.ty,
            original: field,
        })
@@ -1,9 +1,14 @@
 //! Code to convert the Rust-styled field/variant (e.g. `my_field`, `MyType`) to the
 //! case of the source (e.g. `my-field`, `MY_FIELD`).

-use self::RenameRule::*;
+// See https://users.rust-lang.org/t/psa-dealing-with-warning-unused-import-std-ascii-asciiext-in-today-s-nightly/13726
+#[allow(deprecated, unused_imports)]
+use std::ascii::AsciiExt;
+
 use std::fmt::{self, Debug, Display};

+use self::RenameRule::*;
+
 /// The different possible ways to change case of fields in a struct, or variants in an enum.
 #[derive(Copy, Clone, PartialEq)]
 pub enum RenameRule {
@@ -54,8 +59,8 @@ impl RenameRule {
    }

    /// Apply a renaming rule to an enum variant, returning the version expected in the source.
-    pub fn apply_to_variant(self, variant: &str) -> String {
-        match self {
+    pub fn apply_to_variant(&self, variant: &str) -> String {
+        match *self {
            None | PascalCase => variant.to_owned(),
            LowerCase => variant.to_ascii_lowercase(),
            UpperCase => variant.to_ascii_uppercase(),
@@ -79,8 +84,8 @@ impl RenameRule {
    }

    /// Apply a renaming rule to a struct field, returning the version expected in the source.
-    pub fn apply_to_field(self, field: &str) -> String {
-        match self {
+    pub fn apply_to_field(&self, field: &str) -> String {
+        match *self {
            None | LowerCase | SnakeCase => field.to_owned(),
            UpperCase => field.to_ascii_uppercase(),
            PascalCase => {
@@ -107,14 +112,6 @@ impl RenameRule {
            ScreamingKebabCase => ScreamingSnakeCase.apply_to_field(field).replace('_', "-"),
        }
    }
-
-    /// Returns the `RenameRule` if it is not `None`, `rule_b` otherwise.
-    pub fn or(self, rule_b: Self) -> Self {
-        match self {
-            None => rule_b,
-            _ => self,
-        }
-    }
 }

 pub struct ParseError<'a> {
@@ -1,13 +1,11 @@
-use crate::internals::ast::{Container, Data, Field, Style};
-use crate::internals::attr::{Default, Identifier, TagType};
-use crate::internals::{ungroup, Ctxt, Derive};
+use internals::ast::{Container, Data, Field, Style};
+use internals::attr::{Identifier, TagType};
+use internals::{ungroup, Ctxt, Derive};
 use syn::{Member, Type};

-// Cross-cutting checks that require looking at more than a single attrs object.
-// Simpler checks should happen when parsing and building the attrs.
+/// Cross-cutting checks that require looking at more than a single attrs
+/// object. Simpler checks should happen when parsing and building the attrs.
 pub fn check(cx: &Ctxt, cont: &mut Container, derive: Derive) {
-    check_default_on_tuple(cx, cont);
-    check_remote_generic(cx, cont);
    check_getter(cx, cont);
    check_flatten(cx, cont);
    check_identifier(cx, cont);
@@ -18,63 +16,8 @@ pub fn check(cx: &Ctxt, cont: &mut Container, derive: Derive) {
    check_from_and_try_from(cx, cont);
 }

-// If some field of a tuple struct is marked #[serde(default)] then all fields
-// after it must also be marked with that attribute, or the struct must have a
-// container-level serde(default) attribute. A field's default value is only
-// used for tuple fields if the sequence is exhausted at that point; that means
-// all subsequent fields will fail to deserialize if they don't have their own
-// default.
-fn check_default_on_tuple(cx: &Ctxt, cont: &Container) {
-    if let Default::None = cont.attrs.default() {
-        if let Data::Struct(Style::Tuple, fields) = &cont.data {
-            let mut first_default_index = None;
-            for (i, field) in fields.iter().enumerate() {
-                // Skipped fields automatically get the #[serde(default)]
-                // attribute. We are interested only on non-skipped fields here.
-                if field.attrs.skip_deserializing() {
-                    continue;
-                }
-                if let Default::None = field.attrs.default() {
-                    if let Some(first) = first_default_index {
-                        cx.error_spanned_by(
-                            field.ty,
-                            format!("field must have #[serde(default)] because previous field {} has #[serde(default)]", first),
-                        );
-                    }
-                    continue;
-                }
-                if first_default_index.is_none() {
-                    first_default_index = Some(i);
-                }
-            }
-        }
-    }
-}
-
-// Remote derive definition type must have either all of the generics of the
-// remote type:
-//
-//     #[serde(remote = "Generic")]
-//     struct Generic<T> {…}
-//
-// or none of them, i.e. defining impls for one concrete instantiation of the
-// remote type only:
-//
-//     #[serde(remote = "Generic<T>")]
-//     struct ConcreteDef {…}
-//
-fn check_remote_generic(cx: &Ctxt, cont: &Container) {
-    if let Some(remote) = cont.attrs.remote() {
-        let local_has_generic = !cont.generics.params.is_empty();
-        let remote_has_generic = !remote.segments.last().unwrap().arguments.is_none();
-        if local_has_generic && remote_has_generic {
-            cx.error_spanned_by(remote, "remove generic parameters from this path");
-        }
-    }
-}
-
-// Getters are only allowed inside structs (not enums) with the `remote`
-// attribute.
+/// Getters are only allowed inside structs (not enums) with the `remote`
+/// attribute.
 fn check_getter(cx: &Ctxt, cont: &Container) {
    match cont.data {
        Data::Enum(_) => {
@@ -96,7 +39,7 @@ fn check_getter(cx: &Ctxt, cont: &Container) {
    }
 }

-// Flattening has some restrictions we can test.
+/// Flattening has some restrictions we can test.
 fn check_flatten(cx: &Ctxt, cont: &Container) {
    match &cont.data {
        Data::Enum(variants) => {
@@ -135,16 +78,18 @@ fn check_flatten_field(cx: &Ctxt, style: Style, field: &Field) {
    }
 }

-// The `other` attribute must be used at most once and it must be the last
-// variant of an enum.
-//
-// Inside a `variant_identifier` all variants must be unit variants. Inside a
-// `field_identifier` all but possibly one variant must be unit variants. The
-// last variant may be a newtype variant which is an implicit "other" case.
+/// The `other` attribute must be used at most once and it must be the last
+/// variant of an enum.
+///
+/// Inside a `variant_identifier` all variants must be unit variants. Inside a
+/// `field_identifier` all but possibly one variant must be unit variants. The
+/// last variant may be a newtype variant which is an implicit "other" case.
 fn check_identifier(cx: &Ctxt, cont: &Container) {
    let variants = match &cont.data {
        Data::Enum(variants) => variants,
-        Data::Struct(_, _) => return,
+        Data::Struct(_, _) => {
+            return;
+        }
    };

    for (i, variant) in variants.iter().enumerate() {
@@ -221,15 +166,17 @@ fn check_identifier(cx: &Ctxt, cont: &Container) {
    }
 }

-// Skip-(de)serializing attributes are not allowed on variants marked
-// (de)serialize_with.
+/// Skip-(de)serializing attributes are not allowed on variants marked
+/// (de)serialize_with.
 fn check_variant_skip_attrs(cx: &Ctxt, cont: &Container) {
    let variants = match &cont.data {
        Data::Enum(variants) => variants,
-        Data::Struct(_, _) => return,
+        Data::Struct(_, _) => {
+            return;
+        }
    };

-    for variant in variants {
+    for variant in variants.iter() {
        if variant.attrs.serialize_with().is_some() {
            if variant.attrs.skip_serializing() {
                cx.error_spanned_by(
@@ -294,9 +241,10 @@ fn check_variant_skip_attrs(cx: &Ctxt, cont: &Container) {
    }
 }

-// The tag of an internally-tagged struct variant must not be the same as either
-// one of its fields, as this would result in duplicate keys in the serialized
-// output and/or ambiguity in the to-be-deserialized input.
+/// The tag of an internally-tagged struct variant must not be
+/// the same as either one of its fields, as this would result in
+/// duplicate keys in the serialized output and/or ambiguity in
+/// the to-be-deserialized input.
 fn check_internal_tag_field_name_conflict(cx: &Ctxt, cont: &Container) {
    let variants = match &cont.data {
        Data::Enum(variants) => variants,
@@ -318,24 +266,19 @@ fn check_internal_tag_field_name_conflict(cx: &Ctxt, cont: &Container) {
    for variant in variants {
        match variant.style {
            Style::Struct => {
-                if variant.attrs.untagged() {
-                    continue;
-                }
                for field in &variant.fields {
-                    let check_ser =
-                        !(field.attrs.skip_serializing() || variant.attrs.skip_serializing());
-                    let check_de =
-                        !(field.attrs.skip_deserializing() || variant.attrs.skip_deserializing());
+                    let check_ser = !field.attrs.skip_serializing();
+                    let check_de = !field.attrs.skip_deserializing();
                    let name = field.attrs.name();
                    let ser_name = name.serialize_name();

-                    if check_ser && ser_name.value == tag {
+                    if check_ser && ser_name == tag {
                        diagnose_conflict();
                        return;
                    }

                    for de_name in field.attrs.aliases() {
-                        if check_de && de_name.value == tag {
+                        if check_de && de_name == tag {
                            diagnose_conflict();
                            return;
                        }
@@ -347,8 +290,8 @@ fn check_internal_tag_field_name_conflict(cx: &Ctxt, cont: &Container) {
    }
 }

-// In the case of adjacently-tagged enums, the type and the contents tag must
-// differ, for the same reason.
+/// In the case of adjacently-tagged enums, the type and the
+/// contents tag must differ, for the same reason.
 fn check_adjacent_tag_conflict(cx: &Ctxt, cont: &Container) {
    let (type_tag, content_tag) = match cont.attrs.tag() {
        TagType::Adjacent { tag, content } => (tag, content),
@@ -366,7 +309,7 @@ fn check_adjacent_tag_conflict(cx: &Ctxt, cont: &Container) {
    }
 }

-// Enums and unit structs cannot be transparent.
+/// Enums and unit structs cannot be transparent.
 fn check_transparent(cx: &Ctxt, cont: &mut Container, derive: Derive) {
    if !cont.attrs.transparent() {
        return;
@@ -2,6 +2,7 @@ use quote::ToTokens;
 use std::cell::RefCell;
 use std::fmt::Display;
 use std::thread;
+use syn;

 /// A type to collect errors together and format them.
 ///
@@ -43,18 +44,12 @@ impl Ctxt {
    }

    /// Consume this object, producing a formatted error string if there are errors.
-    pub fn check(self) -> syn::Result<()> {
-        let mut errors = self.errors.borrow_mut().take().unwrap().into_iter();
-
-        let Some(mut combined) = errors.next() else {
-            return Ok(());
-        };
-
-        for rest in errors {
-            combined.combine(rest);
+    pub fn check(self) -> Result<(), Vec<syn::Error>> {
+        let errors = self.errors.borrow_mut().take().unwrap();
+        match errors.len() {
+            0 => Ok(()),
+            _ => Err(errors),
        }
-
-        Err(combined)
    }
 }

@@ -1,19 +1,19 @@
 pub mod ast;
 pub mod attr;
-pub mod name;
+
+mod ctxt;
+pub use self::ctxt::Ctxt;
+
+mod receiver;
+pub use self::receiver::replace_receiver;

 mod case;
 mod check;
-mod ctxt;
-mod receiver;
 mod respan;
 mod symbol;

 use syn::Type;

-pub use self::ctxt::Ctxt;
-pub use self::receiver::replace_receiver;
-
 #[derive(Copy, Clone)]
 pub enum Derive {
    Serialize,
@@ -1,113 +0,0 @@
-use crate::internals::attr::{Attr, VecAttr};
-use proc_macro2::{Ident, Span, TokenStream};
-use quote::ToTokens;
-use std::cmp::Ordering;
-use std::collections::BTreeSet;
-use std::fmt::{self, Display};
-use syn::LitStr;
-
-pub struct MultiName {
-    pub(crate) serialize: Name,
-    pub(crate) serialize_renamed: bool,
-    pub(crate) deserialize: Name,
-    pub(crate) deserialize_renamed: bool,
-    pub(crate) deserialize_aliases: BTreeSet<Name>,
-}
-
-impl MultiName {
-    pub(crate) fn from_attrs(
-        source_name: Name,
-        ser_name: Attr<Name>,
-        de_name: Attr<Name>,
-        de_aliases: Option<VecAttr<Name>>,
-    ) -> Self {
-        let mut alias_set = BTreeSet::new();
-        if let Some(de_aliases) = de_aliases {
-            for alias_name in de_aliases.get() {
-                alias_set.insert(alias_name);
-            }
-        }
-
-        let ser_name = ser_name.get();
-        let ser_renamed = ser_name.is_some();
-        let de_name = de_name.get();
-        let de_renamed = de_name.is_some();
-        MultiName {
-            serialize: ser_name.unwrap_or_else(|| source_name.clone()),
-            serialize_renamed: ser_renamed,
-            deserialize: de_name.unwrap_or(source_name),
-            deserialize_renamed: de_renamed,
-            deserialize_aliases: alias_set,
-        }
-    }
-
-    /// Return the container name for the container when serializing.
-    pub fn serialize_name(&self) -> &Name {
-        &self.serialize
-    }
-
-    /// Return the container name for the container when deserializing.
-    pub fn deserialize_name(&self) -> &Name {
-        &self.deserialize
-    }
-
-    pub(crate) fn deserialize_aliases(&self) -> &BTreeSet<Name> {
-        &self.deserialize_aliases
-    }
-}
-
-#[derive(Clone)]
-pub struct Name {
-    pub value: String,
-    pub span: Span,
-}
-
-impl ToTokens for Name {
-    fn to_tokens(&self, tokens: &mut TokenStream) {
-        LitStr::new(&self.value, self.span).to_tokens(tokens);
-    }
-}
-
-impl Ord for Name {
-    fn cmp(&self, other: &Self) -> Ordering {
-        Ord::cmp(&self.value, &other.value)
-    }
-}
-
-impl PartialOrd for Name {
-    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
-        Some(Ord::cmp(self, other))
-    }
-}
-
-impl Eq for Name {}
-
-impl PartialEq for Name {
-    fn eq(&self, other: &Self) -> bool {
-        self.value == other.value
-    }
-}
-
-impl From<&Ident> for Name {
-    fn from(ident: &Ident) -> Self {
-        Name {
-            value: ident.to_string(),
-            span: ident.span(),
-        }
-    }
-}
-
-impl From<&LitStr> for Name {
-    fn from(lit: &LitStr) -> Self {
-        Name {
-            value: lit.value(),
-            span: lit.span(),
-        }
-    }
-}
-
-impl Display for Name {
-    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
-        Display::fmt(&self.value, formatter)
-    }
-}
@@ -1,10 +1,11 @@
-use crate::internals::respan::respan;
+use internals::respan::respan;
 use proc_macro2::Span;
 use quote::ToTokens;
 use std::mem;
+use syn::punctuated::Punctuated;
 use syn::{
    parse_quote, Data, DeriveInput, Expr, ExprPath, GenericArgument, GenericParam, Generics, Macro,
-    Path, PathArguments, QSelf, ReturnType, Token, Type, TypeParamBound, TypePath, WherePredicate,
+    Path, PathArguments, QSelf, ReturnType, Type, TypeParamBound, TypePath, WherePredicate,
 };

 pub fn replace_receiver(input: &mut DeriveInput) {
@@ -48,7 +49,7 @@ impl ReplaceReceiver<'_> {

        path.leading_colon = Some(**path.segments.pairs().next().unwrap().punct().unwrap());

-        let segments = mem::take(&mut path.segments);
+        let segments = mem::replace(&mut path.segments, Punctuated::new());
        path.segments = segments.into_pairs().skip(1).collect();
    }

@@ -83,7 +84,7 @@ impl ReplaceReceiver<'_> {
            self.visit_type_mut_impl(ty);
            return;
        };
-        *ty = Type::Path(self.self_ty(span));
+        *ty = self.self_ty(span).into();
    }

    // `Self::Assoc` -> `<Receiver>::Assoc`
@@ -106,7 +107,6 @@ impl ReplaceReceiver<'_> {

    fn visit_type_mut_impl(&mut self, ty: &mut Type) {
        match ty {
-            #![cfg_attr(all(test, exhaustive), deny(non_exhaustive_omitted_patterns))]
            Type::Array(ty) => {
                self.visit_type_mut(&mut ty.elem);
                self.visit_expr_mut(&mut ty.len);
@@ -147,6 +147,7 @@ impl ReplaceReceiver<'_> {

            Type::Infer(_) | Type::Never(_) | Type::Verbatim(_) => {}

+            #[cfg_attr(all(test, exhaustive), deny(non_exhaustive_omitted_patterns))]
            _ => {}
        }
    }
@@ -177,14 +178,11 @@ impl ReplaceReceiver<'_> {
            PathArguments::AngleBracketed(arguments) => {
                for arg in &mut arguments.args {
                    match arg {
-                        #![cfg_attr(all(test, exhaustive), deny(non_exhaustive_omitted_patterns))]
                        GenericArgument::Type(arg) => self.visit_type_mut(arg),
-                        GenericArgument::AssocType(arg) => self.visit_type_mut(&mut arg.ty),
+                        GenericArgument::Binding(arg) => self.visit_type_mut(&mut arg.ty),
                        GenericArgument::Lifetime(_)
-                        | GenericArgument::Const(_)
-                        | GenericArgument::AssocConst(_)
-                        | GenericArgument::Constraint(_) => {}
-                        _ => {}
+                        | GenericArgument::Constraint(_)
+                        | GenericArgument::Const(_) => {}
                    }
                }
            }
@@ -206,12 +204,8 @@ impl ReplaceReceiver<'_> {

    fn visit_type_param_bound_mut(&mut self, bound: &mut TypeParamBound) {
        match bound {
-            #![cfg_attr(all(test, exhaustive), deny(non_exhaustive_omitted_patterns))]
            TypeParamBound::Trait(bound) => self.visit_path_mut(&mut bound.path),
-            TypeParamBound::Lifetime(_)
-            | TypeParamBound::PreciseCapture(_)
-            | TypeParamBound::Verbatim(_) => {}
-            _ => {}
+            TypeParamBound::Lifetime(_) => {}
        }
    }

@@ -229,15 +223,13 @@ impl ReplaceReceiver<'_> {
        if let Some(where_clause) = &mut generics.where_clause {
            for predicate in &mut where_clause.predicates {
                match predicate {
-                    #![cfg_attr(all(test, exhaustive), deny(non_exhaustive_omitted_patterns))]
                    WherePredicate::Type(predicate) => {
                        self.visit_type_mut(&mut predicate.bounded_ty);
                        for bound in &mut predicate.bounds {
                            self.visit_type_param_bound_mut(bound);
                        }
                    }
-                    WherePredicate::Lifetime(_) => {}
-                    _ => {}
+                    WherePredicate::Lifetime(_) | WherePredicate::Eq(_) => {}
                }
            }
        }
@@ -13,19 +13,15 @@ pub const DEFAULT: Symbol = Symbol("default");
 pub const DENY_UNKNOWN_FIELDS: Symbol = Symbol("deny_unknown_fields");
 pub const DESERIALIZE: Symbol = Symbol("deserialize");
 pub const DESERIALIZE_WITH: Symbol = Symbol("deserialize_with");
-pub const EXPECTING: Symbol = Symbol("expecting");
 pub const FIELD_IDENTIFIER: Symbol = Symbol("field_identifier");
 pub const FLATTEN: Symbol = Symbol("flatten");
 pub const FROM: Symbol = Symbol("from");
 pub const GETTER: Symbol = Symbol("getter");
 pub const INTO: Symbol = Symbol("into");
-pub const NON_EXHAUSTIVE: Symbol = Symbol("non_exhaustive");
 pub const OTHER: Symbol = Symbol("other");
 pub const REMOTE: Symbol = Symbol("remote");
 pub const RENAME: Symbol = Symbol("rename");
 pub const RENAME_ALL: Symbol = Symbol("rename_all");
-pub const RENAME_ALL_FIELDS: Symbol = Symbol("rename_all_fields");
-pub const REPR: Symbol = Symbol("repr");
 pub const SERDE: Symbol = Symbol("serde");
 pub const SERIALIZE: Symbol = Symbol("serialize");
 pub const SERIALIZE_WITH: Symbol = Symbol("serialize_with");
@@ -39,6 +35,7 @@ pub const TRY_FROM: Symbol = Symbol("try_from");
 pub const UNTAGGED: Symbol = Symbol("untagged");
 pub const VARIANT_IDENTIFIER: Symbol = Symbol("variant_identifier");
 pub const WITH: Symbol = Symbol("with");
+pub const EXPECTING: Symbol = Symbol("expecting");

 impl PartialEq<Symbol> for Ident {
    fn eq(&self, word: &Symbol) -> bool {
@@ -46,7 +43,7 @@ impl PartialEq<Symbol> for Ident {
    }
 }

-impl PartialEq<Symbol> for &Ident {
+impl<'a> PartialEq<Symbol> for &'a Ident {
    fn eq(&self, word: &Symbol) -> bool {
        *self == word.0
    }
@@ -58,7 +55,7 @@ impl PartialEq<Symbol> for Path {
    }
 }

-impl PartialEq<Symbol> for &Path {
+impl<'a> PartialEq<Symbol> for &'a Path {
    fn eq(&self, word: &Symbol) -> bool {
        self.is_ident(word.0)
    }
@@ -1,7 +1,7 @@
 //! This crate provides Serde's two derive macros.
 //!
-//! ```edition2021
-//! # use serde_derive::{Deserialize, Serialize};
+//! ```edition2018
+//! # use serde_derive::{Serialize, Deserialize};
 //! #
 //! #[derive(Serialize, Deserialize)]
 //! # struct S;
@@ -13,8 +13,8 @@
 //!
 //! [https://serde.rs/derive.html]: https://serde.rs/derive.html

-#![doc(html_root_url = "https://docs.rs/serde_derive/1.0.228")]
-#![cfg_attr(not(check_cfg), allow(unexpected_cfgs))]
+#![doc(html_root_url = "https://docs.rs/serde_derive/1.0.137")]
+#![allow(unknown_lints, bare_trait_objects)]
 // Ignored clippy lints
 #![allow(
    // clippy false positive: https://github.com/rust-lang/rust-clippy/issues/7054
@@ -27,7 +27,6 @@
    // clippy bug: https://github.com/rust-lang/rust-clippy/issues/6797
    clippy::manual_map,
    clippy::match_like_matches_macro,
-    clippy::needless_lifetimes,
    clippy::needless_pass_by_value,
    clippy::too_many_arguments,
    clippy::trivially_copy_pass_by_ref,
@@ -41,11 +40,10 @@
    clippy::cast_possible_truncation,
    clippy::checked_conversions,
    clippy::doc_markdown,
-    clippy::elidable_lifetime_names,
    clippy::enum_glob_use,
    clippy::indexing_slicing,
    clippy::items_after_statements,
-    clippy::let_underscore_untyped,
+    clippy::let_underscore_drop,
    clippy::manual_assert,
    clippy::map_err_ignore,
    clippy::match_same_arms,
@@ -53,31 +51,28 @@
    clippy::match_wildcard_for_single_variants,
    clippy::module_name_repetitions,
    clippy::must_use_candidate,
+    clippy::option_if_let_else,
    clippy::similar_names,
    clippy::single_match_else,
    clippy::struct_excessive_bools,
    clippy::too_many_lines,
-    clippy::uninlined_format_args,
    clippy::unseparated_literal_suffix,
    clippy::unused_self,
    clippy::use_self,
    clippy::wildcard_imports
 )]
 #![cfg_attr(all(test, exhaustive), feature(non_exhaustive_omitted_patterns_lint))]
-#![allow(unknown_lints, mismatched_lifetime_syntaxes)]

-extern crate proc_macro2;
+#[macro_use]
 extern crate quote;
+#[macro_use]
 extern crate syn;

-extern crate proc_macro;
+extern crate proc_macro2;

 mod internals;

-use proc_macro::TokenStream;
-use proc_macro2::{Ident, Span};
-use quote::{ToTokens, TokenStreamExt as _};
-use syn::parse_macro_input;
+use proc_macro2::TokenStream;
 use syn::DeriveInput;

 #[macro_use]
@@ -86,42 +81,32 @@ mod bound;
 mod fragment;

 mod de;
-mod deprecated;
 mod dummy;
 mod pretend;
 mod ser;
-mod this;
+mod try;

-#[allow(non_camel_case_types)]
-struct private;
+#[no_mangle]
+pub extern "C" fn derive_serialize(input: TokenStream) -> TokenStream {
+    let mut input: DeriveInput = match syn::parse2(input) {
+        Ok(input) => input,
+        Err(err) => return err.to_compile_error(),
+    };

-impl private {
-    fn ident(&self) -> Ident {
-        Ident::new(
-            concat!("__private", env!("CARGO_PKG_VERSION_PATCH")),
-            Span::call_site(),
-        )
-    }
+    ser::expand_derive_serialize(&mut input).unwrap_or_else(to_compile_errors)
 }

-impl ToTokens for private {
-    fn to_tokens(&self, tokens: &mut proc_macro2::TokenStream) {
-        tokens.append(self.ident());
-    }
+#[no_mangle]
+pub extern "C" fn derive_deserialize(input: TokenStream) -> TokenStream {
+    let mut input: DeriveInput = match syn::parse2(input) {
+        Ok(input) => input,
+        Err(err) => return err.to_compile_error(),
+    };
+
+    de::expand_derive_deserialize(&mut input).unwrap_or_else(to_compile_errors)
 }

-#[proc_macro_derive(Serialize, attributes(serde))]
-pub fn derive_serialize(input: TokenStream) -> TokenStream {
-    let mut input = parse_macro_input!(input as DeriveInput);
-    ser::expand_derive_serialize(&mut input)
-        .unwrap_or_else(syn::Error::into_compile_error)
-        .into()
-}
-
-#[proc_macro_derive(Deserialize, attributes(serde))]
-pub fn derive_deserialize(input: TokenStream) -> TokenStream {
-    let mut input = parse_macro_input!(input as DeriveInput);
-    de::expand_derive_deserialize(&mut input)
-        .unwrap_or_else(syn::Error::into_compile_error)
-        .into()
+fn to_compile_errors(errors: Vec<syn::Error>) -> TokenStream {
+    let compile_errors = errors.iter().map(syn::Error::to_compile_error);
+    quote!(#(#compile_errors)*)
 }
@@ -1,7 +1,7 @@
-use crate::internals::ast::{Container, Data, Field, Style, Variant};
-use crate::private;
 use proc_macro2::TokenStream;
-use quote::{format_ident, quote};
+use quote::format_ident;
+
+use internals::ast::{Container, Data, Field, Style, Variant};

 // Suppress dead_code warnings that would otherwise appear when using a remote
 // derive. Other than this pretend code, a struct annotated with remote derive
@@ -65,14 +65,14 @@ pub fn pretend_used(cont: &Container, is_packed: bool) -> TokenStream {
 fn pretend_fields_used(cont: &Container, is_packed: bool) -> TokenStream {
    match &cont.data {
        Data::Enum(variants) => pretend_fields_used_enum(cont, variants),
-        Data::Struct(Style::Struct | Style::Tuple | Style::Newtype, fields) => {
+        Data::Struct(Style::Struct, fields) => {
            if is_packed {
                pretend_fields_used_struct_packed(cont, fields)
            } else {
                pretend_fields_used_struct(cont, fields)
            }
        }
-        Data::Struct(Style::Unit, _) => quote!(),
+        Data::Struct(_, _) => quote!(),
    }
 }

@@ -84,8 +84,8 @@ fn pretend_fields_used_struct(cont: &Container, fields: &[Field]) -> TokenStream
    let placeholders = (0usize..).map(|i| format_ident!("__v{}", i));

    quote! {
-        match _serde::#private::None::<&#type_ident #ty_generics> {
-            _serde::#private::Some(#type_ident { #(#members: #placeholders),* }) => {}
+        match _serde::__private::None::<&#type_ident #ty_generics> {
+            _serde::__private::Some(#type_ident { #(#members: #placeholders),* }) => {}
            _ => {}
        }
    }
@@ -97,15 +97,29 @@ fn pretend_fields_used_struct_packed(cont: &Container, fields: &[Field]) -> Toke

    let members = fields.iter().map(|field| &field.member).collect::<Vec<_>>();

-    let private2 = private;
-    quote! {
-        match _serde::#private::None::<&#type_ident #ty_generics> {
-            _serde::#private::Some(__v @ #type_ident { #(#members: _),* }) => {
-                #(
-                    let _ = _serde::#private2::ptr::addr_of!(__v.#members);
-                )*
+    #[cfg(ptr_addr_of)]
+    {
+        quote! {
+            match _serde::__private::None::<&#type_ident #ty_generics> {
+                _serde::__private::Some(__v @ #type_ident { #(#members: _),* }) => {
+                    #(
+                        let _ = _serde::__private::ptr::addr_of!(__v.#members);
+                    )*
+                }
+                _ => {}
+            }
+        }
+    }
+
+    #[cfg(not(ptr_addr_of))]
+    {
+        let placeholders = (0usize..).map(|i| format_ident!("__v{}", i));
+
+        quote! {
+            match _serde::__private::None::<#type_ident #ty_generics> {
+                _serde::__private::Some(#type_ident { #(#members: #placeholders),* }) => {}
+                _ => {}
            }
-            _ => {}
        }
    }
 }
@@ -117,21 +131,20 @@ fn pretend_fields_used_enum(cont: &Container, variants: &[Variant]) -> TokenStre
    let patterns = variants
        .iter()
        .filter_map(|variant| match variant.style {
-            Style::Struct | Style::Tuple | Style::Newtype => {
+            Style::Struct => {
                let variant_ident = &variant.ident;
                let members = variant.fields.iter().map(|field| &field.member);
                let placeholders = (0usize..).map(|i| format_ident!("__v{}", i));
                Some(quote!(#type_ident::#variant_ident { #(#members: #placeholders),* }))
            }
-            Style::Unit => None,
+            _ => None,
        })
        .collect::<Vec<_>>();

-    let private2 = private;
    quote! {
-        match _serde::#private::None::<&#type_ident #ty_generics> {
+        match _serde::__private::None::<&#type_ident #ty_generics> {
            #(
-                _serde::#private2::Some(#patterns) => {}
+                _serde::__private::Some(#patterns) => {}
            )*
            _ => {}
        }
@@ -175,8 +188,8 @@ fn pretend_variants_used(cont: &Container) -> TokenStream {
        };

        quote! {
-            match _serde::#private::None {
-                _serde::#private::Some((#(#placeholders,)*)) => {
+            match _serde::__private::None {
+                _serde::__private::Some((#(#placeholders,)*)) => {
                    let _ = #type_ident::#variant_ident #turbofish #pat;
                }
                _ => {}
@@ -1,20 +1,23 @@
-use crate::deprecated::allow_deprecated;
-use crate::fragment::{Fragment, Match, Stmts};
-use crate::internals::ast::{Container, Data, Field, Style, Variant};
-use crate::internals::name::Name;
-use crate::internals::{attr, replace_receiver, Ctxt, Derive};
-use crate::{bound, dummy, pretend, private, this};
 use proc_macro2::{Span, TokenStream};
-use quote::{quote, quote_spanned};
 use syn::spanned::Spanned;
-use syn::{parse_quote, Ident, Index, Member};
+use syn::{self, Ident, Index, Member};

-pub fn expand_derive_serialize(input: &mut syn::DeriveInput) -> syn::Result<TokenStream> {
+use bound;
+use dummy;
+use fragment::{Fragment, Match, Stmts};
+use internals::ast::{Container, Data, Field, Style, Variant};
+use internals::{attr, replace_receiver, Ctxt, Derive};
+use pretend;
+
+pub fn expand_derive_serialize(
+    input: &mut syn::DeriveInput,
+) -> Result<TokenStream, Vec<syn::Error>> {
    replace_receiver(input);

    let ctxt = Ctxt::new();
-    let Some(cont) = Container::from_ast(&ctxt, input, Derive::Serialize, &private.ident()) else {
-        return Err(ctxt.check().unwrap_err());
+    let cont = match Container::from_ast(&ctxt, input, Derive::Serialize) {
+        Some(cont) => cont,
+        None => return Err(ctxt.check().unwrap_err()),
    };
    precondition(&ctxt, &cont);
    ctxt.check()?;
@@ -23,18 +26,16 @@ pub fn expand_derive_serialize(input: &mut syn::DeriveInput) -> syn::Result<Toke
    let params = Parameters::new(&cont);
    let (impl_generics, ty_generics, where_clause) = params.generics.split_for_impl();
    let body = Stmts(serialize_body(&cont, &params));
-    let allow_deprecated = allow_deprecated(input);
+    let serde = cont.attrs.serde_path();

    let impl_block = if let Some(remote) = cont.attrs.remote() {
        let vis = &input.vis;
        let used = pretend::pretend_used(&cont, params.is_packed);
        quote! {
-            #[automatically_derived]
-            #allow_deprecated
            impl #impl_generics #ident #ty_generics #where_clause {
-                #vis fn serialize<__S>(__self: &#remote #ty_generics, __serializer: __S) -> _serde::#private::Result<__S::Ok, __S::Error>
+                #vis fn serialize<__S>(__self: &#remote #ty_generics, __serializer: __S) -> #serde::__private::Result<__S::Ok, __S::Error>
                where
-                    __S: _serde::Serializer,
+                    __S: #serde::Serializer,
                {
                    #used
                    #body
@@ -44,11 +45,10 @@ pub fn expand_derive_serialize(input: &mut syn::DeriveInput) -> syn::Result<Toke
    } else {
        quote! {
            #[automatically_derived]
-            #allow_deprecated
-            impl #impl_generics _serde::Serialize for #ident #ty_generics #where_clause {
-                fn serialize<__S>(&self, __serializer: __S) -> _serde::#private::Result<__S::Ok, __S::Error>
+            impl #impl_generics #serde::Serialize for #ident #ty_generics #where_clause {
+                fn serialize<__S>(&self, __serializer: __S) -> #serde::__private::Result<__S::Ok, __S::Error>
                where
-                    __S: _serde::Serializer,
+                    __S: #serde::Serializer,
                {
                    #body
                }
@@ -58,6 +58,8 @@ pub fn expand_derive_serialize(input: &mut syn::DeriveInput) -> syn::Result<Toke

    Ok(dummy::wrap_in_const(
        cont.attrs.custom_serde_path(),
+        "SERIALIZE",
+        ident,
        impl_block,
    ))
 }
@@ -80,13 +82,9 @@ struct Parameters {
    self_var: Ident,

    /// Path to the type the impl is for. Either a single `Ident` for local
-    /// types (does not include generic parameters) or `some::remote::Path` for
-    /// remote types.
-    this_type: syn::Path,
-
-    /// Same as `this_type` but using `::<T>` for generic parameters for use in
-    /// expression position.
-    this_value: syn::Path,
+    /// types or `some::remote::Ident` for remote types. Does not include
+    /// generic parameters.
+    this: syn::Path,

    /// Generics including any explicit and inferred bounds for the impl.
    generics: syn::Generics,
@@ -107,15 +105,18 @@ impl Parameters {
            Ident::new("self", Span::call_site())
        };

-        let this_type = this::this_type(cont);
-        let this_value = this::this_value(cont);
+        let this = match cont.attrs.remote() {
+            Some(remote) => remote.clone(),
+            None => cont.ident.clone().into(),
+        };
+
        let is_packed = cont.attrs.is_packed();
+
        let generics = build_generics(cont);

        Parameters {
            self_var,
-            this_type,
-            this_value,
+            this,
            generics,
            is_remote,
            is_packed,
@@ -125,7 +126,7 @@ impl Parameters {
    /// Type name to use in error messages and `&'static str` arguments to
    /// various Serializer methods.
    fn type_name(&self) -> String {
-        self.this_type.segments.last().unwrap().ident.to_string()
+        self.this.segments.last().unwrap().ident.to_string()
    }
 }

@@ -152,7 +153,7 @@ fn build_generics(cont: &Container) -> syn::Generics {
 }

 // Fields with a `skip_serializing` or `serialize_with` attribute, or which
-// belong to a variant with a `skip_serializing` or `serialize_with` attribute,
+// belong to a variant with a 'skip_serializing` or `serialize_with` attribute,
 // are not serialized by us so we do not generate a bound. Fields with a `bound`
 // attribute specify their own bound so we do not generate one. All other fields
 // may need a `T: Serialize` bound where T is the type of the field.
@@ -214,7 +215,7 @@ fn serialize_into(params: &Parameters, type_into: &syn::Type) -> Fragment {
    let self_var = &params.self_var;
    quote_block! {
        _serde::Serialize::serialize(
-            &_serde::#private::Into::<#type_into>::into(_serde::#private::Clone::clone(#self_var)),
+            &_serde::__private::Into::<#type_into>::into(_serde::__private::Clone::clone(#self_var)),
            __serializer)
    }
 }
@@ -286,25 +287,16 @@ fn serialize_tuple_struct(
        .fold(quote!(0), |sum, expr| quote!(#sum + #expr));

    quote_block! {
-        let #let_mut __serde_state = _serde::Serializer::serialize_tuple_struct(__serializer, #type_name, #len)?;
+        let #let_mut __serde_state = try!(_serde::Serializer::serialize_tuple_struct(__serializer, #type_name, #len));
        #(#serialize_stmts)*
        _serde::ser::SerializeTupleStruct::end(__serde_state)
    }
 }

 fn serialize_struct(params: &Parameters, fields: &[Field], cattrs: &attr::Container) -> Fragment {
-    assert!(
-        fields.len() as u64 <= u64::from(u32::MAX),
-        "too many fields in {}: {}, maximum supported count is {}",
-        cattrs.name().serialize_name(),
-        fields.len(),
-        u32::MAX,
-    );
+    assert!(fields.len() as u64 <= u64::from(u32::max_value()));

-    let has_non_skipped_flatten = fields
-        .iter()
-        .any(|field| field.attrs.flatten() && !field.attrs.skip_serializing());
-    if has_non_skipped_flatten {
+    if cattrs.has_flatten() {
        serialize_struct_as_map(params, fields, cattrs)
    } else {
        serialize_struct_as_struct(params, fields, cattrs)
@@ -317,7 +309,7 @@ fn serialize_struct_tag_field(cattrs: &attr::Container, struct_trait: &StructTra
            let type_name = cattrs.name().serialize_name();
            let func = struct_trait.serialize_field(Span::call_site());
            quote! {
-                #func(&mut __serde_state, #tag, #type_name)?;
+                try!(#func(&mut __serde_state, #tag, #type_name));
            }
        }
        _ => quote! {},
@@ -358,7 +350,7 @@ fn serialize_struct_as_struct(
        );

    quote_block! {
-        let #let_mut __serde_state = _serde::Serializer::serialize_struct(__serializer, #type_name, #len)?;
+        let #let_mut __serde_state = try!(_serde::Serializer::serialize_struct(__serializer, #type_name, #len));
        #tag_field
        #(#serialize_fields)*
        _serde::ser::SerializeStruct::end(__serde_state)
@@ -383,8 +375,26 @@ fn serialize_struct_as_map(

    let let_mut = mut_if(serialized_fields.peek().is_some() || tag_field_exists);

+    let len = if cattrs.has_flatten() {
+        quote!(_serde::__private::None)
+    } else {
+        let len = serialized_fields
+            .map(|field| match field.attrs.skip_serializing_if() {
+                None => quote!(1),
+                Some(path) => {
+                    let field_expr = get_member(params, field, &field.member);
+                    quote!(if #path(#field_expr) { 0 } else { 1 })
+                }
+            })
+            .fold(
+                quote!(#tag_field_exists as usize),
+                |sum, expr| quote!(#sum + #expr),
+            );
+        quote!(_serde::__private::Some(#len))
+    };
+
    quote_block! {
-        let #let_mut __serde_state = _serde::Serializer::serialize_map(__serializer, _serde::#private::None)?;
+        let #let_mut __serde_state = try!(_serde::Serializer::serialize_map(__serializer, #len));
        #tag_field
        #(#serialize_fields)*
        _serde::ser::SerializeMap::end(__serde_state)
@@ -392,11 +402,11 @@ fn serialize_struct_as_map(
 }

 fn serialize_enum(params: &Parameters, variants: &[Variant], cattrs: &attr::Container) -> Fragment {
-    assert!(variants.len() as u64 <= u64::from(u32::MAX));
+    assert!(variants.len() as u64 <= u64::from(u32::max_value()));

    let self_var = &params.self_var;

-    let mut arms: Vec<_> = variants
+    let arms: Vec<_> = variants
        .iter()
        .enumerate()
        .map(|(variant_index, variant)| {
@@ -404,12 +414,6 @@ fn serialize_enum(params: &Parameters, variants: &[Variant], cattrs: &attr::Cont
        })
        .collect();

-    if cattrs.remote().is_some() && cattrs.non_exhaustive() {
-        arms.push(quote! {
-            ref unrecognized => _serde::#private::Err(_serde::ser::Error::custom(_serde::#private::ser::CannotSerializeVariant(unrecognized))),
-        });
-    }
-
    quote_expr! {
        match *#self_var {
            #(#arms)*
@@ -423,7 +427,7 @@ fn serialize_variant(
    variant_index: u32,
    cattrs: &attr::Container,
 ) -> TokenStream {
-    let this_value = &params.this_value;
+    let this = &params.this;
    let variant_ident = &variant.ident;

    if variant.attrs.skip_serializing() {
@@ -433,7 +437,7 @@ fn serialize_variant(
            variant_ident
        );
        let skipped_err = quote! {
-            _serde::#private::Err(_serde::ser::Error::custom(#skipped_msg))
+            _serde::__private::Err(_serde::ser::Error::custom(#skipped_msg))
        };
        let fields_pat = match variant.style {
            Style::Unit => quote!(),
@@ -441,56 +445,47 @@ fn serialize_variant(
            Style::Struct => quote!({ .. }),
        };
        quote! {
-            #this_value::#variant_ident #fields_pat => #skipped_err,
+            #this::#variant_ident #fields_pat => #skipped_err,
        }
    } else {
        // variant wasn't skipped
        let case = match variant.style {
            Style::Unit => {
                quote! {
-                    #this_value::#variant_ident
+                    #this::#variant_ident
                }
            }
            Style::Newtype => {
                quote! {
-                    #this_value::#variant_ident(ref __field0)
+                    #this::#variant_ident(ref __field0)
                }
            }
            Style::Tuple => {
                let field_names = (0..variant.fields.len())
                    .map(|i| Ident::new(&format!("__field{}", i), Span::call_site()));
                quote! {
-                    #this_value::#variant_ident(#(ref #field_names),*)
+                    #this::#variant_ident(#(ref #field_names),*)
                }
            }
            Style::Struct => {
                let members = variant.fields.iter().map(|f| &f.member);
                quote! {
-                    #this_value::#variant_ident { #(ref #members),* }
+                    #this::#variant_ident { #(ref #members),* }
                }
            }
        };

-        let body = Match(match (cattrs.tag(), variant.attrs.untagged()) {
-            (attr::TagType::External, false) => {
+        let body = Match(match cattrs.tag() {
+            attr::TagType::External => {
                serialize_externally_tagged_variant(params, variant, variant_index, cattrs)
            }
-            (attr::TagType::Internal { tag }, false) => {
+            attr::TagType::Internal { tag } => {
                serialize_internally_tagged_variant(params, variant, cattrs, tag)
            }
-            (attr::TagType::Adjacent { tag, content }, false) => {
-                serialize_adjacently_tagged_variant(
-                    params,
-                    variant,
-                    cattrs,
-                    variant_index,
-                    tag,
-                    content,
-                )
-            }
-            (attr::TagType::None, _) | (_, true) => {
-                serialize_untagged_variant(params, variant, cattrs)
+            attr::TagType::Adjacent { tag, content } => {
+                serialize_adjacently_tagged_variant(params, variant, cattrs, tag, content)
            }
+            attr::TagType::None => serialize_untagged_variant(params, variant, cattrs),
        });

        quote! {
@@ -567,7 +562,7 @@ fn serialize_externally_tagged_variant(
            },
            params,
            &variant.fields,
-            type_name,
+            &type_name,
        ),
    }
 }
@@ -587,7 +582,7 @@ fn serialize_internally_tagged_variant(
    if let Some(path) = variant.attrs.serialize_with() {
        let ser = wrap_serialize_variant_with(params, path, variant);
        return quote_expr! {
-            _serde::#private::ser::serialize_tagged_newtype(
+            _serde::__private::ser::serialize_tagged_newtype(
                __serializer,
                #enum_ident_str,
                #variant_ident_str,
@@ -601,10 +596,10 @@ fn serialize_internally_tagged_variant(
    match effective_style(variant) {
        Style::Unit => {
            quote_block! {
-                let mut __struct = _serde::Serializer::serialize_struct(
-                    __serializer, #type_name, 1)?;
-                _serde::ser::SerializeStruct::serialize_field(
-                    &mut __struct, #tag, #variant_name)?;
+                let mut __struct = try!(_serde::Serializer::serialize_struct(
+                    __serializer, #type_name, 1));
+                try!(_serde::ser::SerializeStruct::serialize_field(
+                    &mut __struct, #tag, #variant_name));
                _serde::ser::SerializeStruct::end(__struct)
            }
        }
@@ -616,7 +611,7 @@ fn serialize_internally_tagged_variant(
            }

            let span = field.original.span();
-            let func = quote_spanned!(span=> _serde::#private::ser::serialize_tagged_newtype);
+            let func = quote_spanned!(span=> _serde::__private::ser::serialize_tagged_newtype);
            quote_expr! {
                #func(
                    __serializer,
@@ -632,7 +627,7 @@ fn serialize_internally_tagged_variant(
            StructVariant::InternallyTagged { tag, variant_name },
            params,
            &variant.fields,
-            type_name,
+            &type_name,
        ),
        Style::Tuple => unreachable!("checked in serde_derive_internals"),
    }
@@ -642,20 +637,12 @@ fn serialize_adjacently_tagged_variant(
    params: &Parameters,
    variant: &Variant,
    cattrs: &attr::Container,
-    variant_index: u32,
    tag: &str,
    content: &str,
 ) -> Fragment {
-    let this_type = &params.this_type;
+    let this = &params.this;
    let type_name = cattrs.name().serialize_name();
    let variant_name = variant.attrs.name().serialize_name();
-    let serialize_variant = quote! {
-        &_serde::#private::ser::AdjacentlyTaggedEnumVariant {
-            enum_name: #type_name,
-            variant_index: #variant_index,
-            variant_name: #variant_name,
-        }
-    };

    let inner = Stmts(if let Some(path) = variant.attrs.serialize_with() {
        let ser = wrap_serialize_variant_with(params, path, variant);
@@ -666,10 +653,10 @@ fn serialize_adjacently_tagged_variant(
        match effective_style(variant) {
            Style::Unit => {
                return quote_block! {
-                    let mut __struct = _serde::Serializer::serialize_struct(
-                        __serializer, #type_name, 1)?;
-                    _serde::ser::SerializeStruct::serialize_field(
-                        &mut __struct, #tag, #serialize_variant)?;
+                    let mut __struct = try!(_serde::Serializer::serialize_struct(
+                        __serializer, #type_name, 1));
+                    try!(_serde::ser::SerializeStruct::serialize_field(
+                        &mut __struct, #tag, #variant_name));
                    _serde::ser::SerializeStruct::end(__struct)
                };
            }
@@ -683,12 +670,12 @@ fn serialize_adjacently_tagged_variant(
                let span = field.original.span();
                let func = quote_spanned!(span=> _serde::ser::SerializeStruct::serialize_field);
                return quote_block! {
-                    let mut __struct = _serde::Serializer::serialize_struct(
-                        __serializer, #type_name, 2)?;
-                    _serde::ser::SerializeStruct::serialize_field(
-                        &mut __struct, #tag, #serialize_variant)?;
-                    #func(
-                        &mut __struct, #content, #field_expr)?;
+                    let mut __struct = try!(_serde::Serializer::serialize_struct(
+                        __serializer, #type_name, 2));
+                    try!(_serde::ser::SerializeStruct::serialize_field(
+                        &mut __struct, #tag, #variant_name));
+                    try!(#func(
+                        &mut __struct, #content, #field_expr));
                    _serde::ser::SerializeStruct::end(__struct)
                };
            }
@@ -699,13 +686,13 @@ fn serialize_adjacently_tagged_variant(
                StructVariant::Untagged,
                params,
                &variant.fields,
-                variant_name,
+                &variant_name,
            ),
        }
    });

    let fields_ty = variant.fields.iter().map(|f| &f.ty);
-    let fields_ident: &[_] = &match variant.style {
+    let fields_ident: &Vec<_> = &match variant.style {
        Style::Unit => {
            if variant.attrs.serialize_with().is_some() {
                vec![]
@@ -730,15 +717,13 @@ fn serialize_adjacently_tagged_variant(
    let (wrapper_impl_generics, wrapper_ty_generics, _) = wrapper_generics.split_for_impl();

    quote_block! {
-        #[doc(hidden)]
        struct __AdjacentlyTagged #wrapper_generics #where_clause {
            data: (#(&'__a #fields_ty,)*),
-            phantom: _serde::#private::PhantomData<#this_type #ty_generics>,
+            phantom: _serde::__private::PhantomData<#this #ty_generics>,
        }

-        #[automatically_derived]
        impl #wrapper_impl_generics _serde::Serialize for __AdjacentlyTagged #wrapper_ty_generics #where_clause {
-            fn serialize<__S>(&self, __serializer: __S) -> _serde::#private::Result<__S::Ok, __S::Error>
+            fn serialize<__S>(&self, __serializer: __S) -> _serde::__private::Result<__S::Ok, __S::Error>
            where
                __S: _serde::Serializer,
            {
@@ -749,15 +734,15 @@ fn serialize_adjacently_tagged_variant(
            }
        }

-        let mut __struct = _serde::Serializer::serialize_struct(
-            __serializer, #type_name, 2)?;
-        _serde::ser::SerializeStruct::serialize_field(
-            &mut __struct, #tag, #serialize_variant)?;
-        _serde::ser::SerializeStruct::serialize_field(
+        let mut __struct = try!(_serde::Serializer::serialize_struct(
+            __serializer, #type_name, 2));
+        try!(_serde::ser::SerializeStruct::serialize_field(
+            &mut __struct, #tag, #variant_name));
+        try!(_serde::ser::SerializeStruct::serialize_field(
            &mut __struct, #content, &__AdjacentlyTagged {
                data: (#(#fields_ident,)*),
-                phantom: _serde::#private::PhantomData::<#this_type #ty_generics>,
-            })?;
+                phantom: _serde::__private::PhantomData::<#this #ty_generics>,
+            }));
        _serde::ser::SerializeStruct::end(__struct)
    }
 }
@@ -796,16 +781,16 @@ fn serialize_untagged_variant(
        Style::Tuple => serialize_tuple_variant(TupleVariant::Untagged, params, &variant.fields),
        Style::Struct => {
            let type_name = cattrs.name().serialize_name();
-            serialize_struct_variant(StructVariant::Untagged, params, &variant.fields, type_name)
+            serialize_struct_variant(StructVariant::Untagged, params, &variant.fields, &type_name)
        }
    }
 }

-enum TupleVariant<'a> {
+enum TupleVariant {
    ExternallyTagged {
-        type_name: &'a Name,
+        type_name: String,
        variant_index: u32,
-        variant_name: &'a Name,
+        variant_name: String,
    },
    Untagged,
 }
@@ -847,21 +832,21 @@ fn serialize_tuple_variant(
            variant_name,
        } => {
            quote_block! {
-                let #let_mut __serde_state = _serde::Serializer::serialize_tuple_variant(
+                let #let_mut __serde_state = try!(_serde::Serializer::serialize_tuple_variant(
                    __serializer,
                    #type_name,
                    #variant_index,
                    #variant_name,
-                    #len)?;
+                    #len));
                #(#serialize_stmts)*
                _serde::ser::SerializeTupleVariant::end(__serde_state)
            }
        }
        TupleVariant::Untagged => {
            quote_block! {
-                let #let_mut __serde_state = _serde::Serializer::serialize_tuple(
+                let #let_mut __serde_state = try!(_serde::Serializer::serialize_tuple(
                    __serializer,
-                    #len)?;
+                    #len));
                #(#serialize_stmts)*
                _serde::ser::SerializeTuple::end(__serde_state)
            }
@@ -872,20 +857,20 @@ fn serialize_tuple_variant(
 enum StructVariant<'a> {
    ExternallyTagged {
        variant_index: u32,
-        variant_name: &'a Name,
+        variant_name: String,
    },
    InternallyTagged {
        tag: &'a str,
-        variant_name: &'a Name,
+        variant_name: String,
    },
    Untagged,
 }

-fn serialize_struct_variant(
-    context: StructVariant,
+fn serialize_struct_variant<'a>(
+    context: StructVariant<'a>,
    params: &Parameters,
    fields: &[Field],
-    name: &Name,
+    name: &str,
 ) -> Fragment {
    if fields.iter().any(|field| field.attrs.flatten()) {
        return serialize_struct_variant_with_flatten(context, params, fields, name);
@@ -924,40 +909,40 @@ fn serialize_struct_variant(
            variant_name,
        } => {
            quote_block! {
-                let #let_mut __serde_state = _serde::Serializer::serialize_struct_variant(
+                let #let_mut __serde_state = try!(_serde::Serializer::serialize_struct_variant(
                    __serializer,
                    #name,
                    #variant_index,
                    #variant_name,
                    #len,
-                )?;
+                ));
                #(#serialize_fields)*
                _serde::ser::SerializeStructVariant::end(__serde_state)
            }
        }
        StructVariant::InternallyTagged { tag, variant_name } => {
            quote_block! {
-                let mut __serde_state = _serde::Serializer::serialize_struct(
+                let mut __serde_state = try!(_serde::Serializer::serialize_struct(
                    __serializer,
                    #name,
                    #len + 1,
-                )?;
-                _serde::ser::SerializeStruct::serialize_field(
+                ));
+                try!(_serde::ser::SerializeStruct::serialize_field(
                    &mut __serde_state,
                    #tag,
                    #variant_name,
-                )?;
+                ));
                #(#serialize_fields)*
                _serde::ser::SerializeStruct::end(__serde_state)
            }
        }
        StructVariant::Untagged => {
            quote_block! {
-                let #let_mut __serde_state = _serde::Serializer::serialize_struct(
+                let #let_mut __serde_state = try!(_serde::Serializer::serialize_struct(
                    __serializer,
                    #name,
                    #len,
-                )?;
+                ));
                #(#serialize_fields)*
                _serde::ser::SerializeStruct::end(__serde_state)
            }
@@ -965,11 +950,11 @@ fn serialize_struct_variant(
    }
 }

-fn serialize_struct_variant_with_flatten(
-    context: StructVariant,
+fn serialize_struct_variant_with_flatten<'a>(
+    context: StructVariant<'a>,
    params: &Parameters,
    fields: &[Field],
-    name: &Name,
+    name: &str,
 ) -> Fragment {
    let struct_trait = StructTrait::SerializeMap;
    let serialize_fields = serialize_struct_visitor(fields, params, true, &struct_trait);
@@ -986,7 +971,7 @@ fn serialize_struct_variant_with_flatten(
            variant_index,
            variant_name,
        } => {
-            let this_type = &params.this_type;
+            let this = &params.this;
            let fields_ty = fields.iter().map(|f| &f.ty);
            let members = &fields.iter().map(|f| &f.member).collect::<Vec<_>>();

@@ -995,22 +980,20 @@ fn serialize_struct_variant_with_flatten(
            let (wrapper_impl_generics, wrapper_ty_generics, _) = wrapper_generics.split_for_impl();

            quote_block! {
-                #[doc(hidden)]
                struct __EnumFlatten #wrapper_generics #where_clause {
                    data: (#(&'__a #fields_ty,)*),
-                    phantom: _serde::#private::PhantomData<#this_type #ty_generics>,
+                    phantom: _serde::__private::PhantomData<#this #ty_generics>,
                }

-                #[automatically_derived]
                impl #wrapper_impl_generics _serde::Serialize for __EnumFlatten #wrapper_ty_generics #where_clause {
-                    fn serialize<__S>(&self, __serializer: __S) -> _serde::#private::Result<__S::Ok, __S::Error>
+                    fn serialize<__S>(&self, __serializer: __S) -> _serde::__private::Result<__S::Ok, __S::Error>
                    where
                        __S: _serde::Serializer,
                    {
                        let (#(#members,)*) = self.data;
-                        let #let_mut __serde_state = _serde::Serializer::serialize_map(
+                        let #let_mut __serde_state = try!(_serde::Serializer::serialize_map(
                            __serializer,
-                            _serde::#private::None)?;
+                            _serde::__private::None));
                        #(#serialize_fields)*
                        _serde::ser::SerializeMap::end(__serde_state)
                    }
@@ -1023,29 +1006,29 @@ fn serialize_struct_variant_with_flatten(
                    #variant_name,
                    &__EnumFlatten {
                        data: (#(#members,)*),
-                        phantom: _serde::#private::PhantomData::<#this_type #ty_generics>,
+                        phantom: _serde::__private::PhantomData::<#this #ty_generics>,
                    })
            }
        }
        StructVariant::InternallyTagged { tag, variant_name } => {
            quote_block! {
-                let #let_mut __serde_state = _serde::Serializer::serialize_map(
+                let #let_mut __serde_state = try!(_serde::Serializer::serialize_map(
                    __serializer,
-                    _serde::#private::None)?;
-                _serde::ser::SerializeMap::serialize_entry(
+                    _serde::__private::None));
+                try!(_serde::ser::SerializeMap::serialize_entry(
                    &mut __serde_state,
                    #tag,
                    #variant_name,
-                )?;
+                ));
                #(#serialize_fields)*
                _serde::ser::SerializeMap::end(__serde_state)
            }
        }
        StructVariant::Untagged => {
            quote_block! {
-                let #let_mut __serde_state = _serde::Serializer::serialize_map(
+                let #let_mut __serde_state = try!(_serde::Serializer::serialize_map(
                    __serializer,
-                    _serde::#private::None)?;
+                    _serde::__private::None));
                #(#serialize_fields)*
                _serde::ser::SerializeMap::end(__serde_state)
            }
@@ -1090,7 +1073,7 @@ fn serialize_tuple_struct_visitor(
            let span = field.original.span();
            let func = tuple_trait.serialize_element(span);
            let ser = quote! {
-                #func(&mut __serde_state, #field_expr)?;
+                try!(#func(&mut __serde_state, #field_expr));
            };

            match skip {
@@ -1134,12 +1117,12 @@ fn serialize_struct_visitor(
            let ser = if field.attrs.flatten() {
                let func = quote_spanned!(span=> _serde::Serialize::serialize);
                quote! {
-                    #func(&#field_expr, _serde::#private::ser::FlatMapSerializer(&mut __serde_state))?;
+                    try!(#func(&#field_expr, _serde::__private::ser::FlatMapSerializer(&mut __serde_state)));
                }
            } else {
                let func = struct_trait.serialize_field(span);
                quote! {
-                    #func(&mut __serde_state, #key_expr, #field_expr)?;
+                    try!(#func(&mut __serde_state, #key_expr, #field_expr));
                }
            };

@@ -1151,7 +1134,7 @@ fn serialize_struct_visitor(
                            if !#skip {
                                #ser
                            } else {
-                                #skip_func(&mut __serde_state, #key_expr)?;
+                                try!(#skip_func(&mut __serde_state, #key_expr));
                            }
                        }
                    } else {
@@ -1209,7 +1192,7 @@ fn wrap_serialize_with(
    field_tys: &[&syn::Type],
    field_exprs: &[TokenStream],
 ) -> TokenStream {
-    let this_type = &params.this_type;
+    let this = &params.this;
    let (_, ty_generics, where_clause) = params.generics.split_for_impl();

    let wrapper_generics = if field_exprs.is_empty() {
@@ -1226,44 +1209,31 @@ fn wrap_serialize_with(
        })
    });

-    let self_var = quote!(self);
-    let serializer_var = quote!(__s);
-
-    // If #serialize_with returns wrong type, error will be reported on here.
-    // We attach span of the path to this piece so error will be reported
-    // on the #[serde(with = "...")]
-    //                       ^^^^^
-    let wrapper_serialize = quote_spanned! {serialize_with.span()=>
-        #serialize_with(#(#self_var.values.#field_access, )* #serializer_var)
-    };
-
-    quote!(&{
-        #[doc(hidden)]
+    quote!({
        struct __SerializeWith #wrapper_impl_generics #where_clause {
            values: (#(&'__a #field_tys, )*),
-            phantom: _serde::#private::PhantomData<#this_type #ty_generics>,
+            phantom: _serde::__private::PhantomData<#this #ty_generics>,
        }

-        #[automatically_derived]
        impl #wrapper_impl_generics _serde::Serialize for __SerializeWith #wrapper_ty_generics #where_clause {
-            fn serialize<__S>(&#self_var, #serializer_var: __S) -> _serde::#private::Result<__S::Ok, __S::Error>
+            fn serialize<__S>(&self, __s: __S) -> _serde::__private::Result<__S::Ok, __S::Error>
            where
                __S: _serde::Serializer,
            {
-                #wrapper_serialize
+                #serialize_with(#(self.values.#field_access, )* __s)
            }
        }

-        __SerializeWith {
+        &__SerializeWith {
            values: (#(#field_exprs, )*),
-            phantom: _serde::#private::PhantomData::<#this_type #ty_generics>,
+            phantom: _serde::__private::PhantomData::<#this #ty_generics>,
        }
    })
 }

 // Serialization of an empty struct results in code like:
 //
-//     let mut __serde_state = serializer.serialize_struct("S", 0)?;
+//     let mut __serde_state = try!(serializer.serialize_struct("S", 0));
 //     _serde::ser::SerializeStruct::end(__serde_state)
 //
 // where we want to omit the `mut` to avoid a warning.
@@ -1292,11 +1262,11 @@ fn get_member(params: &Parameters, field: &Field, member: &Member) -> TokenStrea
                quote!(&#self_var.#member)
            };
            let ty = field.ty;
-            quote!(_serde::#private::ser::constrain::<#ty>(#inner))
+            quote!(_serde::__private::ser::constrain::<#ty>(#inner))
        }
        (true, Some(getter)) => {
            let ty = field.ty;
-            quote!(_serde::#private::ser::constrain::<#ty>(&#getter(#self_var)))
+            quote!(_serde::__private::ser::constrain::<#ty>(&#getter(#self_var)))
        }
        (false, Some(_)) => {
            unreachable!("getter is only allowed for remote impls");
@@ -1,32 +0,0 @@
-use crate::internals::ast::Container;
-use syn::{Path, PathArguments, Token};
-
-pub fn this_type(cont: &Container) -> Path {
-    if let Some(remote) = cont.attrs.remote() {
-        let mut this = remote.clone();
-        for segment in &mut this.segments {
-            if let PathArguments::AngleBracketed(arguments) = &mut segment.arguments {
-                arguments.colon2_token = None;
-            }
-        }
-        this
-    } else {
-        Path::from(cont.ident.clone())
-    }
-}
-
-pub fn this_value(cont: &Container) -> Path {
-    if let Some(remote) = cont.attrs.remote() {
-        let mut this = remote.clone();
-        for segment in &mut this.segments {
-            if let PathArguments::AngleBracketed(arguments) = &mut segment.arguments {
-                if arguments.colon2_token.is_none() {
-                    arguments.colon2_token = Some(Token![::](arguments.lt_token.span));
-                }
-            }
-        }
-        this
-    } else {
-        Path::from(cont.ident.clone())
-    }
-}
@@ -0,0 +1,24 @@
+use proc_macro2::{Punct, Spacing, TokenStream};
+
+// None of our generated code requires the `From::from` error conversion
+// performed by the standard library's `try!` macro. With this simplified macro
+// we see a significant improvement in type checking and borrow checking time of
+// the generated code and a slight improvement in binary size.
+pub fn replacement() -> TokenStream {
+    // Cannot pass `$expr` to `quote!` prior to Rust 1.17.0 so interpolate it.
+    let dollar = Punct::new('$', Spacing::Alone);
+
+    quote! {
+        #[allow(unused_macros)]
+        macro_rules! try {
+            (#dollar __expr:expr) => {
+                match #dollar __expr {
+                    _serde::__private::Ok(__val) => __val,
+                    _serde::__private::Err(__err) => {
+                        return _serde::__private::Err(__err);
+                    }
+                }
+            }
+        }
+    }
+}
@@ -0,0 +1 @@
+msrv = "1.31.0"
@@ -1,32 +1,23 @@
 [package]
 name = "serde_derive_internals"
-version = "0.29.1"
+version = "0.26.0" # remember to update html_root_url
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>", "David Tolnay <dtolnay@gmail.com>"]
-description = "AST representation used by Serde derive macros. Unstable."
-documentation = "https://docs.rs/serde_derive_internals"
-edition = "2021"
-exclude = ["build.rs"]
-homepage = "https://serde.rs"
-keywords = ["serde", "serialization"]
+rust-version = "1.31"
 license = "MIT OR Apache-2.0"
+description = "AST representation used by Serde derive macros. Unstable."
+homepage = "https://serde.rs"
 repository = "https://github.com/serde-rs/serde"
-rust-version = "1.68"
+documentation = "https://docs.rs/serde_derive_internals"
+keywords = ["serde", "serialization"]
+include = ["lib.rs", "src/**/*.rs", "LICENSE-APACHE", "LICENSE-MIT"]

 [lib]
 path = "lib.rs"

 [dependencies]
-proc-macro2 = { workspace = true }
-quote = { workspace = true }
-syn = { workspace = true, features = ["clone-impls", "derive", "parsing", "printing"] }
+proc-macro2 = "1.0"
+quote = "1.0"
+syn = { version = "1.0.90", default-features = false, features = ["derive", "parsing", "printing", "clone-impls"] }

 [package.metadata.docs.rs]
 targets = ["x86_64-unknown-linux-gnu"]
-rustdoc-args = [
-    "--generate-link-to-definition",
-    "--generate-macro-expansion",
-    "--extern-html-root-url=core=https://doc.rust-lang.org",
-    "--extern-html-root-url=alloc=https://doc.rust-lang.org",
-    "--extern-html-root-url=std=https://doc.rust-lang.org",
-    "--extern-html-root-url=proc_macro=https://doc.rust-lang.org",
-]
@@ -1,17 +1,6 @@
 use std::path::Path;

 fn main() {
-    // Warning: build.rs is not published to crates.io.
-
-    println!("cargo:rerun-if-changed=build.rs");
-    println!("cargo:rerun-if-changed=src/mod.rs");
-
-    println!("cargo:rustc-cfg=check_cfg");
-    println!("cargo:rustc-check-cfg=cfg(check_cfg)");
-    println!("cargo:rustc-check-cfg=cfg(exhaustive)");
-    println!("cargo:rustc-check-cfg=cfg(serde_build_from_git)");
-    println!("cargo:rustc-check-cfg=cfg(feature, values(\"deserialize_in_place\"))");
-
    // Sometimes on Windows the git checkout does not correctly wire up the
    // symlink from serde_derive_internals/src to serde_derive/src/internals.
    // When this happens we'll just build based on relative paths within the git
@@ -1,5 +1,5 @@
-#![doc(html_root_url = "https://docs.rs/serde_derive_internals/0.29.1")]
-#![cfg_attr(not(check_cfg), allow(unexpected_cfgs))]
+#![doc(html_root_url = "https://docs.rs/serde_derive_internals/0.26.0")]
+#![allow(unknown_lints, bare_trait_objects)]
 // Ignored clippy lints
 #![allow(
    clippy::cognitive_complexity,
@@ -9,7 +9,6 @@
    // clippy bug: https://github.com/rust-lang/rust-clippy/issues/6797
    clippy::manual_map,
    clippy::missing_panics_doc,
-    clippy::needless_lifetimes,
    clippy::redundant_field_names,
    clippy::result_unit_err,
    clippy::should_implement_trait,
@@ -21,10 +20,9 @@
 // Ignored clippy_pedantic lints
 #![allow(
    clippy::doc_markdown,
-    clippy::elidable_lifetime_names,
    clippy::enum_glob_use,
    clippy::items_after_statements,
-    clippy::let_underscore_untyped,
+    clippy::let_underscore_drop,
    clippy::manual_assert,
    clippy::match_same_arms,
    // clippy bug: https://github.com/rust-lang/rust-clippy/issues/6984
@@ -32,20 +30,18 @@
    clippy::missing_errors_doc,
    clippy::module_name_repetitions,
    clippy::must_use_candidate,
-    clippy::return_self_not_must_use,
    clippy::similar_names,
-    clippy::single_match_else,
    clippy::struct_excessive_bools,
    clippy::too_many_lines,
-    clippy::uninlined_format_args,
    clippy::unused_self,
    clippy::wildcard_imports
 )]
-#![allow(unknown_lints, mismatched_lifetime_syntaxes)]
+
+#[macro_use]
+extern crate syn;

 extern crate proc_macro2;
 extern crate quote;
-extern crate syn;

 #[cfg_attr(serde_build_from_git, path = "../serde_derive/src/internals/mod.rs")]
 #[cfg_attr(not(serde_build_from_git), path = "src/mod.rs")]
@@ -0,0 +1 @@
+msrv = "1.13.0"
@@ -0,0 +1,24 @@
+[package]
+name = "serde_test"
+version = "1.0.137" # remember to update html_root_url
+authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>", "David Tolnay <dtolnay@gmail.com>"]
+rust-version = "1.13"
+license = "MIT OR Apache-2.0"
+description = "Token De/Serializer for testing De/Serialize implementations"
+homepage = "https://serde.rs"
+repository = "https://github.com/serde-rs/serde"
+documentation = "https://docs.serde.rs/serde_test/"
+keywords = ["serde", "serialization"]
+readme = "crates-io.md"
+include = ["build.rs", "src/**/*.rs", "crates-io.md", "README.md", "LICENSE-APACHE", "LICENSE-MIT"]
+build = "build.rs"
+
+[dependencies]
+serde = { version = "1.0.60", path = "../serde" }
+
+[dev-dependencies]
+serde = { version = "1.0", path = "../serde" }
+serde_derive = { version = "1.0", path = "../serde_derive" }
+
+[package.metadata.docs.rs]
+targets = ["x86_64-unknown-linux-gnu"]
@@ -0,0 +1 @@
+../README.md
@@ -0,0 +1,48 @@
+use std::env;
+use std::process::Command;
+use std::str::{self, FromStr};
+
+// The rustc-cfg strings below are *not* public API. Please let us know by
+// opening a GitHub issue if your build environment requires some way to enable
+// these cfgs other than by executing our build script.
+fn main() {
+    let minor = match rustc_minor_version() {
+        Some(minor) => minor,
+        None => return,
+    };
+
+    // #[track_caller] stabilized in Rust 1.46:
+    // https://blog.rust-lang.org/2020/08/27/Rust-1.46.0.html#track_caller
+    if minor >= 46 {
+        println!("cargo:rustc-cfg=track_caller");
+    }
+}
+
+fn rustc_minor_version() -> Option<u32> {
+    let rustc = match env::var_os("RUSTC") {
+        Some(rustc) => rustc,
+        None => return None,
+    };
+
+    let output = match Command::new(rustc).arg("--version").output() {
+        Ok(output) => output,
+        Err(_) => return None,
+    };
+
+    let version = match str::from_utf8(&output.stdout) {
+        Ok(version) => version,
+        Err(_) => return None,
+    };
+
+    let mut pieces = version.split('.');
+    if pieces.next() != Some("rustc 1") {
+        return None;
+    }
+
+    let next = match pieces.next() {
+        Some(next) => next,
+        None => return None,
+    };
+
+    u32::from_str(next).ok()
+}
@@ -0,0 +1 @@
+../crates-io.md
@@ -0,0 +1,223 @@
+use serde::{Deserialize, Serialize};
+
+use de::Deserializer;
+use ser::Serializer;
+use token::Token;
+
+use std::fmt::Debug;
+
+/// Runs both `assert_ser_tokens` and `assert_de_tokens`.
+///
+/// ```edition2018
+/// # use serde::{Serialize, Deserialize};
+/// # use serde_test::{assert_tokens, Token};
+/// #
+/// #[derive(Serialize, Deserialize, PartialEq, Debug)]
+/// struct S {
+///     a: u8,
+///     b: u8,
+/// }
+///
+/// let s = S { a: 0, b: 0 };
+/// assert_tokens(&s, &[
+///     Token::Struct { name: "S", len: 2 },
+///     Token::Str("a"),
+///     Token::U8(0),
+///     Token::Str("b"),
+///     Token::U8(0),
+///     Token::StructEnd,
+/// ]);
+/// ```
+#[cfg_attr(track_caller, track_caller)]
+pub fn assert_tokens<'de, T>(value: &T, tokens: &'de [Token])
+where
+    T: Serialize + Deserialize<'de> + PartialEq + Debug,
+{
+    assert_ser_tokens(value, tokens);
+    assert_de_tokens(value, tokens);
+}
+
+/// Asserts that `value` serializes to the given `tokens`.
+///
+/// ```edition2018
+/// # use serde::{Serialize, Deserialize};
+/// # use serde_test::{assert_ser_tokens, Token};
+/// #
+/// #[derive(Serialize, Deserialize, PartialEq, Debug)]
+/// struct S {
+///     a: u8,
+///     b: u8,
+/// }
+///
+/// let s = S { a: 0, b: 0 };
+/// assert_ser_tokens(&s, &[
+///     Token::Struct { name: "S", len: 2 },
+///     Token::Str("a"),
+///     Token::U8(0),
+///     Token::Str("b"),
+///     Token::U8(0),
+///     Token::StructEnd,
+/// ]);
+/// ```
+#[cfg_attr(track_caller, track_caller)]
+pub fn assert_ser_tokens<T: ?Sized>(value: &T, tokens: &[Token])
+where
+    T: Serialize,
+{
+    let mut ser = Serializer::new(tokens);
+    match value.serialize(&mut ser) {
+        Ok(_) => {}
+        Err(err) => panic!("value failed to serialize: {}", err),
+    }
+
+    if ser.remaining() > 0 {
+        panic!("{} remaining tokens", ser.remaining());
+    }
+}
+
+/// Asserts that `value` serializes to the given `tokens`, and then yields
+/// `error`.
+///
+/// ```edition2018
+/// use std::sync::{Arc, Mutex};
+/// use std::thread;
+///
+/// use serde::Serialize;
+/// use serde_test::{assert_ser_tokens_error, Token};
+///
+/// #[derive(Serialize)]
+/// struct Example {
+///     lock: Arc<Mutex<u32>>,
+/// }
+///
+/// fn main() {
+///     let example = Example { lock: Arc::new(Mutex::new(0)) };
+///     let lock = example.lock.clone();
+///
+///     let _ = thread::spawn(move || {
+///         // This thread will acquire the mutex first, unwrapping the result
+///         // of `lock` because the lock has not been poisoned.
+///         let _guard = lock.lock().unwrap();
+///
+///         // This panic while holding the lock (`_guard` is in scope) will
+///         // poison the mutex.
+///         panic!()
+///     }).join();
+///
+///     let expected = &[
+///         Token::Struct { name: "Example", len: 1 },
+///         Token::Str("lock"),
+///     ];
+///     let error = "lock poison error while serializing";
+///     assert_ser_tokens_error(&example, expected, error);
+/// }
+/// ```
+#[cfg_attr(track_caller, track_caller)]
+pub fn assert_ser_tokens_error<T: ?Sized>(value: &T, tokens: &[Token], error: &str)
+where
+    T: Serialize,
+{
+    let mut ser = Serializer::new(tokens);
+    match value.serialize(&mut ser) {
+        Ok(_) => panic!("value serialized successfully"),
+        Err(e) => assert_eq!(e, *error),
+    }
+
+    if ser.remaining() > 0 {
+        panic!("{} remaining tokens", ser.remaining());
+    }
+}
+
+/// Asserts that the given `tokens` deserialize into `value`.
+///
+/// ```edition2018
+/// # use serde::{Serialize, Deserialize};
+/// # use serde_test::{assert_de_tokens, Token};
+/// #
+/// #[derive(Serialize, Deserialize, PartialEq, Debug)]
+/// struct S {
+///     a: u8,
+///     b: u8,
+/// }
+///
+/// let s = S { a: 0, b: 0 };
+/// assert_de_tokens(&s, &[
+///     Token::Struct { name: "S", len: 2 },
+///     Token::Str("a"),
+///     Token::U8(0),
+///     Token::Str("b"),
+///     Token::U8(0),
+///     Token::StructEnd,
+/// ]);
+/// ```
+#[cfg_attr(track_caller, track_caller)]
+pub fn assert_de_tokens<'de, T>(value: &T, tokens: &'de [Token])
+where
+    T: Deserialize<'de> + PartialEq + Debug,
+{
+    let mut de = Deserializer::new(tokens);
+    let mut deserialized_val = match T::deserialize(&mut de) {
+        Ok(v) => {
+            assert_eq!(v, *value);
+            v
+        }
+        Err(e) => panic!("tokens failed to deserialize: {}", e),
+    };
+    if de.remaining() > 0 {
+        panic!("{} remaining tokens", de.remaining());
+    }
+
+    // Do the same thing for deserialize_in_place. This isn't *great* because a
+    // no-op impl of deserialize_in_place can technically succeed here. Still,
+    // this should catch a lot of junk.
+    let mut de = Deserializer::new(tokens);
+    match T::deserialize_in_place(&mut de, &mut deserialized_val) {
+        Ok(()) => {
+            assert_eq!(deserialized_val, *value);
+        }
+        Err(e) => panic!("tokens failed to deserialize_in_place: {}", e),
+    }
+    if de.remaining() > 0 {
+        panic!("{} remaining tokens", de.remaining());
+    }
+}
+
+/// Asserts that the given `tokens` yield `error` when deserializing.
+///
+/// ```edition2018
+/// # use serde::{Serialize, Deserialize};
+/// # use serde_test::{assert_de_tokens_error, Token};
+/// #
+/// #[derive(Serialize, Deserialize, PartialEq, Debug)]
+/// #[serde(deny_unknown_fields)]
+/// struct S {
+///     a: u8,
+///     b: u8,
+/// }
+///
+/// assert_de_tokens_error::<S>(
+///     &[
+///         Token::Struct { name: "S", len: 2 },
+///         Token::Str("x"),
+///     ],
+///     "unknown field `x`, expected `a` or `b`",
+/// );
+/// ```
+#[cfg_attr(track_caller, track_caller)]
+pub fn assert_de_tokens_error<'de, T>(tokens: &'de [Token], error: &str)
+where
+    T: Deserialize<'de>,
+{
+    let mut de = Deserializer::new(tokens);
+    match T::deserialize(&mut de) {
+        Ok(_) => panic!("tokens deserialized successfully"),
+        Err(e) => assert_eq!(e, *error),
+    }
+
+    // There may be one token left if a peek caused the error
+    de.next_token_opt();
+
+    if de.remaining() > 0 {
+        panic!("{} remaining tokens", de.remaining());
+    }
+}
@@ -0,0 +1,847 @@
+use std::fmt;
+
+use serde::ser::{
+    SerializeMap, SerializeSeq, SerializeStruct, SerializeStructVariant, SerializeTuple,
+    SerializeTupleStruct, SerializeTupleVariant,
+};
+use serde::{Deserialize, Deserializer, Serialize, Serializer};
+
+#[derive(Debug, PartialEq, Eq, PartialOrd, Ord)]
+pub struct Readable<T: ?Sized>(T);
+#[derive(Debug, PartialEq, Eq, PartialOrd, Ord)]
+pub struct Compact<T: ?Sized>(T);
+
+/// Trait to determine whether a value is represented in human-readable or
+/// compact form.
+///
+/// ```edition2018
+/// use serde::{Deserialize, Deserializer, Serialize, Serializer};
+/// use serde_test::{assert_tokens, Configure, Token};
+///
+/// #[derive(Debug, PartialEq)]
+/// struct Example(u8, u8);
+///
+/// impl Serialize for Example {
+///     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+///     where
+///         S: Serializer,
+///     {
+///         if serializer.is_human_readable() {
+///             format!("{}.{}", self.0, self.1).serialize(serializer)
+///         } else {
+///             (self.0, self.1).serialize(serializer)
+///         }
+///     }
+/// }
+///
+/// impl<'de> Deserialize<'de> for Example {
+///     fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+///     where
+///         D: Deserializer<'de>,
+///     {
+///         use serde::de::Error;
+///         if deserializer.is_human_readable() {
+///             let s = String::deserialize(deserializer)?;
+///             let parts: Vec<_> = s.split('.').collect();
+///             Ok(Example(
+///                 parts[0].parse().map_err(D::Error::custom)?,
+///                 parts[1].parse().map_err(D::Error::custom)?,
+///             ))
+///         } else {
+///             let (x, y) = Deserialize::deserialize(deserializer)?;
+///             Ok(Example(x, y))
+///         }
+///     }
+/// }
+///
+/// fn main() {
+///     assert_tokens(
+///         &Example(1, 0).compact(),
+///         &[
+///             Token::Tuple { len: 2 },
+///             Token::U8(1),
+///             Token::U8(0),
+///             Token::TupleEnd,
+///         ],
+///     );
+///     assert_tokens(&Example(1, 0).readable(), &[Token::Str("1.0")]);
+/// }
+/// ```
+pub trait Configure {
+    /// Marks `self` as using `is_human_readable == true`
+    fn readable(self) -> Readable<Self>
+    where
+        Self: Sized,
+    {
+        Readable(self)
+    }
+    /// Marks `self` as using `is_human_readable == false`
+    fn compact(self) -> Compact<Self>
+    where
+        Self: Sized,
+    {
+        Compact(self)
+    }
+}
+
+impl<T: ?Sized> Configure for T {}
+
+impl<T: ?Sized> Serialize for Readable<T>
+where
+    T: Serialize,
+{
+    #[inline]
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        self.0.serialize(Readable(serializer))
+    }
+}
+impl<T: ?Sized> Serialize for Compact<T>
+where
+    T: Serialize,
+{
+    #[inline]
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        self.0.serialize(Compact(serializer))
+    }
+}
+impl<'de, T> Deserialize<'de> for Readable<T>
+where
+    T: Deserialize<'de>,
+{
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        T::deserialize(Readable(deserializer)).map(Readable)
+    }
+}
+impl<'de, T> Deserialize<'de> for Compact<T>
+where
+    T: Deserialize<'de>,
+{
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        T::deserialize(Compact(deserializer)).map(Compact)
+    }
+}
+
+impl<'de, T> DeserializeSeed<'de> for Readable<T>
+where
+    T: DeserializeSeed<'de>,
+{
+    type Value = T::Value;
+
+    fn deserialize<D>(self, deserializer: D) -> Result<Self::Value, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        self.0.deserialize(Readable(deserializer))
+    }
+}
+impl<'de, T> DeserializeSeed<'de> for Compact<T>
+where
+    T: DeserializeSeed<'de>,
+{
+    type Value = T::Value;
+
+    fn deserialize<D>(self, deserializer: D) -> Result<Self::Value, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        self.0.deserialize(Compact(deserializer))
+    }
+}
+
+macro_rules! forward_method {
+    ($name: ident (self $(, $arg: ident : $arg_type: ty)* ) -> $return_type: ty) => {
+        fn $name (self $(, $arg : $arg_type)* ) -> $return_type {
+            (self.0).$name( $($arg),* )
+        }
+    };
+}
+
+macro_rules! forward_serialize_methods {
+    ( $( $name: ident $arg_type: ty ),* ) => {
+        $(
+            forward_method!($name(self, v : $arg_type) -> Result<Self::Ok, Self::Error>);
+        )*
+    };
+}
+
+macro_rules! impl_serializer {
+    ($wrapper:ident, $is_human_readable:expr) => {
+        impl<S> Serializer for $wrapper<S>
+        where
+            S: Serializer,
+        {
+            type Ok = S::Ok;
+            type Error = S::Error;
+
+            type SerializeSeq = $wrapper<S::SerializeSeq>;
+            type SerializeTuple = $wrapper<S::SerializeTuple>;
+            type SerializeTupleStruct = $wrapper<S::SerializeTupleStruct>;
+            type SerializeTupleVariant = $wrapper<S::SerializeTupleVariant>;
+            type SerializeMap = $wrapper<S::SerializeMap>;
+            type SerializeStruct = $wrapper<S::SerializeStruct>;
+            type SerializeStructVariant = $wrapper<S::SerializeStructVariant>;
+
+            fn is_human_readable(&self) -> bool {
+                $is_human_readable
+            }
+
+            forward_serialize_methods! {
+                serialize_bool bool,
+                serialize_i8 i8,
+                serialize_i16 i16,
+                serialize_i32 i32,
+                serialize_i64 i64,
+                serialize_u8 u8,
+                serialize_u16 u16,
+                serialize_u32 u32,
+                serialize_u64 u64,
+                serialize_f32 f32,
+                serialize_f64 f64,
+                serialize_char char,
+                serialize_str &str,
+                serialize_bytes &[u8],
+                serialize_unit_struct &'static str
+
+            }
+
+            fn serialize_unit(self) -> Result<S::Ok, S::Error> {
+                self.0.serialize_unit()
+            }
+
+            fn serialize_unit_variant(
+                self,
+                name: &'static str,
+                variant_index: u32,
+                variant: &'static str,
+            ) -> Result<S::Ok, S::Error> {
+                self.0.serialize_unit_variant(name, variant_index, variant)
+            }
+
+            fn serialize_newtype_struct<T: ?Sized>(
+                self,
+                name: &'static str,
+                value: &T,
+            ) -> Result<S::Ok, S::Error>
+            where
+                T: Serialize,
+            {
+                self.0.serialize_newtype_struct(name, &$wrapper(value))
+            }
+
+            fn serialize_newtype_variant<T: ?Sized>(
+                self,
+                name: &'static str,
+                variant_index: u32,
+                variant: &'static str,
+                value: &T,
+            ) -> Result<S::Ok, S::Error>
+            where
+                T: Serialize,
+            {
+                self.0
+                    .serialize_newtype_variant(name, variant_index, variant, &$wrapper(value))
+            }
+
+            fn serialize_none(self) -> Result<S::Ok, Self::Error> {
+                self.0.serialize_none()
+            }
+
+            fn serialize_some<T: ?Sized>(self, value: &T) -> Result<S::Ok, Self::Error>
+            where
+                T: Serialize,
+            {
+                self.0.serialize_some(&$wrapper(value))
+            }
+
+            fn serialize_seq(self, len: Option<usize>) -> Result<Self::SerializeSeq, Self::Error> {
+                self.0.serialize_seq(len).map($wrapper)
+            }
+
+            fn serialize_tuple(self, len: usize) -> Result<Self::SerializeTuple, Self::Error> {
+                self.0.serialize_tuple(len).map($wrapper)
+            }
+
+            fn serialize_tuple_struct(
+                self,
+                name: &'static str,
+                len: usize,
+            ) -> Result<Self::SerializeTupleStruct, Self::Error> {
+                self.0.serialize_tuple_struct(name, len).map($wrapper)
+            }
+
+            fn serialize_tuple_variant(
+                self,
+                name: &'static str,
+                variant_index: u32,
+                variant: &'static str,
+                len: usize,
+            ) -> Result<Self::SerializeTupleVariant, Self::Error> {
+                self.0
+                    .serialize_tuple_variant(name, variant_index, variant, len)
+                    .map($wrapper)
+            }
+
+            fn serialize_map(self, len: Option<usize>) -> Result<Self::SerializeMap, Self::Error> {
+                self.0.serialize_map(len).map($wrapper)
+            }
+
+            fn serialize_struct(
+                self,
+                name: &'static str,
+                len: usize,
+            ) -> Result<Self::SerializeStruct, Self::Error> {
+                self.0.serialize_struct(name, len).map($wrapper)
+            }
+
+            fn serialize_struct_variant(
+                self,
+                name: &'static str,
+                variant_index: u32,
+                variant: &'static str,
+                len: usize,
+            ) -> Result<Self::SerializeStructVariant, Self::Error> {
+                self.0
+                    .serialize_struct_variant(name, variant_index, variant, len)
+                    .map($wrapper)
+            }
+        }
+
+        impl<S> SerializeSeq for $wrapper<S>
+        where
+            S: SerializeSeq,
+        {
+            type Ok = S::Ok;
+            type Error = S::Error;
+            fn serialize_element<T: ?Sized>(&mut self, value: &T) -> Result<(), S::Error>
+            where
+                T: Serialize,
+            {
+                self.0.serialize_element(&$wrapper(value))
+            }
+            fn end(self) -> Result<S::Ok, S::Error> {
+                self.0.end()
+            }
+        }
+
+        impl<S> SerializeTuple for $wrapper<S>
+        where
+            S: SerializeTuple,
+        {
+            type Ok = S::Ok;
+            type Error = S::Error;
+            fn serialize_element<T: ?Sized>(&mut self, value: &T) -> Result<(), S::Error>
+            where
+                T: Serialize,
+            {
+                self.0.serialize_element(&$wrapper(value))
+            }
+            fn end(self) -> Result<S::Ok, S::Error> {
+                self.0.end()
+            }
+        }
+
+        impl<S> SerializeTupleStruct for $wrapper<S>
+        where
+            S: SerializeTupleStruct,
+        {
+            type Ok = S::Ok;
+            type Error = S::Error;
+            fn serialize_field<T: ?Sized>(&mut self, value: &T) -> Result<(), S::Error>
+            where
+                T: Serialize,
+            {
+                self.0.serialize_field(&$wrapper(value))
+            }
+            fn end(self) -> Result<S::Ok, S::Error> {
+                self.0.end()
+            }
+        }
+
+        impl<S> SerializeTupleVariant for $wrapper<S>
+        where
+            S: SerializeTupleVariant,
+        {
+            type Ok = S::Ok;
+            type Error = S::Error;
+            fn serialize_field<T: ?Sized>(&mut self, value: &T) -> Result<(), S::Error>
+            where
+                T: Serialize,
+            {
+                self.0.serialize_field(&$wrapper(value))
+            }
+            fn end(self) -> Result<S::Ok, S::Error> {
+                self.0.end()
+            }
+        }
+
+        impl<S> SerializeMap for $wrapper<S>
+        where
+            S: SerializeMap,
+        {
+            type Ok = S::Ok;
+            type Error = S::Error;
+            fn serialize_key<T: ?Sized>(&mut self, key: &T) -> Result<(), S::Error>
+            where
+                T: Serialize,
+            {
+                self.0.serialize_key(&$wrapper(key))
+            }
+            fn serialize_value<T: ?Sized>(&mut self, value: &T) -> Result<(), S::Error>
+            where
+                T: Serialize,
+            {
+                self.0.serialize_value(&$wrapper(value))
+            }
+            fn serialize_entry<K: ?Sized, V: ?Sized>(
+                &mut self,
+                key: &K,
+                value: &V,
+            ) -> Result<(), S::Error>
+            where
+                K: Serialize,
+                V: Serialize,
+            {
+                self.0.serialize_entry(key, &$wrapper(value))
+            }
+            fn end(self) -> Result<S::Ok, S::Error> {
+                self.0.end()
+            }
+        }
+
+        impl<S> SerializeStruct for $wrapper<S>
+        where
+            S: SerializeStruct,
+        {
+            type Ok = S::Ok;
+            type Error = S::Error;
+            fn serialize_field<T: ?Sized>(
+                &mut self,
+                name: &'static str,
+                field: &T,
+            ) -> Result<(), S::Error>
+            where
+                T: Serialize,
+            {
+                self.0.serialize_field(name, &$wrapper(field))
+            }
+            fn end(self) -> Result<S::Ok, S::Error> {
+                self.0.end()
+            }
+        }
+
+        impl<S> SerializeStructVariant for $wrapper<S>
+        where
+            S: SerializeStructVariant,
+        {
+            type Ok = S::Ok;
+            type Error = S::Error;
+            fn serialize_field<T: ?Sized>(
+                &mut self,
+                name: &'static str,
+                field: &T,
+            ) -> Result<(), S::Error>
+            where
+                T: Serialize,
+            {
+                self.0.serialize_field(name, &$wrapper(field))
+            }
+            fn end(self) -> Result<S::Ok, S::Error> {
+                self.0.end()
+            }
+        }
+    };
+}
+
+impl_serializer!(Readable, true);
+impl_serializer!(Compact, false);
+
+use serde::de::{DeserializeSeed, EnumAccess, Error, MapAccess, SeqAccess, VariantAccess, Visitor};
+
+macro_rules! forward_deserialize_methods {
+    ( $wrapper : ident ( $( $name: ident ),* ) ) => {
+        $(
+            fn $name<V>(self, visitor: V) -> Result<V::Value, D::Error>
+            where
+                V: Visitor<'de>,
+            {
+                (self.0).$name($wrapper(visitor))
+            }
+        )*
+    };
+}
+
+macro_rules! impl_deserializer {
+    ($wrapper:ident, $is_human_readable:expr) => {
+        impl<'de, D> Deserializer<'de> for $wrapper<D>
+        where
+            D: Deserializer<'de>,
+        {
+            type Error = D::Error;
+
+            forward_deserialize_methods! {
+                $wrapper (
+                    deserialize_any,
+                    deserialize_bool,
+                    deserialize_u8,
+                    deserialize_u16,
+                    deserialize_u32,
+                    deserialize_u64,
+                    deserialize_i8,
+                    deserialize_i16,
+                    deserialize_i32,
+                    deserialize_i64,
+                    deserialize_f32,
+                    deserialize_f64,
+                    deserialize_char,
+                    deserialize_str,
+                    deserialize_string,
+                    deserialize_bytes,
+                    deserialize_byte_buf,
+                    deserialize_option,
+                    deserialize_unit,
+                    deserialize_seq,
+                    deserialize_map,
+                    deserialize_identifier,
+                    deserialize_ignored_any
+                )
+            }
+
+            fn deserialize_unit_struct<V>(
+                self,
+                name: &'static str,
+                visitor: V,
+            ) -> Result<V::Value, D::Error>
+            where
+                V: Visitor<'de>,
+            {
+                self.0.deserialize_unit_struct(name, $wrapper(visitor))
+            }
+            fn deserialize_newtype_struct<V>(
+                self,
+                name: &'static str,
+                visitor: V,
+            ) -> Result<V::Value, D::Error>
+            where
+                V: Visitor<'de>,
+            {
+                self.0.deserialize_newtype_struct(name, $wrapper(visitor))
+            }
+            fn deserialize_tuple<V>(self, len: usize, visitor: V) -> Result<V::Value, D::Error>
+            where
+                V: Visitor<'de>,
+            {
+                self.0.deserialize_tuple(len, $wrapper(visitor))
+            }
+            fn deserialize_tuple_struct<V>(
+                self,
+                name: &'static str,
+                len: usize,
+                visitor: V,
+            ) -> Result<V::Value, D::Error>
+            where
+                V: Visitor<'de>,
+            {
+                self.0
+                    .deserialize_tuple_struct(name, len, $wrapper(visitor))
+            }
+            fn deserialize_struct<V>(
+                self,
+                name: &'static str,
+                fields: &'static [&'static str],
+                visitor: V,
+            ) -> Result<V::Value, D::Error>
+            where
+                V: Visitor<'de>,
+            {
+                self.0.deserialize_struct(name, fields, $wrapper(visitor))
+            }
+            fn deserialize_enum<V>(
+                self,
+                name: &'static str,
+                variants: &'static [&'static str],
+                visitor: V,
+            ) -> Result<V::Value, D::Error>
+            where
+                V: Visitor<'de>,
+            {
+                self.0.deserialize_enum(name, variants, $wrapper(visitor))
+            }
+
+            fn is_human_readable(&self) -> bool {
+                $is_human_readable
+            }
+        }
+
+        impl<'de, D> Visitor<'de> for $wrapper<D>
+        where
+            D: Visitor<'de>,
+        {
+            type Value = D::Value;
+            fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+                self.0.expecting(formatter)
+            }
+            fn visit_bool<E>(self, v: bool) -> Result<D::Value, E>
+            where
+                E: Error,
+            {
+                self.0.visit_bool(v)
+            }
+            fn visit_i8<E>(self, v: i8) -> Result<D::Value, E>
+            where
+                E: Error,
+            {
+                self.0.visit_i8(v)
+            }
+            fn visit_i16<E>(self, v: i16) -> Result<D::Value, E>
+            where
+                E: Error,
+            {
+                self.0.visit_i16(v)
+            }
+            fn visit_i32<E>(self, v: i32) -> Result<D::Value, E>
+            where
+                E: Error,
+            {
+                self.0.visit_i32(v)
+            }
+            fn visit_i64<E>(self, v: i64) -> Result<D::Value, E>
+            where
+                E: Error,
+            {
+                self.0.visit_i64(v)
+            }
+            fn visit_u8<E>(self, v: u8) -> Result<D::Value, E>
+            where
+                E: Error,
+            {
+                self.0.visit_u8(v)
+            }
+            fn visit_u16<E>(self, v: u16) -> Result<D::Value, E>
+            where
+                E: Error,
+            {
+                self.0.visit_u16(v)
+            }
+            fn visit_u32<E>(self, v: u32) -> Result<D::Value, E>
+            where
+                E: Error,
+            {
+                self.0.visit_u32(v)
+            }
+            fn visit_u64<E>(self, v: u64) -> Result<D::Value, E>
+            where
+                E: Error,
+            {
+                self.0.visit_u64(v)
+            }
+            fn visit_f32<E>(self, v: f32) -> Result<D::Value, E>
+            where
+                E: Error,
+            {
+                self.0.visit_f32(v)
+            }
+            fn visit_f64<E>(self, v: f64) -> Result<D::Value, E>
+            where
+                E: Error,
+            {
+                self.0.visit_f64(v)
+            }
+            fn visit_char<E>(self, v: char) -> Result<D::Value, E>
+            where
+                E: Error,
+            {
+                self.0.visit_char(v)
+            }
+            fn visit_str<E>(self, v: &str) -> Result<D::Value, E>
+            where
+                E: Error,
+            {
+                self.0.visit_str(v)
+            }
+            fn visit_borrowed_str<E>(self, v: &'de str) -> Result<D::Value, E>
+            where
+                E: Error,
+            {
+                self.0.visit_borrowed_str(v)
+            }
+            fn visit_string<E>(self, v: String) -> Result<D::Value, E>
+            where
+                E: Error,
+            {
+                self.0.visit_string(v)
+            }
+            fn visit_bytes<E>(self, v: &[u8]) -> Result<D::Value, E>
+            where
+                E: Error,
+            {
+                self.0.visit_bytes(v)
+            }
+            fn visit_borrowed_bytes<E>(self, v: &'de [u8]) -> Result<D::Value, E>
+            where
+                E: Error,
+            {
+                self.0.visit_borrowed_bytes(v)
+            }
+            fn visit_byte_buf<E>(self, v: Vec<u8>) -> Result<D::Value, E>
+            where
+                E: Error,
+            {
+                self.0.visit_byte_buf(v)
+            }
+            fn visit_none<E>(self) -> Result<D::Value, E>
+            where
+                E: Error,
+            {
+                self.0.visit_none()
+            }
+            fn visit_some<D2>(self, deserializer: D2) -> Result<Self::Value, D2::Error>
+            where
+                D2: Deserializer<'de>,
+            {
+                self.0.visit_some($wrapper(deserializer))
+            }
+            fn visit_unit<E>(self) -> Result<D::Value, E>
+            where
+                E: Error,
+            {
+                self.0.visit_unit()
+            }
+            fn visit_newtype_struct<D2>(self, deserializer: D2) -> Result<Self::Value, D2::Error>
+            where
+                D2: Deserializer<'de>,
+            {
+                self.0.visit_newtype_struct($wrapper(deserializer))
+            }
+            fn visit_seq<V>(self, seq: V) -> Result<D::Value, V::Error>
+            where
+                V: SeqAccess<'de>,
+            {
+                self.0.visit_seq($wrapper(seq))
+            }
+            fn visit_map<V>(self, map: V) -> Result<D::Value, V::Error>
+            where
+                V: MapAccess<'de>,
+            {
+                self.0.visit_map($wrapper(map))
+            }
+            fn visit_enum<V>(self, data: V) -> Result<D::Value, V::Error>
+            where
+                V: EnumAccess<'de>,
+            {
+                self.0.visit_enum($wrapper(data))
+            }
+        }
+
+        impl<'de, D> SeqAccess<'de> for $wrapper<D>
+        where
+            D: SeqAccess<'de>,
+        {
+            type Error = D::Error;
+            fn next_element_seed<T>(&mut self, seed: T) -> Result<Option<T::Value>, D::Error>
+            where
+                T: DeserializeSeed<'de>,
+            {
+                self.0.next_element_seed($wrapper(seed))
+            }
+            fn size_hint(&self) -> Option<usize> {
+                self.0.size_hint()
+            }
+        }
+
+        impl<'de, D> MapAccess<'de> for $wrapper<D>
+        where
+            D: MapAccess<'de>,
+        {
+            type Error = D::Error;
+            fn next_key_seed<K>(&mut self, seed: K) -> Result<Option<K::Value>, D::Error>
+            where
+                K: DeserializeSeed<'de>,
+            {
+                self.0.next_key_seed($wrapper(seed))
+            }
+            fn next_value_seed<V>(&mut self, seed: V) -> Result<V::Value, D::Error>
+            where
+                V: DeserializeSeed<'de>,
+            {
+                self.0.next_value_seed($wrapper(seed))
+            }
+            fn next_entry_seed<K, V>(
+                &mut self,
+                kseed: K,
+                vseed: V,
+            ) -> Result<Option<(K::Value, V::Value)>, D::Error>
+            where
+                K: DeserializeSeed<'de>,
+                V: DeserializeSeed<'de>,
+            {
+                self.0.next_entry_seed($wrapper(kseed), $wrapper(vseed))
+            }
+            fn size_hint(&self) -> Option<usize> {
+                self.0.size_hint()
+            }
+        }
+
+        impl<'de, D> EnumAccess<'de> for $wrapper<D>
+        where
+            D: EnumAccess<'de>,
+        {
+            type Error = D::Error;
+            type Variant = $wrapper<D::Variant>;
+            fn variant_seed<V>(self, seed: V) -> Result<(V::Value, Self::Variant), Self::Error>
+            where
+                V: DeserializeSeed<'de>,
+            {
+                self.0
+                    .variant_seed($wrapper(seed))
+                    .map(|(value, variant)| (value, $wrapper(variant)))
+            }
+        }
+
+        impl<'de, D> VariantAccess<'de> for $wrapper<D>
+        where
+            D: VariantAccess<'de>,
+        {
+            type Error = D::Error;
+            fn unit_variant(self) -> Result<(), D::Error> {
+                self.0.unit_variant()
+            }
+            fn newtype_variant_seed<T>(self, seed: T) -> Result<T::Value, D::Error>
+            where
+                T: DeserializeSeed<'de>,
+            {
+                self.0.newtype_variant_seed($wrapper(seed))
+            }
+            fn tuple_variant<V>(self, len: usize, visitor: V) -> Result<V::Value, D::Error>
+            where
+                V: Visitor<'de>,
+            {
+                self.0.tuple_variant(len, $wrapper(visitor))
+            }
+            fn struct_variant<V>(
+                self,
+                fields: &'static [&'static str],
+                visitor: V,
+            ) -> Result<V::Value, D::Error>
+            where
+                V: Visitor<'de>,
+            {
+                self.0.struct_variant(fields, $wrapper(visitor))
+            }
+        }
+    };
+}
+
+impl_deserializer!(Readable, true);
+impl_deserializer!(Compact, false);
@@ -0,0 +1,683 @@
+use serde::de::value::{MapAccessDeserializer, SeqAccessDeserializer};
+use serde::de::{
+    self, Deserialize, DeserializeSeed, EnumAccess, IntoDeserializer, MapAccess, SeqAccess,
+    VariantAccess, Visitor,
+};
+
+use error::Error;
+use token::Token;
+
+#[derive(Debug)]
+pub struct Deserializer<'de> {
+    tokens: &'de [Token],
+}
+
+macro_rules! assert_next_token {
+    ($de:expr, $expected:expr) => {
+        match $de.next_token_opt() {
+            Some(token) if token == $expected => {}
+            Some(other) => panic!(
+                "expected Token::{} but deserialization wants Token::{}",
+                other, $expected
+            ),
+            None => panic!(
+                "end of tokens but deserialization wants Token::{}",
+                $expected
+            ),
+        }
+    };
+}
+
+macro_rules! unexpected {
+    ($token:expr) => {
+        panic!("deserialization did not expect this token: {}", $token)
+    };
+}
+
+macro_rules! end_of_tokens {
+    () => {
+        panic!("ran out of tokens to deserialize")
+    };
+}
+
+impl<'de> Deserializer<'de> {
+    pub fn new(tokens: &'de [Token]) -> Self {
+        Deserializer { tokens: tokens }
+    }
+
+    fn peek_token_opt(&self) -> Option<Token> {
+        self.tokens.first().cloned()
+    }
+
+    fn peek_token(&self) -> Token {
+        match self.peek_token_opt() {
+            Some(token) => token,
+            None => end_of_tokens!(),
+        }
+    }
+
+    pub fn next_token_opt(&mut self) -> Option<Token> {
+        match self.tokens.split_first() {
+            Some((&first, rest)) => {
+                self.tokens = rest;
+                Some(first)
+            }
+            None => None,
+        }
+    }
+
+    fn next_token(&mut self) -> Token {
+        match self.tokens.split_first() {
+            Some((&first, rest)) => {
+                self.tokens = rest;
+                first
+            }
+            None => end_of_tokens!(),
+        }
+    }
+
+    pub fn remaining(&self) -> usize {
+        self.tokens.len()
+    }
+
+    fn visit_seq<V>(
+        &mut self,
+        len: Option<usize>,
+        end: Token,
+        visitor: V,
+    ) -> Result<V::Value, Error>
+    where
+        V: Visitor<'de>,
+    {
+        let value = visitor.visit_seq(DeserializerSeqVisitor {
+            de: self,
+            len: len,
+            end: end,
+        })?;
+        assert_next_token!(self, end);
+        Ok(value)
+    }
+
+    fn visit_map<V>(
+        &mut self,
+        len: Option<usize>,
+        end: Token,
+        visitor: V,
+    ) -> Result<V::Value, Error>
+    where
+        V: Visitor<'de>,
+    {
+        let value = visitor.visit_map(DeserializerMapVisitor {
+            de: self,
+            len: len,
+            end: end,
+        })?;
+        assert_next_token!(self, end);
+        Ok(value)
+    }
+}
+
+impl<'de, 'a> de::Deserializer<'de> for &'a mut Deserializer<'de> {
+    type Error = Error;
+
+    forward_to_deserialize_any! {
+        bool i8 i16 i32 i64 i128 u8 u16 u32 u64 u128 f32 f64 char str string
+        bytes byte_buf unit seq map identifier ignored_any
+    }
+
+    fn deserialize_any<V>(self, visitor: V) -> Result<V::Value, Error>
+    where
+        V: Visitor<'de>,
+    {
+        let token = self.next_token();
+        match token {
+            Token::Bool(v) => visitor.visit_bool(v),
+            Token::I8(v) => visitor.visit_i8(v),
+            Token::I16(v) => visitor.visit_i16(v),
+            Token::I32(v) => visitor.visit_i32(v),
+            Token::I64(v) => visitor.visit_i64(v),
+            Token::U8(v) => visitor.visit_u8(v),
+            Token::U16(v) => visitor.visit_u16(v),
+            Token::U32(v) => visitor.visit_u32(v),
+            Token::U64(v) => visitor.visit_u64(v),
+            Token::F32(v) => visitor.visit_f32(v),
+            Token::F64(v) => visitor.visit_f64(v),
+            Token::Char(v) => visitor.visit_char(v),
+            Token::Str(v) => visitor.visit_str(v),
+            Token::BorrowedStr(v) => visitor.visit_borrowed_str(v),
+            Token::String(v) => visitor.visit_string(v.to_owned()),
+            Token::Bytes(v) => visitor.visit_bytes(v),
+            Token::BorrowedBytes(v) => visitor.visit_borrowed_bytes(v),
+            Token::ByteBuf(v) => visitor.visit_byte_buf(v.to_vec()),
+            Token::None => visitor.visit_none(),
+            Token::Some => visitor.visit_some(self),
+            Token::Unit | Token::UnitStruct { .. } => visitor.visit_unit(),
+            Token::NewtypeStruct { .. } => visitor.visit_newtype_struct(self),
+            Token::Seq { len } => self.visit_seq(len, Token::SeqEnd, visitor),
+            Token::Tuple { len } => self.visit_seq(Some(len), Token::TupleEnd, visitor),
+            Token::TupleStruct { len, .. } => {
+                self.visit_seq(Some(len), Token::TupleStructEnd, visitor)
+            }
+            Token::Map { len } => self.visit_map(len, Token::MapEnd, visitor),
+            Token::Struct { len, .. } => self.visit_map(Some(len), Token::StructEnd, visitor),
+            Token::Enum { .. } => {
+                let variant = self.next_token();
+                let next = self.peek_token();
+                match (variant, next) {
+                    (Token::Str(variant), Token::Unit) => {
+                        self.next_token();
+                        visitor.visit_str(variant)
+                    }
+                    (Token::BorrowedStr(variant), Token::Unit) => {
+                        self.next_token();
+                        visitor.visit_borrowed_str(variant)
+                    }
+                    (Token::String(variant), Token::Unit) => {
+                        self.next_token();
+                        visitor.visit_string(variant.to_string())
+                    }
+                    (Token::Bytes(variant), Token::Unit) => {
+                        self.next_token();
+                        visitor.visit_bytes(variant)
+                    }
+                    (Token::BorrowedBytes(variant), Token::Unit) => {
+                        self.next_token();
+                        visitor.visit_borrowed_bytes(variant)
+                    }
+                    (Token::ByteBuf(variant), Token::Unit) => {
+                        self.next_token();
+                        visitor.visit_byte_buf(variant.to_vec())
+                    }
+                    (Token::U8(variant), Token::Unit) => {
+                        self.next_token();
+                        visitor.visit_u8(variant)
+                    }
+                    (Token::U16(variant), Token::Unit) => {
+                        self.next_token();
+                        visitor.visit_u16(variant)
+                    }
+                    (Token::U32(variant), Token::Unit) => {
+                        self.next_token();
+                        visitor.visit_u32(variant)
+                    }
+                    (Token::U64(variant), Token::Unit) => {
+                        self.next_token();
+                        visitor.visit_u64(variant)
+                    }
+                    (variant, Token::Unit) => unexpected!(variant),
+                    (variant, _) => {
+                        visitor.visit_map(EnumMapVisitor::new(self, variant, EnumFormat::Any))
+                    }
+                }
+            }
+            Token::UnitVariant { variant, .. } => visitor.visit_str(variant),
+            Token::NewtypeVariant { variant, .. } => visitor.visit_map(EnumMapVisitor::new(
+                self,
+                Token::Str(variant),
+                EnumFormat::Any,
+            )),
+            Token::TupleVariant { variant, .. } => visitor.visit_map(EnumMapVisitor::new(
+                self,
+                Token::Str(variant),
+                EnumFormat::Seq,
+            )),
+            Token::StructVariant { variant, .. } => visitor.visit_map(EnumMapVisitor::new(
+                self,
+                Token::Str(variant),
+                EnumFormat::Map,
+            )),
+            Token::SeqEnd
+            | Token::TupleEnd
+            | Token::TupleStructEnd
+            | Token::MapEnd
+            | Token::StructEnd
+            | Token::TupleVariantEnd
+            | Token::StructVariantEnd => {
+                unexpected!(token);
+            }
+        }
+    }
+
+    fn deserialize_option<V>(self, visitor: V) -> Result<V::Value, Error>
+    where
+        V: Visitor<'de>,
+    {
+        match self.peek_token() {
+            Token::Unit | Token::None => {
+                self.next_token();
+                visitor.visit_none()
+            }
+            Token::Some => {
+                self.next_token();
+                visitor.visit_some(self)
+            }
+            _ => self.deserialize_any(visitor),
+        }
+    }
+
+    fn deserialize_enum<V>(
+        self,
+        name: &'static str,
+        _variants: &'static [&'static str],
+        visitor: V,
+    ) -> Result<V::Value, Error>
+    where
+        V: Visitor<'de>,
+    {
+        match self.peek_token() {
+            Token::Enum { name: n } if name == n => {
+                self.next_token();
+
+                visitor.visit_enum(DeserializerEnumVisitor { de: self })
+            }
+            Token::UnitVariant { name: n, .. }
+            | Token::NewtypeVariant { name: n, .. }
+            | Token::TupleVariant { name: n, .. }
+            | Token::StructVariant { name: n, .. }
+                if name == n =>
+            {
+                visitor.visit_enum(DeserializerEnumVisitor { de: self })
+            }
+            _ => self.deserialize_any(visitor),
+        }
+    }
+
+    fn deserialize_unit_struct<V>(self, name: &'static str, visitor: V) -> Result<V::Value, Error>
+    where
+        V: Visitor<'de>,
+    {
+        match self.peek_token() {
+            Token::UnitStruct { .. } => {
+                assert_next_token!(self, Token::UnitStruct { name: name });
+                visitor.visit_unit()
+            }
+            _ => self.deserialize_any(visitor),
+        }
+    }
+
+    fn deserialize_newtype_struct<V>(
+        self,
+        name: &'static str,
+        visitor: V,
+    ) -> Result<V::Value, Error>
+    where
+        V: Visitor<'de>,
+    {
+        match self.peek_token() {
+            Token::NewtypeStruct { .. } => {
+                assert_next_token!(self, Token::NewtypeStruct { name: name });
+                visitor.visit_newtype_struct(self)
+            }
+            _ => self.deserialize_any(visitor),
+        }
+    }
+
+    fn deserialize_tuple<V>(self, len: usize, visitor: V) -> Result<V::Value, Error>
+    where
+        V: Visitor<'de>,
+    {
+        match self.peek_token() {
+            Token::Unit | Token::UnitStruct { .. } => {
+                self.next_token();
+                visitor.visit_unit()
+            }
+            Token::Seq { .. } => {
+                self.next_token();
+                self.visit_seq(Some(len), Token::SeqEnd, visitor)
+            }
+            Token::Tuple { .. } => {
+                self.next_token();
+                self.visit_seq(Some(len), Token::TupleEnd, visitor)
+            }
+            Token::TupleStruct { .. } => {
+                self.next_token();
+                self.visit_seq(Some(len), Token::TupleStructEnd, visitor)
+            }
+            _ => self.deserialize_any(visitor),
+        }
+    }
+
+    fn deserialize_tuple_struct<V>(
+        self,
+        name: &'static str,
+        len: usize,
+        visitor: V,
+    ) -> Result<V::Value, Error>
+    where
+        V: Visitor<'de>,
+    {
+        match self.peek_token() {
+            Token::Unit => {
+                self.next_token();
+                visitor.visit_unit()
+            }
+            Token::UnitStruct { .. } => {
+                assert_next_token!(self, Token::UnitStruct { name: name });
+                visitor.visit_unit()
+            }
+            Token::Seq { .. } => {
+                self.next_token();
+                self.visit_seq(Some(len), Token::SeqEnd, visitor)
+            }
+            Token::Tuple { .. } => {
+                self.next_token();
+                self.visit_seq(Some(len), Token::TupleEnd, visitor)
+            }
+            Token::TupleStruct { len: n, .. } => {
+                assert_next_token!(self, Token::TupleStruct { name: name, len: n });
+                self.visit_seq(Some(len), Token::TupleStructEnd, visitor)
+            }
+            _ => self.deserialize_any(visitor),
+        }
+    }
+
+    fn deserialize_struct<V>(
+        self,
+        name: &'static str,
+        fields: &'static [&'static str],
+        visitor: V,
+    ) -> Result<V::Value, Error>
+    where
+        V: Visitor<'de>,
+    {
+        match self.peek_token() {
+            Token::Struct { len: n, .. } => {
+                assert_next_token!(self, Token::Struct { name: name, len: n });
+                self.visit_map(Some(fields.len()), Token::StructEnd, visitor)
+            }
+            Token::Map { .. } => {
+                self.next_token();
+                self.visit_map(Some(fields.len()), Token::MapEnd, visitor)
+            }
+            _ => self.deserialize_any(visitor),
+        }
+    }
+
+    fn is_human_readable(&self) -> bool {
+        panic!(
+            "Types which have different human-readable and compact representations \
+             must explicitly mark their test cases with `serde_test::Configure`"
+        );
+    }
+}
+
+//////////////////////////////////////////////////////////////////////////
+
+struct DeserializerSeqVisitor<'a, 'de: 'a> {
+    de: &'a mut Deserializer<'de>,
+    len: Option<usize>,
+    end: Token,
+}
+
+impl<'de, 'a> SeqAccess<'de> for DeserializerSeqVisitor<'a, 'de> {
+    type Error = Error;
+
+    fn next_element_seed<T>(&mut self, seed: T) -> Result<Option<T::Value>, Error>
+    where
+        T: DeserializeSeed<'de>,
+    {
+        if self.de.peek_token_opt() == Some(self.end) {
+            return Ok(None);
+        }
+        self.len = self.len.map(|len| len.saturating_sub(1));
+        seed.deserialize(&mut *self.de).map(Some)
+    }
+
+    fn size_hint(&self) -> Option<usize> {
+        self.len
+    }
+}
+
+//////////////////////////////////////////////////////////////////////////
+
+struct DeserializerMapVisitor<'a, 'de: 'a> {
+    de: &'a mut Deserializer<'de>,
+    len: Option<usize>,
+    end: Token,
+}
+
+impl<'de, 'a> MapAccess<'de> for DeserializerMapVisitor<'a, 'de> {
+    type Error = Error;
+
+    fn next_key_seed<K>(&mut self, seed: K) -> Result<Option<K::Value>, Error>
+    where
+        K: DeserializeSeed<'de>,
+    {
+        if self.de.peek_token_opt() == Some(self.end) {
+            return Ok(None);
+        }
+        self.len = self.len.map(|len| len.saturating_sub(1));
+        seed.deserialize(&mut *self.de).map(Some)
+    }
+
+    fn next_value_seed<V>(&mut self, seed: V) -> Result<V::Value, Error>
+    where
+        V: DeserializeSeed<'de>,
+    {
+        seed.deserialize(&mut *self.de)
+    }
+
+    fn size_hint(&self) -> Option<usize> {
+        self.len
+    }
+}
+
+//////////////////////////////////////////////////////////////////////////
+
+struct DeserializerEnumVisitor<'a, 'de: 'a> {
+    de: &'a mut Deserializer<'de>,
+}
+
+impl<'de, 'a> EnumAccess<'de> for DeserializerEnumVisitor<'a, 'de> {
+    type Error = Error;
+    type Variant = Self;
+
+    fn variant_seed<V>(self, seed: V) -> Result<(V::Value, Self), Error>
+    where
+        V: DeserializeSeed<'de>,
+    {
+        match self.de.peek_token() {
+            Token::UnitVariant { variant: v, .. }
+            | Token::NewtypeVariant { variant: v, .. }
+            | Token::TupleVariant { variant: v, .. }
+            | Token::StructVariant { variant: v, .. } => {
+                let de = v.into_deserializer();
+                let value = seed.deserialize(de)?;
+                Ok((value, self))
+            }
+            _ => {
+                let value = seed.deserialize(&mut *self.de)?;
+                Ok((value, self))
+            }
+        }
+    }
+}
+
+impl<'de, 'a> VariantAccess<'de> for DeserializerEnumVisitor<'a, 'de> {
+    type Error = Error;
+
+    fn unit_variant(self) -> Result<(), Error> {
+        match self.de.peek_token() {
+            Token::UnitVariant { .. } => {
+                self.de.next_token();
+                Ok(())
+            }
+            _ => Deserialize::deserialize(self.de),
+        }
+    }
+
+    fn newtype_variant_seed<T>(self, seed: T) -> Result<T::Value, Self::Error>
+    where
+        T: DeserializeSeed<'de>,
+    {
+        match self.de.peek_token() {
+            Token::NewtypeVariant { .. } => {
+                self.de.next_token();
+                seed.deserialize(self.de)
+            }
+            _ => seed.deserialize(self.de),
+        }
+    }
+
+    fn tuple_variant<V>(self, len: usize, visitor: V) -> Result<V::Value, Error>
+    where
+        V: Visitor<'de>,
+    {
+        match self.de.peek_token() {
+            Token::TupleVariant { len: enum_len, .. } => {
+                let token = self.de.next_token();
+
+                if len == enum_len {
+                    self.de
+                        .visit_seq(Some(len), Token::TupleVariantEnd, visitor)
+                } else {
+                    unexpected!(token);
+                }
+            }
+            Token::Seq {
+                len: Some(enum_len),
+            } => {
+                let token = self.de.next_token();
+
+                if len == enum_len {
+                    self.de.visit_seq(Some(len), Token::SeqEnd, visitor)
+                } else {
+                    unexpected!(token);
+                }
+            }
+            _ => de::Deserializer::deserialize_any(self.de, visitor),
+        }
+    }
+
+    fn struct_variant<V>(
+        self,
+        fields: &'static [&'static str],
+        visitor: V,
+    ) -> Result<V::Value, Error>
+    where
+        V: Visitor<'de>,
+    {
+        match self.de.peek_token() {
+            Token::StructVariant { len: enum_len, .. } => {
+                let token = self.de.next_token();
+
+                if fields.len() == enum_len {
+                    self.de
+                        .visit_map(Some(fields.len()), Token::StructVariantEnd, visitor)
+                } else {
+                    unexpected!(token);
+                }
+            }
+            Token::Map {
+                len: Some(enum_len),
+            } => {
+                let token = self.de.next_token();
+
+                if fields.len() == enum_len {
+                    self.de
+                        .visit_map(Some(fields.len()), Token::MapEnd, visitor)
+                } else {
+                    unexpected!(token);
+                }
+            }
+            _ => de::Deserializer::deserialize_any(self.de, visitor),
+        }
+    }
+}
+
+//////////////////////////////////////////////////////////////////////////
+
+struct EnumMapVisitor<'a, 'de: 'a> {
+    de: &'a mut Deserializer<'de>,
+    variant: Option<Token>,
+    format: EnumFormat,
+}
+
+enum EnumFormat {
+    Seq,
+    Map,
+    Any,
+}
+
+impl<'a, 'de> EnumMapVisitor<'a, 'de> {
+    fn new(de: &'a mut Deserializer<'de>, variant: Token, format: EnumFormat) -> Self {
+        EnumMapVisitor {
+            de: de,
+            variant: Some(variant),
+            format: format,
+        }
+    }
+}
+
+impl<'de, 'a> MapAccess<'de> for EnumMapVisitor<'a, 'de> {
+    type Error = Error;
+
+    fn next_key_seed<K>(&mut self, seed: K) -> Result<Option<K::Value>, Error>
+    where
+        K: DeserializeSeed<'de>,
+    {
+        match self.variant.take() {
+            Some(Token::Str(variant)) => seed.deserialize(variant.into_deserializer()).map(Some),
+            Some(Token::Bytes(variant)) => seed
+                .deserialize(BytesDeserializer { value: variant })
+                .map(Some),
+            Some(Token::U32(variant)) => seed.deserialize(variant.into_deserializer()).map(Some),
+            Some(other) => unexpected!(other),
+            None => Ok(None),
+        }
+    }
+
+    fn next_value_seed<V>(&mut self, seed: V) -> Result<V::Value, Error>
+    where
+        V: DeserializeSeed<'de>,
+    {
+        match self.format {
+            EnumFormat::Seq => {
+                let value = {
+                    let visitor = DeserializerSeqVisitor {
+                        de: self.de,
+                        len: None,
+                        end: Token::TupleVariantEnd,
+                    };
+                    seed.deserialize(SeqAccessDeserializer::new(visitor))?
+                };
+                assert_next_token!(self.de, Token::TupleVariantEnd);
+                Ok(value)
+            }
+            EnumFormat::Map => {
+                let value = {
+                    let visitor = DeserializerMapVisitor {
+                        de: self.de,
+                        len: None,
+                        end: Token::StructVariantEnd,
+                    };
+                    seed.deserialize(MapAccessDeserializer::new(visitor))?
+                };
+                assert_next_token!(self.de, Token::StructVariantEnd);
+                Ok(value)
+            }
+            EnumFormat::Any => seed.deserialize(&mut *self.de),
+        }
+    }
+}
+
+struct BytesDeserializer {
+    value: &'static [u8],
+}
+
+impl<'de> de::Deserializer<'de> for BytesDeserializer {
+    type Error = Error;
+
+    fn deserialize_any<V>(self, visitor: V) -> Result<V::Value, Self::Error>
+    where
+        V: de::Visitor<'de>,
+    {
+        visitor.visit_bytes(self.value)
+    }
+
+    forward_to_deserialize_any! {
+        bool i8 i16 i32 i64 i128 u8 u16 u32 u64 u128 f32 f64 char str string
+        bytes byte_buf option unit unit_struct newtype_struct seq tuple
+        tuple_struct map struct enum identifier ignored_any
+    }
+}
@@ -0,0 +1,43 @@
+use std::error;
+use std::fmt::{self, Display};
+
+use serde::{de, ser};
+
+#[derive(Clone, Debug)]
+pub struct Error {
+    msg: String,
+}
+
+impl ser::Error for Error {
+    fn custom<T: Display>(msg: T) -> Self {
+        Error {
+            msg: msg.to_string(),
+        }
+    }
+}
+
+impl de::Error for Error {
+    fn custom<T: Display>(msg: T) -> Self {
+        Error {
+            msg: msg.to_string(),
+        }
+    }
+}
+
+impl fmt::Display for Error {
+    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+        formatter.write_str(&self.msg)
+    }
+}
+
+impl error::Error for Error {
+    fn description(&self) -> &str {
+        &self.msg
+    }
+}
+
+impl PartialEq<str> for Error {
+    fn eq(&self, other: &str) -> bool {
+        self.msg == other
+    }
+}
@@ -0,0 +1,192 @@
+//! This crate provides a convenient concise way to write unit tests for
+//! implementations of [`Serialize`] and [`Deserialize`].
+//!
+//! [`Serialize`]: https://docs.serde.rs/serde/ser/trait.Serialize.html
+//! [`Deserialize`]: https://docs.serde.rs/serde/de/trait.Deserialize.html
+//!
+//! The `Serialize` impl for a value can be characterized by the sequence of
+//! [`Serializer`] calls that are made in the course of serializing the value,
+//! so `serde_test` provides a [`Token`] abstraction which corresponds roughly
+//! to `Serializer` method calls. There is an [`assert_ser_tokens`] function to
+//! test that a value serializes to a particular sequence of method calls, an
+//! [`assert_de_tokens`] function to test that a value can be deserialized from
+//! a particular sequence of method calls, and an [`assert_tokens`] function to
+//! test both directions. There are also functions to test expected failure
+//! conditions.
+//!
+//! [`Serializer`]: https://docs.serde.rs/serde/ser/trait.Serializer.html
+//! [`Token`]: https://docs.serde.rs/serde_test/enum.Token.html
+//! [`assert_ser_tokens`]: https://docs.serde.rs/serde_test/fn.assert_ser_tokens.html
+//! [`assert_de_tokens`]: https://docs.serde.rs/serde_test/fn.assert_de_tokens.html
+//! [`assert_tokens`]: https://docs.serde.rs/serde_test/fn.assert_tokens.html
+//!
+//! Here is an example from the [`linked-hash-map`] crate.
+//!
+//! [`linked-hash-map`]: https://github.com/contain-rs/linked-hash-map
+//!
+//! ```edition2018
+//! # const IGNORE: &str = stringify! {
+//! use linked_hash_map::LinkedHashMap;
+//! # };
+//! use serde_test::{Token, assert_tokens};
+//!
+//! # use std::fmt;
+//! # use std::marker::PhantomData;
+//! #
+//! # use serde::ser::{Serialize, Serializer, SerializeMap};
+//! # use serde::de::{Deserialize, Deserializer, Visitor, MapAccess};
+//! #
+//! # // Dumb imitation of LinkedHashMap.
+//! # #[derive(PartialEq, Debug)]
+//! # struct LinkedHashMap<K, V>(Vec<(K, V)>);
+//! #
+//! # impl<K, V> LinkedHashMap<K, V> {
+//! #     fn new() -> Self {
+//! #         LinkedHashMap(Vec::new())
+//! #     }
+//! #
+//! #     fn insert(&mut self, k: K, v: V) {
+//! #         self.0.push((k, v));
+//! #     }
+//! # }
+//! #
+//! # impl<K, V> Serialize for LinkedHashMap<K, V>
+//! # where
+//! #     K: Serialize,
+//! #     V: Serialize,
+//! # {
+//! #     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+//! #     where
+//! #         S: Serializer,
+//! #     {
+//! #         let mut map = serializer.serialize_map(Some(self.0.len()))?;
+//! #         for &(ref k, ref v) in &self.0 {
+//! #             map.serialize_entry(k, v)?;
+//! #         }
+//! #         map.end()
+//! #     }
+//! # }
+//! #
+//! # struct LinkedHashMapVisitor<K, V>(PhantomData<(K, V)>);
+//! #
+//! # impl<'de, K, V> Visitor<'de> for LinkedHashMapVisitor<K, V>
+//! # where
+//! #     K: Deserialize<'de>,
+//! #     V: Deserialize<'de>,
+//! # {
+//! #     type Value = LinkedHashMap<K, V>;
+//! #
+//! #     fn expecting(&self, _: &mut fmt::Formatter) -> fmt::Result {
+//! #         unimplemented!()
+//! #     }
+//! #
+//! #     fn visit_map<M>(self, mut access: M) -> Result<Self::Value, M::Error>
+//! #     where
+//! #         M: MapAccess<'de>,
+//! #     {
+//! #         let mut map = LinkedHashMap::new();
+//! #         while let Some((key, value)) = access.next_entry()? {
+//! #             map.insert(key, value);
+//! #         }
+//! #         Ok(map)
+//! #     }
+//! # }
+//! #
+//! # impl<'de, K, V> Deserialize<'de> for LinkedHashMap<K, V>
+//! # where
+//! #     K: Deserialize<'de>,
+//! #     V: Deserialize<'de>,
+//! # {
+//! #     fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+//! #     where
+//! #         D: Deserializer<'de>,
+//! #     {
+//! #         deserializer.deserialize_map(LinkedHashMapVisitor(PhantomData))
+//! #     }
+//! # }
+//! #
+//! #[test]
+//! # fn not_a_test_ser_de_empty() {}
+//! fn test_ser_de_empty() {
+//!     let map = LinkedHashMap::<char, u32>::new();
+//!
+//!     assert_tokens(&map, &[
+//!         Token::Map { len: Some(0) },
+//!         Token::MapEnd,
+//!     ]);
+//! }
+//!
+//! #[test]
+//! # fn not_a_test_ser_de() {}
+//! fn test_ser_de() {
+//!     let mut map = LinkedHashMap::new();
+//!     map.insert('b', 20);
+//!     map.insert('a', 10);
+//!     map.insert('c', 30);
+//!
+//!     assert_tokens(&map, &[
+//!         Token::Map { len: Some(3) },
+//!         Token::Char('b'),
+//!         Token::I32(20),
+//!
+//!         Token::Char('a'),
+//!         Token::I32(10),
+//!
+//!         Token::Char('c'),
+//!         Token::I32(30),
+//!         Token::MapEnd,
+//!     ]);
+//! }
+//! #
+//! # fn main() {
+//! #     test_ser_de_empty();
+//! #     test_ser_de();
+//! # }
+//! ```
+
+#![doc(html_root_url = "https://docs.rs/serde_test/1.0.137")]
+#![cfg_attr(feature = "cargo-clippy", allow(renamed_and_removed_lints))]
+// Ignored clippy lints
+#![cfg_attr(feature = "cargo-clippy", allow(float_cmp, needless_doctest_main))]
+// Ignored clippy_pedantic lints
+#![cfg_attr(
+    feature = "cargo-clippy",
+    allow(
+        cloned_instead_of_copied,
+        doc_link_with_quotes, // https://github.com/rust-lang/rust-clippy/issues/8961
+        empty_line_after_outer_attr,
+        manual_assert,
+        missing_docs_in_private_items,
+        missing_panics_doc,
+        module_name_repetitions,
+        must_use_candidate,
+        redundant_field_names,
+        too_many_lines,
+        type_repetition_in_bounds, // https://github.com/rust-lang/rust-clippy/issues/8772
+        use_debug,
+        use_self
+    )
+)]
+
+#[macro_use]
+extern crate serde;
+
+mod de;
+mod error;
+mod ser;
+
+mod assert;
+mod configure;
+mod token;
+
+pub use assert::{
+    assert_de_tokens, assert_de_tokens_error, assert_ser_tokens, assert_ser_tokens_error,
+    assert_tokens,
+};
+pub use token::Token;
+
+pub use configure::{Compact, Configure, Readable};
+
+// Not public API.
+#[doc(hidden)]
+pub use de::Deserializer;
@@ -0,0 +1,464 @@
+use serde::{ser, Serialize};
+
+use error::Error;
+use token::Token;
+
+/// A `Serializer` that ensures that a value serializes to a given list of
+/// tokens.
+#[derive(Debug)]
+pub struct Serializer<'a> {
+    tokens: &'a [Token],
+}
+
+impl<'a> Serializer<'a> {
+    /// Creates the serializer.
+    pub fn new(tokens: &'a [Token]) -> Self {
+        Serializer { tokens: tokens }
+    }
+
+    /// Pulls the next token off of the serializer, ignoring it.
+    fn next_token(&mut self) -> Option<Token> {
+        if let Some((&first, rest)) = self.tokens.split_first() {
+            self.tokens = rest;
+            Some(first)
+        } else {
+            None
+        }
+    }
+
+    pub fn remaining(&self) -> usize {
+        self.tokens.len()
+    }
+}
+
+macro_rules! assert_next_token {
+    ($ser:expr, $actual:ident) => {{
+        assert_next_token!($ser, stringify!($actual), Token::$actual, true);
+    }};
+    ($ser:expr, $actual:ident($v:expr)) => {{
+        assert_next_token!(
+            $ser,
+            format_args!(concat!(stringify!($actual), "({:?})"), $v),
+            Token::$actual(v),
+            v == $v
+        );
+    }};
+    ($ser:expr, $actual:ident { $($k:ident),* }) => {{
+        let compare = ($($k,)*);
+        let field_format = || {
+            use std::fmt::Write;
+            let mut buffer = String::new();
+            $(
+                write!(&mut buffer, concat!(stringify!($k), ": {:?}, "), $k).unwrap();
+            )*
+            buffer
+        };
+        assert_next_token!(
+            $ser,
+            format_args!(concat!(stringify!($actual), " {{ {}}}"), field_format()),
+            Token::$actual { $($k),* },
+            ($($k,)*) == compare
+        );
+    }};
+    ($ser:expr, $actual:expr, $pat:pat, $guard:expr) => {
+        match $ser.next_token() {
+            Some($pat) if $guard => {}
+            Some(expected) => {
+                panic!("expected Token::{} but serialized as {}",
+                       expected, $actual);
+            }
+            None => {
+                panic!("expected end of tokens, but {} was serialized",
+                       $actual);
+            }
+        }
+    };
+}
+
+impl<'s, 'a> ser::Serializer for &'s mut Serializer<'a> {
+    type Ok = ();
+    type Error = Error;
+
+    type SerializeSeq = Self;
+    type SerializeTuple = Self;
+    type SerializeTupleStruct = Self;
+    type SerializeTupleVariant = Variant<'s, 'a>;
+    type SerializeMap = Self;
+    type SerializeStruct = Self;
+    type SerializeStructVariant = Variant<'s, 'a>;
+
+    fn serialize_bool(self, v: bool) -> Result<(), Error> {
+        assert_next_token!(self, Bool(v));
+        Ok(())
+    }
+
+    fn serialize_i8(self, v: i8) -> Result<(), Error> {
+        assert_next_token!(self, I8(v));
+        Ok(())
+    }
+
+    fn serialize_i16(self, v: i16) -> Result<(), Error> {
+        assert_next_token!(self, I16(v));
+        Ok(())
+    }
+
+    fn serialize_i32(self, v: i32) -> Result<(), Error> {
+        assert_next_token!(self, I32(v));
+        Ok(())
+    }
+
+    fn serialize_i64(self, v: i64) -> Result<(), Error> {
+        assert_next_token!(self, I64(v));
+        Ok(())
+    }
+
+    fn serialize_u8(self, v: u8) -> Result<(), Error> {
+        assert_next_token!(self, U8(v));
+        Ok(())
+    }
+
+    fn serialize_u16(self, v: u16) -> Result<(), Error> {
+        assert_next_token!(self, U16(v));
+        Ok(())
+    }
+
+    fn serialize_u32(self, v: u32) -> Result<(), Error> {
+        assert_next_token!(self, U32(v));
+        Ok(())
+    }
+
+    fn serialize_u64(self, v: u64) -> Result<(), Error> {
+        assert_next_token!(self, U64(v));
+        Ok(())
+    }
+
+    fn serialize_f32(self, v: f32) -> Result<(), Error> {
+        assert_next_token!(self, F32(v));
+        Ok(())
+    }
+
+    fn serialize_f64(self, v: f64) -> Result<(), Error> {
+        assert_next_token!(self, F64(v));
+        Ok(())
+    }
+
+    fn serialize_char(self, v: char) -> Result<(), Error> {
+        assert_next_token!(self, Char(v));
+        Ok(())
+    }
+
+    fn serialize_str(self, v: &str) -> Result<(), Error> {
+        match self.tokens.first() {
+            Some(&Token::BorrowedStr(_)) => assert_next_token!(self, BorrowedStr(v)),
+            Some(&Token::String(_)) => assert_next_token!(self, String(v)),
+            _ => assert_next_token!(self, Str(v)),
+        }
+        Ok(())
+    }
+
+    fn serialize_bytes(self, v: &[u8]) -> Result<(), Self::Error> {
+        match self.tokens.first() {
+            Some(&Token::BorrowedBytes(_)) => assert_next_token!(self, BorrowedBytes(v)),
+            Some(&Token::ByteBuf(_)) => assert_next_token!(self, ByteBuf(v)),
+            _ => assert_next_token!(self, Bytes(v)),
+        }
+        Ok(())
+    }
+
+    fn serialize_unit(self) -> Result<(), Error> {
+        assert_next_token!(self, Unit);
+        Ok(())
+    }
+
+    fn serialize_unit_struct(self, name: &'static str) -> Result<(), Error> {
+        assert_next_token!(self, UnitStruct { name });
+        Ok(())
+    }
+
+    fn serialize_unit_variant(
+        self,
+        name: &'static str,
+        _variant_index: u32,
+        variant: &'static str,
+    ) -> Result<(), Error> {
+        if self.tokens.first() == Some(&Token::Enum { name: name }) {
+            self.next_token();
+            assert_next_token!(self, Str(variant));
+            assert_next_token!(self, Unit);
+        } else {
+            assert_next_token!(self, UnitVariant { name, variant });
+        }
+        Ok(())
+    }
+
+    fn serialize_newtype_struct<T: ?Sized>(self, name: &'static str, value: &T) -> Result<(), Error>
+    where
+        T: Serialize,
+    {
+        assert_next_token!(self, NewtypeStruct { name });
+        value.serialize(self)
+    }
+
+    fn serialize_newtype_variant<T: ?Sized>(
+        self,
+        name: &'static str,
+        _variant_index: u32,
+        variant: &'static str,
+        value: &T,
+    ) -> Result<(), Error>
+    where
+        T: Serialize,
+    {
+        if self.tokens.first() == Some(&Token::Enum { name: name }) {
+            self.next_token();
+            assert_next_token!(self, Str(variant));
+        } else {
+            assert_next_token!(self, NewtypeVariant { name, variant });
+        }
+        value.serialize(self)
+    }
+
+    fn serialize_none(self) -> Result<(), Error> {
+        assert_next_token!(self, None);
+        Ok(())
+    }
+
+    fn serialize_some<T: ?Sized>(self, value: &T) -> Result<(), Error>
+    where
+        T: Serialize,
+    {
+        assert_next_token!(self, Some);
+        value.serialize(self)
+    }
+
+    fn serialize_seq(self, len: Option<usize>) -> Result<Self, Error> {
+        assert_next_token!(self, Seq { len });
+        Ok(self)
+    }
+
+    fn serialize_tuple(self, len: usize) -> Result<Self, Error> {
+        assert_next_token!(self, Tuple { len });
+        Ok(self)
+    }
+
+    fn serialize_tuple_struct(self, name: &'static str, len: usize) -> Result<Self, Error> {
+        assert_next_token!(self, TupleStruct { name, len });
+        Ok(self)
+    }
+
+    fn serialize_tuple_variant(
+        self,
+        name: &'static str,
+        _variant_index: u32,
+        variant: &'static str,
+        len: usize,
+    ) -> Result<Self::SerializeTupleVariant, Error> {
+        if self.tokens.first() == Some(&Token::Enum { name: name }) {
+            self.next_token();
+            assert_next_token!(self, Str(variant));
+            let len = Some(len);
+            assert_next_token!(self, Seq { len });
+            Ok(Variant {
+                ser: self,
+                end: Token::SeqEnd,
+            })
+        } else {
+            assert_next_token!(self, TupleVariant { name, variant, len });
+            Ok(Variant {
+                ser: self,
+                end: Token::TupleVariantEnd,
+            })
+        }
+    }
+
+    fn serialize_map(self, len: Option<usize>) -> Result<Self, Error> {
+        assert_next_token!(self, Map { len });
+        Ok(self)
+    }
+
+    fn serialize_struct(self, name: &'static str, len: usize) -> Result<Self, Error> {
+        assert_next_token!(self, Struct { name, len });
+        Ok(self)
+    }
+
+    fn serialize_struct_variant(
+        self,
+        name: &'static str,
+        _variant_index: u32,
+        variant: &'static str,
+        len: usize,
+    ) -> Result<Self::SerializeStructVariant, Error> {
+        if self.tokens.first() == Some(&Token::Enum { name: name }) {
+            self.next_token();
+            assert_next_token!(self, Str(variant));
+            let len = Some(len);
+            assert_next_token!(self, Map { len });
+            Ok(Variant {
+                ser: self,
+                end: Token::MapEnd,
+            })
+        } else {
+            assert_next_token!(self, StructVariant { name, variant, len });
+            Ok(Variant {
+                ser: self,
+                end: Token::StructVariantEnd,
+            })
+        }
+    }
+
+    fn is_human_readable(&self) -> bool {
+        panic!(
+            "Types which have different human-readable and compact representations \
+             must explicitly mark their test cases with `serde_test::Configure`"
+        );
+    }
+}
+
+pub struct Variant<'s, 'a: 's> {
+    ser: &'s mut Serializer<'a>,
+    end: Token,
+}
+
+impl<'s, 'a> ser::SerializeSeq for &'s mut Serializer<'a> {
+    type Ok = ();
+    type Error = Error;
+
+    fn serialize_element<T: ?Sized>(&mut self, value: &T) -> Result<(), Error>
+    where
+        T: Serialize,
+    {
+        value.serialize(&mut **self)
+    }
+
+    fn end(self) -> Result<(), Error> {
+        assert_next_token!(self, SeqEnd);
+        Ok(())
+    }
+}
+
+impl<'s, 'a> ser::SerializeTuple for &'s mut Serializer<'a> {
+    type Ok = ();
+    type Error = Error;
+
+    fn serialize_element<T: ?Sized>(&mut self, value: &T) -> Result<(), Error>
+    where
+        T: Serialize,
+    {
+        value.serialize(&mut **self)
+    }
+
+    fn end(self) -> Result<(), Error> {
+        assert_next_token!(self, TupleEnd);
+        Ok(())
+    }
+}
+
+impl<'s, 'a> ser::SerializeTupleStruct for &'s mut Serializer<'a> {
+    type Ok = ();
+    type Error = Error;
+
+    fn serialize_field<T: ?Sized>(&mut self, value: &T) -> Result<(), Error>
+    where
+        T: Serialize,
+    {
+        value.serialize(&mut **self)
+    }
+
+    fn end(self) -> Result<(), Error> {
+        assert_next_token!(self, TupleStructEnd);
+        Ok(())
+    }
+}
+
+impl<'s, 'a> ser::SerializeTupleVariant for Variant<'s, 'a> {
+    type Ok = ();
+    type Error = Error;
+
+    fn serialize_field<T: ?Sized>(&mut self, value: &T) -> Result<(), Error>
+    where
+        T: Serialize,
+    {
+        value.serialize(&mut *self.ser)
+    }
+
+    fn end(self) -> Result<(), Error> {
+        match self.end {
+            Token::TupleVariantEnd => assert_next_token!(self.ser, TupleVariantEnd),
+            Token::SeqEnd => assert_next_token!(self.ser, SeqEnd),
+            _ => unreachable!(),
+        }
+        Ok(())
+    }
+}
+
+impl<'s, 'a> ser::SerializeMap for &'s mut Serializer<'a> {
+    type Ok = ();
+    type Error = Error;
+
+    fn serialize_key<T: ?Sized>(&mut self, key: &T) -> Result<(), Self::Error>
+    where
+        T: Serialize,
+    {
+        key.serialize(&mut **self)
+    }
+
+    fn serialize_value<T: ?Sized>(&mut self, value: &T) -> Result<(), Self::Error>
+    where
+        T: Serialize,
+    {
+        value.serialize(&mut **self)
+    }
+
+    fn end(self) -> Result<(), Self::Error> {
+        assert_next_token!(self, MapEnd);
+        Ok(())
+    }
+}
+
+impl<'s, 'a> ser::SerializeStruct for &'s mut Serializer<'a> {
+    type Ok = ();
+    type Error = Error;
+
+    fn serialize_field<T: ?Sized>(
+        &mut self,
+        key: &'static str,
+        value: &T,
+    ) -> Result<(), Self::Error>
+    where
+        T: Serialize,
+    {
+        key.serialize(&mut **self)?;
+        value.serialize(&mut **self)
+    }
+
+    fn end(self) -> Result<(), Self::Error> {
+        assert_next_token!(self, StructEnd);
+        Ok(())
+    }
+}
+
+impl<'s, 'a> ser::SerializeStructVariant for Variant<'s, 'a> {
+    type Ok = ();
+    type Error = Error;
+
+    fn serialize_field<T: ?Sized>(
+        &mut self,
+        key: &'static str,
+        value: &T,
+    ) -> Result<(), Self::Error>
+    where
+        T: Serialize,
+    {
+        key.serialize(&mut *self.ser)?;
+        value.serialize(&mut *self.ser)
+    }
+
+    fn end(self) -> Result<(), Self::Error> {
+        match self.end {
+            Token::StructVariantEnd => assert_next_token!(self.ser, StructVariantEnd),
+            Token::MapEnd => assert_next_token!(self.ser, MapEnd),
+            _ => unreachable!(),
+        }
+        Ok(())
+    }
+}
@@ -0,0 +1,519 @@
+use std::fmt::{self, Debug, Display};
+
+#[derive(Copy, Clone, PartialEq, Debug)]
+pub enum Token {
+    /// A serialized `bool`.
+    ///
+    /// ```edition2018
+    /// # use serde_test::{assert_tokens, Token};
+    /// #
+    /// assert_tokens(&true, &[Token::Bool(true)]);
+    /// ```
+    Bool(bool),
+
+    /// A serialized `i8`.
+    ///
+    /// ```edition2018
+    /// # use serde_test::{assert_tokens, Token};
+    /// #
+    /// assert_tokens(&0i8, &[Token::I8(0)]);
+    /// ```
+    I8(i8),
+
+    /// A serialized `i16`.
+    ///
+    /// ```edition2018
+    /// # use serde_test::{assert_tokens, Token};
+    /// #
+    /// assert_tokens(&0i16, &[Token::I16(0)]);
+    /// ```
+    I16(i16),
+
+    /// A serialized `i32`.
+    ///
+    /// ```edition2018
+    /// # use serde_test::{assert_tokens, Token};
+    /// #
+    /// assert_tokens(&0i32, &[Token::I32(0)]);
+    /// ```
+    I32(i32),
+
+    /// A serialized `i64`.
+    ///
+    /// ```edition2018
+    /// # use serde_test::{assert_tokens, Token};
+    /// #
+    /// assert_tokens(&0i64, &[Token::I64(0)]);
+    /// ```
+    I64(i64),
+
+    /// A serialized `u8`.
+    ///
+    /// ```edition2018
+    /// # use serde_test::{assert_tokens, Token};
+    /// #
+    /// assert_tokens(&0u8, &[Token::U8(0)]);
+    /// ```
+    U8(u8),
+
+    /// A serialized `u16`.
+    ///
+    /// ```edition2018
+    /// # use serde_test::{assert_tokens, Token};
+    /// #
+    /// assert_tokens(&0u16, &[Token::U16(0)]);
+    /// ```
+    U16(u16),
+
+    /// A serialized `u32`.
+    ///
+    /// ```edition2018
+    /// # use serde_test::{assert_tokens, Token};
+    /// #
+    /// assert_tokens(&0u32, &[Token::U32(0)]);
+    /// ```
+    U32(u32),
+
+    /// A serialized `u64`.
+    ///
+    /// ```edition2018
+    /// # use serde_test::{assert_tokens, Token};
+    /// #
+    /// assert_tokens(&0u64, &[Token::U64(0)]);
+    /// ```
+    U64(u64),
+
+    /// A serialized `f32`.
+    ///
+    /// ```edition2018
+    /// # use serde_test::{assert_tokens, Token};
+    /// #
+    /// assert_tokens(&0f32, &[Token::F32(0.0)]);
+    /// ```
+    F32(f32),
+
+    /// A serialized `f64`.
+    ///
+    /// ```edition2018
+    /// # use serde_test::{assert_tokens, Token};
+    /// #
+    /// assert_tokens(&0f64, &[Token::F64(0.0)]);
+    /// ```
+    F64(f64),
+
+    /// A serialized `char`.
+    ///
+    /// ```edition2018
+    /// # use serde_test::{assert_tokens, Token};
+    /// #
+    /// assert_tokens(&'\n', &[Token::Char('\n')]);
+    /// ```
+    Char(char),
+
+    /// A serialized `str`.
+    ///
+    /// ```edition2018
+    /// # use serde_test::{assert_tokens, Token};
+    /// #
+    /// let s = String::from("transient");
+    /// assert_tokens(&s, &[Token::Str("transient")]);
+    /// ```
+    Str(&'static str),
+
+    /// A borrowed `str`.
+    ///
+    /// ```edition2018
+    /// # use serde_test::{assert_tokens, Token};
+    /// #
+    /// let s: &str = "borrowed";
+    /// assert_tokens(&s, &[Token::BorrowedStr("borrowed")]);
+    /// ```
+    BorrowedStr(&'static str),
+
+    /// A serialized `String`.
+    ///
+    /// ```edition2018
+    /// # use serde_test::{assert_tokens, Token};
+    /// #
+    /// let s = String::from("owned");
+    /// assert_tokens(&s, &[Token::String("owned")]);
+    /// ```
+    String(&'static str),
+
+    /// A serialized `[u8]`
+    Bytes(&'static [u8]),
+
+    /// A borrowed `[u8]`.
+    BorrowedBytes(&'static [u8]),
+
+    /// A serialized `ByteBuf`
+    ByteBuf(&'static [u8]),
+
+    /// A serialized `Option<T>` containing none.
+    ///
+    /// ```edition2018
+    /// # use serde_test::{assert_tokens, Token};
+    /// #
+    /// let opt = None::<char>;
+    /// assert_tokens(&opt, &[Token::None]);
+    /// ```
+    None,
+
+    /// The header to a serialized `Option<T>` containing some value.
+    ///
+    /// The tokens of the value follow after this header.
+    ///
+    /// ```edition2018
+    /// # use serde_test::{assert_tokens, Token};
+    /// #
+    /// let opt = Some('c');
+    /// assert_tokens(&opt, &[
+    ///     Token::Some,
+    ///     Token::Char('c'),
+    /// ]);
+    /// ```
+    Some,
+
+    /// A serialized `()`.
+    ///
+    /// ```edition2018
+    /// # use serde_test::{assert_tokens, Token};
+    /// #
+    /// assert_tokens(&(), &[Token::Unit]);
+    /// ```
+    Unit,
+
+    /// A serialized unit struct of the given name.
+    ///
+    /// ```edition2018
+    /// # use serde::{Serialize, Deserialize};
+    /// # use serde_test::{assert_tokens, Token};
+    /// #
+    /// # fn main() {
+    /// #[derive(Serialize, Deserialize, PartialEq, Debug)]
+    /// struct X;
+    ///
+    /// assert_tokens(&X, &[Token::UnitStruct { name: "X" }]);
+    /// # }
+    /// ```
+    UnitStruct { name: &'static str },
+
+    /// A unit variant of an enum.
+    ///
+    /// ```edition2018
+    /// # use serde::{Serialize, Deserialize};
+    /// # use serde_test::{assert_tokens, Token};
+    /// #
+    /// # fn main() {
+    /// #[derive(Serialize, Deserialize, PartialEq, Debug)]
+    /// enum E {
+    ///     A,
+    /// }
+    ///
+    /// let a = E::A;
+    /// assert_tokens(&a, &[Token::UnitVariant { name: "E", variant: "A" }]);
+    /// # }
+    /// ```
+    UnitVariant {
+        name: &'static str,
+        variant: &'static str,
+    },
+
+    /// The header to a serialized newtype struct of the given name.
+    ///
+    /// After this header is the value contained in the newtype struct.
+    ///
+    /// ```edition2018
+    /// # use serde::{Serialize, Deserialize};
+    /// # use serde_test::{assert_tokens, Token};
+    /// #
+    /// # fn main() {
+    /// #[derive(Serialize, Deserialize, PartialEq, Debug)]
+    /// struct N(String);
+    ///
+    /// let n = N("newtype".to_owned());
+    /// assert_tokens(&n, &[
+    ///     Token::NewtypeStruct { name: "N" },
+    ///     Token::String("newtype"),
+    /// ]);
+    /// # }
+    /// ```
+    NewtypeStruct { name: &'static str },
+
+    /// The header to a newtype variant of an enum.
+    ///
+    /// After this header is the value contained in the newtype variant.
+    ///
+    /// ```edition2018
+    /// # use serde::{Serialize, Deserialize};
+    /// # use serde_test::{assert_tokens, Token};
+    /// #
+    /// # fn main() {
+    /// #[derive(Serialize, Deserialize, PartialEq, Debug)]
+    /// enum E {
+    ///     B(u8),
+    /// }
+    ///
+    /// let b = E::B(0);
+    /// assert_tokens(&b, &[
+    ///     Token::NewtypeVariant { name: "E", variant: "B" },
+    ///     Token::U8(0),
+    /// ]);
+    /// # }
+    /// ```
+    NewtypeVariant {
+        name: &'static str,
+        variant: &'static str,
+    },
+
+    /// The header to a sequence.
+    ///
+    /// After this header are the elements of the sequence, followed by
+    /// `SeqEnd`.
+    ///
+    /// ```edition2018
+    /// # use serde_test::{assert_tokens, Token};
+    /// #
+    /// let vec = vec!['a', 'b', 'c'];
+    /// assert_tokens(&vec, &[
+    ///     Token::Seq { len: Some(3) },
+    ///     Token::Char('a'),
+    ///     Token::Char('b'),
+    ///     Token::Char('c'),
+    ///     Token::SeqEnd,
+    /// ]);
+    /// ```
+    Seq { len: Option<usize> },
+
+    /// An indicator of the end of a sequence.
+    SeqEnd,
+
+    /// The header to a tuple.
+    ///
+    /// After this header are the elements of the tuple, followed by `TupleEnd`.
+    ///
+    /// ```edition2018
+    /// # use serde_test::{assert_tokens, Token};
+    /// #
+    /// let tuple = ('a', 100);
+    /// assert_tokens(&tuple, &[
+    ///     Token::Tuple { len: 2 },
+    ///     Token::Char('a'),
+    ///     Token::I32(100),
+    ///     Token::TupleEnd,
+    /// ]);
+    /// ```
+    Tuple { len: usize },
+
+    /// An indicator of the end of a tuple.
+    TupleEnd,
+
+    /// The header to a tuple struct.
+    ///
+    /// After this header are the fields of the tuple struct, followed by
+    /// `TupleStructEnd`.
+    ///
+    /// ```edition2018
+    /// # use serde::{Serialize, Deserialize};
+    /// # use serde_test::{assert_tokens, Token};
+    /// #
+    /// # fn main() {
+    /// #[derive(Serialize, Deserialize, PartialEq, Debug)]
+    /// struct T(u8, u8);
+    ///
+    /// let t = T(0, 0);
+    /// assert_tokens(&t, &[
+    ///     Token::TupleStruct { name: "T", len: 2 },
+    ///     Token::U8(0),
+    ///     Token::U8(0),
+    ///     Token::TupleStructEnd,
+    /// ]);
+    /// # }
+    /// ```
+    TupleStruct { name: &'static str, len: usize },
+
+    /// An indicator of the end of a tuple struct.
+    TupleStructEnd,
+
+    /// The header to a tuple variant of an enum.
+    ///
+    /// After this header are the fields of the tuple variant, followed by
+    /// `TupleVariantEnd`.
+    ///
+    /// ```edition2018
+    /// # use serde::{Serialize, Deserialize};
+    /// # use serde_test::{assert_tokens, Token};
+    /// #
+    /// # fn main() {
+    /// #[derive(Serialize, Deserialize, PartialEq, Debug)]
+    /// enum E {
+    ///     C(u8, u8),
+    /// }
+    ///
+    /// let c = E::C(0, 0);
+    /// assert_tokens(&c, &[
+    ///     Token::TupleVariant { name: "E", variant: "C", len: 2 },
+    ///     Token::U8(0),
+    ///     Token::U8(0),
+    ///     Token::TupleVariantEnd,
+    /// ]);
+    /// # }
+    /// ```
+    TupleVariant {
+        name: &'static str,
+        variant: &'static str,
+        len: usize,
+    },
+
+    /// An indicator of the end of a tuple variant.
+    TupleVariantEnd,
+
+    /// The header to a map.
+    ///
+    /// After this header are the entries of the map, followed by `MapEnd`.
+    ///
+    /// ```edition2018
+    /// # use serde_test::{assert_tokens, Token};
+    /// #
+    /// use std::collections::BTreeMap;
+    ///
+    /// let mut map = BTreeMap::new();
+    /// map.insert('A', 65);
+    /// map.insert('Z', 90);
+    ///
+    /// assert_tokens(&map, &[
+    ///     Token::Map { len: Some(2) },
+    ///     Token::Char('A'),
+    ///     Token::I32(65),
+    ///     Token::Char('Z'),
+    ///     Token::I32(90),
+    ///     Token::MapEnd,
+    /// ]);
+    /// ```
+    Map { len: Option<usize> },
+
+    /// An indicator of the end of a map.
+    MapEnd,
+
+    /// The header of a struct.
+    ///
+    /// After this header are the fields of the struct, followed by `StructEnd`.
+    ///
+    /// ```edition2018
+    /// # use serde::{Serialize, Deserialize};
+    /// # use serde_test::{assert_tokens, Token};
+    /// #
+    /// # fn main() {
+    /// #[derive(Serialize, Deserialize, PartialEq, Debug)]
+    /// struct S {
+    ///     a: u8,
+    ///     b: u8,
+    /// }
+    ///
+    /// let s = S { a: 0, b: 0 };
+    /// assert_tokens(&s, &[
+    ///     Token::Struct { name: "S", len: 2 },
+    ///     Token::Str("a"),
+    ///     Token::U8(0),
+    ///     Token::Str("b"),
+    ///     Token::U8(0),
+    ///     Token::StructEnd,
+    /// ]);
+    /// # }
+    /// ```
+    Struct { name: &'static str, len: usize },
+
+    /// An indicator of the end of a struct.
+    StructEnd,
+
+    /// The header of a struct variant of an enum.
+    ///
+    /// After this header are the fields of the struct variant, followed by
+    /// `StructVariantEnd`.
+    ///
+    /// ```edition2018
+    /// # use serde::{Serialize, Deserialize};
+    /// # use serde_test::{assert_tokens, Token};
+    /// #
+    /// # fn main() {
+    /// #[derive(Serialize, Deserialize, PartialEq, Debug)]
+    /// enum E {
+    ///     D { d: u8 },
+    /// }
+    ///
+    /// let d = E::D { d: 0 };
+    /// assert_tokens(&d, &[
+    ///     Token::StructVariant { name: "E", variant: "D", len: 1 },
+    ///     Token::Str("d"),
+    ///     Token::U8(0),
+    ///     Token::StructVariantEnd,
+    /// ]);
+    /// # }
+    /// ```
+    StructVariant {
+        name: &'static str,
+        variant: &'static str,
+        len: usize,
+    },
+
+    /// An indicator of the end of a struct variant.
+    StructVariantEnd,
+
+    /// The header to an enum of the given name.
+    ///
+    /// ```edition2018
+    /// # use serde::{Serialize, Deserialize};
+    /// # use serde_test::{assert_tokens, Token};
+    /// #
+    /// # fn main() {
+    /// #[derive(Serialize, Deserialize, PartialEq, Debug)]
+    /// enum E {
+    ///     A,
+    ///     B(u8),
+    ///     C(u8, u8),
+    ///     D { d: u8 },
+    /// }
+    ///
+    /// let a = E::A;
+    /// assert_tokens(&a, &[
+    ///     Token::Enum { name: "E" },
+    ///     Token::Str("A"),
+    ///     Token::Unit,
+    /// ]);
+    ///
+    /// let b = E::B(0);
+    /// assert_tokens(&b, &[
+    ///     Token::Enum { name: "E" },
+    ///     Token::Str("B"),
+    ///     Token::U8(0),
+    /// ]);
+    ///
+    /// let c = E::C(0, 0);
+    /// assert_tokens(&c, &[
+    ///     Token::Enum { name: "E" },
+    ///     Token::Str("C"),
+    ///     Token::Seq { len: Some(2) },
+    ///     Token::U8(0),
+    ///     Token::U8(0),
+    ///     Token::SeqEnd,
+    /// ]);
+    ///
+    /// let d = E::D { d: 0 };
+    /// assert_tokens(&d, &[
+    ///     Token::Enum { name: "E" },
+    ///     Token::Str("D"),
+    ///     Token::Map { len: Some(1) },
+    ///     Token::Str("d"),
+    ///     Token::U8(0),
+    ///     Token::MapEnd,
+    /// ]);
+    /// # }
+    /// ```
+    Enum { name: &'static str },
+}
+
+impl Display for Token {
+    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+        Debug::fmt(self, formatter)
+    }
+}
@@ -2,20 +2,28 @@
 name = "serde_test_suite"
 version = "0.0.0"
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>", "David Tolnay <dtolnay@gmail.com>"]
-edition = "2021"
+edition = "2018"
 publish = false
+build = "build.rs"

 [features]
+expandtest = []
 unstable = ["serde/unstable"]

 [dependencies]
 serde = { path = "../serde" }

+[build-dependencies]
+toolchain_find = "0.2"
+
 [dev-dependencies]
-automod = "1.0.1"
-foldhash = "0.2"
+fnv = "1.0"
+macrotest = "=1.0.9"
+prettyplease = "=0.1.14"
 rustversion = "1.0"
 serde = { path = "../serde", features = ["rc"] }
-serde_derive = { path = "../serde_derive", features = ["deserialize_in_place"] }
-serde_test = "1.0.176"
-trybuild = { version = "1.0.108", features = ["diff"] }
+wa-serde-derive = { path = "../wa-serde-derive" }
+serde_test = { path = "../serde_test" }
+trybuild = { version = "1.0.49", features = ["diff"] }
+
+[workspace]
@@ -0,0 +1,25 @@
+use std::process::{Command, ExitStatus, Stdio};
+
+fn has_cargo_expand() -> bool {
+    let cargo_expand = if cfg!(windows) {
+        "cargo-expand.exe"
+    } else {
+        "cargo-expand"
+    };
+
+    Command::new(cargo_expand)
+        .arg("--version")
+        .stdin(Stdio::null())
+        .stdout(Stdio::null())
+        .stderr(Stdio::null())
+        .status()
+        .as_ref()
+        .map(ExitStatus::success)
+        .unwrap_or(false)
+}
+
+fn main() {
+    if cfg!(feature = "expandtest") && has_cargo_expand() {
+        println!("cargo:rustc-cfg=expandtest");
+    }
+}
@@ -1,2 +0,0 @@
-/target/
-/Cargo.lock
@@ -1,19 +1,11 @@
 [package]
 name = "serde_derive_tests_no_std"
 version = "0.0.0"
-authors = ["David Tolnay <dtolnay@gmail.com>"]
-edition = "2021"
+edition = "2018"
 publish = false

 [dependencies]
 libc = { version = "0.2", default-features = false }
-serde = { path = "../../serde", default-features = false }
-serde_derive = { path = "../../serde_derive" }
-
-[profile.dev]
-panic = "abort"
-
-[profile.release]
-panic = "abort"
+serde = { path = "../../serde", default-features = false, features = ["derive"] }

 [workspace]
@@ -1,13 +1,15 @@
+#![feature(lang_items, start)]
 #![no_std]
-#![no_main]

-use core::ffi::c_int;
-
-#[no_mangle]
-extern "C" fn main(_argc: c_int, _argv: *const *const u8) -> c_int {
+#[start]
+fn start(_argc: isize, _argv: *const *const u8) -> isize {
    0
 }

+#[lang = "eh_personality"]
+#[no_mangle]
+pub extern "C" fn rust_eh_personality() {}
+
 #[panic_handler]
 fn panic(_info: &core::panic::PanicInfo) -> ! {
    unsafe {
@@ -17,24 +19,24 @@ fn panic(_info: &core::panic::PanicInfo) -> ! {

 //////////////////////////////////////////////////////////////////////////////

-use serde_derive::{Deserialize, Serialize};
+use serde::{Serialize, Deserialize};

 #[derive(Serialize, Deserialize)]
-pub struct Unit;
+struct Unit;

 #[derive(Serialize, Deserialize)]
-pub struct Newtype(u8);
+struct Newtype(u8);

 #[derive(Serialize, Deserialize)]
-pub struct Tuple(u8, u8);
+struct Tuple(u8, u8);

 #[derive(Serialize, Deserialize)]
-pub struct Struct {
+struct Struct {
    f: u8,
 }

 #[derive(Serialize, Deserialize)]
-pub enum Enum {
+enum Enum {
    Unit,
    Newtype(u8),
    Tuple(u8, u8),
@@ -1,6 +1,8 @@
-#[cfg_attr(target_os = "emscripten", ignore = "disabled on Emscripten")]
-#[rustversion::attr(not(nightly), ignore = "requires nightly")]
-#[cfg_attr(miri, ignore = "incompatible with miri")]
+#![cfg(any())]
+
+#[cfg_attr(target_os = "emscripten", ignore)]
+#[rustversion::attr(not(nightly), ignore)]
+#[cfg_attr(miri, ignore)]
 #[allow(unused_attributes)]
 #[test]
 fn ui() {
@@ -0,0 +1,13 @@
+use serde::{Deserialize, Serialize};
+
+#[derive(Serialize, Deserialize)]
+enum DeEnum<B, C, D> {
+    Unit,
+    Seq(i8, B, C, D),
+    Map { a: i8, b: B, c: C, d: D },
+
+    // Make sure we can support more than one variant.
+    _Unit2,
+    _Seq2(i8, B, C, D),
+    _Map2 { a: i8, b: B, c: C, d: D },
+}
@@ -0,0 +1,448 @@
+use serde::{Deserialize, Serialize};
+trait AssociatedType {
+    type X;
+}
+impl AssociatedType for i32 {
+    type X = i32;
+}
+struct DefaultTyParam<T: AssociatedType<X = i32> = i32> {
+    phantom: PhantomData<T>,
+}
+#[doc(hidden)]
+#[allow(non_upper_case_globals, unused_attributes, unused_qualifications)]
+const _: () = {
+    #[allow(unused_extern_crates, clippy::useless_attribute)]
+    extern crate serde as _serde;
+    #[automatically_derived]
+    impl<T: AssociatedType<X = i32>> _serde::Serialize for DefaultTyParam<T> {
+        fn serialize<__S>(
+            &self,
+            __serializer: __S,
+        ) -> _serde::__private::Result<__S::Ok, __S::Error>
+        where
+            __S: _serde::Serializer,
+        {
+            let mut __serde_state = match _serde::Serializer::serialize_struct(
+                __serializer,
+                "DefaultTyParam",
+                false as usize + 1,
+            ) {
+                _serde::__private::Ok(__val) => __val,
+                _serde::__private::Err(__err) => {
+                    return _serde::__private::Err(__err);
+                }
+            };
+            match _serde::ser::SerializeStruct::serialize_field(
+                &mut __serde_state,
+                "phantom",
+                &self.phantom,
+            ) {
+                _serde::__private::Ok(__val) => __val,
+                _serde::__private::Err(__err) => {
+                    return _serde::__private::Err(__err);
+                }
+            };
+            _serde::ser::SerializeStruct::end(__serde_state)
+        }
+    }
+};
+#[doc(hidden)]
+#[allow(non_upper_case_globals, unused_attributes, unused_qualifications)]
+const _: () = {
+    #[allow(unused_extern_crates, clippy::useless_attribute)]
+    extern crate serde as _serde;
+    #[automatically_derived]
+    impl<'de, T: AssociatedType<X = i32>> _serde::Deserialize<'de>
+    for DefaultTyParam<T> {
+        fn deserialize<__D>(
+            __deserializer: __D,
+        ) -> _serde::__private::Result<Self, __D::Error>
+        where
+            __D: _serde::Deserializer<'de>,
+        {
+            #[allow(non_camel_case_types)]
+            enum __Field {
+                __field0,
+                __ignore,
+            }
+            struct __FieldVisitor;
+            impl<'de> _serde::de::Visitor<'de> for __FieldVisitor {
+                type Value = __Field;
+                fn expecting(
+                    &self,
+                    __formatter: &mut _serde::__private::Formatter,
+                ) -> _serde::__private::fmt::Result {
+                    _serde::__private::Formatter::write_str(
+                        __formatter,
+                        "field identifier",
+                    )
+                }
+                fn visit_u64<__E>(
+                    self,
+                    __value: u64,
+                ) -> _serde::__private::Result<Self::Value, __E>
+                where
+                    __E: _serde::de::Error,
+                {
+                    match __value {
+                        0u64 => _serde::__private::Ok(__Field::__field0),
+                        _ => _serde::__private::Ok(__Field::__ignore),
+                    }
+                }
+                fn visit_str<__E>(
+                    self,
+                    __value: &str,
+                ) -> _serde::__private::Result<Self::Value, __E>
+                where
+                    __E: _serde::de::Error,
+                {
+                    match __value {
+                        "phantom" => _serde::__private::Ok(__Field::__field0),
+                        _ => _serde::__private::Ok(__Field::__ignore),
+                    }
+                }
+                fn visit_bytes<__E>(
+                    self,
+                    __value: &[u8],
+                ) -> _serde::__private::Result<Self::Value, __E>
+                where
+                    __E: _serde::de::Error,
+                {
+                    match __value {
+                        b"phantom" => _serde::__private::Ok(__Field::__field0),
+                        _ => _serde::__private::Ok(__Field::__ignore),
+                    }
+                }
+            }
+            impl<'de> _serde::Deserialize<'de> for __Field {
+                #[inline]
+                fn deserialize<__D>(
+                    __deserializer: __D,
+                ) -> _serde::__private::Result<Self, __D::Error>
+                where
+                    __D: _serde::Deserializer<'de>,
+                {
+                    _serde::Deserializer::deserialize_identifier(
+                        __deserializer,
+                        __FieldVisitor,
+                    )
+                }
+            }
+            struct __Visitor<'de, T: AssociatedType<X = i32>> {
+                marker: _serde::__private::PhantomData<DefaultTyParam<T>>,
+                lifetime: _serde::__private::PhantomData<&'de ()>,
+            }
+            impl<'de, T: AssociatedType<X = i32>> _serde::de::Visitor<'de>
+            for __Visitor<'de, T> {
+                type Value = DefaultTyParam<T>;
+                fn expecting(
+                    &self,
+                    __formatter: &mut _serde::__private::Formatter,
+                ) -> _serde::__private::fmt::Result {
+                    _serde::__private::Formatter::write_str(
+                        __formatter,
+                        "struct DefaultTyParam",
+                    )
+                }
+                #[inline]
+                fn visit_seq<__A>(
+                    self,
+                    mut __seq: __A,
+                ) -> _serde::__private::Result<Self::Value, __A::Error>
+                where
+                    __A: _serde::de::SeqAccess<'de>,
+                {
+                    let __field0 = match match _serde::de::SeqAccess::next_element::<
+                        PhantomData<T>,
+                    >(&mut __seq) {
+                        _serde::__private::Ok(__val) => __val,
+                        _serde::__private::Err(__err) => {
+                            return _serde::__private::Err(__err);
+                        }
+                    } {
+                        _serde::__private::Some(__value) => __value,
+                        _serde::__private::None => {
+                            return _serde::__private::Err(
+                                _serde::de::Error::invalid_length(
+                                    0usize,
+                                    &"struct DefaultTyParam with 1 element",
+                                ),
+                            );
+                        }
+                    };
+                    _serde::__private::Ok(DefaultTyParam {
+                        phantom: __field0,
+                    })
+                }
+                #[inline]
+                fn visit_map<__A>(
+                    self,
+                    mut __map: __A,
+                ) -> _serde::__private::Result<Self::Value, __A::Error>
+                where
+                    __A: _serde::de::MapAccess<'de>,
+                {
+                    let mut __field0: _serde::__private::Option<PhantomData<T>> = _serde::__private::None;
+                    while let _serde::__private::Some(__key)
+                        = match _serde::de::MapAccess::next_key::<__Field>(&mut __map) {
+                            _serde::__private::Ok(__val) => __val,
+                            _serde::__private::Err(__err) => {
+                                return _serde::__private::Err(__err);
+                            }
+                        } {
+                        match __key {
+                            __Field::__field0 => {
+                                if _serde::__private::Option::is_some(&__field0) {
+                                    return _serde::__private::Err(
+                                        <__A::Error as _serde::de::Error>::duplicate_field(
+                                            "phantom",
+                                        ),
+                                    );
+                                }
+                                __field0 = _serde::__private::Some(
+                                    match _serde::de::MapAccess::next_value::<
+                                        PhantomData<T>,
+                                    >(&mut __map) {
+                                        _serde::__private::Ok(__val) => __val,
+                                        _serde::__private::Err(__err) => {
+                                            return _serde::__private::Err(__err);
+                                        }
+                                    },
+                                );
+                            }
+                            _ => {
+                                let _ = match _serde::de::MapAccess::next_value::<
+                                    _serde::de::IgnoredAny,
+                                >(&mut __map) {
+                                    _serde::__private::Ok(__val) => __val,
+                                    _serde::__private::Err(__err) => {
+                                        return _serde::__private::Err(__err);
+                                    }
+                                };
+                            }
+                        }
+                    }
+                    let __field0 = match __field0 {
+                        _serde::__private::Some(__field0) => __field0,
+                        _serde::__private::None => {
+                            match _serde::__private::de::missing_field("phantom") {
+                                _serde::__private::Ok(__val) => __val,
+                                _serde::__private::Err(__err) => {
+                                    return _serde::__private::Err(__err);
+                                }
+                            }
+                        }
+                    };
+                    _serde::__private::Ok(DefaultTyParam {
+                        phantom: __field0,
+                    })
+                }
+            }
+            const FIELDS: &'static [&'static str] = &["phantom"];
+            _serde::Deserializer::deserialize_struct(
+                __deserializer,
+                "DefaultTyParam",
+                FIELDS,
+                __Visitor {
+                    marker: _serde::__private::PhantomData::<DefaultTyParam<T>>,
+                    lifetime: _serde::__private::PhantomData,
+                },
+            )
+        }
+        fn deserialize_in_place<__D>(
+            __deserializer: __D,
+            __place: &mut Self,
+        ) -> _serde::__private::Result<(), __D::Error>
+        where
+            __D: _serde::Deserializer<'de>,
+        {
+            #[allow(non_camel_case_types)]
+            enum __Field {
+                __field0,
+                __ignore,
+            }
+            struct __FieldVisitor;
+            impl<'de> _serde::de::Visitor<'de> for __FieldVisitor {
+                type Value = __Field;
+                fn expecting(
+                    &self,
+                    __formatter: &mut _serde::__private::Formatter,
+                ) -> _serde::__private::fmt::Result {
+                    _serde::__private::Formatter::write_str(
+                        __formatter,
+                        "field identifier",
+                    )
+                }
+                fn visit_u64<__E>(
+                    self,
+                    __value: u64,
+                ) -> _serde::__private::Result<Self::Value, __E>
+                where
+                    __E: _serde::de::Error,
+                {
+                    match __value {
+                        0u64 => _serde::__private::Ok(__Field::__field0),
+                        _ => _serde::__private::Ok(__Field::__ignore),
+                    }
+                }
+                fn visit_str<__E>(
+                    self,
+                    __value: &str,
+                ) -> _serde::__private::Result<Self::Value, __E>
+                where
+                    __E: _serde::de::Error,
+                {
+                    match __value {
+                        "phantom" => _serde::__private::Ok(__Field::__field0),
+                        _ => _serde::__private::Ok(__Field::__ignore),
+                    }
+                }
+                fn visit_bytes<__E>(
+                    self,
+                    __value: &[u8],
+                ) -> _serde::__private::Result<Self::Value, __E>
+                where
+                    __E: _serde::de::Error,
+                {
+                    match __value {
+                        b"phantom" => _serde::__private::Ok(__Field::__field0),
+                        _ => _serde::__private::Ok(__Field::__ignore),
+                    }
+                }
+            }
+            impl<'de> _serde::Deserialize<'de> for __Field {
+                #[inline]
+                fn deserialize<__D>(
+                    __deserializer: __D,
+                ) -> _serde::__private::Result<Self, __D::Error>
+                where
+                    __D: _serde::Deserializer<'de>,
+                {
+                    _serde::Deserializer::deserialize_identifier(
+                        __deserializer,
+                        __FieldVisitor,
+                    )
+                }
+            }
+            struct __Visitor<'de, 'place, T: AssociatedType<X = i32> + 'place> {
+                place: &'place mut DefaultTyParam<T>,
+                lifetime: _serde::__private::PhantomData<&'de ()>,
+            }
+            impl<
+                'de,
+                'place,
+                T: AssociatedType<X = i32> + 'place,
+            > _serde::de::Visitor<'de> for __Visitor<'de, 'place, T> {
+                type Value = ();
+                fn expecting(
+                    &self,
+                    __formatter: &mut _serde::__private::Formatter,
+                ) -> _serde::__private::fmt::Result {
+                    _serde::__private::Formatter::write_str(
+                        __formatter,
+                        "struct DefaultTyParam",
+                    )
+                }
+                #[inline]
+                fn visit_seq<__A>(
+                    self,
+                    mut __seq: __A,
+                ) -> _serde::__private::Result<Self::Value, __A::Error>
+                where
+                    __A: _serde::de::SeqAccess<'de>,
+                {
+                    if let _serde::__private::None
+                        = match _serde::de::SeqAccess::next_element_seed(
+                            &mut __seq,
+                            _serde::__private::de::InPlaceSeed(&mut self.place.phantom),
+                        ) {
+                            _serde::__private::Ok(__val) => __val,
+                            _serde::__private::Err(__err) => {
+                                return _serde::__private::Err(__err);
+                            }
+                        } {
+                        return _serde::__private::Err(
+                            _serde::de::Error::invalid_length(
+                                0usize,
+                                &"struct DefaultTyParam with 1 element",
+                            ),
+                        );
+                    }
+                    _serde::__private::Ok(())
+                }
+                #[inline]
+                fn visit_map<__A>(
+                    self,
+                    mut __map: __A,
+                ) -> _serde::__private::Result<Self::Value, __A::Error>
+                where
+                    __A: _serde::de::MapAccess<'de>,
+                {
+                    let mut __field0: bool = false;
+                    while let _serde::__private::Some(__key)
+                        = match _serde::de::MapAccess::next_key::<__Field>(&mut __map) {
+                            _serde::__private::Ok(__val) => __val,
+                            _serde::__private::Err(__err) => {
+                                return _serde::__private::Err(__err);
+                            }
+                        } {
+                        match __key {
+                            __Field::__field0 => {
+                                if __field0 {
+                                    return _serde::__private::Err(
+                                        <__A::Error as _serde::de::Error>::duplicate_field(
+                                            "phantom",
+                                        ),
+                                    );
+                                }
+                                match _serde::de::MapAccess::next_value_seed(
+                                    &mut __map,
+                                    _serde::__private::de::InPlaceSeed(&mut self.place.phantom),
+                                ) {
+                                    _serde::__private::Ok(__val) => __val,
+                                    _serde::__private::Err(__err) => {
+                                        return _serde::__private::Err(__err);
+                                    }
+                                };
+                                __field0 = true;
+                            }
+                            _ => {
+                                let _ = match _serde::de::MapAccess::next_value::<
+                                    _serde::de::IgnoredAny,
+                                >(&mut __map) {
+                                    _serde::__private::Ok(__val) => __val,
+                                    _serde::__private::Err(__err) => {
+                                        return _serde::__private::Err(__err);
+                                    }
+                                };
+                            }
+                        }
+                    }
+                    if !__field0 {
+                        self
+                            .place
+                            .phantom = match _serde::__private::de::missing_field(
+                            "phantom",
+                        ) {
+                            _serde::__private::Ok(__val) => __val,
+                            _serde::__private::Err(__err) => {
+                                return _serde::__private::Err(__err);
+                            }
+                        };
+                    }
+                    _serde::__private::Ok(())
+                }
+            }
+            const FIELDS: &'static [&'static str] = &["phantom"];
+            _serde::Deserializer::deserialize_struct(
+                __deserializer,
+                "DefaultTyParam",
+                FIELDS,
+                __Visitor {
+                    place: __place,
+                    lifetime: _serde::__private::PhantomData,
+                },
+            )
+        }
+    }
+};
--- a/Show More
+++ b/Show More
Author	SHA1	Message	Date
David Tolnay	af31449cb1	Run test suite on wa-serde-derive	2022-07-01 17:56:18 -07:00
David Tolnay	1afae183b0	Compile serde_derive to wasm	2022-07-01 17:55:51 -07:00
				`@@ -0,0 +1 @@`
				`test_suite/tests/expand/*.expanded.rs linguist-generated`