Release 1.0.215

Revert the colliding aliases hard error (PRs #2562 & #2853)

.github/FUNDING.yml

@@ -0,0 +1 @@
+github: dtolnay

.github/workflows/ci.yml

@@ -18,16 +18,22 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 45
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: dtolnay/rust-toolchain@nightly
       - run: cd test_suite && cargo test --features unstable
+      - uses: actions/upload-artifact@v4
+        if: always()
+        with:
+          name: Cargo.lock
+          path: Cargo.lock
+        continue-on-error: true
 
   windows:
     name: Test suite (windows)
     runs-on: windows-latest
     timeout-minutes: 45
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: dtolnay/rust-toolchain@nightly
       - run: cd test_suite && cargo test --features unstable -- --skip ui --exact
 
@@ -40,7 +46,7 @@ jobs:
         rust: [stable, beta]
     timeout-minutes: 45
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: dtolnay/rust-toolchain@master
         with:
           toolchain: ${{matrix.rust}}
@@ -56,7 +62,7 @@ jobs:
         os: [ubuntu, windows]
     timeout-minutes: 45
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: dtolnay/rust-toolchain@nightly
       - run: cd serde && cargo build
       - run: cd serde && cargo build --no-default-features
@@ -80,84 +86,71 @@ jobs:
         rust: [1.31.0, 1.34.0]
     timeout-minutes: 45
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - 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
 
   derive:
-    name: Rust 1.56.0
+    name: Rust 1.61.0
     runs-on: ubuntu-latest
     timeout-minutes: 45
     steps:
-      - uses: actions/checkout@v3
-      - uses: dtolnay/rust-toolchain@1.56.0
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@1.61.0
+      - 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
       - run: cd serde && cargo check --no-default-features
       - run: cd serde && cargo check
       - run: cd serde_derive && cargo check
-      - run: cd precompiled/serde_derive && cargo check
 
   alloc:
     name: Rust 1.36.0
     runs-on: ubuntu-latest
     timeout-minutes: 45
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: dtolnay/rust-toolchain@1.36.0
+      - run: sed -i '/"test_suite"/d' Cargo.toml
       - run: cd serde && cargo build --no-default-features --features alloc
 
-  precompiled:
-    name: Precompiled
-    runs-on: ubuntu-latest
-    timeout-minutes: 45
-    steps:
-      - uses: actions/checkout@v3
-      - uses: dtolnay/rust-toolchain@nightly
-        with:
-          components: rust-src
-          targets: x86_64-unknown-linux-musl
-      - run: precompiled/build.sh
-      - name: replace serde_derive dependency with precompiled
-        run: |
-          # FIXME: consider using `cargo rm serde_derive` but it's currently broken
-          # https://github.com/rust-lang/cargo/issues/12419
-          sed -i '/serde_derive =/d' serde/Cargo.toml
-          sed -i '/derive = \["serde_derive"\]/d' serde/Cargo.toml
-          sed -i '/"serde_derive"/d' Cargo.toml
-          sed -i '/\[workspace\]/d' precompiled/serde_derive/Cargo.toml
-          cargo add --dev serde_derive --path precompiled/serde_derive --manifest-path test_suite/Cargo.toml
-          git diff
-      - run: cd test_suite && cargo test --features unstable -- --skip ui --exact
-
-  macos:
-    name: macOS
-    runs-on: macos-latest
-    timeout-minutes: 45
-    steps:
-      - uses: actions/checkout@v3
-      - uses: dtolnay/rust-toolchain@stable
-      - run: cd precompiled/serde_derive && cargo check
-
   minimal:
     name: Minimal versions
     runs-on: ubuntu-latest
     timeout-minutes: 45
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: dtolnay/rust-toolchain@nightly
       - run: cargo generate-lockfile -Z minimal-versions
       - run: cargo check --locked --workspace
 
+  doc:
+    name: Documentation
+    runs-on: ubuntu-latest
+    timeout-minutes: 45
+    env:
+      RUSTDOCFLAGS: -Dwarnings
+    steps:
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@nightly
+      - uses: dtolnay/install@cargo-docs-rs
+      - run: cargo docs-rs -p serde
+      - run: cargo docs-rs -p serde_derive
+      - run: cargo docs-rs -p serde_derive_internals
+
   clippy:
     name: Clippy
     runs-on: ubuntu-latest
     if: github.event_name != 'pull_request'
     timeout-minutes: 45
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: dtolnay/rust-toolchain@clippy
       - run: cd serde && cargo clippy --features rc,unstable -- -Dclippy::all -Dclippy::pedantic
       - run: cd serde_derive && cargo clippy -- -Dclippy::all -Dclippy::pedantic
@@ -170,7 +163,7 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 45
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: dtolnay/rust-toolchain@miri
       - run: cargo miri setup
       - run: cd serde && cargo miri test --features derive,rc,unstable
@@ -186,6 +179,7 @@ jobs:
     if: github.event_name != 'pull_request'
     timeout-minutes: 45
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@stable
       - uses: dtolnay/install@cargo-outdated
       - run: cargo outdated --workspace --exit-code 1

Cargo.toml

@@ -8,3 +8,8 @@ members = [
 
 [patch.crates-io]
 serde = { path = "serde" }
+
+[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 }

README.md

@@ -1,13 +1,13 @@
-# Serde   [![Build Status]][actions] [![Latest Version]][crates.io] [![serde: rustc 1.31+]][Rust 1.31] [![serde_derive: rustc 1.56+]][Rust 1.56]
+# Serde   [![Build Status]][actions] [![Latest Version]][crates.io] [![serde msrv]][Rust 1.31] [![serde_derive msrv]][Rust 1.61]
 
 [Build Status]: https://img.shields.io/github/actions/workflow/status/serde-rs/serde/ci.yml?branch=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: rustc 1.31+]: https://img.shields.io/badge/serde-rustc_1.31+-lightgray.svg
-[serde_derive: rustc 1.56+]: https://img.shields.io/badge/serde_derive-rustc_1.56+-lightgray.svg
+[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 1.31]: https://blog.rust-lang.org/2018/12/06/Rust-1.31-and-rust-2018.html
-[Rust 1.56]: https://blog.rust-lang.org/2021/10/21/Rust-1.56.0.html
+[Rust 1.61]: https://blog.rust-lang.org/2022/05/19/Rust-1.61.0.html
 
 **Serde is a framework for *ser*ializing and *de*serializing Rust data structures efficiently and generically.**
 

crates-io.md

@@ -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

precompiled/.gitignore

@@ -1 +0,0 @@
-/serde_derive/serde_derive-x86_64-unknown-linux-gnu

precompiled/Cargo.toml

@@ -1,14 +0,0 @@
-[workspace]
-members = ["bin", "proc-macro2"]
-resolver = "2"
-
-[patch.crates-io]
-proc-macro2 = { path = "proc-macro2" }
-
-[profile.precompiled]
-inherits = "release"
-codegen-units = 1
-lto = true
-opt-level = "z"
-panic = "abort"
-strip = true

precompiled/bin/Cargo.toml

@@ -1,17 +0,0 @@
-[package]
-name = "serde_derive"
-version = "1.0.183"
-authors = ["David Tolnay <dtolnay@gmail.com>"]
-publish = false
-
-[lib]
-doctest = false
-
-[[bin]]
-name = "serde_derive"
-path = "main.rs"
-
-[dependencies]
-proc-macro2 = "1"
-quote = { version = "1", default-features = false }
-syn = { version = "2.0.28", default-features = false, features = ["clone-impls", "derive", "full", "parsing", "printing"] }

precompiled/bin/build.rs

@@ -1,4 +0,0 @@
-fn main() {
-    println!("cargo:rustc-cfg=precompiled");
-    println!("cargo:rustc-cfg=feature=\"deserialize_in_place\"");
-}

precompiled/bin/main.rs

@@ -1,45 +0,0 @@
-extern crate proc_macro2;
-
-use proc_macro2::watt;
-use proc_macro2::watt::buffer::InputBuffer;
-use std::alloc::{GlobalAlloc, Layout, System};
-use std::io::{self, Read, Write};
-use std::sync::atomic::Ordering;
-
-struct MonotonicAllocator;
-
-#[global_allocator]
-static ALLOCATOR: MonotonicAllocator = MonotonicAllocator;
-
-unsafe impl GlobalAlloc for MonotonicAllocator {
-    unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
-        System.alloc(layout)
-    }
-
-    unsafe fn dealloc(&self, _ptr: *mut u8, _layout: Layout) {
-        // Leak: this cuts 3% of code size from the precompiled macro binary.
-        // There is no way that serde_derive would fill up all memory on the
-        // host. When the subprocess exits, operating system will clean this up.
-    }
-}
-
-fn main() {
-    let mut buf = Vec::new();
-    io::stdin().read_to_end(&mut buf).unwrap();
-
-    let mut buf = InputBuffer::new(&buf);
-    let derive = match buf.read_u8() {
-        0 => serde_derive::derive_serialize,
-        1 => serde_derive::derive_deserialize,
-        2 => {
-            serde_derive::DESERIALIZE_IN_PLACE.store(true, Ordering::Relaxed);
-            serde_derive::derive_deserialize
-        }
-        _ => unreachable!(),
-    };
-
-    let input = watt::load(&mut buf);
-    let output = derive(input);
-    let bytes = watt::linearize(output);
-    io::stdout().write_all(&bytes).unwrap();
-}

precompiled/bin/src

@@ -1 +0,0 @@
-../../serde_derive/src

precompiled/build.sh

@@ -1,21 +0,0 @@
-#!/bin/bash
-
-cd -- "$(dirname -- "${BASH_SOURCE[0]}")" &>/dev/null
-set -e -x
-
-# TODO: Sanitize host filesystem paths. https://github.com/rust-lang/cargo/issues/12137
-
-cargo +nightly build \
-    --manifest-path bin/Cargo.toml \
-    --bin serde_derive \
-    --profile precompiled \
-    -Z unstable-options \
-    -Z build-std=std,panic_abort \
-    -Z build-std-features=panic_immediate_abort \
-    --target x86_64-unknown-linux-musl \
-    --out-dir serde_derive
-
-rm -f serde_derive/serde_derive-x86_64-unknown-linux-gnu
-mv serde_derive/serde_derive{,-x86_64-unknown-linux-gnu}
-
-#upx --best --lzma serde_derive/serde_derive-x86_64-unknown-linux-gnu

precompiled/proc-macro2/Cargo.toml

@@ -1,8 +0,0 @@
-[package]
-name = "proc-macro2"
-version = "1.0.66"
-edition = "2021"
-publish = false
-
-[dependencies]
-proc-macro2 = { package = "proc-macro2-fallback", version = "1" }

precompiled/proc-macro2/src/lib.rs

@@ -1,815 +0,0 @@
-#[doc(hidden)]
-pub mod watt;
-
-use crate::extra::DelimSpan;
-use crate::watt::Identity;
-use std::cmp::Ordering;
-use std::fmt::{self, Debug, Display};
-use std::hash::{Hash, Hasher};
-use std::ops::RangeBounds;
-use std::str::FromStr;
-
-pub use proc_macro2::{Delimiter, Spacing};
-
-#[derive(Copy, Clone)]
-pub struct Span {
-    lo: u32,
-    hi: u32,
-}
-
-impl Span {
-    pub fn call_site() -> Self {
-        Span { lo: 0, hi: 0 }
-    }
-
-    pub fn join(&self, other: Self) -> Option<Self> {
-        Some(Span {
-            lo: self.lo,
-            hi: other.hi,
-        })
-    }
-}
-
-#[derive(Clone)]
-pub enum TokenTree {
-    Group(Group),
-    Ident(Ident),
-    Punct(Punct),
-    Literal(Literal),
-}
-
-impl TokenTree {
-    pub fn span(&self) -> Span {
-        match self {
-            TokenTree::Group(group) => group.span(),
-            TokenTree::Ident(ident) => ident.span(),
-            TokenTree::Punct(punct) => punct.span(),
-            TokenTree::Literal(literal) => literal.span(),
-        }
-    }
-
-    pub fn set_span(&mut self, span: Span) {
-        match self {
-            TokenTree::Group(group) => group.set_span(span),
-            TokenTree::Ident(ident) => ident.set_span(span),
-            TokenTree::Punct(punct) => punct.set_span(span),
-            TokenTree::Literal(literal) => literal.set_span(span),
-        }
-    }
-}
-
-impl From<Group> for TokenTree {
-    fn from(group: Group) -> Self {
-        TokenTree::Group(group)
-    }
-}
-
-impl From<Ident> for TokenTree {
-    fn from(ident: Ident) -> Self {
-        TokenTree::Ident(ident)
-    }
-}
-
-impl From<Punct> for TokenTree {
-    fn from(punct: Punct) -> Self {
-        TokenTree::Punct(punct)
-    }
-}
-
-impl From<Literal> for TokenTree {
-    fn from(literal: Literal) -> Self {
-        TokenTree::Literal(literal)
-    }
-}
-
-impl Debug for TokenTree {
-    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
-        match self {
-            TokenTree::Group(group) => Debug::fmt(group, formatter),
-            TokenTree::Ident(ident) => {
-                let mut debug = formatter.debug_struct("Ident");
-                debug.field("sym", &format_args!("{}", ident));
-                debug.finish()
-            }
-            TokenTree::Punct(punct) => Debug::fmt(punct, formatter),
-            TokenTree::Literal(literal) => Debug::fmt(literal, formatter),
-        }
-    }
-}
-
-#[derive(Clone)]
-pub struct Group {
-    delimiter: Delimiter,
-    stream: Vec<TokenTree>,
-    span: Span,
-    span_open: Span,
-    span_close: Span,
-    identity: u32,
-}
-
-impl Group {
-    pub fn new(delimiter: Delimiter, stream: TokenStream) -> Self {
-        Group {
-            delimiter,
-            stream: stream.content,
-            span: Span::call_site(),
-            span_open: Span::call_site(),
-            span_close: Span::call_site(),
-            identity: Identity::NOVEL,
-        }
-    }
-
-    pub fn stream(&self) -> TokenStream {
-        TokenStream {
-            content: self.stream.clone(),
-        }
-    }
-
-    pub fn delimiter(&self) -> Delimiter {
-        self.delimiter
-    }
-
-    pub fn span(&self) -> Span {
-        self.span
-    }
-
-    pub fn span_open(&self) -> Span {
-        self.span_open
-    }
-
-    pub fn span_close(&self) -> Span {
-        self.span_close
-    }
-
-    pub fn delim_span(&self) -> DelimSpan {
-        DelimSpan {
-            join: self.span,
-            open: self.span_open,
-            close: self.span_close,
-        }
-    }
-
-    pub fn set_span(&mut self, span: Span) {
-        self.span = span;
-        self.identity |= Identity::RESPANNED;
-    }
-}
-
-impl Display for Group {
-    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
-        let (open, close) = match self.delimiter {
-            Delimiter::Parenthesis => ("(", ")"),
-            Delimiter::Brace => ("{ ", "}"),
-            Delimiter::Bracket => ("[", "]"),
-            Delimiter::None => ("", ""),
-        };
-
-        formatter.write_str(open)?;
-        display_tokens(&self.stream, formatter)?;
-        if self.delimiter == Delimiter::Brace && !self.stream.is_empty() {
-            formatter.write_str(" ")?;
-        }
-        formatter.write_str(close)?;
-
-        Ok(())
-    }
-}
-
-impl Debug for Group {
-    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
-        let mut debug = formatter.debug_struct("Group");
-        debug.field("delimiter", &self.delimiter);
-        debug.field("stream", &self.stream);
-        debug.finish()
-    }
-}
-
-#[derive(Clone)]
-pub struct Ident {
-    fallback: proc_macro2::Ident,
-    span: Span,
-    identity: u32,
-}
-
-impl Ident {
-    pub fn new(string: &str, span: Span) -> Self {
-        Ident {
-            fallback: proc_macro2::Ident::new(string, proc_macro2::Span::call_site()),
-            span,
-            identity: Identity::NOVEL,
-        }
-    }
-
-    pub fn new_raw(string: &str, span: Span) -> Self {
-        Ident {
-            fallback: proc_macro2::Ident::new_raw(string, proc_macro2::Span::call_site()),
-            span,
-            identity: Identity::NOVEL,
-        }
-    }
-
-    pub fn span(&self) -> Span {
-        self.span
-    }
-
-    pub fn set_span(&mut self, span: Span) {
-        self.span = span;
-        self.identity |= Identity::RESPANNED;
-    }
-}
-
-impl Display for Ident {
-    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
-        Display::fmt(&self.fallback, formatter)
-    }
-}
-
-impl Debug for Ident {
-    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
-        Debug::fmt(&self.fallback, formatter)
-    }
-}
-
-impl Eq for Ident {}
-
-impl PartialEq for Ident {
-    fn eq(&self, other: &Self) -> bool {
-        PartialEq::eq(&self.fallback, &other.fallback)
-    }
-}
-
-impl<T> PartialEq<T> for Ident
-where
-    T: ?Sized + AsRef<str>,
-{
-    fn eq(&self, other: &T) -> bool {
-        PartialEq::eq(&self.fallback, other)
-    }
-}
-
-impl Ord for Ident {
-    fn cmp(&self, other: &Self) -> Ordering {
-        Ord::cmp(&self.fallback, &other.fallback)
-    }
-}
-
-impl PartialOrd for Ident {
-    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
-        PartialOrd::partial_cmp(&self.fallback, &other.fallback)
-    }
-}
-
-impl Hash for Ident {
-    fn hash<H: Hasher>(&self, hasher: &mut H) {
-        Hash::hash(&self.fallback, hasher);
-    }
-}
-
-#[derive(Clone)]
-pub struct Punct {
-    fallback: proc_macro2::Punct,
-    span: Span,
-    identity: u32,
-}
-
-impl Punct {
-    pub fn new(ch: char, spacing: Spacing) -> Self {
-        Punct {
-            fallback: proc_macro2::Punct::new(ch, spacing),
-            span: Span::call_site(),
-            identity: Identity::NOVEL,
-        }
-    }
-
-    pub fn as_char(&self) -> char {
-        self.fallback.as_char()
-    }
-
-    pub fn spacing(&self) -> Spacing {
-        self.fallback.spacing()
-    }
-
-    pub fn span(&self) -> Span {
-        self.span
-    }
-
-    pub fn set_span(&mut self, span: Span) {
-        self.span = span;
-        self.identity |= Identity::RESPANNED;
-    }
-}
-
-impl Display for Punct {
-    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
-        Display::fmt(&self.fallback, formatter)
-    }
-}
-
-impl Debug for Punct {
-    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
-        Debug::fmt(&self.fallback, formatter)
-    }
-}
-
-#[derive(Clone)]
-pub struct Literal {
-    fallback: proc_macro2::Literal,
-    span: Span,
-    identity: u32,
-}
-
-impl Literal {
-    pub fn u8_suffixed(n: u8) -> Self {
-        Literal {
-            fallback: proc_macro2::Literal::u8_suffixed(n),
-            span: Span::call_site(),
-            identity: Identity::NOVEL,
-        }
-    }
-
-    pub fn u16_suffixed(n: u16) -> Self {
-        Literal {
-            fallback: proc_macro2::Literal::u16_suffixed(n),
-            span: Span::call_site(),
-            identity: Identity::NOVEL,
-        }
-    }
-
-    pub fn u32_suffixed(n: u32) -> Self {
-        Literal {
-            fallback: proc_macro2::Literal::u32_suffixed(n),
-            span: Span::call_site(),
-            identity: Identity::NOVEL,
-        }
-    }
-
-    pub fn u64_suffixed(n: u64) -> Self {
-        Literal {
-            fallback: proc_macro2::Literal::u64_suffixed(n),
-            span: Span::call_site(),
-            identity: Identity::NOVEL,
-        }
-    }
-
-    pub fn u128_suffixed(n: u128) -> Self {
-        Literal {
-            fallback: proc_macro2::Literal::u128_suffixed(n),
-            span: Span::call_site(),
-            identity: Identity::NOVEL,
-        }
-    }
-
-    pub fn usize_suffixed(n: usize) -> Self {
-        Literal {
-            fallback: proc_macro2::Literal::usize_suffixed(n),
-            span: Span::call_site(),
-            identity: Identity::NOVEL,
-        }
-    }
-
-    pub fn i8_suffixed(n: i8) -> Self {
-        Literal {
-            fallback: proc_macro2::Literal::i8_suffixed(n),
-            span: Span::call_site(),
-            identity: Identity::NOVEL,
-        }
-    }
-
-    pub fn i16_suffixed(n: i16) -> Self {
-        Literal {
-            fallback: proc_macro2::Literal::i16_suffixed(n),
-            span: Span::call_site(),
-            identity: Identity::NOVEL,
-        }
-    }
-
-    pub fn i32_suffixed(n: i32) -> Self {
-        Literal {
-            fallback: proc_macro2::Literal::i32_suffixed(n),
-            span: Span::call_site(),
-            identity: Identity::NOVEL,
-        }
-    }
-
-    pub fn i64_suffixed(n: i64) -> Self {
-        Literal {
-            fallback: proc_macro2::Literal::i64_suffixed(n),
-            span: Span::call_site(),
-            identity: Identity::NOVEL,
-        }
-    }
-
-    pub fn i128_suffixed(n: i128) -> Self {
-        Literal {
-            fallback: proc_macro2::Literal::i128_suffixed(n),
-            span: Span::call_site(),
-            identity: Identity::NOVEL,
-        }
-    }
-
-    pub fn isize_suffixed(n: isize) -> Self {
-        Literal {
-            fallback: proc_macro2::Literal::isize_suffixed(n),
-            span: Span::call_site(),
-            identity: Identity::NOVEL,
-        }
-    }
-
-    pub fn u8_unsuffixed(n: u8) -> Self {
-        Literal {
-            fallback: proc_macro2::Literal::u8_unsuffixed(n),
-            span: Span::call_site(),
-            identity: Identity::NOVEL,
-        }
-    }
-
-    pub fn u16_unsuffixed(n: u16) -> Self {
-        Literal {
-            fallback: proc_macro2::Literal::u16_unsuffixed(n),
-            span: Span::call_site(),
-            identity: Identity::NOVEL,
-        }
-    }
-
-    pub fn u32_unsuffixed(n: u32) -> Self {
-        Literal {
-            fallback: proc_macro2::Literal::u32_unsuffixed(n),
-            span: Span::call_site(),
-            identity: Identity::NOVEL,
-        }
-    }
-
-    pub fn u64_unsuffixed(n: u64) -> Self {
-        Literal {
-            fallback: proc_macro2::Literal::u64_unsuffixed(n),
-            span: Span::call_site(),
-            identity: Identity::NOVEL,
-        }
-    }
-
-    pub fn u128_unsuffixed(n: u128) -> Self {
-        Literal {
-            fallback: proc_macro2::Literal::u128_unsuffixed(n),
-            span: Span::call_site(),
-            identity: Identity::NOVEL,
-        }
-    }
-
-    pub fn usize_unsuffixed(n: usize) -> Self {
-        Literal {
-            fallback: proc_macro2::Literal::usize_unsuffixed(n),
-            span: Span::call_site(),
-            identity: Identity::NOVEL,
-        }
-    }
-
-    pub fn i8_unsuffixed(n: i8) -> Self {
-        Literal {
-            fallback: proc_macro2::Literal::i8_unsuffixed(n),
-            span: Span::call_site(),
-            identity: Identity::NOVEL,
-        }
-    }
-
-    pub fn i16_unsuffixed(n: i16) -> Self {
-        Literal {
-            fallback: proc_macro2::Literal::i16_unsuffixed(n),
-            span: Span::call_site(),
-            identity: Identity::NOVEL,
-        }
-    }
-
-    pub fn i32_unsuffixed(n: i32) -> Self {
-        Literal {
-            fallback: proc_macro2::Literal::i32_unsuffixed(n),
-            span: Span::call_site(),
-            identity: Identity::NOVEL,
-        }
-    }
-
-    pub fn i64_unsuffixed(n: i64) -> Self {
-        Literal {
-            fallback: proc_macro2::Literal::i64_unsuffixed(n),
-            span: Span::call_site(),
-            identity: Identity::NOVEL,
-        }
-    }
-
-    pub fn i128_unsuffixed(n: i128) -> Self {
-        Literal {
-            fallback: proc_macro2::Literal::i128_unsuffixed(n),
-            span: Span::call_site(),
-            identity: Identity::NOVEL,
-        }
-    }
-
-    pub fn isize_unsuffixed(n: isize) -> Self {
-        Literal {
-            fallback: proc_macro2::Literal::isize_unsuffixed(n),
-            span: Span::call_site(),
-            identity: Identity::NOVEL,
-        }
-    }
-
-    pub fn f64_unsuffixed(f: f64) -> Self {
-        Literal {
-            fallback: proc_macro2::Literal::f64_unsuffixed(f),
-            span: Span::call_site(),
-            identity: Identity::NOVEL,
-        }
-    }
-
-    pub fn f64_suffixed(f: f64) -> Self {
-        Literal {
-            fallback: proc_macro2::Literal::f64_suffixed(f),
-            span: Span::call_site(),
-            identity: Identity::NOVEL,
-        }
-    }
-
-    pub fn f32_unsuffixed(f: f32) -> Self {
-        Literal {
-            fallback: proc_macro2::Literal::f32_unsuffixed(f),
-            span: Span::call_site(),
-            identity: Identity::NOVEL,
-        }
-    }
-
-    pub fn f32_suffixed(f: f32) -> Self {
-        Literal {
-            fallback: proc_macro2::Literal::f32_suffixed(f),
-            span: Span::call_site(),
-            identity: Identity::NOVEL,
-        }
-    }
-
-    pub fn string(string: &str) -> Self {
-        Literal {
-            fallback: proc_macro2::Literal::string(string),
-            span: Span::call_site(),
-            identity: Identity::NOVEL,
-        }
-    }
-
-    pub fn character(ch: char) -> Self {
-        Literal {
-            fallback: proc_macro2::Literal::character(ch),
-            span: Span::call_site(),
-            identity: Identity::NOVEL,
-        }
-    }
-
-    pub fn byte_string(s: &[u8]) -> Self {
-        Literal {
-            fallback: proc_macro2::Literal::byte_string(s),
-            span: Span::call_site(),
-            identity: Identity::NOVEL,
-        }
-    }
-
-    pub fn span(&self) -> Span {
-        self.span
-    }
-
-    pub fn set_span(&mut self, span: Span) {
-        self.span = span;
-        self.identity |= Identity::RESPANNED;
-    }
-
-    pub fn subspan<R: RangeBounds<usize>>(&self, range: R) -> Option<Span> {
-        let _ = range;
-        None
-    }
-}
-
-impl FromStr for Literal {
-    type Err = LexError;
-
-    fn from_str(repr: &str) -> Result<Self, Self::Err> {
-        let fallback = match proc_macro2::Literal::from_str(repr) {
-            Ok(literal) => literal,
-            Err(error) => {
-                return Err(LexError {
-                    fallback: error,
-                    span: Span::call_site(),
-                });
-            }
-        };
-        Ok(Literal {
-            fallback,
-            span: Span::call_site(),
-            identity: Identity::NOVEL,
-        })
-    }
-}
-
-impl Display for Literal {
-    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
-        Display::fmt(&self.fallback, formatter)
-    }
-}
-
-impl Debug for Literal {
-    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
-        Debug::fmt(&self.fallback, formatter)
-    }
-}
-
-#[derive(Clone)]
-pub struct TokenStream {
-    content: Vec<TokenTree>,
-}
-
-impl TokenStream {
-    pub fn new() -> Self {
-        TokenStream {
-            content: Vec::new(),
-        }
-    }
-
-    pub fn is_empty(&self) -> bool {
-        self.content.is_empty()
-    }
-}
-
-impl IntoIterator for TokenStream {
-    type Item = TokenTree;
-    type IntoIter = token_stream::IntoIter;
-
-    fn into_iter(self) -> Self::IntoIter {
-        token_stream::IntoIter {
-            iter: self.content.into_iter(),
-        }
-    }
-}
-
-impl Extend<TokenStream> for TokenStream {
-    fn extend<I: IntoIterator<Item = TokenStream>>(&mut self, streams: I) {
-        self.content.extend(streams.into_iter().flatten());
-    }
-}
-
-impl Extend<TokenTree> for TokenStream {
-    fn extend<I: IntoIterator<Item = TokenTree>>(&mut self, streams: I) {
-        self.content.extend(streams);
-    }
-}
-
-impl FromIterator<TokenStream> for TokenStream {
-    fn from_iter<I: IntoIterator<Item = TokenStream>>(streams: I) -> Self {
-        let content = streams.into_iter().flatten().collect();
-        TokenStream { content }
-    }
-}
-
-impl FromIterator<TokenTree> for TokenStream {
-    fn from_iter<I: IntoIterator<Item = TokenTree>>(streams: I) -> Self {
-        let content = streams.into_iter().collect();
-        TokenStream { content }
-    }
-}
-
-impl FromStr for TokenStream {
-    type Err = LexError;
-
-    fn from_str(string: &str) -> Result<Self, Self::Err> {
-        let fallback = match proc_macro2::TokenStream::from_str(string) {
-            Ok(token_stream) => token_stream,
-            Err(error) => {
-                return Err(LexError {
-                    fallback: error,
-                    span: Span::call_site(),
-                });
-            }
-        };
-
-        fn convert_token_stream(stream: proc_macro2::TokenStream) -> TokenStream {
-            TokenStream {
-                content: stream.into_iter().map(convert_token_tree).collect(),
-            }
-        }
-
-        fn convert_token_tree(token: proc_macro2::TokenTree) -> TokenTree {
-            match token {
-                proc_macro2::TokenTree::Group(group) => TokenTree::Group(Group::new(
-                    group.delimiter(),
-                    convert_token_stream(group.stream()),
-                )),
-                proc_macro2::TokenTree::Ident(ident) => TokenTree::Ident(Ident {
-                    fallback: ident,
-                    span: Span::call_site(),
-                    identity: Identity::NOVEL,
-                }),
-                proc_macro2::TokenTree::Punct(punct) => TokenTree::Punct(Punct {
-                    fallback: punct,
-                    span: Span::call_site(),
-                    identity: Identity::NOVEL,
-                }),
-                proc_macro2::TokenTree::Literal(literal) => TokenTree::Literal(Literal {
-                    fallback: literal,
-                    span: Span::call_site(),
-                    identity: Identity::NOVEL,
-                }),
-            }
-        }
-
-        Ok(convert_token_stream(fallback))
-    }
-}
-
-fn display_tokens(tokens: &[TokenTree], formatter: &mut fmt::Formatter) -> fmt::Result {
-    let mut joint = false;
-    for (i, token) in tokens.iter().enumerate() {
-        if i != 0 && !joint {
-            write!(formatter, " ")?;
-        }
-        joint = false;
-        match token {
-            TokenTree::Group(group) => Display::fmt(group, formatter),
-            TokenTree::Ident(ident) => Display::fmt(ident, formatter),
-            TokenTree::Punct(punct) => {
-                joint = punct.spacing() == Spacing::Joint;
-                Display::fmt(punct, formatter)
-            }
-            TokenTree::Literal(literal) => Display::fmt(literal, formatter),
-        }?;
-    }
-
-    Ok(())
-}
-
-impl Display for TokenStream {
-    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
-        display_tokens(&self.content, formatter)
-    }
-}
-
-impl Debug for TokenStream {
-    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
-        formatter.write_str("TokenStream ")?;
-        formatter.debug_list().entries(&self.content).finish()
-    }
-}
-
-pub struct LexError {
-    fallback: proc_macro2::LexError,
-    span: Span,
-}
-
-impl LexError {
-    pub fn span(&self) -> Span {
-        self.span
-    }
-}
-
-impl Debug for LexError {
-    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
-        Debug::fmt(&self.fallback, formatter)
-    }
-}
-
-pub mod token_stream {
-    use super::*;
-
-    #[derive(Clone)]
-    pub struct IntoIter {
-        pub(crate) iter: <Vec<TokenTree> as IntoIterator>::IntoIter,
-    }
-
-    impl Iterator for IntoIter {
-        type Item = TokenTree;
-
-        fn next(&mut self) -> Option<Self::Item> {
-            self.iter.next()
-        }
-
-        fn size_hint(&self) -> (usize, Option<usize>) {
-            self.iter.size_hint()
-        }
-    }
-}
-
-pub mod extra {
-    use crate::Span;
-
-    #[derive(Copy, Clone)]
-    pub struct DelimSpan {
-        pub(crate) join: Span,
-        pub(crate) open: Span,
-        pub(crate) close: Span,
-    }
-
-    impl DelimSpan {
-        pub fn join(&self) -> Span {
-            self.join
-        }
-
-        pub fn open(&self) -> Span {
-            self.open
-        }
-
-        pub fn close(&self) -> Span {
-            self.close
-        }
-    }
-}

precompiled/proc-macro2/src/watt/buffer.rs

@@ -1,69 +0,0 @@
-use std::str;
-
-pub struct OutputBuffer {
-    bytes: Vec<u8>,
-}
-
-impl OutputBuffer {
-    pub fn new() -> Self {
-        OutputBuffer { bytes: Vec::new() }
-    }
-
-    pub fn write_u8(&mut self, value: u8) {
-        self.bytes.push(value);
-    }
-
-    pub fn write_u16(&mut self, value: u16) {
-        self.bytes.extend_from_slice(&value.to_le_bytes());
-    }
-
-    pub fn write_u32(&mut self, value: u32) {
-        self.bytes.extend_from_slice(&value.to_le_bytes());
-    }
-
-    pub fn write_str(&mut self, value: &str) {
-        self.bytes.extend_from_slice(value.as_bytes());
-    }
-
-    pub fn into_bytes(self) -> Vec<u8> {
-        self.bytes
-    }
-}
-
-pub struct InputBuffer<'a> {
-    bytes: &'a [u8],
-}
-
-impl<'a> InputBuffer<'a> {
-    pub fn new(bytes: &'a [u8]) -> Self {
-        InputBuffer { bytes }
-    }
-
-    pub fn is_empty(&self) -> bool {
-        self.bytes.is_empty()
-    }
-
-    pub fn read_u8(&mut self) -> u8 {
-        let (first, rest) = self.bytes.split_first().unwrap();
-        self.bytes = rest;
-        *first
-    }
-
-    pub fn read_u16(&mut self) -> u16 {
-        let (value, rest) = self.bytes.split_at(2);
-        self.bytes = rest;
-        u16::from_le_bytes([value[0], value[1]])
-    }
-
-    pub fn read_u32(&mut self) -> u32 {
-        let (value, rest) = self.bytes.split_at(4);
-        self.bytes = rest;
-        u32::from_le_bytes([value[0], value[1], value[2], value[3]])
-    }
-
-    pub fn read_str(&mut self, len: usize) -> &'a str {
-        let (string, rest) = self.bytes.split_at(len);
-        self.bytes = rest;
-        str::from_utf8(string).unwrap()
-    }
-}

precompiled/proc-macro2/src/watt/bytecode.rs

@@ -1,17 +0,0 @@
-pub enum Bytecode {}
-
-impl Bytecode {
-    pub const GROUP_PARENTHESIS: u8 = 0;
-    pub const GROUP_BRACE: u8 = 1;
-    pub const GROUP_BRACKET: u8 = 2;
-    pub const GROUP_NONE: u8 = 3;
-    pub const IDENT: u8 = 4;
-    pub const PUNCT_ALONE: u8 = 5;
-    pub const PUNCT_JOINT: u8 = 6;
-    pub const LITERAL: u8 = 7;
-    pub const LOAD_GROUP: u8 = 8;
-    pub const LOAD_IDENT: u8 = 9;
-    pub const LOAD_PUNCT: u8 = 10;
-    pub const LOAD_LITERAL: u8 = 11;
-    pub const SET_SPAN: u8 = 12;
-}

precompiled/proc-macro2/src/watt/mod.rs

@@ -1,205 +0,0 @@
-pub mod buffer;
-pub mod bytecode;
-
-use crate::watt::buffer::{InputBuffer, OutputBuffer};
-use crate::watt::bytecode::Bytecode;
-use crate::{Delimiter, Group, Ident, Literal, Punct, Spacing, Span, TokenStream, TokenTree};
-use std::str::FromStr;
-
-pub enum Kind {
-    Group(Delimiter),
-    Ident,
-    Punct(Spacing),
-    Literal,
-}
-
-pub enum Identity {}
-
-impl Identity {
-    pub const RESPANNED: u32 = 1 << 31;
-    pub const NOVEL: u32 = u32::MAX;
-}
-
-impl Span {
-    fn is_call_site(&self) -> bool {
-        self.lo == 0 && self.hi == 0
-    }
-}
-
-fn post_increment(counter: &mut u32) -> impl FnMut() -> u32 + '_ {
-    || {
-        let value = *counter;
-        *counter += 1;
-        value
-    }
-}
-
-pub fn load(buf: &mut InputBuffer) -> TokenStream {
-    let mut span_counter = 1;
-    let mut next_span = post_increment(&mut span_counter);
-    let mut next_span = || {
-        let next = next_span();
-        Span { lo: next, hi: next }
-    };
-
-    let [mut group_counter, mut ident_counter, mut punct_counter, mut literal_counter] = [0; 4];
-    let mut next_group = post_increment(&mut group_counter);
-    let mut next_ident = post_increment(&mut ident_counter);
-    let mut next_punct = post_increment(&mut punct_counter);
-    let mut next_literal = post_increment(&mut literal_counter);
-
-    let mut trees = Vec::new();
-    while !buf.is_empty() {
-        match match buf.read_u8() {
-            Bytecode::GROUP_PARENTHESIS => Kind::Group(Delimiter::Parenthesis),
-            Bytecode::GROUP_BRACE => Kind::Group(Delimiter::Brace),
-            Bytecode::GROUP_BRACKET => Kind::Group(Delimiter::Bracket),
-            Bytecode::GROUP_NONE => Kind::Group(Delimiter::None),
-            Bytecode::IDENT => Kind::Ident,
-            Bytecode::PUNCT_ALONE => Kind::Punct(Spacing::Alone),
-            Bytecode::PUNCT_JOINT => Kind::Punct(Spacing::Joint),
-            Bytecode::LITERAL => Kind::Literal,
-            _ => unreachable!(),
-        } {
-            Kind::Group(delimiter) => {
-                let len = buf.read_u32();
-                let stream = trees.drain(trees.len() - len as usize..).collect();
-                trees.push(TokenTree::Group(Group {
-                    delimiter,
-                    stream,
-                    span: next_span(),
-                    span_open: next_span(),
-                    span_close: next_span(),
-                    identity: next_group(),
-                }));
-            }
-            Kind::Ident => {
-                let len = buf.read_u16();
-                let repr = buf.read_str(len as usize);
-                let ident = if let Some(repr) = repr.strip_prefix("r#") {
-                    proc_macro2::Ident::new_raw(repr, proc_macro2::Span::call_site())
-                } else if repr == "$crate" {
-                    proc_macro2::Ident::new("crate", proc_macro2::Span::call_site())
-                } else {
-                    proc_macro2::Ident::new(repr, proc_macro2::Span::call_site())
-                };
-                trees.push(TokenTree::Ident(Ident {
-                    fallback: ident,
-                    span: next_span(),
-                    identity: next_ident(),
-                }));
-            }
-            Kind::Punct(spacing) => {
-                let ch = buf.read_u8();
-                assert!(ch.is_ascii());
-                let punct = proc_macro2::Punct::new(ch as char, spacing);
-                trees.push(TokenTree::Punct(Punct {
-                    fallback: punct,
-                    span: next_span(),
-                    identity: next_punct(),
-                }));
-            }
-            Kind::Literal => {
-                let len = buf.read_u16();
-                let repr = buf.read_str(len as usize);
-                let literal = proc_macro2::Literal::from_str(repr).unwrap();
-                trees.push(TokenTree::Literal(Literal {
-                    fallback: literal,
-                    span: next_span(),
-                    identity: next_literal(),
-                }));
-            }
-        }
-    }
-
-    TokenStream { content: trees }
-}
-
-pub fn linearize(tokens: TokenStream) -> Vec<u8> {
-    let mut buf = OutputBuffer::new();
-    for token in &tokens.content {
-        linearize_token(token, &mut buf);
-    }
-    buf.into_bytes()
-}
-
-fn linearize_token(token: &TokenTree, buf: &mut OutputBuffer) {
-    let needs_span;
-    match token {
-        TokenTree::Group(group) => {
-            if group.identity < Identity::NOVEL {
-                buf.write_u8(Bytecode::LOAD_GROUP);
-                buf.write_u32(group.identity & !Identity::RESPANNED);
-                needs_span = group.identity >= Identity::RESPANNED;
-            } else {
-                let len = group.stream.len();
-                assert!(len <= u32::MAX as usize);
-                for token in &group.stream {
-                    linearize_token(token, buf);
-                }
-                buf.write_u8(match group.delimiter {
-                    Delimiter::Parenthesis => Bytecode::GROUP_PARENTHESIS,
-                    Delimiter::Brace => Bytecode::GROUP_BRACE,
-                    Delimiter::Bracket => Bytecode::GROUP_BRACKET,
-                    Delimiter::None => Bytecode::GROUP_NONE,
-                });
-                buf.write_u32(len as u32);
-                needs_span = !group.span.is_call_site();
-            }
-        }
-        TokenTree::Ident(ident) => {
-            if ident.identity < Identity::NOVEL {
-                buf.write_u8(Bytecode::LOAD_IDENT);
-                buf.write_u32(ident.identity & !Identity::RESPANNED);
-                needs_span = ident.identity >= Identity::RESPANNED;
-            } else {
-                buf.write_u8(Bytecode::IDENT);
-                let repr = ident.to_string();
-                assert!(repr.len() <= u16::MAX as usize);
-                buf.write_u16(repr.len() as u16);
-                buf.write_str(&repr);
-                linearize_span(ident.span, buf);
-                needs_span = false;
-            }
-        }
-        TokenTree::Punct(punct) => {
-            if punct.identity < Identity::NOVEL {
-                buf.write_u8(Bytecode::LOAD_PUNCT);
-                buf.write_u32(punct.identity & !Identity::RESPANNED);
-                needs_span = punct.identity >= Identity::RESPANNED;
-            } else {
-                buf.write_u8(match punct.spacing() {
-                    Spacing::Alone => Bytecode::PUNCT_ALONE,
-                    Spacing::Joint => Bytecode::PUNCT_JOINT,
-                });
-                let ch = punct.as_char();
-                assert!(ch.is_ascii());
-                buf.write_u8(ch as u8);
-                needs_span = !punct.span.is_call_site();
-            }
-        }
-        TokenTree::Literal(literal) => {
-            if literal.identity < Identity::NOVEL {
-                buf.write_u8(Bytecode::LOAD_LITERAL);
-                buf.write_u32(literal.identity & !Identity::RESPANNED);
-                needs_span = literal.identity >= Identity::RESPANNED;
-            } else {
-                buf.write_u8(Bytecode::LITERAL);
-                let repr = literal.to_string();
-                assert!(repr.len() <= u16::MAX as usize);
-                buf.write_u16(repr.len() as u16);
-                buf.write_str(&repr);
-                needs_span = !literal.span.is_call_site();
-            }
-        }
-    }
-    if needs_span {
-        buf.write_u8(Bytecode::SET_SPAN);
-        linearize_span(token.span(), buf);
-    }
-}
-
-fn linearize_span(span: Span, buf: &mut OutputBuffer) {
-    buf.write_u32(span.lo);
-    buf.write_u32(span.hi);
-}

precompiled/serde_derive/Cargo.toml

@@ -1,36 +0,0 @@
-[package]
-name = "serde_derive"
-version = "1.0.183"
-authors = ["David Tolnay <dtolnay@gmail.com>"]
-categories = ["no-std", "no-std::no-alloc"]
-description = "Implementation of #[derive(Serialize, Deserialize)]"
-documentation = "https://serde.rs/derive.html"
-edition = "2015"
-homepage = "https://serde.rs"
-include = ["serde_derive-x86_64-unknown-linux-gnu", "src", "LICENSE-APACHE", "LICENSE-MIT"]
-keywords = ["serde", "serialization", "no_std", "derive"]
-license = "MIT OR Apache-2.0"
-readme = "crates-io.md"
-repository = "https://github.com/serde-rs/serde"
-rust-version = "1.56"
-
-[features]
-default = []
-deserialize_in_place = []
-
-[lib]
-proc-macro = true
-
-[target.'cfg(not(all(target_arch = "x86_64", target_os = "linux", target_env = "gnu")))'.dependencies]
-proc-macro2 = "1"
-quote = "1"
-syn = "2.0.28"
-
-[dev-dependencies]
-serde = { version = "1", path = "../../serde" }
-
-[package.metadata.docs.rs]
-targets = ["x86_64-unknown-linux-gnu"]
-rustdoc-args = ["--generate-link-to-definition"]
-
-[workspace]

precompiled/serde_derive/LICENSE-APACHE

@@ -1 +0,0 @@
-../../LICENSE-APACHE

precompiled/serde_derive/LICENSE-MIT

@@ -1 +0,0 @@
-../../LICENSE-MIT

precompiled/serde_derive/README.md

@@ -1 +0,0 @@
-../../README.md

precompiled/serde_derive/crates-io.md

@@ -1 +0,0 @@
-../../crates-io.md

precompiled/serde_derive/src/bound.rs

@@ -1 +0,0 @@
-../../../serde_derive/src/bound.rs

precompiled/serde_derive/src/buffer.rs

@@ -1 +0,0 @@
-../../proc-macro2/src/watt/buffer.rs

precompiled/serde_derive/src/bytecode.rs

@@ -1 +0,0 @@
-../../proc-macro2/src/watt/bytecode.rs

precompiled/serde_derive/src/de.rs

@@ -1 +0,0 @@
-../../../serde_derive/src/de.rs

precompiled/serde_derive/src/dummy.rs

@@ -1 +0,0 @@
-../../../serde_derive/src/dummy.rs

precompiled/serde_derive/src/fragment.rs

@@ -1 +0,0 @@
-../../../serde_derive/src/fragment.rs

precompiled/serde_derive/src/internals

@@ -1 +0,0 @@
-../../../serde_derive/src/internals/

precompiled/serde_derive/src/lib.rs

@@ -1,22 +0,0 @@
-//! This crate provides Serde's two derive macros.
-//!
-//! ```edition2021
-//! # use serde_derive::{Deserialize, Serialize};
-//! #
-//! #[derive(Serialize, Deserialize)]
-//! # struct S;
-//! #
-//! # fn main() {}
-//! ```
-//!
-//! Please refer to [https://serde.rs/derive.html] for how to set this up.
-//!
-//! [https://serde.rs/derive.html]: https://serde.rs/derive.html
-
-#![doc(html_root_url = "https://docs.rs/serde_derive/1.0.183")]
-
-#[cfg(not(all(target_arch = "x86_64", target_os = "linux", target_env = "gnu")))]
-include!("lib_from_source.rs");
-
-#[cfg(all(target_arch = "x86_64", target_os = "linux", target_env = "gnu"))]
-include!("lib_precompiled.rs");

precompiled/serde_derive/src/lib_from_source.rs

@@ -1,35 +0,0 @@
-extern crate proc_macro;
-extern crate proc_macro2;
-extern crate quote;
-extern crate syn;
-
-#[macro_use]
-mod bound;
-#[macro_use]
-mod fragment;
-
-mod de;
-mod dummy;
-mod internals;
-mod pretend;
-mod ser;
-mod this;
-
-use proc_macro::TokenStream;
-use syn::{parse_macro_input, DeriveInput};
-
-#[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()
-}

precompiled/serde_derive/src/lib_precompiled.rs

@@ -1,234 +0,0 @@
-extern crate proc_macro;
-
-mod buffer;
-mod bytecode;
-
-use crate::buffer::{InputBuffer, OutputBuffer};
-use crate::bytecode::Bytecode;
-use proc_macro::{Delimiter, Group, Ident, Literal, Punct, Spacing, Span, TokenStream, TokenTree};
-use std::io::{ErrorKind, Read, Write};
-use std::iter::FromIterator;
-use std::path::Path;
-use std::process::{Command, ExitStatus, Stdio};
-use std::str::FromStr;
-
-#[proc_macro_derive(Serialize, attributes(serde))]
-pub fn derive_serialize(input: TokenStream) -> TokenStream {
-    derive(0, input)
-}
-
-#[proc_macro_derive(Deserialize, attributes(serde))]
-pub fn derive_deserialize(input: TokenStream) -> TokenStream {
-    derive(1 + cfg!(feature = "deserialize_in_place") as u8, input)
-}
-
-fn derive(select: u8, input: TokenStream) -> TokenStream {
-    let mut memory = TokenMemory::default();
-    let mut buf = OutputBuffer::new();
-    buf.write_u8(select);
-
-    memory.spans.push(Span::call_site());
-    for token in input {
-        memory.linearize_token(token, &mut buf);
-    }
-
-    let exe_path = Path::new(concat!(
-        env!("CARGO_MANIFEST_DIR"),
-        "/serde_derive-x86_64-unknown-linux-gnu",
-    ));
-    let mut child = match Command::new(exe_path)
-        .stdin(Stdio::piped())
-        .stdout(Stdio::piped())
-        .spawn()
-    {
-        Ok(child) => child,
-        Err(io_error) => {
-            if io_error.kind() == ErrorKind::NotFound {
-                panic!(
-                    "file missing from serde_derive manifest directory during macro expansion: {}",
-                    exe_path.display(),
-                );
-            } else {
-                panic!("failed to spawn process: {}", io_error);
-            }
-        }
-    };
-
-    let mut stdin = child.stdin.take().unwrap();
-    let mut buf = buf.into_bytes();
-    stdin.write_all(&buf).unwrap();
-    drop(stdin);
-
-    let mut stdout = child.stdout.take().unwrap();
-    buf.clear();
-    stdout.read_to_end(&mut buf).unwrap();
-
-    let success = child.wait().as_ref().map_or(true, ExitStatus::success);
-    if !success || buf.is_empty() {
-        panic!();
-    }
-
-    let mut buf = InputBuffer::new(&buf);
-    memory.receive(&mut buf)
-}
-
-#[derive(Default)]
-struct TokenMemory {
-    spans: Vec<Span>,
-    groups: Vec<Group>,
-    idents: Vec<Ident>,
-    puncts: Vec<Punct>,
-    literals: Vec<Literal>,
-}
-
-enum Kind {
-    Group(Delimiter),
-    Ident,
-    Punct(Spacing),
-    Literal,
-}
-
-impl TokenMemory {
-    // Depth-first post-order traversal.
-    fn linearize_token(&mut self, token: TokenTree, buf: &mut OutputBuffer) {
-        match token {
-            TokenTree::Group(group) => {
-                let mut len = 0usize;
-                for token in group.stream() {
-                    self.linearize_token(token, buf);
-                    len += 1;
-                }
-                assert!(len <= u32::MAX as usize);
-                buf.write_u8(match group.delimiter() {
-                    Delimiter::Parenthesis => Bytecode::GROUP_PARENTHESIS,
-                    Delimiter::Brace => Bytecode::GROUP_BRACE,
-                    Delimiter::Bracket => Bytecode::GROUP_BRACKET,
-                    Delimiter::None => Bytecode::GROUP_NONE,
-                });
-                buf.write_u32(len as u32);
-                self.spans
-                    .extend([group.span(), group.span_open(), group.span_close()]);
-                self.groups.push(group);
-            }
-            TokenTree::Ident(ident) => {
-                buf.write_u8(Bytecode::IDENT);
-                let repr = ident.to_string();
-                assert!(repr.len() <= u16::MAX as usize);
-                buf.write_u16(repr.len() as u16);
-                buf.write_str(&repr);
-                self.spans.push(ident.span());
-                self.idents.push(ident);
-            }
-            TokenTree::Punct(punct) => {
-                buf.write_u8(match punct.spacing() {
-                    Spacing::Alone => Bytecode::PUNCT_ALONE,
-                    Spacing::Joint => Bytecode::PUNCT_JOINT,
-                });
-                let ch = punct.as_char();
-                assert!(ch.is_ascii());
-                buf.write_u8(ch as u8);
-                self.spans.push(punct.span());
-                self.puncts.push(punct);
-            }
-            TokenTree::Literal(literal) => {
-                buf.write_u8(Bytecode::LITERAL);
-                let repr = literal.to_string();
-                assert!(repr.len() <= u16::MAX as usize);
-                buf.write_u16(repr.len() as u16);
-                buf.write_str(&repr);
-                self.spans.push(literal.span());
-                self.literals.push(literal);
-            }
-        }
-    }
-
-    fn receive(&self, buf: &mut InputBuffer) -> TokenStream {
-        let mut trees = Vec::new();
-        while !buf.is_empty() {
-            match match buf.read_u8() {
-                Bytecode::GROUP_PARENTHESIS => Kind::Group(Delimiter::Parenthesis),
-                Bytecode::GROUP_BRACE => Kind::Group(Delimiter::Brace),
-                Bytecode::GROUP_BRACKET => Kind::Group(Delimiter::Bracket),
-                Bytecode::GROUP_NONE => Kind::Group(Delimiter::None),
-                Bytecode::IDENT => Kind::Ident,
-                Bytecode::PUNCT_ALONE => Kind::Punct(Spacing::Alone),
-                Bytecode::PUNCT_JOINT => Kind::Punct(Spacing::Joint),
-                Bytecode::LITERAL => Kind::Literal,
-                Bytecode::LOAD_GROUP => {
-                    let identity = buf.read_u32();
-                    let group = self.groups[identity as usize].clone();
-                    trees.push(TokenTree::Group(group));
-                    continue;
-                }
-                Bytecode::LOAD_IDENT => {
-                    let identity = buf.read_u32();
-                    let ident = self.idents[identity as usize].clone();
-                    trees.push(TokenTree::Ident(ident));
-                    continue;
-                }
-                Bytecode::LOAD_PUNCT => {
-                    let identity = buf.read_u32();
-                    let punct = self.puncts[identity as usize].clone();
-                    trees.push(TokenTree::Punct(punct));
-                    continue;
-                }
-                Bytecode::LOAD_LITERAL => {
-                    let identity = buf.read_u32();
-                    let literal = self.literals[identity as usize].clone();
-                    trees.push(TokenTree::Literal(literal));
-                    continue;
-                }
-                Bytecode::SET_SPAN => {
-                    trees.last_mut().unwrap().set_span(self.read_span(buf));
-                    continue;
-                }
-                _ => unreachable!(),
-            } {
-                Kind::Group(delimiter) => {
-                    let len = buf.read_u32();
-                    let stream = trees.drain(trees.len() - len as usize..).collect();
-                    let group = Group::new(delimiter, stream);
-                    trees.push(TokenTree::Group(group));
-                }
-                Kind::Ident => {
-                    let len = buf.read_u16();
-                    let repr = buf.read_str(len as usize);
-                    let span = self.read_span(buf);
-                    let ident = if let Some(repr) = repr.strip_prefix("r#") {
-                        Ident::new_raw(repr, span)
-                    } else {
-                        Ident::new(repr, span)
-                    };
-                    trees.push(TokenTree::Ident(ident));
-                }
-                Kind::Punct(spacing) => {
-                    let ch = buf.read_u8();
-                    assert!(ch.is_ascii());
-                    let punct = Punct::new(ch as char, spacing);
-                    trees.push(TokenTree::Punct(punct));
-                }
-                Kind::Literal => {
-                    let len = buf.read_u16();
-                    let repr = buf.read_str(len as usize);
-                    let literal = Literal::from_str(repr).unwrap();
-                    trees.push(TokenTree::Literal(literal));
-                }
-            }
-        }
-
-        TokenStream::from_iter(trees)
-    }
-
-    fn read_span(&self, buf: &mut InputBuffer) -> Span {
-        let lo = buf.read_u32();
-        let hi = buf.read_u32();
-        let span = self.spans[lo as usize];
-        if lo == hi {
-            span
-        } else {
-            #[cfg(any())] // FIXME
-            return span.join(self.spans[hi as usize]).unwrap_or(span);
-            span
-        }
-    }
-}

precompiled/serde_derive/src/pretend.rs

@@ -1 +0,0 @@
-../../../serde_derive/src/pretend.rs

precompiled/serde_derive/src/ser.rs

@@ -1 +0,0 @@
-../../../serde_derive/src/ser.rs

precompiled/serde_derive/src/this.rs

@@ -1 +0,0 @@
-../../../serde_derive/src/this.rs

serde/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "serde"
-version = "1.0.183" # remember to update html_root_url and serde_derive dependency
+version = "1.0.215"
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>", "David Tolnay <dtolnay@gmail.com>"]
 build = "build.rs"
 categories = ["encoding", "no-std", "no-std::no-alloc"]
@@ -15,7 +15,7 @@ repository = "https://github.com/serde-rs/serde"
 rust-version = "1.31"
 
 [dependencies]
-serde_derive = { version = "=1.0.183", optional = true, path = "../serde_derive" }
+serde_derive = { version = "1", optional = true, path = "../serde_derive" }
 
 [dev-dependencies]
 serde_derive = { version = "1", path = "../serde_derive" }
@@ -27,10 +27,18 @@ doc-scrape-examples = false
 features = ["derive", "rc"]
 
 [package.metadata.docs.rs]
-features = ["derive"]
+features = ["derive", "rc", "unstable"]
 targets = ["x86_64-unknown-linux-gnu"]
 rustdoc-args = ["--generate-link-to-definition"]
 
+# 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 = "=1.0.215", path = "../serde_derive" }
+
 
 ### FEATURES #################################################################
 

serde/build.rs

@@ -13,6 +13,23 @@ fn main() {
         None => return,
     };
 
+    if minor >= 77 {
+        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_core_try_from)");
+        println!("cargo:rustc-check-cfg=cfg(no_diagnostic_namespace)");
+        println!("cargo:rustc-check-cfg=cfg(no_float_copysign)");
+        println!("cargo:rustc-check-cfg=cfg(no_num_nonzero_signed)");
+        println!("cargo:rustc-check-cfg=cfg(no_relaxed_trait_bounds)");
+        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_systemtime_checked_add)");
+        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";
 
@@ -27,16 +44,10 @@ fn main() {
         println!("cargo:rustc-cfg=no_relaxed_trait_bounds");
     }
 
-    // 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 emscripten && minor < 40 {
-        println!("cargo:rustc-cfg=no_integer128");
-    }
-
-    // Current minimum supported version of serde_derive crate is Rust 1.56.
-    if minor < 56 {
-        println!("cargo:rustc-cfg=no_serde_derive");
+    // f32::copysign and f64::copysign stabilized in Rust 1.35.
+    // https://blog.rust-lang.org/2019/05/23/Rust-1.35.0.html#copy-the-sign-of-a-floating-point-number-onto-another
+    if minor < 35 {
+        println!("cargo:rustc-cfg=no_float_copysign");
     }
 
     // Support for #[cfg(target_has_atomic = "...")] stabilized in Rust 1.60.
@@ -60,11 +71,40 @@ fn main() {
         }
     }
 
+    // Current minimum supported version of serde_derive crate is Rust 1.61.
+    if minor < 61 {
+        println!("cargo:rustc-cfg=no_serde_derive");
+    }
+
     // 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");
     }
+
+    // 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> {

serde/src/de/ignored_any.rs

@@ -129,12 +129,10 @@ impl<'de> Visitor<'de> for IgnoredAny {
         Ok(IgnoredAny)
     }
 
-    serde_if_integer128! {
-        #[inline]
-        fn visit_i128<E>(self, x: i128) -> Result<Self::Value, E> {
-            let _ = x;
-            Ok(IgnoredAny)
-        }
+    #[inline]
+    fn visit_i128<E>(self, x: i128) -> Result<Self::Value, E> {
+        let _ = x;
+        Ok(IgnoredAny)
     }
 
     #[inline]
@@ -143,12 +141,10 @@ impl<'de> Visitor<'de> for IgnoredAny {
         Ok(IgnoredAny)
     }
 
-    serde_if_integer128! {
-        #[inline]
-        fn visit_u128<E>(self, x: u128) -> Result<Self::Value, E> {
-            let _ = x;
-            Ok(IgnoredAny)
-        }
+    #[inline]
+    fn visit_u128<E>(self, x: u128) -> Result<Self::Value, E> {
+        let _ = x;
+        Ok(IgnoredAny)
     }
 
     #[inline]

serde/src/de/mod.rs

@@ -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\>
@@ -118,19 +118,16 @@ use crate::lib::*;
 
 pub mod value;
 
-#[cfg(not(no_integer128))]
-mod format;
 mod ignored_any;
 mod impls;
 pub(crate) mod size_hint;
-mod utf8;
 
 pub use self::ignored_any::IgnoredAny;
 
-#[cfg(not(any(feature = "std", feature = "unstable")))]
+#[cfg(all(not(feature = "std"), no_core_error))]
 #[doc(no_inline)]
 pub use crate::std_error::Error as StdError;
-#[cfg(all(feature = "unstable", not(feature = "std")))]
+#[cfg(not(any(feature = "std", no_core_error)))]
 #[doc(no_inline)]
 pub use core::error::Error as StdError;
 #[cfg(feature = "std")]
@@ -404,20 +401,20 @@ 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 `{}`", f),
+            Float(f) => write!(formatter, "floating point `{}`", WithDecimalPoint(f)),
             Char(c) => write!(formatter, "character `{}`", c),
             Str(s) => write!(formatter, "string {:?}", s),
-            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"),
+            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"),
             Other(other) => formatter.write_str(other),
         }
     }
@@ -489,13 +486,13 @@ where
     }
 }
 
-impl<'a> Expected for &'a str {
+impl Expected for &str {
     fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
         formatter.write_str(self)
     }
 }
 
-impl<'a> Display for Expected + 'a {
+impl Display for Expected + '_ {
     fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
         Expected::fmt(self, formatter)
     }
@@ -534,6 +531,13 @@ impl<'a> Display for Expected + 'a {
 /// 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(
+        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.
     ///
@@ -950,18 +954,15 @@ pub trait Deserializer<'de>: Sized {
     where
         V: Visitor<'de>;
 
-    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 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"))
     }
 
     /// Hint that the `Deserialize` type is expecting a `u8` value.
@@ -984,18 +985,15 @@ pub trait Deserializer<'de>: Sized {
     where
         V: Visitor<'de>;
 
-    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 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"))
     }
 
     /// Hint that the `Deserialize` type is expecting a `f32` value.
@@ -1367,20 +1365,20 @@ pub trait Visitor<'de>: Sized {
         Err(Error::invalid_type(Unexpected::Signed(v), &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 `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,
+        ))
     }
 
     /// The input contains a `u8`.
@@ -1429,20 +1427,20 @@ pub trait Visitor<'de>: Sized {
         Err(Error::invalid_type(Unexpected::Unsigned(v), &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 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,
+        ))
     }
 
     /// The input contains an `f32`.
@@ -1478,7 +1476,7 @@ pub trait Visitor<'de>: Sized {
     where
         E: Error,
     {
-        self.visit_str(utf8::encode(v).as_str())
+        self.visit_str(v.encode_utf8(&mut [0u8; 4]))
     }
 
     /// The input contains a string. The lifetime of the string is ephemeral and
@@ -1533,6 +1531,7 @@ 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,
@@ -1555,7 +1554,6 @@ pub trait Visitor<'de>: Sized {
     where
         E: Error,
     {
-        let _ = v;
         Err(Error::invalid_type(Unexpected::Bytes(v), &self))
     }
 
@@ -1592,6 +1590,7 @@ 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,
@@ -1742,9 +1741,9 @@ pub trait SeqAccess<'de> {
     }
 }
 
-impl<'de, 'a, A: ?Sized> SeqAccess<'de> for &'a mut A
+impl<'de, A> SeqAccess<'de> for &mut A
 where
-    A: SeqAccess<'de>,
+    A: ?Sized + SeqAccess<'de>,
 {
     type Error = A::Error;
 
@@ -1895,9 +1894,9 @@ pub trait MapAccess<'de> {
     }
 }
 
-impl<'de, 'a, A: ?Sized> MapAccess<'de> for &'a mut A
+impl<'de, A> MapAccess<'de> for &mut A
 where
-    A: MapAccess<'de>,
+    A: ?Sized + MapAccess<'de>,
 {
     type Error = A::Error;
 
@@ -2285,10 +2284,10 @@ impl Display for OneOf {
             1 => write!(formatter, "`{}`", self.names[0]),
             2 => write!(formatter, "`{}` or `{}`", self.names[0], self.names[1]),
             _ => {
-                tri!(write!(formatter, "one of "));
+                tri!(formatter.write_str("one of "));
                 for (i, alt) in self.names.iter().enumerate() {
                     if i > 0 {
-                        tri!(write!(formatter, ", "));
+                        tri!(formatter.write_str(", "));
                     }
                     tri!(write!(formatter, "`{}`", alt));
                 }
@@ -2297,3 +2296,40 @@ impl Display for OneOf {
         }
     }
 }
+
+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(())
+    }
+}

serde/src/de/utf8.rs

@@ -1,46 +0,0 @@
-use crate::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, 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()
-    }
-}

serde/src/de/value.rs

@@ -112,6 +112,7 @@ impl Debug for Error {
 }
 
 #[cfg(feature = "std")]
+#[cfg_attr(docsrs, doc(cfg(feature = "std")))]
 impl error::Error for Error {
     fn description(&self) -> &str {
         &self.err
@@ -174,6 +175,17 @@ 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()
@@ -184,12 +196,14 @@ 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,
@@ -222,6 +236,18 @@ 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 {
@@ -276,6 +302,17 @@ 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
@@ -292,20 +329,17 @@ 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,
@@ -369,6 +403,17 @@ 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,
@@ -458,6 +503,17 @@ 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,
@@ -537,6 +593,17 @@ 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,
@@ -565,6 +632,7 @@ 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>,
@@ -581,6 +649,7 @@ 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,
@@ -638,6 +707,18 @@ 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
@@ -668,6 +749,7 @@ 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>,
@@ -684,6 +766,7 @@ 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,
@@ -744,6 +827,18 @@ 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
@@ -821,6 +916,17 @@ 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
@@ -869,6 +975,17 @@ 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
@@ -948,6 +1065,19 @@ 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>,
@@ -979,7 +1109,7 @@ struct ExpectedInSeq(usize);
 impl Expected for ExpectedInSeq {
     fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
         if self.0 == 1 {
-            write!(formatter, "1 element in sequence")
+            formatter.write_str("1 element in sequence")
         } else {
             write!(formatter, "{} elements in sequence", self.0)
         }
@@ -1002,6 +1132,7 @@ 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>,
@@ -1015,6 +1146,7 @@ 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,
@@ -1028,6 +1160,7 @@ where
 }
 
 #[cfg(feature = "std")]
+#[cfg_attr(docsrs, doc(cfg(feature = "std")))]
 impl<'de, T, S, E> IntoDeserializer<'de, E> for HashSet<T, S>
 where
     T: IntoDeserializer<'de, E> + Eq + Hash,
@@ -1076,6 +1209,17 @@ 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.
@@ -1190,6 +1334,21 @@ 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,
@@ -1404,7 +1563,7 @@ struct ExpectedInMap(usize);
 impl Expected for ExpectedInMap {
     fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
         if self.0 == 1 {
-            write!(formatter, "1 element in map")
+            formatter.write_str("1 element in map")
         } else {
             write!(formatter, "{} elements in map", self.0)
         }
@@ -1414,6 +1573,7 @@ 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,
@@ -1428,6 +1588,7 @@ where
 }
 
 #[cfg(feature = "std")]
+#[cfg_attr(docsrs, doc(cfg(feature = "std")))]
 impl<'de, K, V, S, E> IntoDeserializer<'de, E> for HashMap<K, V, S>
 where
     K: IntoDeserializer<'de, E> + Eq + Hash,
@@ -1489,6 +1650,17 @@ 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>,
@@ -1542,6 +1714,17 @@ where
     }
 }
 
+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 {

serde/src/integer128.rs

@@ -1,82 +1,9 @@
-/// 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.
-///
-/// ```edition2021
-/// # 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.
-///
-/// ```edition2021
-/// macro_rules! serde_if_integer128 {
-///     ($($tt:tt)*) => {
-///         $($tt)*
-///     };
-/// }
-/// ```
-///
-/// When built without support for 128-bit integers, this macro expands to
-/// nothing.
-///
-/// ```edition2021
-/// macro_rules! serde_if_integer128 {
-///     ($($tt:tt)*) => {};
-/// }
-/// ```
-#[cfg(not(no_integer128))]
+// No longer used. Old versions of serde used this macro for supporting targets
+// that did not yet have 128-bit integer support.
 #[macro_export]
+#[doc(hidden)]
 macro_rules! serde_if_integer128 {
     ($($tt:tt)*) => {
         $($tt)*
     };
 }
-
-#[cfg(no_integer128)]
-#[macro_export]
-#[doc(hidden)]
-macro_rules! serde_if_integer128 {
-    ($($tt:tt)*) => {};
-}

serde/src/lib.rs

@@ -63,6 +63,7 @@
 //!   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
@@ -89,18 +90,22 @@
 //! [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/1.0.183")]
+#![doc(html_root_url = "https://docs.rs/serde/1.0.215")]
 // Support using Serde without the standard library!
 #![cfg_attr(not(feature = "std"), 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(error_in_core, never_type))]
+#![cfg_attr(feature = "unstable", feature(never_type))]
 #![allow(unknown_lints, bare_trait_objects, deprecated)]
 // Ignored clippy and clippy_pedantic lints
 #![allow(
@@ -114,11 +119,11 @@
     // 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::option_if_let_else,
     clippy::single_match_else,
     clippy::type_complexity,
     clippy::use_self,
@@ -127,6 +132,7 @@
     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,
@@ -138,6 +144,7 @@
     clippy::too_many_lines,
     // preference
     clippy::doc_markdown,
+    clippy::needless_lifetimes,
     clippy::unseparated_literal_suffix,
     // false positive
     clippy::needless_doctest_main,
@@ -166,22 +173,25 @@ mod lib {
         pub use std::*;
     }
 
-    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::{iter, num, ptr, str};
     pub use self::core::{u16, u32, u64, u8, usize};
 
+    #[cfg(any(feature = "std", feature = "alloc"))]
+    pub use self::core::{cmp, mem, slice};
+
     pub use self::core::cell::{Cell, RefCell};
-    pub use self::core::clone::{self, Clone};
+    pub use self::core::clone;
     pub use self::core::cmp::Reverse;
-    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::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::num::Wrapping;
     pub use self::core::ops::{Bound, Range, RangeFrom, RangeInclusive, RangeTo};
-    pub use self::core::option::{self, Option};
-    pub use self::core::result::{self, Result};
+    pub use self::core::option;
+    pub use self::core::result;
     pub use self::core::time::Duration;
 
     #[cfg(all(feature = "alloc", not(feature = "std")))]
@@ -229,8 +239,13 @@ mod lib {
     #[cfg(feature = "std")]
     pub use std::ffi::CString;
 
+    #[cfg(all(not(no_core_net), not(feature = "std")))]
+    pub use self::core::net;
     #[cfg(feature = "std")]
-    pub use std::{error, net};
+    pub use std::net;
+
+    #[cfg(feature = "std")]
+    pub use std::error;
 
     #[cfg(feature = "std")]
     pub use std::collections::{HashMap, HashSet};
@@ -267,6 +282,9 @@ mod lib {
     pub use std::sync::atomic::{AtomicI64, AtomicU64};
     #[cfg(all(feature = "std", 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
@@ -293,6 +311,8 @@ mod integer128;
 pub mod de;
 pub mod ser;
 
+mod format;
+
 #[doc(inline)]
 pub use crate::de::{Deserialize, Deserializer};
 #[doc(inline)]
@@ -306,7 +326,7 @@ pub mod __private;
 #[path = "de/seed.rs"]
 mod seed;
 
-#[cfg(not(any(feature = "std", feature = "unstable")))]
+#[cfg(all(not(feature = "std"), no_core_error))]
 mod std_error;
 
 // Re-export #[derive(Serialize, Deserialize)].
@@ -319,6 +339,7 @@ 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};
 
 #[cfg(all(not(no_serde_derive), any(feature = "std", feature = "alloc")))]

serde/src/macros.rs

@@ -123,7 +123,7 @@ 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::Error>
+        fn $func<$v>(self, $($arg: $ty,)* visitor: $v) -> $crate::__private::Result<$v::Value, <Self as $crate::de::Deserializer<$l>>::Error>
         where
             $v: $crate::de::Visitor<$l>,
         {
@@ -154,9 +154,7 @@ macro_rules! forward_to_deserialize_any_helper {
         forward_to_deserialize_any_method!{deserialize_i64<$l, $v>()}
     };
     (i128<$l:tt, $v:ident>) => {
-        serde_if_integer128! {
-            forward_to_deserialize_any_method!{deserialize_i128<$l, $v>()}
-        }
+        forward_to_deserialize_any_method!{deserialize_i128<$l, $v>()}
     };
     (u8<$l:tt, $v:ident>) => {
         forward_to_deserialize_any_method!{deserialize_u8<$l, $v>()}
@@ -171,9 +169,7 @@ macro_rules! forward_to_deserialize_any_helper {
         forward_to_deserialize_any_method!{deserialize_u64<$l, $v>()}
     };
     (u128<$l:tt, $v:ident>) => {
-        serde_if_integer128! {
-            forward_to_deserialize_any_method!{deserialize_u128<$l, $v>()}
-        }
+        forward_to_deserialize_any_method!{deserialize_u128<$l, $v>()}
     };
     (f32<$l:tt, $v:ident>) => {
         forward_to_deserialize_any_method!{deserialize_f32<$l, $v>()}

serde/src/private/de.rs

@@ -313,6 +313,19 @@ mod content {
         }
     }
 
+    impl<'a, 'de, E> de::IntoDeserializer<'de, E> for &'a Content<'de>
+    where
+        E: de::Error,
+    {
+        type Deserializer = ContentRefDeserializer<'a, 'de, E>;
+
+        fn into_deserializer(self) -> Self::Deserializer {
+            ContentRefDeserializer::new(self)
+        }
+    }
+
+    /// Used to capture data in [`Content`] from other deserializers.
+    /// Cannot capture externally tagged enums, `i128` and `u128`.
     struct ContentVisitor<'de> {
         value: PhantomData<Content<'de>>,
     }
@@ -474,14 +487,16 @@ mod content {
         where
             D: Deserializer<'de>,
         {
-            Deserialize::deserialize(deserializer).map(|v| Content::Some(Box::new(v)))
+            let v = tri!(Deserialize::deserialize(deserializer));
+            Ok(Content::Some(Box::new(v)))
         }
 
         fn visit_newtype_struct<D>(self, deserializer: D) -> Result<Self::Value, D::Error>
         where
             D: Deserializer<'de>,
         {
-            Deserialize::deserialize(deserializer).map(|v| Content::Newtype(Box::new(v)))
+            let v = tri!(Deserialize::deserialize(deserializer));
+            Ok(Content::Newtype(Box::new(v)))
         }
 
         fn visit_seq<V>(self, mut visitor: V) -> Result<Self::Value, V::Error>
@@ -528,6 +543,8 @@ mod content {
         Content(Content<'de>),
     }
 
+    /// Serves as a seed for deserializing a key of internally tagged enum.
+    /// Cannot capture externally tagged enums, `i128` and `u128`.
     struct TagOrContentVisitor<'de> {
         name: &'static str,
         value: PhantomData<TagOrContent<'de>>,
@@ -814,6 +831,9 @@ mod content {
 
     /// Used by generated code to deserialize an internally tagged enum.
     ///
+    /// Captures map or sequence from the original deserializer and searches
+    /// a tag in it (in case of sequence, tag is the first element of sequence).
+    ///
     /// Not public API.
     pub struct TaggedContentVisitor<T> {
         tag_name: &'static str,
@@ -897,7 +917,9 @@ mod content {
 
     /// Not public API.
     pub struct TagOrContentFieldVisitor {
+        /// Name of the tag field of the adjacently tagged enum
         pub tag: &'static str,
+        /// Name of the content field of the adjacently tagged enum
         pub content: &'static str,
     }
 
@@ -972,7 +994,9 @@ mod content {
 
     /// Not public API.
     pub struct TagContentOtherFieldVisitor {
+        /// Name of the tag field of the adjacently tagged enum
         pub tag: &'static str,
+        /// Name of the content field of the adjacently tagged enum
         pub content: &'static str,
     }
 
@@ -1087,8 +1111,7 @@ mod content {
         V: Visitor<'de>,
         E: de::Error,
     {
-        let seq = content.into_iter().map(ContentDeserializer::new);
-        let mut seq_visitor = SeqDeserializer::new(seq);
+        let mut seq_visitor = SeqDeserializer::new(content.into_iter());
         let value = tri!(visitor.visit_seq(&mut seq_visitor));
         tri!(seq_visitor.end());
         Ok(value)
@@ -1102,10 +1125,7 @@ mod content {
         V: Visitor<'de>,
         E: de::Error,
     {
-        let map = content
-            .into_iter()
-            .map(|(k, v)| (ContentDeserializer::new(k), ContentDeserializer::new(v)));
-        let mut map_visitor = MapDeserializer::new(map);
+        let mut map_visitor = MapDeserializer::new(content.into_iter());
         let value = tri!(visitor.visit_map(&mut map_visitor));
         tri!(map_visitor.end());
         Ok(value)
@@ -1683,8 +1703,7 @@ mod content {
         V: Visitor<'de>,
         E: de::Error,
     {
-        let seq = content.iter().map(ContentRefDeserializer::new);
-        let mut seq_visitor = SeqDeserializer::new(seq);
+        let mut seq_visitor = SeqDeserializer::new(content.iter());
         let value = tri!(visitor.visit_seq(&mut seq_visitor));
         tri!(seq_visitor.end());
         Ok(value)
@@ -1698,12 +1717,13 @@ mod content {
         V: Visitor<'de>,
         E: de::Error,
     {
-        let map = content.iter().map(|(k, v)| {
-            (
-                ContentRefDeserializer::new(k),
-                ContentRefDeserializer::new(v),
-            )
-        });
+        fn content_ref_deserializer_pair<'a, 'de>(
+            (k, v): &'a (Content<'de>, Content<'de>),
+        ) -> (&'a Content<'de>, &'a Content<'de>) {
+            (k, v)
+        }
+
+        let map = content.iter().map(content_ref_deserializer_pair);
         let mut map_visitor = MapDeserializer::new(map);
         let value = tri!(visitor.visit_map(&mut map_visitor));
         tri!(map_visitor.end());
@@ -1887,10 +1907,19 @@ mod content {
         where
             V: Visitor<'de>,
         {
+            // Covered by tests/test_enum_untagged.rs
+            //      with_optional_field::*
             match *self.content {
                 Content::None => visitor.visit_none(),
                 Content::Some(ref v) => visitor.visit_some(ContentRefDeserializer::new(v)),
                 Content::Unit => visitor.visit_unit(),
+                // This case is to support data formats which do not encode an
+                // indication whether a value is optional. An example of such a
+                // format is JSON, and a counterexample is RON. When requesting
+                // `deserialize_any` in JSON, the data format never performs
+                // `Visitor::visit_some` but we still must be able to
+                // deserialize the resulting Content into data structures with
+                // optional fields.
                 _ => visitor.visit_some(self),
             }
         }
@@ -1920,10 +1949,21 @@ mod content {
         where
             V: Visitor<'de>,
         {
+            // Covered by tests/test_enum_untagged.rs
+            //      newtype_struct
             match *self.content {
                 Content::Newtype(ref v) => {
                     visitor.visit_newtype_struct(ContentRefDeserializer::new(v))
                 }
+                // This case is to support data formats that encode newtype
+                // structs and their underlying data the same, with no
+                // indication whether a newtype wrapper was present. For example
+                // JSON does this, while RON does not. In RON a newtype's name
+                // is included in the serialized representation and it knows to
+                // call `Visitor::visit_newtype_struct` from `deserialize_any`.
+                // JSON's `deserialize_any` never calls `visit_newtype_struct`
+                // but in this code we still must be able to deserialize the
+                // resulting Content into newtypes.
                 _ => visitor.visit_newtype_struct(self),
             }
         }
@@ -2128,6 +2168,10 @@ mod content {
         fn unit_variant(self) -> Result<(), E> {
             match self.value {
                 Some(value) => de::Deserialize::deserialize(ContentRefDeserializer::new(value)),
+                // Covered by tests/test_annotations.rs
+                //      test_partially_untagged_adjacently_tagged_enum
+                // Covered by tests/test_enum_untagged.rs
+                //      newtype_enum::unit
                 None => Ok(()),
             }
         }
@@ -2137,6 +2181,11 @@ mod content {
             T: de::DeserializeSeed<'de>,
         {
             match self.value {
+                // Covered by tests/test_annotations.rs
+                //      test_partially_untagged_enum_desugared
+                //      test_partially_untagged_enum_generic
+                // Covered by tests/test_enum_untagged.rs
+                //      newtype_enum::newtype
                 Some(value) => seed.deserialize(ContentRefDeserializer::new(value)),
                 None => Err(de::Error::invalid_type(
                     de::Unexpected::UnitVariant,
@@ -2150,9 +2199,13 @@ mod content {
             V: de::Visitor<'de>,
         {
             match self.value {
-                Some(Content::Seq(v)) => {
-                    de::Deserializer::deserialize_any(SeqRefDeserializer::new(v), visitor)
-                }
+                // Covered by tests/test_annotations.rs
+                //      test_partially_untagged_enum
+                //      test_partially_untagged_enum_desugared
+                // Covered by tests/test_enum_untagged.rs
+                //      newtype_enum::tuple0
+                //      newtype_enum::tuple2
+                Some(Content::Seq(v)) => visit_content_seq_ref(v, visitor),
                 Some(other) => Err(de::Error::invalid_type(
                     other.unexpected(),
                     &"tuple variant",
@@ -2173,12 +2226,13 @@ mod content {
             V: de::Visitor<'de>,
         {
             match self.value {
-                Some(Content::Map(v)) => {
-                    de::Deserializer::deserialize_any(MapRefDeserializer::new(v), visitor)
-                }
-                Some(Content::Seq(v)) => {
-                    de::Deserializer::deserialize_any(SeqRefDeserializer::new(v), visitor)
-                }
+                // Covered by tests/test_enum_untagged.rs
+                //      newtype_enum::struct_from_map
+                Some(Content::Map(v)) => visit_content_map_ref(v, visitor),
+                // Covered by tests/test_enum_untagged.rs
+                //      newtype_enum::struct_from_seq
+                //      newtype_enum::empty_struct_from_seq
+                Some(Content::Seq(v)) => visit_content_seq_ref(v, visitor),
                 Some(other) => Err(de::Error::invalid_type(
                     other.unexpected(),
                     &"struct variant",
@@ -2191,158 +2245,6 @@ mod content {
         }
     }
 
-    struct SeqRefDeserializer<'a, 'de: 'a, E>
-    where
-        E: de::Error,
-    {
-        iter: <&'a [Content<'de>] as IntoIterator>::IntoIter,
-        err: PhantomData<E>,
-    }
-
-    impl<'a, 'de, E> SeqRefDeserializer<'a, 'de, E>
-    where
-        E: de::Error,
-    {
-        fn new(slice: &'a [Content<'de>]) -> Self {
-            SeqRefDeserializer {
-                iter: slice.iter(),
-                err: PhantomData,
-            }
-        }
-    }
-
-    impl<'de, 'a, E> de::Deserializer<'de> for SeqRefDeserializer<'a, 'de, E>
-    where
-        E: de::Error,
-    {
-        type Error = E;
-
-        #[inline]
-        fn deserialize_any<V>(mut self, visitor: V) -> Result<V::Value, Self::Error>
-        where
-            V: de::Visitor<'de>,
-        {
-            let len = self.iter.len();
-            if len == 0 {
-                visitor.visit_unit()
-            } else {
-                let ret = tri!(visitor.visit_seq(&mut self));
-                let remaining = self.iter.len();
-                if remaining == 0 {
-                    Ok(ret)
-                } else {
-                    Err(de::Error::invalid_length(len, &"fewer elements in array"))
-                }
-            }
-        }
-
-        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, E> de::SeqAccess<'de> for SeqRefDeserializer<'a, 'de, E>
-    where
-        E: de::Error,
-    {
-        type Error = E;
-
-        fn next_element_seed<T>(&mut self, seed: T) -> Result<Option<T::Value>, Self::Error>
-        where
-            T: de::DeserializeSeed<'de>,
-        {
-            match self.iter.next() {
-                Some(value) => seed
-                    .deserialize(ContentRefDeserializer::new(value))
-                    .map(Some),
-                None => Ok(None),
-            }
-        }
-
-        fn size_hint(&self) -> Option<usize> {
-            size_hint::from_bounds(&self.iter)
-        }
-    }
-
-    struct MapRefDeserializer<'a, 'de: 'a, E>
-    where
-        E: de::Error,
-    {
-        iter: <&'a [(Content<'de>, Content<'de>)] as IntoIterator>::IntoIter,
-        value: Option<&'a Content<'de>>,
-        err: PhantomData<E>,
-    }
-
-    impl<'a, 'de, E> MapRefDeserializer<'a, 'de, E>
-    where
-        E: de::Error,
-    {
-        fn new(map: &'a [(Content<'de>, Content<'de>)]) -> Self {
-            MapRefDeserializer {
-                iter: map.iter(),
-                value: None,
-                err: PhantomData,
-            }
-        }
-    }
-
-    impl<'de, 'a, E> de::MapAccess<'de> for MapRefDeserializer<'a, 'de, E>
-    where
-        E: de::Error,
-    {
-        type Error = E;
-
-        fn next_key_seed<T>(&mut self, seed: T) -> Result<Option<T::Value>, Self::Error>
-        where
-            T: de::DeserializeSeed<'de>,
-        {
-            match self.iter.next() {
-                Some((key, value)) => {
-                    self.value = Some(value);
-                    seed.deserialize(ContentRefDeserializer::new(key)).map(Some)
-                }
-                None => Ok(None),
-            }
-        }
-
-        fn next_value_seed<T>(&mut self, seed: T) -> Result<T::Value, Self::Error>
-        where
-            T: de::DeserializeSeed<'de>,
-        {
-            match self.value.take() {
-                Some(value) => seed.deserialize(ContentRefDeserializer::new(value)),
-                None => Err(de::Error::custom("value is missing")),
-            }
-        }
-
-        fn size_hint(&self) -> Option<usize> {
-            size_hint::from_bounds(&self.iter)
-        }
-    }
-
-    impl<'de, 'a, E> de::Deserializer<'de> for MapRefDeserializer<'a, 'de, E>
-    where
-        E: de::Error,
-    {
-        type Error = E;
-
-        #[inline]
-        fn deserialize_any<V>(self, visitor: V) -> Result<V::Value, Self::Error>
-        where
-            V: de::Visitor<'de>,
-        {
-            visitor.visit_map(self)
-        }
-
-        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, E> de::IntoDeserializer<'de, E> for ContentDeserializer<'de, E>
     where
         E: de::Error,
@@ -2703,6 +2605,17 @@ where
         visitor.visit_unit()
     }
 
+    fn deserialize_unit_struct<V>(
+        self,
+        _name: &'static str,
+        visitor: V,
+    ) -> Result<V::Value, Self::Error>
+    where
+        V: Visitor<'de>,
+    {
+        visitor.visit_unit()
+    }
+
     fn deserialize_ignored_any<V>(self, visitor: V) -> Result<V::Value, Self::Error>
     where
         V: Visitor<'de>,
@@ -2727,7 +2640,6 @@ where
         deserialize_string()
         deserialize_bytes()
         deserialize_byte_buf()
-        deserialize_unit_struct(&'static str)
         deserialize_seq()
         deserialize_tuple(usize)
         deserialize_tuple_struct(&'static str, usize)

serde/src/private/doc.rs

@@ -56,7 +56,10 @@ macro_rules! __serialize_unimplemented {
 #[macro_export]
 macro_rules! __serialize_unimplemented_method {
     ($func:ident $(<$t:ident>)* ($($arg:ty),*) -> $ret:ident) => {
-        fn $func $(<$t: ?Sized + $crate::Serialize>)* (self $(, _: $arg)*) -> $crate::__private::Result<Self::$ret, Self::Error> {
+        fn $func $(<$t>)* (self $(, _: $arg)*) -> $crate::__private::Result<Self::$ret, Self::Error>
+        where
+            $($t: ?Sized + $crate::Serialize,)*
+        {
             unimplemented!()
         }
     };

serde/src/private/ser.rs

@@ -51,8 +51,6 @@ enum Unsupported {
     String,
     ByteArray,
     Optional,
-    #[cfg(any(feature = "std", feature = "alloc"))]
-    UnitStruct,
     Sequence,
     Tuple,
     TupleStruct,
@@ -69,8 +67,6 @@ 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"),
-            #[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"),
@@ -174,9 +170,9 @@ where
         Err(self.bad_type(Unsupported::Optional))
     }
 
-    fn serialize_some<T: ?Sized>(self, _: &T) -> Result<Self::Ok, Self::Error>
+    fn serialize_some<T>(self, _: &T) -> Result<Self::Ok, Self::Error>
     where
-        T: Serialize,
+        T: ?Sized + Serialize,
     {
         Err(self.bad_type(Unsupported::Optional))
     }
@@ -205,18 +201,18 @@ where
         map.end()
     }
 
-    fn serialize_newtype_struct<T: ?Sized>(
+    fn serialize_newtype_struct<T>(
         self,
         _: &'static str,
         value: &T,
     ) -> Result<Self::Ok, Self::Error>
     where
-        T: Serialize,
+        T: ?Sized + Serialize,
     {
         value.serialize(self)
     }
 
-    fn serialize_newtype_variant<T: ?Sized>(
+    fn serialize_newtype_variant<T>(
         self,
         _: &'static str,
         _: u32,
@@ -224,7 +220,7 @@ where
         inner_value: &T,
     ) -> Result<Self::Ok, Self::Error>
     where
-        T: Serialize,
+        T: ?Sized + Serialize,
     {
         let mut map = tri!(self.delegate.serialize_map(Some(2)));
         tri!(map.serialize_entry(self.tag, self.variant_name));
@@ -327,9 +323,9 @@ where
     }
 
     #[cfg(not(any(feature = "std", feature = "alloc")))]
-    fn collect_str<T: ?Sized>(self, _: &T) -> Result<Self::Ok, Self::Error>
+    fn collect_str<T>(self, _: &T) -> Result<Self::Ok, Self::Error>
     where
-        T: Display,
+        T: ?Sized + Display,
     {
         Err(self.bad_type(Unsupported::String))
     }
@@ -364,9 +360,9 @@ mod content {
         type Ok = M::Ok;
         type Error = M::Error;
 
-        fn serialize_field<T: ?Sized>(&mut self, value: &T) -> Result<(), M::Error>
+        fn serialize_field<T>(&mut self, value: &T) -> Result<(), M::Error>
         where
-            T: Serialize,
+            T: ?Sized + Serialize,
         {
             let value = tri!(value.serialize(ContentSerializer::<M::Error>::new()));
             self.fields.push(value);
@@ -404,13 +400,9 @@ mod content {
         type Ok = M::Ok;
         type Error = M::Error;
 
-        fn serialize_field<T: ?Sized>(
-            &mut self,
-            key: &'static str,
-            value: &T,
-        ) -> Result<(), M::Error>
+        fn serialize_field<T>(&mut self, key: &'static str, value: &T) -> Result<(), M::Error>
         where
-            T: Serialize,
+            T: ?Sized + Serialize,
         {
             let value = tri!(value.serialize(ContentSerializer::<M::Error>::new()));
             self.fields.push((key, value));
@@ -635,9 +627,9 @@ mod content {
             Ok(Content::None)
         }
 
-        fn serialize_some<T: ?Sized>(self, value: &T) -> Result<Content, E>
+        fn serialize_some<T>(self, value: &T) -> Result<Content, E>
         where
-            T: Serialize,
+            T: ?Sized + Serialize,
         {
             Ok(Content::Some(Box::new(tri!(value.serialize(self)))))
         }
@@ -659,13 +651,9 @@ mod content {
             Ok(Content::UnitVariant(name, variant_index, variant))
         }
 
-        fn serialize_newtype_struct<T: ?Sized>(
-            self,
-            name: &'static str,
-            value: &T,
-        ) -> Result<Content, E>
+        fn serialize_newtype_struct<T>(self, name: &'static str, value: &T) -> Result<Content, E>
         where
-            T: Serialize,
+            T: ?Sized + Serialize,
         {
             Ok(Content::NewtypeStruct(
                 name,
@@ -673,7 +661,7 @@ mod content {
             ))
         }
 
-        fn serialize_newtype_variant<T: ?Sized>(
+        fn serialize_newtype_variant<T>(
             self,
             name: &'static str,
             variant_index: u32,
@@ -681,7 +669,7 @@ mod content {
             value: &T,
         ) -> Result<Content, E>
         where
-            T: Serialize,
+            T: ?Sized + Serialize,
         {
             Ok(Content::NewtypeVariant(
                 name,
@@ -782,9 +770,9 @@ mod content {
         type Ok = Content;
         type Error = E;
 
-        fn serialize_element<T: ?Sized>(&mut self, value: &T) -> Result<(), E>
+        fn serialize_element<T>(&mut self, value: &T) -> Result<(), E>
         where
-            T: Serialize,
+            T: ?Sized + Serialize,
         {
             let value = tri!(value.serialize(ContentSerializer::<E>::new()));
             self.elements.push(value);
@@ -808,9 +796,9 @@ mod content {
         type Ok = Content;
         type Error = E;
 
-        fn serialize_element<T: ?Sized>(&mut self, value: &T) -> Result<(), E>
+        fn serialize_element<T>(&mut self, value: &T) -> Result<(), E>
         where
-            T: Serialize,
+            T: ?Sized + Serialize,
         {
             let value = tri!(value.serialize(ContentSerializer::<E>::new()));
             self.elements.push(value);
@@ -835,9 +823,9 @@ mod content {
         type Ok = Content;
         type Error = E;
 
-        fn serialize_field<T: ?Sized>(&mut self, value: &T) -> Result<(), E>
+        fn serialize_field<T>(&mut self, value: &T) -> Result<(), E>
         where
-            T: Serialize,
+            T: ?Sized + Serialize,
         {
             let value = tri!(value.serialize(ContentSerializer::<E>::new()));
             self.fields.push(value);
@@ -864,9 +852,9 @@ mod content {
         type Ok = Content;
         type Error = E;
 
-        fn serialize_field<T: ?Sized>(&mut self, value: &T) -> Result<(), E>
+        fn serialize_field<T>(&mut self, value: &T) -> Result<(), E>
         where
-            T: Serialize,
+            T: ?Sized + Serialize,
         {
             let value = tri!(value.serialize(ContentSerializer::<E>::new()));
             self.fields.push(value);
@@ -896,18 +884,18 @@ mod content {
         type Ok = Content;
         type Error = E;
 
-        fn serialize_key<T: ?Sized>(&mut self, key: &T) -> Result<(), E>
+        fn serialize_key<T>(&mut self, key: &T) -> Result<(), E>
         where
-            T: Serialize,
+            T: ?Sized + Serialize,
         {
             let key = tri!(key.serialize(ContentSerializer::<E>::new()));
             self.key = Some(key);
             Ok(())
         }
 
-        fn serialize_value<T: ?Sized>(&mut self, value: &T) -> Result<(), E>
+        fn serialize_value<T>(&mut self, value: &T) -> Result<(), E>
         where
-            T: Serialize,
+            T: ?Sized + Serialize,
         {
             let key = self
                 .key
@@ -922,10 +910,10 @@ mod content {
             Ok(Content::Map(self.entries))
         }
 
-        fn serialize_entry<K: ?Sized, V: ?Sized>(&mut self, key: &K, value: &V) -> Result<(), E>
+        fn serialize_entry<K, V>(&mut self, key: &K, value: &V) -> Result<(), E>
         where
-            K: Serialize,
-            V: Serialize,
+            K: ?Sized + Serialize,
+            V: ?Sized + Serialize,
         {
             let key = tri!(key.serialize(ContentSerializer::<E>::new()));
             let value = tri!(value.serialize(ContentSerializer::<E>::new()));
@@ -947,9 +935,9 @@ mod content {
         type Ok = Content;
         type Error = E;
 
-        fn serialize_field<T: ?Sized>(&mut self, key: &'static str, value: &T) -> Result<(), E>
+        fn serialize_field<T>(&mut self, key: &'static str, value: &T) -> Result<(), E>
         where
-            T: Serialize,
+            T: ?Sized + Serialize,
         {
             let value = tri!(value.serialize(ContentSerializer::<E>::new()));
             self.fields.push((key, value));
@@ -976,9 +964,9 @@ mod content {
         type Ok = Content;
         type Error = E;
 
-        fn serialize_field<T: ?Sized>(&mut self, key: &'static str, value: &T) -> Result<(), E>
+        fn serialize_field<T>(&mut self, key: &'static str, value: &T) -> Result<(), E>
         where
-            T: Serialize,
+            T: ?Sized + Serialize,
         {
             let value = tri!(value.serialize(ContentSerializer::<E>::new()));
             self.fields.push((key, value));
@@ -1088,9 +1076,9 @@ where
         Ok(())
     }
 
-    fn serialize_some<T: ?Sized>(self, value: &T) -> Result<Self::Ok, Self::Error>
+    fn serialize_some<T>(self, value: &T) -> Result<Self::Ok, Self::Error>
     where
-        T: Serialize,
+        T: ?Sized + Serialize,
     {
         value.serialize(self)
     }
@@ -1100,7 +1088,7 @@ where
     }
 
     fn serialize_unit_struct(self, _: &'static str) -> Result<Self::Ok, Self::Error> {
-        Err(Self::bad_type(Unsupported::UnitStruct))
+        Ok(())
     }
 
     fn serialize_unit_variant(
@@ -1112,18 +1100,18 @@ where
         Err(Self::bad_type(Unsupported::Enum))
     }
 
-    fn serialize_newtype_struct<T: ?Sized>(
+    fn serialize_newtype_struct<T>(
         self,
         _: &'static str,
         value: &T,
     ) -> Result<Self::Ok, Self::Error>
     where
-        T: Serialize,
+        T: ?Sized + Serialize,
     {
         value.serialize(self)
     }
 
-    fn serialize_newtype_variant<T: ?Sized>(
+    fn serialize_newtype_variant<T>(
         self,
         _: &'static str,
         _: u32,
@@ -1131,10 +1119,9 @@ where
         value: &T,
     ) -> Result<Self::Ok, Self::Error>
     where
-        T: Serialize,
+        T: ?Sized + Serialize,
     {
-        tri!(self.0.serialize_key(variant));
-        self.0.serialize_value(value)
+        self.0.serialize_entry(variant, value)
     }
 
     fn serialize_seq(self, _: Option<usize>) -> Result<Self::SerializeSeq, Self::Error> {
@@ -1202,28 +1189,24 @@ where
     type Ok = ();
     type Error = M::Error;
 
-    fn serialize_key<T: ?Sized>(&mut self, key: &T) -> Result<(), Self::Error>
+    fn serialize_key<T>(&mut self, key: &T) -> Result<(), Self::Error>
     where
-        T: Serialize,
+        T: ?Sized + Serialize,
     {
         self.0.serialize_key(key)
     }
 
-    fn serialize_value<T: ?Sized>(&mut self, value: &T) -> Result<(), Self::Error>
+    fn serialize_value<T>(&mut self, value: &T) -> Result<(), Self::Error>
     where
-        T: Serialize,
+        T: ?Sized + Serialize,
     {
         self.0.serialize_value(value)
     }
 
-    fn serialize_entry<K: ?Sized, V: ?Sized>(
-        &mut self,
-        key: &K,
-        value: &V,
-    ) -> Result<(), Self::Error>
+    fn serialize_entry<K, V>(&mut self, key: &K, value: &V) -> Result<(), Self::Error>
     where
-        K: Serialize,
-        V: Serialize,
+        K: ?Sized + Serialize,
+        V: ?Sized + Serialize,
     {
         self.0.serialize_entry(key, value)
     }
@@ -1244,13 +1227,9 @@ where
     type Ok = ();
     type Error = M::Error;
 
-    fn serialize_field<T: ?Sized>(
-        &mut self,
-        key: &'static str,
-        value: &T,
-    ) -> Result<(), Self::Error>
+    fn serialize_field<T>(&mut self, key: &'static str, value: &T) -> Result<(), Self::Error>
     where
-        T: Serialize,
+        T: ?Sized + Serialize,
     {
         self.0.serialize_entry(key, value)
     }
@@ -1289,9 +1268,9 @@ where
     type Ok = ();
     type Error = M::Error;
 
-    fn serialize_field<T: ?Sized>(&mut self, value: &T) -> Result<(), Self::Error>
+    fn serialize_field<T>(&mut self, value: &T) -> Result<(), Self::Error>
     where
-        T: Serialize,
+        T: ?Sized + Serialize,
     {
         let value = tri!(value.serialize(ContentSerializer::<M::Error>::new()));
         self.fields.push(value);
@@ -1335,13 +1314,9 @@ where
     type Ok = ();
     type Error = M::Error;
 
-    fn serialize_field<T: ?Sized>(
-        &mut self,
-        key: &'static str,
-        value: &T,
-    ) -> Result<(), Self::Error>
+    fn serialize_field<T>(&mut self, key: &'static str, value: &T) -> Result<(), Self::Error>
     where
-        T: Serialize,
+        T: ?Sized + Serialize,
     {
         let value = tri!(value.serialize(ContentSerializer::<M::Error>::new()));
         self.fields.push((key, value));
@@ -1370,3 +1345,16 @@ impl Serialize for AdjacentlyTaggedEnumVariant {
         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);
+
+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)
+    }
+}

serde/src/ser/fmt.rs

@@ -35,7 +35,7 @@ macro_rules! fmt_primitives {
 ///     }
 /// }
 /// ```
-impl<'a, 'b> Serializer for &'a mut fmt::Formatter<'b> {
+impl<'a> Serializer for &mut fmt::Formatter<'a> {
     type Ok = ();
     type Error = fmt::Error;
     type SerializeSeq = Impossible<(), fmt::Error>;
@@ -52,10 +52,12 @@ impl<'a, 'b> Serializer for &'a mut fmt::Formatter<'b> {
         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,
@@ -63,13 +65,6 @@ impl<'a, 'b> Serializer for &'a mut fmt::Formatter<'b> {
         serialize_unit_struct: &'static str,
     }
 
-    serde_if_integer128! {
-        fmt_primitives! {
-            serialize_i128: i128,
-            serialize_u128: u128,
-        }
-    }
-
     fn serialize_unit_variant(
         self,
         _name: &'static str,
@@ -79,9 +74,9 @@ impl<'a, 'b> Serializer for &'a mut fmt::Formatter<'b> {
         Display::fmt(variant, self)
     }
 
-    fn serialize_newtype_struct<T: ?Sized>(self, _name: &'static str, value: &T) -> fmt::Result
+    fn serialize_newtype_struct<T>(self, _name: &'static str, value: &T) -> fmt::Result
     where
-        T: Serialize,
+        T: ?Sized + Serialize,
     {
         Serialize::serialize(value, self)
     }
@@ -94,9 +89,9 @@ impl<'a, 'b> Serializer for &'a mut fmt::Formatter<'b> {
         Err(fmt::Error)
     }
 
-    fn serialize_some<T: ?Sized>(self, _value: &T) -> fmt::Result
+    fn serialize_some<T>(self, _value: &T) -> fmt::Result
     where
-        T: Serialize,
+        T: ?Sized + Serialize,
     {
         Err(fmt::Error)
     }
@@ -105,7 +100,7 @@ impl<'a, 'b> Serializer for &'a mut fmt::Formatter<'b> {
         Err(fmt::Error)
     }
 
-    fn serialize_newtype_variant<T: ?Sized>(
+    fn serialize_newtype_variant<T>(
         self,
         _name: &'static str,
         _variant_index: u32,
@@ -113,7 +108,7 @@ impl<'a, 'b> Serializer for &'a mut fmt::Formatter<'b> {
         _value: &T,
     ) -> fmt::Result
     where
-        T: Serialize,
+        T: ?Sized + Serialize,
     {
         Err(fmt::Error)
     }
@@ -166,9 +161,9 @@ impl<'a, 'b> Serializer for &'a mut fmt::Formatter<'b> {
         Err(fmt::Error)
     }
 
-    fn collect_str<T: ?Sized>(self, value: &T) -> fmt::Result
+    fn collect_str<T>(self, value: &T) -> fmt::Result
     where
-        T: Display,
+        T: ?Sized + Display,
     {
         Display::fmt(value, self)
     }

serde/src/ser/impls.rs

@@ -24,20 +24,17 @@ 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 {
@@ -51,6 +48,7 @@ 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>
@@ -73,6 +71,7 @@ impl<'a> Serialize for fmt::Arguments<'a> {
 ////////////////////////////////////////////////////////////////////////////////
 
 #[cfg(any(feature = "std", not(no_core_cstr)))]
+#[cfg_attr(docsrs, doc(cfg(feature = "std")))]
 impl Serialize for CStr {
     #[inline]
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
@@ -84,6 +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"))))]
 impl Serialize for CString {
     #[inline]
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
@@ -114,7 +114,10 @@ where
 
 ////////////////////////////////////////////////////////////////////////////////
 
-impl<T: ?Sized> Serialize for PhantomData<T> {
+impl<T> Serialize for PhantomData<T>
+where
+    T: ?Sized,
+{
     #[inline]
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
     where
@@ -182,9 +185,13 @@ where
     }
 }
 
-#[cfg(all(any(feature = "std", feature = "alloc"), not(no_relaxed_trait_bounds)))]
+#[cfg(not(no_relaxed_trait_bounds))]
 macro_rules! seq_impl {
-    ($ty:ident <T $(: $tbound1:ident $(+ $tbound2:ident)*)* $(, $typaram:ident : $bound:ident)*>) => {
+    (
+        $(#[$attr:meta])*
+        $ty:ident <T $(: $tbound1:ident $(+ $tbound2:ident)*)* $(, $typaram:ident : $bound:ident)*>
+    ) => {
+        $(#[$attr])*
         impl<T $(, $typaram)*> Serialize for $ty<T $(, $typaram)*>
         where
             T: Serialize,
@@ -200,9 +207,13 @@ macro_rules! seq_impl {
     }
 }
 
-#[cfg(all(any(feature = "std", feature = "alloc"), no_relaxed_trait_bounds))]
+#[cfg(no_relaxed_trait_bounds)]
 macro_rules! seq_impl {
-    ($ty:ident <T $(: $tbound1:ident $(+ $tbound2:ident)*)* $(, $typaram:ident : $bound:ident)*>) => {
+    (
+        $(#[$attr:meta])*
+        $ty:ident <T $(: $tbound1:ident $(+ $tbound2:ident)*)* $(, $typaram:ident : $bound:ident)*>
+    ) => {
+        $(#[$attr])*
         impl<T $(, $typaram)*> Serialize for $ty<T $(, $typaram)*>
         where
             T: Serialize $(+ $tbound1 $(+ $tbound2)*)*,
@@ -219,23 +230,41 @@ macro_rules! seq_impl {
     }
 }
 
-#[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"))))]
+    BinaryHeap<T: Ord>
+}
 
-#[cfg(any(feature = "std", feature = "alloc"))]
-seq_impl!(BTreeSet<T: Ord>);
+seq_impl! {
+    #[cfg(any(feature = "std", feature = "alloc"))]
+    #[cfg_attr(docsrs, doc(cfg(any(feature = "std", feature = "alloc"))))]
+    BTreeSet<T: Ord>
+}
 
-#[cfg(feature = "std")]
-seq_impl!(HashSet<T: Eq + Hash, H: BuildHasher>);
+seq_impl! {
+    #[cfg(feature = "std")]
+    #[cfg_attr(docsrs, doc(cfg(feature = "std")))]
+    HashSet<T: Eq + Hash, H: BuildHasher>
+}
 
-#[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"))))]
+    LinkedList<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"))))]
+    Vec<T>
+}
 
-#[cfg(any(feature = "std", feature = "alloc"))]
-seq_impl!(VecDeque<T>);
+seq_impl! {
+    #[cfg(any(feature = "std", feature = "alloc"))]
+    #[cfg_attr(docsrs, doc(cfg(any(feature = "std", feature = "alloc"))))]
+    VecDeque<T>
+}
 
 ////////////////////////////////////////////////////////////////////////////////
 
@@ -342,6 +371,7 @@ 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
@@ -356,28 +386,46 @@ 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,)+
             {
-                #[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()
-                }
+                tuple_impl_body!($len => ($($n)+));
             }
         )+
-    }
+    };
+}
+
+macro_rules! tuple_impl_body {
+    ($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)
@@ -397,9 +445,13 @@ tuple_impls! {
 
 ////////////////////////////////////////////////////////////////////////////////
 
-#[cfg(all(any(feature = "std", feature = "alloc"), not(no_relaxed_trait_bounds)))]
+#[cfg(not(no_relaxed_trait_bounds))]
 macro_rules! map_impl {
-    ($ty:ident <K $(: $kbound1:ident $(+ $kbound2:ident)*)*, V $(, $typaram:ident : $bound:ident)*>) => {
+    (
+        $(#[$attr:meta])*
+        $ty:ident <K $(: $kbound1:ident $(+ $kbound2:ident)*)*, V $(, $typaram:ident : $bound:ident)*>
+    ) => {
+        $(#[$attr])*
         impl<K, V $(, $typaram)*> Serialize for $ty<K, V $(, $typaram)*>
         where
             K: Serialize,
@@ -416,9 +468,13 @@ macro_rules! map_impl {
     }
 }
 
-#[cfg(all(any(feature = "std", feature = "alloc"), no_relaxed_trait_bounds))]
+#[cfg(no_relaxed_trait_bounds)]
 macro_rules! map_impl {
-    ($ty:ident <K $(: $kbound1:ident $(+ $kbound2:ident)*)*, V $(, $typaram:ident : $bound:ident)*>) => {
+    (
+        $(#[$attr:meta])*
+        $ty:ident <K $(: $kbound1:ident $(+ $kbound2:ident)*)*, V $(, $typaram:ident : $bound:ident)*>
+    ) => {
+        $(#[$attr])*
         impl<K, V $(, $typaram)*> Serialize for $ty<K, V $(, $typaram)*>
         where
             K: Serialize $(+ $kbound1 $(+ $kbound2)*)*,
@@ -436,20 +492,26 @@ macro_rules! map_impl {
     }
 }
 
-#[cfg(any(feature = "std", feature = "alloc"))]
-map_impl!(BTreeMap<K: Ord, V>);
+map_impl! {
+    #[cfg(any(feature = "std", feature = "alloc"))]
+    #[cfg_attr(docsrs, doc(cfg(any(feature = "std", feature = "alloc"))))]
+    BTreeMap<K: Ord, V>
+}
 
-#[cfg(feature = "std")]
-map_impl!(HashMap<K: Eq + Hash, V, H: BuildHasher>);
+map_impl! {
+    #[cfg(feature = "std")]
+    #[cfg_attr(docsrs, doc(cfg(feature = "std")))]
+    HashMap<K: Eq + Hash, V, H: BuildHasher>
+}
 
 ////////////////////////////////////////////////////////////////////////////////
 
 macro_rules! deref_impl {
     (
-        $(#[doc = $doc:tt])*
+        $(#[$attr:meta])*
         <$($desc:tt)+
     ) => {
-        $(#[doc = $doc])*
+        $(#[$attr])*
         impl <$($desc)+ {
             #[inline]
             fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
@@ -462,13 +524,20 @@ macro_rules! deref_impl {
     };
 }
 
-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 T where T: ?Sized + Serialize
+}
 
-#[cfg(any(feature = "std", feature = "alloc"))]
-deref_impl!(<T: ?Sized> Serialize for Box<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(all(feature = "rc", any(feature = "std", feature = "alloc")))]
 deref_impl! {
     /// This impl requires the [`"rc"`] Cargo feature of Serde.
     ///
@@ -478,10 +547,11 @@ deref_impl! {
     /// repeated data.
     ///
     /// [`"rc"`]: https://serde.rs/feature-flags.html#-features-rc
-    <T: ?Sized> Serialize for Rc<T> where T: Serialize
+    #[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
 }
 
-#[cfg(all(feature = "rc", any(feature = "std", feature = "alloc")))]
 deref_impl! {
     /// This impl requires the [`"rc"`] Cargo feature of Serde.
     ///
@@ -491,11 +561,16 @@ deref_impl! {
     /// repeated data.
     ///
     /// [`"rc"`]: https://serde.rs/feature-flags.html#-features-rc
-    <T: ?Sized> Serialize for Arc<T> where T: Serialize
+    #[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
 }
 
-#[cfg(any(feature = "std", feature = "alloc"))]
-deref_impl!(<'a, T: ?Sized> Serialize for Cow<'a, T> where T: Serialize + ToOwned);
+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
+}
 
 ////////////////////////////////////////////////////////////////////////////////
 
@@ -503,9 +578,13 @@ deref_impl!(<'a, T: ?Sized> Serialize for Cow<'a, T> where T: Serialize + ToOwne
 ///
 /// [`"rc"`]: https://serde.rs/feature-flags.html#-features-rc
 #[cfg(all(feature = "rc", any(feature = "std", feature = "alloc")))]
-impl<T: ?Sized> Serialize for RcWeak<T>
+#[cfg_attr(
+    docsrs,
+    doc(cfg(all(feature = "rc", any(feature = "std", feature = "alloc"))))
+)]
+impl<T> Serialize for RcWeak<T>
 where
-    T: Serialize,
+    T: ?Sized + Serialize,
 {
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
     where
@@ -519,9 +598,13 @@ where
 ///
 /// [`"rc"`]: https://serde.rs/feature-flags.html#-features-rc
 #[cfg(all(feature = "rc", any(feature = "std", feature = "alloc")))]
-impl<T: ?Sized> Serialize for ArcWeak<T>
+#[cfg_attr(
+    docsrs,
+    doc(cfg(all(feature = "rc", any(feature = "std", feature = "alloc"))))
+)]
+impl<T> Serialize for ArcWeak<T>
 where
-    T: Serialize,
+    T: ?Sized + Serialize,
 {
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
     where
@@ -553,6 +636,7 @@ nonzero_integers! {
     NonZeroU16,
     NonZeroU32,
     NonZeroU64,
+    NonZeroU128,
     NonZeroUsize,
 }
 
@@ -562,22 +646,10 @@ nonzero_integers! {
     NonZeroI16,
     NonZeroI32,
     NonZeroI64,
+    NonZeroI128,
     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,
@@ -590,9 +662,9 @@ where
     }
 }
 
-impl<T: ?Sized> Serialize for RefCell<T>
+impl<T> Serialize for RefCell<T>
 where
-    T: Serialize,
+    T: ?Sized + Serialize,
 {
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
     where
@@ -606,9 +678,10 @@ where
 }
 
 #[cfg(feature = "std")]
-impl<T: ?Sized> Serialize for Mutex<T>
+#[cfg_attr(docsrs, doc(cfg(feature = "std")))]
+impl<T> Serialize for Mutex<T>
 where
-    T: Serialize,
+    T: ?Sized + Serialize,
 {
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
     where
@@ -622,9 +695,10 @@ where
 }
 
 #[cfg(feature = "std")]
-impl<T: ?Sized> Serialize for RwLock<T>
+#[cfg_attr(docsrs, doc(cfg(feature = "std")))]
+impl<T> Serialize for RwLock<T>
 where
-    T: Serialize,
+    T: ?Sized + Serialize,
 {
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
     where
@@ -675,6 +749,7 @@ impl Serialize for Duration {
 ////////////////////////////////////////////////////////////////////////////////
 
 #[cfg(feature = "std")]
+#[cfg_attr(docsrs, doc(cfg(feature = "std")))]
 impl Serialize for SystemTime {
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
     where
@@ -698,27 +773,17 @@ 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(feature = "std")]
+#[cfg(any(feature = "std", not(no_core_net)))]
 macro_rules! serialize_display_bounded_length {
     ($value:expr, $max:expr, $serializer:expr) => {{
         let mut buffer = [0u8; $max];
-        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)
+        let mut writer = crate::format::Buf::new(&mut buffer);
+        write!(&mut writer, "{}", $value).unwrap();
+        $serializer.serialize_str(writer.as_str())
     }};
 }
 
-#[cfg(feature = "std")]
+#[cfg(any(feature = "std", not(no_core_net)))]
 impl Serialize for net::IpAddr {
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
     where
@@ -742,7 +807,7 @@ impl Serialize for net::IpAddr {
     }
 }
 
-#[cfg(feature = "std")]
+#[cfg(any(feature = "std", not(no_core_net)))]
 const DEC_DIGITS_LUT: &[u8] = b"\
       0001020304050607080910111213141516171819\
       2021222324252627282930313233343536373839\
@@ -750,7 +815,7 @@ const DEC_DIGITS_LUT: &[u8] = b"\
       6061626364656667686970717273747576777879\
       8081828384858687888990919293949596979899";
 
-#[cfg(feature = "std")]
+#[cfg(any(feature = "std", not(no_core_net)))]
 #[inline]
 fn format_u8(mut n: u8, out: &mut [u8]) -> usize {
     if n >= 100 {
@@ -771,7 +836,7 @@ fn format_u8(mut n: u8, out: &mut [u8]) -> usize {
     }
 }
 
-#[cfg(feature = "std")]
+#[cfg(any(feature = "std", not(no_core_net)))]
 #[test]
 fn test_format_u8() {
     let mut i = 0u8;
@@ -788,7 +853,7 @@ fn test_format_u8() {
     }
 }
 
-#[cfg(feature = "std")]
+#[cfg(any(feature = "std", not(no_core_net)))]
 impl Serialize for net::Ipv4Addr {
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
     where
@@ -812,7 +877,7 @@ impl Serialize for net::Ipv4Addr {
     }
 }
 
-#[cfg(feature = "std")]
+#[cfg(any(feature = "std", not(no_core_net)))]
 impl Serialize for net::Ipv6Addr {
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
     where
@@ -828,7 +893,7 @@ impl Serialize for net::Ipv6Addr {
     }
 }
 
-#[cfg(feature = "std")]
+#[cfg(any(feature = "std", not(no_core_net)))]
 impl Serialize for net::SocketAddr {
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
     where
@@ -852,7 +917,7 @@ impl Serialize for net::SocketAddr {
     }
 }
 
-#[cfg(feature = "std")]
+#[cfg(any(feature = "std", not(no_core_net)))]
 impl Serialize for net::SocketAddrV4 {
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
     where
@@ -868,7 +933,7 @@ impl Serialize for net::SocketAddrV4 {
     }
 }
 
-#[cfg(feature = "std")]
+#[cfg(any(feature = "std", not(no_core_net)))]
 impl Serialize for net::SocketAddrV6 {
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
     where
@@ -890,6 +955,7 @@ impl Serialize for net::SocketAddrV6 {
 ////////////////////////////////////////////////////////////////////////////////
 
 #[cfg(feature = "std")]
+#[cfg_attr(docsrs, doc(cfg(feature = "std")))]
 impl Serialize for Path {
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
     where
@@ -903,6 +969,7 @@ impl Serialize for Path {
 }
 
 #[cfg(feature = "std")]
+#[cfg_attr(docsrs, doc(cfg(feature = "std")))]
 impl Serialize for PathBuf {
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
     where
@@ -913,6 +980,7 @@ impl Serialize for PathBuf {
 }
 
 #[cfg(all(feature = "std", any(unix, windows)))]
+#[cfg_attr(docsrs, doc(cfg(all(feature = "std", any(unix, windows)))))]
 impl Serialize for OsStr {
     #[cfg(unix)]
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
@@ -935,6 +1003,7 @@ impl Serialize for OsStr {
 }
 
 #[cfg(all(feature = "std", any(unix, windows)))]
+#[cfg_attr(docsrs, doc(cfg(all(feature = "std", any(unix, windows)))))]
 impl Serialize for OsString {
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
     where
@@ -959,6 +1028,20 @@ 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)
+    }
+}
+
 impl<T> Serialize for Reverse<T>
 where
     T: Serialize,
@@ -979,6 +1062,7 @@ macro_rules! atomic_impl {
     ($($ty:ident $size:expr)*) => {
         $(
             #[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

serde/src/ser/impossible.rs

@@ -72,9 +72,9 @@ where
     type Ok = Ok;
     type Error = Error;
 
-    fn serialize_element<T: ?Sized>(&mut self, value: &T) -> Result<(), Error>
+    fn serialize_element<T>(&mut self, value: &T) -> Result<(), Error>
     where
-        T: Serialize,
+        T: ?Sized + Serialize,
     {
         let _ = value;
         match self.void {}
@@ -92,9 +92,9 @@ where
     type Ok = Ok;
     type Error = Error;
 
-    fn serialize_element<T: ?Sized>(&mut self, value: &T) -> Result<(), Error>
+    fn serialize_element<T>(&mut self, value: &T) -> Result<(), Error>
     where
-        T: Serialize,
+        T: ?Sized + Serialize,
     {
         let _ = value;
         match self.void {}
@@ -112,9 +112,9 @@ where
     type Ok = Ok;
     type Error = Error;
 
-    fn serialize_field<T: ?Sized>(&mut self, value: &T) -> Result<(), Error>
+    fn serialize_field<T>(&mut self, value: &T) -> Result<(), Error>
     where
-        T: Serialize,
+        T: ?Sized + Serialize,
     {
         let _ = value;
         match self.void {}
@@ -132,9 +132,9 @@ where
     type Ok = Ok;
     type Error = Error;
 
-    fn serialize_field<T: ?Sized>(&mut self, value: &T) -> Result<(), Error>
+    fn serialize_field<T>(&mut self, value: &T) -> Result<(), Error>
     where
-        T: Serialize,
+        T: ?Sized + Serialize,
     {
         let _ = value;
         match self.void {}
@@ -152,17 +152,17 @@ where
     type Ok = Ok;
     type Error = Error;
 
-    fn serialize_key<T: ?Sized>(&mut self, key: &T) -> Result<(), Error>
+    fn serialize_key<T>(&mut self, key: &T) -> Result<(), Error>
     where
-        T: Serialize,
+        T: ?Sized + Serialize,
     {
         let _ = key;
         match self.void {}
     }
 
-    fn serialize_value<T: ?Sized>(&mut self, value: &T) -> Result<(), Error>
+    fn serialize_value<T>(&mut self, value: &T) -> Result<(), Error>
     where
-        T: Serialize,
+        T: ?Sized + Serialize,
     {
         let _ = value;
         match self.void {}
@@ -180,9 +180,9 @@ where
     type Ok = Ok;
     type Error = Error;
 
-    fn serialize_field<T: ?Sized>(&mut self, key: &'static str, value: &T) -> Result<(), Error>
+    fn serialize_field<T>(&mut self, key: &'static str, value: &T) -> Result<(), Error>
     where
-        T: Serialize,
+        T: ?Sized + Serialize,
     {
         let _ = key;
         let _ = value;
@@ -201,9 +201,9 @@ where
     type Ok = Ok;
     type Error = Error;
 
-    fn serialize_field<T: ?Sized>(&mut self, key: &'static str, value: &T) -> Result<(), Error>
+    fn serialize_field<T>(&mut self, key: &'static str, value: &T) -> Result<(), Error>
     where
-        T: Serialize,
+        T: ?Sized + Serialize,
     {
         let _ = key;
         let _ = value;

serde/src/ser/mod.rs

@@ -61,8 +61,8 @@
 //!    - 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\>
@@ -115,10 +115,10 @@ mod impossible;
 
 pub use self::impossible::Impossible;
 
-#[cfg(not(any(feature = "std", feature = "unstable")))]
+#[cfg(all(not(feature = "std"), no_core_error))]
 #[doc(no_inline)]
 pub use crate::std_error::Error as StdError;
-#[cfg(all(feature = "unstable", not(feature = "std")))]
+#[cfg(not(any(feature = "std", no_core_error)))]
 #[doc(no_inline)]
 pub use core::error::Error as StdError;
 #[cfg(feature = "std")]
@@ -215,6 +215,13 @@ declare_error_trait!(Error: Sized + Debug + Display);
 /// [`linked-hash-map`]: https://crates.io/crates/linked-hash-map
 /// [`serde_derive`]: https://crates.io/crates/serde_derive
 /// [derive section of the manual]: https://serde.rs/derive.html
+#[cfg_attr(
+    not(no_diagnostic_namespace),
+    diagnostic::on_unimplemented(
+        note = "for local types consider adding `#[derive(serde::Serialize)]` to your `{Self}` type",
+        note = "for types from other crates check whether the crate offers a `serde` feature flag",
+    )
+)]
 pub trait Serialize {
     /// Serialize this value into the given Serde serializer.
     ///
@@ -488,30 +495,27 @@ pub trait Serializer: Sized {
     /// ```
     fn serialize_i64(self, v: i64) -> Result<Self::Ok, Self::Error>;
 
-    serde_if_integer128! {
-        /// Serialize an `i128` value.
-        ///
-        /// ```edition2021
-        /// # use serde::Serializer;
-        /// #
-        /// # serde::__private_serialize!();
-        /// #
-        /// impl Serialize for i128 {
-        ///     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
-        ///     where
-        ///         S: Serializer,
-        ///     {
-        ///         serializer.serialize_i128(*self)
-        ///     }
-        /// }
-        /// ```
-        ///
-        /// This method is available only on Rust compiler versions >=1.26. The
-        /// default behavior unconditionally returns an error.
-        fn serialize_i128(self, v: i128) -> Result<Self::Ok, Self::Error> {
-            let _ = v;
-            Err(Error::custom("i128 is not supported"))
-        }
+    /// Serialize an `i128` value.
+    ///
+    /// ```edition2021
+    /// # use serde::Serializer;
+    /// #
+    /// # serde::__private_serialize!();
+    /// #
+    /// impl Serialize for i128 {
+    ///     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    ///     where
+    ///         S: Serializer,
+    ///     {
+    ///         serializer.serialize_i128(*self)
+    ///     }
+    /// }
+    /// ```
+    ///
+    /// The default behavior unconditionally returns an error.
+    fn serialize_i128(self, v: i128) -> Result<Self::Ok, Self::Error> {
+        let _ = v;
+        Err(Error::custom("i128 is not supported"))
     }
 
     /// Serialize a `u8` value.
@@ -598,30 +602,27 @@ pub trait Serializer: Sized {
     /// ```
     fn serialize_u64(self, v: u64) -> Result<Self::Ok, Self::Error>;
 
-    serde_if_integer128! {
-        /// Serialize a `u128` value.
-        ///
-        /// ```edition2021
-        /// # use serde::Serializer;
-        /// #
-        /// # serde::__private_serialize!();
-        /// #
-        /// impl Serialize for u128 {
-        ///     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
-        ///     where
-        ///         S: Serializer,
-        ///     {
-        ///         serializer.serialize_u128(*self)
-        ///     }
-        /// }
-        /// ```
-        ///
-        /// This method is available only on Rust compiler versions >=1.26. The
-        /// default behavior unconditionally returns an error.
-        fn serialize_u128(self, v: u128) -> Result<Self::Ok, Self::Error> {
-            let _ = v;
-            Err(Error::custom("u128 is not supported"))
-        }
+    /// Serialize a `u128` value.
+    ///
+    /// ```edition2021
+    /// # use serde::Serializer;
+    /// #
+    /// # serde::__private_serialize!();
+    /// #
+    /// impl Serialize for u128 {
+    ///     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    ///     where
+    ///         S: Serializer,
+    ///     {
+    ///         serializer.serialize_u128(*self)
+    ///     }
+    /// }
+    /// ```
+    ///
+    /// The default behavior unconditionally returns an error.
+    fn serialize_u128(self, v: u128) -> Result<Self::Ok, Self::Error> {
+        let _ = v;
+        Err(Error::custom("u128 is not supported"))
     }
 
     /// Serialize an `f32` value.
@@ -802,9 +803,9 @@ pub trait Serializer: Sized {
     /// ```
     ///
     /// [`Some(T)`]: https://doc.rust-lang.org/std/option/enum.Option.html#variant.Some
-    fn serialize_some<T: ?Sized>(self, value: &T) -> Result<Self::Ok, Self::Error>
+    fn serialize_some<T>(self, value: &T) -> Result<Self::Ok, Self::Error>
     where
-        T: Serialize;
+        T: ?Sized + Serialize;
 
     /// Serialize a `()` value.
     ///
@@ -897,13 +898,13 @@ pub trait Serializer: Sized {
     ///     }
     /// }
     /// ```
-    fn serialize_newtype_struct<T: ?Sized>(
+    fn serialize_newtype_struct<T>(
         self,
         name: &'static str,
         value: &T,
     ) -> Result<Self::Ok, Self::Error>
     where
-        T: Serialize;
+        T: ?Sized + Serialize;
 
     /// Serialize a newtype variant like `E::N` in `enum E { N(u8) }`.
     ///
@@ -931,7 +932,7 @@ pub trait Serializer: Sized {
     ///     }
     /// }
     /// ```
-    fn serialize_newtype_variant<T: ?Sized>(
+    fn serialize_newtype_variant<T>(
         self,
         name: &'static str,
         variant_index: u32,
@@ -939,7 +940,7 @@ pub trait Serializer: Sized {
         value: &T,
     ) -> Result<Self::Ok, Self::Error>
     where
-        T: Serialize;
+        T: ?Sized + Serialize;
 
     /// Begin to serialize a variably sized sequence. This call must be
     /// followed by zero or more calls to `serialize_element`, then a call to
@@ -1176,7 +1177,8 @@ pub trait Serializer: Sized {
     /// then a call to `end`.
     ///
     /// The `name` is the name of the struct and the `len` is the number of
-    /// data fields that will be serialized.
+    /// data fields that will be serialized. `len` does not include fields
+    /// which are skipped with [`SerializeStruct::skip_field`].
     ///
     /// ```edition2021
     /// use serde::ser::{Serialize, SerializeStruct, Serializer};
@@ -1213,6 +1215,8 @@ pub trait Serializer: Sized {
     /// The `name` is the name of the enum, the `variant_index` is the index of
     /// this variant within the enum, the `variant` is the name of the variant,
     /// and the `len` is the number of data fields that will be serialized.
+    /// `len` does not include fields which are skipped with
+    /// [`SerializeStructVariant::skip_field`].
     ///
     /// ```edition2021
     /// use serde::ser::{Serialize, SerializeStructVariant, Serializer};
@@ -1352,9 +1356,9 @@ pub trait Serializer: Sized {
     /// [`String`]: https://doc.rust-lang.org/std/string/struct.String.html
     /// [`serialize_str`]: #tymethod.serialize_str
     #[cfg(any(feature = "std", feature = "alloc"))]
-    fn collect_str<T: ?Sized>(self, value: &T) -> Result<Self::Ok, Self::Error>
+    fn collect_str<T>(self, value: &T) -> Result<Self::Ok, Self::Error>
     where
-        T: Display,
+        T: ?Sized + Display,
     {
         self.serialize_str(&value.to_string())
     }
@@ -1385,9 +1389,9 @@ pub trait Serializer: Sized {
     /// }
     /// ```
     #[cfg(not(any(feature = "std", feature = "alloc")))]
-    fn collect_str<T: ?Sized>(self, value: &T) -> Result<Self::Ok, Self::Error>
+    fn collect_str<T>(self, value: &T) -> Result<Self::Ok, Self::Error>
     where
-        T: Display;
+        T: ?Sized + Display;
 
     /// Determine whether `Serialize` implementations should serialize in
     /// human-readable form.
@@ -1499,9 +1503,9 @@ pub trait SerializeSeq {
     type Error: Error;
 
     /// Serialize a sequence element.
-    fn serialize_element<T: ?Sized>(&mut self, value: &T) -> Result<(), Self::Error>
+    fn serialize_element<T>(&mut self, value: &T) -> Result<(), Self::Error>
     where
-        T: Serialize;
+        T: ?Sized + Serialize;
 
     /// Finish serializing a sequence.
     fn end(self) -> Result<Self::Ok, Self::Error>;
@@ -1599,9 +1603,9 @@ pub trait SerializeTuple {
     type Error: Error;
 
     /// Serialize a tuple element.
-    fn serialize_element<T: ?Sized>(&mut self, value: &T) -> Result<(), Self::Error>
+    fn serialize_element<T>(&mut self, value: &T) -> Result<(), Self::Error>
     where
-        T: Serialize;
+        T: ?Sized + Serialize;
 
     /// Finish serializing a tuple.
     fn end(self) -> Result<Self::Ok, Self::Error>;
@@ -1644,9 +1648,9 @@ pub trait SerializeTupleStruct {
     type Error: Error;
 
     /// Serialize a tuple struct field.
-    fn serialize_field<T: ?Sized>(&mut self, value: &T) -> Result<(), Self::Error>
+    fn serialize_field<T>(&mut self, value: &T) -> Result<(), Self::Error>
     where
-        T: Serialize;
+        T: ?Sized + Serialize;
 
     /// Finish serializing a tuple struct.
     fn end(self) -> Result<Self::Ok, Self::Error>;
@@ -1702,9 +1706,9 @@ pub trait SerializeTupleVariant {
     type Error: Error;
 
     /// Serialize a tuple variant field.
-    fn serialize_field<T: ?Sized>(&mut self, value: &T) -> Result<(), Self::Error>
+    fn serialize_field<T>(&mut self, value: &T) -> Result<(), Self::Error>
     where
-        T: Serialize;
+        T: ?Sized + Serialize;
 
     /// Finish serializing a tuple variant.
     fn end(self) -> Result<Self::Ok, Self::Error>;
@@ -1773,9 +1777,9 @@ pub trait SerializeMap {
     /// `serialize_entry` instead as it may be implemented more efficiently in
     /// some formats compared to a pair of calls to `serialize_key` and
     /// `serialize_value`.
-    fn serialize_key<T: ?Sized>(&mut self, key: &T) -> Result<(), Self::Error>
+    fn serialize_key<T>(&mut self, key: &T) -> Result<(), Self::Error>
     where
-        T: Serialize;
+        T: ?Sized + Serialize;
 
     /// Serialize a map value.
     ///
@@ -1783,9 +1787,9 @@ pub trait SerializeMap {
     ///
     /// Calling `serialize_value` before `serialize_key` is incorrect and is
     /// allowed to panic or produce bogus results.
-    fn serialize_value<T: ?Sized>(&mut self, value: &T) -> Result<(), Self::Error>
+    fn serialize_value<T>(&mut self, value: &T) -> Result<(), Self::Error>
     where
-        T: Serialize;
+        T: ?Sized + Serialize;
 
     /// Serialize a map entry consisting of a key and a value.
     ///
@@ -1804,14 +1808,10 @@ pub trait SerializeMap {
     /// [`Serialize`]: ../trait.Serialize.html
     /// [`serialize_key`]: #tymethod.serialize_key
     /// [`serialize_value`]: #tymethod.serialize_value
-    fn serialize_entry<K: ?Sized, V: ?Sized>(
-        &mut self,
-        key: &K,
-        value: &V,
-    ) -> Result<(), Self::Error>
+    fn serialize_entry<K, V>(&mut self, key: &K, value: &V) -> Result<(), Self::Error>
     where
-        K: Serialize,
-        V: Serialize,
+        K: ?Sized + Serialize,
+        V: ?Sized + Serialize,
     {
         tri!(self.serialize_key(key));
         self.serialize_value(value)
@@ -1862,15 +1862,13 @@ pub trait SerializeStruct {
     type Error: Error;
 
     /// Serialize a struct field.
-    fn serialize_field<T: ?Sized>(
-        &mut self,
-        key: &'static str,
-        value: &T,
-    ) -> Result<(), Self::Error>
+    fn serialize_field<T>(&mut self, key: &'static str, value: &T) -> Result<(), Self::Error>
     where
-        T: Serialize;
+        T: ?Sized + Serialize;
 
     /// Indicate that a struct field has been skipped.
+    ///
+    /// The default implementation does nothing.
     #[inline]
     fn skip_field(&mut self, key: &'static str) -> Result<(), Self::Error> {
         let _ = key;
@@ -1928,15 +1926,13 @@ pub trait SerializeStructVariant {
     type Error: Error;
 
     /// Serialize a struct variant field.
-    fn serialize_field<T: ?Sized>(
-        &mut self,
-        key: &'static str,
-        value: &T,
-    ) -> Result<(), Self::Error>
+    fn serialize_field<T>(&mut self, key: &'static str, value: &T) -> Result<(), Self::Error>
     where
-        T: Serialize;
+        T: ?Sized + Serialize;
 
     /// Indicate that a struct variant field has been skipped.
+    ///
+    /// The default implementation does nothing.
     #[inline]
     fn skip_field(&mut self, key: &'static str) -> Result<(), Self::Error> {
         let _ = key;

serde_derive/Cargo.toml

@@ -1,16 +1,18 @@
 [package]
 name = "serde_derive"
-version = "1.0.183" # remember to update html_root_url
+version = "1.0.215"
 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 = "2015"
+exclude = ["build.rs"]
 homepage = "https://serde.rs"
 keywords = ["serde", "serialization", "no_std", "derive"]
 license = "MIT OR Apache-2.0"
 readme = "crates-io.md"
 repository = "https://github.com/serde-rs/serde"
-rust-version = "1.56"
+rust-version = "1.61"
 
 [features]
 default = []
@@ -21,9 +23,9 @@ name = "serde_derive"
 proc-macro = true
 
 [dependencies]
-proc-macro2 = "1.0"
-quote = "1.0"
-syn = "2.0.28"
+proc-macro2 = { workspace = true, features = ["proc-macro"] }
+quote = { workspace = true, features = ["proc-macro"] }
+syn = { workspace = true, features = ["clone-impls", "derive", "parsing", "printing", "proc-macro"] }
 
 [dev-dependencies]
 serde = { version = "1", path = "../serde" }

serde_derive/build.rs

@@ -0,0 +1,8 @@
+fn main() {
+    // Warning: build.rs is not published to crates.io.
+
+    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)");
+}

serde_derive/src/bound.rs

@@ -144,6 +144,7 @@ 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 {
@@ -181,7 +182,6 @@ pub fn with_bound(
 
                 syn::Type::Infer(_) | syn::Type::Never(_) | syn::Type::Verbatim(_) => {}
 
-                #[cfg_attr(all(test, exhaustive), deny(non_exhaustive_omitted_patterns))]
                 _ => {}
             }
         }
@@ -196,16 +196,13 @@ 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::Lifetime(_)
                             | syn::GenericArgument::Const(_)
                             | syn::GenericArgument::AssocConst(_)
                             | syn::GenericArgument::Constraint(_) => {}
-                            #[cfg_attr(
-                                all(test, exhaustive),
-                                deny(non_exhaustive_omitted_patterns)
-                            )]
                             _ => {}
                         }
                     }
@@ -228,9 +225,11 @@ 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::Verbatim(_) => {}
-                #[cfg_attr(all(test, exhaustive), deny(non_exhaustive_omitted_patterns))]
+                syn::TypeParamBound::Lifetime(_)
+                | syn::TypeParamBound::PreciseCapture(_)
+                | syn::TypeParamBound::Verbatim(_) => {}
                 _ => {}
             }
         }

serde_derive/src/de.rs

@@ -1,13 +1,12 @@
 use crate::fragment::{Expr, Fragment, Match, Stmts};
 use crate::internals::ast::{Container, Data, Field, Style, Variant};
+use crate::internals::name::Name;
 use crate::internals::{attr, replace_receiver, ungroup, Ctxt, Derive};
 use crate::{bound, dummy, pretend, this};
 use proc_macro2::{Literal, Span, TokenStream};
 use quote::{quote, quote_spanned, ToTokens};
 use std::collections::BTreeSet;
 use std::ptr;
-#[cfg(precompiled)]
-use std::sync::atomic::Ordering;
 use syn::punctuated::Punctuated;
 use syn::spanned::Spanned;
 use syn::{parse_quote, Ident, Index, Member};
@@ -301,11 +300,6 @@ fn deserialize_body(cont: &Container, params: &Parameters) -> Fragment {
 
 #[cfg(feature = "deserialize_in_place")]
 fn deserialize_in_place_body(cont: &Container, params: &Parameters) -> Option<Stmts> {
-    #[cfg(precompiled)]
-    if !crate::DESERIALIZE_IN_PLACE.load(Ordering::Relaxed) {
-        return None;
-    }
-
     // Only remote derives have getters, and we do not generate
     // deserialize_in_place for remote derives.
     assert!(!params.has_getter);
@@ -378,7 +372,11 @@ fn deserialize_transparent(cont: &Container, params: &Parameters) -> Fragment {
         } else {
             let value = match field.attrs.default() {
                 attr::Default::Default => quote!(_serde::__private::Default::default()),
-                attr::Default::Path(path) => quote!(#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(default = "...")]
+                //                          ^^^^^
+                attr::Default::Path(path) => quote_spanned!(path.span()=> #path()),
                 attr::Default::None => quote!(_serde::__private::PhantomData),
             };
             quote!(#member: #value)
@@ -468,7 +466,10 @@ fn deserialize_tuple(
     cattrs: &attr::Container,
     form: TupleForm,
 ) -> Fragment {
-    assert!(!cattrs.has_flatten());
+    assert!(
+        !has_flatten(fields),
+        "tuples and tuple variants cannot have flatten fields"
+    );
 
     let field_count = fields
         .iter()
@@ -586,7 +587,10 @@ fn deserialize_tuple_in_place(
     fields: &[Field],
     cattrs: &attr::Container,
 ) -> Fragment {
-    assert!(!cattrs.has_flatten());
+    assert!(
+        !has_flatten(fields),
+        "tuples and tuple variants cannot have flatten fields"
+    );
 
     let field_count = fields
         .iter()
@@ -758,7 +762,11 @@ fn deserialize_seq(
         attr::Default::Default => Some(quote!(
             let __default: Self::Value = _serde::__private::Default::default();
         )),
-        attr::Default::Path(path) => Some(quote!(
+        // 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 => {
@@ -840,7 +848,11 @@ fn deserialize_seq_in_place(
         attr::Default::Default => Some(quote!(
             let __default: #this_type #ty_generics = _serde::__private::Default::default();
         )),
-        attr::Default::Path(path) => Some(quote!(
+        // 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 => {
@@ -864,18 +876,23 @@ fn deserialize_newtype_struct(
 ) -> 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(__e)?
+                #func(#deserializer_var)?
             }
         }
         Some(path) => {
-            quote! {
-                #path(__e)?
+            // 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)?
             }
         }
     };
@@ -891,7 +908,7 @@ fn deserialize_newtype_struct(
 
     quote! {
         #[inline]
-        fn visit_newtype_struct<__E>(self, __e: __E) -> _serde::__private::Result<Self::Value, __E::Error>
+        fn visit_newtype_struct<__E>(self, #deserializer_var: __E) -> _serde::__private::Result<Self::Value, __E::Error>
         where
             __E: _serde::Deserializer<#delife>,
         {
@@ -951,29 +968,28 @@ fn deserialize_struct(
     };
     let expecting = cattrs.expecting().unwrap_or(&expecting);
 
-    let field_names_idents: Vec<_> = fields
+    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)| {
-            (
-                field.attrs.name().deserialize_name(),
-                field_i(i),
-                field.attrs.aliases(),
-            )
+        .map(|(i, field)| FieldWithAliases {
+            ident: field_i(i),
+            aliases: field.attrs.aliases(),
         })
         .collect();
-    let field_visitor = deserialize_field_identifier(&field_names_idents, cattrs);
+
+    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 cattrs.has_flatten() => None,
+        _ if has_flatten => None,
         _ => {
-            let mut_seq = if field_names_idents.is_empty() {
+            let mut_seq = if deserialized_fields.is_empty() {
                 quote!(_)
             } else {
                 quote!(mut __seq)
@@ -994,10 +1010,16 @@ fn deserialize_struct(
             })
         }
     };
-    let visit_map = Stmts(deserialize_map(&type_path, params, fields, cattrs));
+    let visit_map = Stmts(deserialize_map(
+        &type_path,
+        params,
+        fields,
+        cattrs,
+        has_flatten,
+    ));
 
     let visitor_seed = match form {
-        StructForm::ExternallyTagged(..) if cattrs.has_flatten() => Some(quote! {
+        StructForm::ExternallyTagged(..) if has_flatten => Some(quote! {
             impl #de_impl_generics _serde::de::DeserializeSeed<#delife> for __Visitor #de_ty_generics #where_clause {
                 type Value = #this_type #ty_generics;
 
@@ -1012,12 +1034,10 @@ fn deserialize_struct(
         _ => None,
     };
 
-    let fields_stmt = if cattrs.has_flatten() {
+    let fields_stmt = if has_flatten {
         None
     } else {
-        let field_names = field_names_idents
-            .iter()
-            .flat_map(|&(_, _, aliases)| aliases);
+        let field_names = deserialized_fields.iter().flat_map(|field| field.aliases);
 
         Some(quote! {
             #[doc(hidden)]
@@ -1032,7 +1052,7 @@ fn deserialize_struct(
         }
     };
     let dispatch = match form {
-        StructForm::Struct if cattrs.has_flatten() => quote! {
+        StructForm::Struct if has_flatten => quote! {
             _serde::Deserializer::deserialize_map(__deserializer, #visitor_expr)
         },
         StructForm::Struct => {
@@ -1041,7 +1061,7 @@ fn deserialize_struct(
                 _serde::Deserializer::deserialize_struct(__deserializer, #type_name, FIELDS, #visitor_expr)
             }
         }
-        StructForm::ExternallyTagged(_) if cattrs.has_flatten() => quote! {
+        StructForm::ExternallyTagged(_) if has_flatten => quote! {
             _serde::de::VariantAccess::newtype_variant_seed(__variant, #visitor_expr)
         },
         StructForm::ExternallyTagged(_) => quote! {
@@ -1098,7 +1118,7 @@ fn deserialize_struct_in_place(
 ) -> Option<Fragment> {
     // for now we do not support in_place deserialization for structs that
     // are represented as map.
-    if cattrs.has_flatten() {
+    if has_flatten(fields) {
         return None;
     }
 
@@ -1110,31 +1130,26 @@ fn deserialize_struct_in_place(
     let expecting = format!("struct {}", params.type_name());
     let expecting = cattrs.expecting().unwrap_or(&expecting);
 
-    let field_names_idents: Vec<_> = fields
+    let deserialized_fields: Vec<_> = fields
         .iter()
         .enumerate()
         .filter(|&(_, field)| !field.attrs.skip_deserializing())
-        .map(|(i, field)| {
-            (
-                field.attrs.name().deserialize_name(),
-                field_i(i),
-                field.attrs.aliases(),
-            )
+        .map(|(i, field)| FieldWithAliases {
+            ident: field_i(i),
+            aliases: field.attrs.aliases(),
         })
         .collect();
 
-    let field_visitor = deserialize_field_identifier(&field_names_idents, cattrs);
+    let field_visitor = deserialize_field_identifier(&deserialized_fields, cattrs, false);
 
-    let mut_seq = if field_names_idents.is_empty() {
+    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 = field_names_idents
-        .iter()
-        .flat_map(|&(_, _, aliases)| aliases);
+    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();
@@ -1217,44 +1232,40 @@ fn deserialize_homogeneous_enum(
     }
 }
 
-fn prepare_enum_variant_enum(
-    variants: &[Variant],
-    cattrs: &attr::Container,
-) -> (TokenStream, Stmts) {
-    let mut deserialized_variants = variants
+fn prepare_enum_variant_enum(variants: &[Variant]) -> (TokenStream, Stmts) {
+    let deserialized_variants = variants
         .iter()
         .enumerate()
-        .filter(|&(_, variant)| !variant.attrs.skip_deserializing());
-
-    let variant_names_idents: Vec<_> = deserialized_variants
-        .clone()
-        .map(|(i, variant)| {
-            (
-                variant.attrs.name().deserialize_name(),
-                field_i(i),
-                variant.attrs.aliases(),
-            )
-        })
-        .collect();
+        .filter(|&(_i, variant)| !variant.attrs.skip_deserializing());
 
     let fallthrough = deserialized_variants
-        .position(|(_, variant)| variant.attrs.other())
-        .map(|other_idx| {
-            let ignore_variant = variant_names_idents[other_idx].1.clone();
+        .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 = variant_names_idents.iter().map(|(name, _, _)| name);
+        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(deserialize_generated_identifier(
-        &variant_names_idents,
-        cattrs,
+        &deserialized_variants,
+        false, // variant identifiers do not depend on the presence of flatten fields
         true,
         None,
         fallthrough,
@@ -1277,7 +1288,7 @@ fn deserialize_externally_tagged_enum(
     let expecting = format!("enum {}", params.type_name());
     let expecting = cattrs.expecting().unwrap_or(&expecting);
 
-    let (variants_stmt, variant_visitor) = prepare_enum_variant_enum(variants, cattrs);
+    let (variants_stmt, variant_visitor) = prepare_enum_variant_enum(variants);
 
     // Match arms to extract a variant from a string
     let variant_arms = variants
@@ -1362,7 +1373,7 @@ fn deserialize_internally_tagged_enum(
     cattrs: &attr::Container,
     tag: &str,
 ) -> Fragment {
-    let (variants_stmt, variant_visitor) = prepare_enum_variant_enum(variants, cattrs);
+    let (variants_stmt, variant_visitor) = prepare_enum_variant_enum(variants);
 
     // Match arms to extract a variant from a string
     let variant_arms = variants
@@ -1416,7 +1427,7 @@ fn deserialize_adjacently_tagged_enum(
         split_with_de_lifetime(params);
     let delife = params.borrowed.de_lifetime();
 
-    let (variants_stmt, variant_visitor) = prepare_enum_variant_enum(variants, cattrs);
+    let (variants_stmt, variant_visitor) = prepare_enum_variant_enum(variants);
 
     let variant_arms: &Vec<_> = &variants
         .iter()
@@ -1744,7 +1755,6 @@ fn deserialize_untagged_enum_after(
                 quote!(__deserializer),
             ))
         });
-    let attempts = first_attempt.into_iter().chain(attempts);
     // 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
@@ -1757,10 +1767,23 @@ fn deserialize_untagged_enum_after(
     );
     let fallthrough_msg = cattrs.expecting().unwrap_or(&fallthrough_msg);
 
+    // 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 = first_attempt.map(|expr| {
+        quote! {
+            if let _serde::__private::Result::<_, __D::Error>::Ok(__ok) = (|| #expr)() {
+                return _serde::__private::Ok(__ok);
+            }
+        }
+    });
+
     quote_block! {
         let __content = <_serde::__private::de::Content as _serde::Deserialize>::deserialize(__deserializer)?;
         let __deserializer = _serde::__private::de::ContentRefDeserializer::<__D::Error>::new(&__content);
 
+        #first_attempt
+
         #(
             if let _serde::__private::Ok(__ok) = #attempts {
                 return _serde::__private::Ok(__ok);
@@ -1835,7 +1858,7 @@ fn deserialize_internally_tagged_variant(
             let this_value = &params.this_value;
             let type_name = params.type_name();
             let variant_name = variant.ident.to_string();
-            let default = variant.fields.get(0).map(|field| {
+            let default = variant.fields.first().map(|field| {
                 let default = Expr(expr_is_missing(field, cattrs));
                 quote!((#default))
             });
@@ -1880,7 +1903,7 @@ fn deserialize_untagged_variant(
             let this_value = &params.this_value;
             let type_name = params.type_name();
             let variant_name = variant.ident.to_string();
-            let default = variant.fields.get(0).map(|field| {
+            let default = variant.fields.first().map(|field| {
                 let default = Expr(expr_is_missing(field, cattrs));
                 quote!((#default))
             });
@@ -1978,27 +2001,35 @@ fn deserialize_untagged_newtype_variant(
     }
 }
 
+struct FieldWithAliases<'a> {
+    ident: Ident,
+    aliases: &'a BTreeSet<Name>,
+}
+
 fn deserialize_generated_identifier(
-    fields: &[(&str, Ident, &BTreeSet<String>)],
-    cattrs: &attr::Container,
+    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<_> = &fields.iter().map(|(_, ident, _)| ident).collect();
+    let field_idents: &Vec<_> = &deserialized_fields
+        .iter()
+        .map(|field| &field.ident)
+        .collect();
 
     let visitor_impl = Stmts(deserialize_identifier(
         &this_value,
-        fields,
+        deserialized_fields,
         is_variant,
         fallthrough,
         None,
-        !is_variant && cattrs.has_flatten(),
+        !is_variant && has_flatten,
         None,
     ));
 
-    let lifetime = if !is_variant && cattrs.has_flatten() {
+    let lifetime = if !is_variant && has_flatten {
         Some(quote!(<'de>))
     } else {
         None
@@ -2036,10 +2067,11 @@ fn deserialize_generated_identifier(
 /// Generates enum and its `Deserialize` implementation that represents each
 /// non-skipped field of the struct
 fn deserialize_field_identifier(
-    fields: &[(&str, Ident, &BTreeSet<String>)],
+    deserialized_fields: &[FieldWithAliases],
     cattrs: &attr::Container,
+    has_flatten: bool,
 ) -> Stmts {
-    let (ignore_variant, fallthrough) = if cattrs.has_flatten() {
+    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))
@@ -2052,8 +2084,8 @@ fn deserialize_field_identifier(
     };
 
     Stmts(deserialize_generated_identifier(
-        fields,
-        cattrs,
+        deserialized_fields,
+        has_flatten,
         false,
         ignore_variant,
         fallthrough,
@@ -2110,18 +2142,15 @@ fn deserialize_custom_identifier(
         (variants, None, None)
     };
 
-    let names_idents: Vec<_> = ordinary
+    let idents_aliases: Vec<_> = ordinary
         .iter()
-        .map(|variant| {
-            (
-                variant.attrs.name().deserialize_name(),
-                variant.ident.clone(),
-                variant.attrs.aliases(),
-            )
+        .map(|variant| FieldWithAliases {
+            ident: variant.ident.clone(),
+            aliases: variant.attrs.aliases(),
         })
         .collect();
 
-    let names = names_idents.iter().flat_map(|&(_, _, aliases)| aliases);
+    let names = idents_aliases.iter().flat_map(|variant| variant.aliases);
 
     let names_const = if fallthrough.is_some() {
         None
@@ -2144,7 +2173,7 @@ fn deserialize_custom_identifier(
     let delife = params.borrowed.de_lifetime();
     let visitor_impl = Stmts(deserialize_identifier(
         &this_value,
-        &names_idents,
+        &idents_aliases,
         is_variant,
         fallthrough,
         fallthrough_borrowed,
@@ -2177,23 +2206,35 @@ fn deserialize_custom_identifier(
 
 fn deserialize_identifier(
     this_value: &TokenStream,
-    fields: &[(&str, Ident, &BTreeSet<String>)],
+    deserialized_fields: &[FieldWithAliases],
     is_variant: bool,
     fallthrough: Option<TokenStream>,
     fallthrough_borrowed: Option<TokenStream>,
     collect_other_fields: bool,
     expecting: Option<&str>,
 ) -> Fragment {
-    let str_mapping = fields.iter().map(|(_, ident, aliases)| {
+    let str_mapping = deserialized_fields.iter().map(|field| {
+        let ident = &field.ident;
+        let aliases = field.aliases;
         // `aliases` also contains a main name
-        quote!(#(#aliases)|* => _serde::__private::Ok(#this_value::#ident))
+        quote! {
+            #(
+                #aliases => _serde::__private::Ok(#this_value::#ident),
+            )*
+        }
     });
-    let bytes_mapping = fields.iter().map(|(_, ident, aliases)| {
+    let bytes_mapping = deserialized_fields.iter().map(|field| {
+        let ident = &field.ident;
         // `aliases` also contains a main name
-        let aliases = aliases
+        let aliases = field
+            .aliases
             .iter()
-            .map(|alias| Literal::byte_string(alias.as_bytes()));
-        quote!(#(#aliases)|* => _serde::__private::Ok(#this_value::#ident))
+            .map(|alias| Literal::byte_string(alias.value.as_bytes()));
+        quote! {
+            #(
+                #aliases => _serde::__private::Ok(#this_value::#ident),
+            )*
+        }
     });
 
     let expecting = expecting.unwrap_or(if is_variant {
@@ -2343,8 +2384,9 @@ fn deserialize_identifier(
             }
         }
     } else {
-        let u64_mapping = fields.iter().enumerate().map(|(i, (_, ident, _))| {
+        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))
         });
 
@@ -2353,7 +2395,11 @@ fn deserialize_identifier(
             fallthrough
         } else {
             let index_expecting = if is_variant { "variant" } else { "field" };
-            let fallthrough_msg = format!("{} index 0 <= i < {}", index_expecting, fields.len());
+            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),
@@ -2386,7 +2432,7 @@ fn deserialize_identifier(
                 __E: _serde::de::Error,
             {
                 match __value {
-                    #(#str_mapping,)*
+                    #(#str_mapping)*
                     _ => {
                         #value_as_borrowed_str_content
                         #fallthrough_borrowed_arm
@@ -2399,7 +2445,7 @@ fn deserialize_identifier(
                 __E: _serde::de::Error,
             {
                 match __value {
-                    #(#bytes_mapping,)*
+                    #(#bytes_mapping)*
                     _ => {
                         #bytes_to_str
                         #value_as_borrowed_bytes_content
@@ -2424,7 +2470,7 @@ fn deserialize_identifier(
             __E: _serde::de::Error,
         {
             match __value {
-                #(#str_mapping,)*
+                #(#str_mapping)*
                 _ => {
                     #value_as_str_content
                     #fallthrough_arm
@@ -2437,7 +2483,7 @@ fn deserialize_identifier(
             __E: _serde::de::Error,
         {
             match __value {
-                #(#bytes_mapping,)*
+                #(#bytes_mapping)*
                 _ => {
                     #bytes_to_str
                     #value_as_bytes_content
@@ -2455,6 +2501,7 @@ fn deserialize_map(
     params: &Parameters,
     fields: &[Field],
     cattrs: &attr::Container,
+    has_flatten: bool,
 ) -> Fragment {
     // Create the field names for the fields.
     let fields_names: Vec<_> = fields
@@ -2475,7 +2522,7 @@ fn deserialize_map(
         });
 
     // Collect contents for flatten fields into a buffer
-    let let_collect = if cattrs.has_flatten() {
+    let let_collect = if has_flatten {
         Some(quote! {
             let mut __collect = _serde::__private::Vec::<_serde::__private::Option<(
                 _serde::__private::de::Content,
@@ -2527,7 +2574,7 @@ fn deserialize_map(
         });
 
     // Visit ignored values to consume them
-    let ignored_arm = if cattrs.has_flatten() {
+    let ignored_arm = if has_flatten {
         Some(quote! {
             __Field::__other(__name) => {
                 __collect.push(_serde::__private::Some((
@@ -2597,7 +2644,7 @@ fn deserialize_map(
             }
         });
 
-    let collected_deny_unknown_fields = if cattrs.has_flatten() && cattrs.deny_unknown_fields() {
+    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()
@@ -2629,7 +2676,11 @@ fn deserialize_map(
         attr::Default::Default => Some(quote!(
             let __default: Self::Value = _serde::__private::Default::default();
         )),
-        attr::Default::Path(path) => Some(quote!(
+        // 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 => {
@@ -2673,7 +2724,10 @@ fn deserialize_map_in_place(
     fields: &[Field],
     cattrs: &attr::Container,
 ) -> Fragment {
-    assert!(!cattrs.has_flatten());
+    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
@@ -2796,7 +2850,11 @@ fn deserialize_map_in_place(
         attr::Default::Default => Some(quote!(
             let __default: #this_type #ty_generics = _serde::__private::Default::default();
         )),
-        attr::Default::Path(path) => Some(quote!(
+        // 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 => {
@@ -2834,7 +2892,15 @@ fn wrap_deserialize_with(
     let (de_impl_generics, de_ty_generics, ty_generics, where_clause) =
         split_with_de_lifetime(params);
     let delife = params.borrowed.de_lifetime();
+    let deserializer_var = quote!(__deserializer);
 
+    // If #deserialize_with 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 = "...")]
+    //                       ^^^^^
+    let value = quote_spanned! {deserialize_with.span()=>
+        #deserialize_with(#deserializer_var)?
+    };
     let wrapper = quote! {
         #[doc(hidden)]
         struct __DeserializeWith #de_impl_generics #where_clause {
@@ -2844,12 +2910,12 @@ fn wrap_deserialize_with(
         }
 
         impl #de_impl_generics _serde::Deserialize<#delife> for __DeserializeWith #de_ty_generics #where_clause {
-            fn deserialize<__D>(__deserializer: __D) -> _serde::__private::Result<Self, __D::Error>
+            fn deserialize<__D>(#deserializer_var: __D) -> _serde::__private::Result<Self, __D::Error>
             where
                 __D: _serde::Deserializer<#delife>,
             {
                 _serde::__private::Ok(__DeserializeWith {
-                    value: #deserialize_with(__deserializer)?,
+                    value: #value,
                     phantom: _serde::__private::PhantomData,
                     lifetime: _serde::__private::PhantomData,
                 })
@@ -2940,7 +3006,11 @@ fn expr_is_missing(field: &Field, cattrs: &attr::Container) -> Fragment {
             return quote_expr!(#func());
         }
         attr::Default::Path(path) => {
-            return quote_expr!(#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(default = "...")]
+            //                          ^^^^^
+            return Fragment::Expr(quote_spanned!(path.span()=> #path()));
         }
         attr::Default::None => { /* below */ }
     }
@@ -2983,6 +3053,10 @@ fn expr_is_missing_seq(
             return quote_spanned!(span=> #assign_to _serde::__private::Default::default());
         }
         attr::Default::Path(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(default = "...")]
+            //                          ^^^^^
             return quote_spanned!(path.span()=> #assign_to #path());
         }
         attr::Default::None => { /* below */ }
@@ -3006,6 +3080,14 @@ fn effective_style(variant: &Variant) -> Style {
     }
 }
 
+/// True if there is any field with a `#[serde(flatten)]` attribute, other than
+/// fields which are skipped.
+fn has_flatten(fields: &[Field]) -> bool {
+    fields
+        .iter()
+        .any(|field| field.attrs.flatten() && !field.attrs.skip_deserializing())
+}
+
 struct DeImplGenerics<'a>(&'a Parameters);
 #[cfg(feature = "deserialize_in_place")]
 struct InPlaceImplGenerics<'a>(&'a Parameters);

serde_derive/src/internals/ast.rs

@@ -63,7 +63,7 @@ impl<'a> Container<'a> {
         item: &'a syn::DeriveInput,
         derive: Derive,
     ) -> Option<Container<'a>> {
-        let mut attrs = attr::Container::from_ast(cx, item);
+        let 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())),
@@ -77,15 +77,11 @@ 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 {
-                        if field.attrs.flatten() {
-                            has_flatten = true;
-                        }
                         field.attrs.rename_by_rules(
                             variant
                                 .attrs
@@ -97,18 +93,11 @@ impl<'a> Container<'a> {
             }
             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,

serde_derive/src/internals/attr.rs

@@ -1,3 +1,4 @@
+use crate::internals::name::{MultiName, Name};
 use crate::internals::symbol::*;
 use crate::internals::{ungroup, Ctxt};
 use proc_macro2::{Spacing, Span, TokenStream, TokenTree};
@@ -8,6 +9,7 @@ use std::iter::FromIterator;
 use syn::meta::ParseNestedMeta;
 use syn::parse::ParseStream;
 use syn::punctuated::Punctuated;
+use syn::spanned::Spanned;
 use syn::{parse_quote, token, Ident, Lifetime, Token};
 
 // This module handles parsing of `#[serde(...)]` attributes. The entrypoints
@@ -20,7 +22,7 @@ use syn::{parse_quote, token, Ident, Lifetime, Token};
 
 pub use crate::internals::case::RenameRule;
 
-struct Attr<'c, T> {
+pub(crate) struct Attr<'c, T> {
     cx: &'c Ctxt,
     name: Symbol,
     tokens: TokenStream,
@@ -61,7 +63,7 @@ impl<'c, T> Attr<'c, T> {
         }
     }
 
-    fn get(self) -> Option<T> {
+    pub(crate) fn get(self) -> Option<T> {
         self.value
     }
 
@@ -89,7 +91,7 @@ impl<'c> BoolAttr<'c> {
     }
 }
 
-struct VecAttr<'c, T> {
+pub(crate) struct VecAttr<'c, T> {
     cx: &'c Ctxt,
     name: Symbol,
     first_dup_tokens: TokenStream,
@@ -124,69 +126,19 @@ impl<'c, T> VecAttr<'c, T> {
         }
     }
 
-    fn get(self) -> Vec<T> {
+    pub(crate) fn get(self) -> Vec<T> {
         self.values
     }
 }
 
-pub struct Name {
-    serialize: String,
-    serialize_renamed: bool,
-    deserialize: String,
-    deserialize_renamed: bool,
-    deserialize_aliases: BTreeSet<String>,
-}
-
-fn unraw(ident: &Ident) -> String {
-    ident.to_string().trim_start_matches("r#").to_owned()
-}
-
-impl Name {
-    fn from_attrs(
-        source_name: String,
-        ser_name: Attr<String>,
-        de_name: Attr<String>,
-        de_aliases: Option<VecAttr<String>>,
-    ) -> Name {
-        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();
-        Name {
-            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) -> &str {
-        &self.serialize
-    }
-
-    /// Return the container name for the container when deserializing.
-    pub fn deserialize_name(&self) -> &str {
-        &self.deserialize
-    }
-
-    fn deserialize_aliases(&self) -> &BTreeSet<String> {
-        &self.deserialize_aliases
-    }
+fn unraw(ident: &Ident) -> Ident {
+    Ident::new(ident.to_string().trim_start_matches("r#"), ident.span())
 }
 
 #[derive(Copy, Clone)]
 pub struct RenameAllRules {
-    serialize: RenameRule,
-    deserialize: RenameRule,
+    pub serialize: RenameRule,
+    pub deserialize: RenameRule,
 }
 
 impl RenameAllRules {
@@ -202,7 +154,7 @@ impl RenameAllRules {
 
 /// Represents struct or enum attribute information.
 pub struct Container {
-    name: Name,
+    name: MultiName,
     transparent: bool,
     deny_unknown_fields: bool,
     default: Default,
@@ -216,11 +168,11 @@ pub struct Container {
     type_into: Option<syn::Type>,
     remote: Option<syn::Path>,
     identifier: Identifier,
-    has_flatten: bool,
     serde_path: Option<syn::Path>,
     is_packed: bool,
     /// Error message generated when type can't be deserialized
     expecting: Option<String>,
+    non_exhaustive: bool,
 }
 
 /// Styles of representing an enum.
@@ -306,9 +258,12 @@ impl Container {
         let mut variant_identifier = BoolAttr::none(cx, VARIANT_IDENTIFIER);
         let mut serde_path = Attr::none(cx, CRATE);
         let mut expecting = Attr::none(cx, EXPECTING);
+        let mut non_exhaustive = false;
 
         for attr in &item.attrs {
             if attr.path() != SERDE {
+                non_exhaustive |=
+                    matches!(&attr.meta, syn::Meta::Path(path) if path == NON_EXHAUSTIVE);
                 continue;
             }
 
@@ -323,8 +278,8 @@ impl Container {
                     // #[serde(rename = "foo")]
                     // #[serde(rename(serialize = "foo", deserialize = "bar"))]
                     let (ser, de) = get_renames(cx, RENAME, &meta)?;
-                    ser_name.set_opt(&meta.path, ser.as_ref().map(syn::LitStr::value));
-                    de_name.set_opt(&meta.path, de.as_ref().map(syn::LitStr::value));
+                    ser_name.set_opt(&meta.path, ser.as_ref().map(Name::from));
+                    de_name.set_opt(&meta.path, de.as_ref().map(Name::from));
                 } else if meta.path == RENAME_ALL {
                     // #[serde(rename_all = "foo")]
                     // #[serde(rename_all(serialize = "foo", deserialize = "bar"))]
@@ -563,7 +518,7 @@ impl Container {
         }
 
         Container {
-            name: Name::from_attrs(unraw(&item.ident), ser_name, de_name, None),
+            name: MultiName::from_attrs(Name::from(&unraw(&item.ident)), ser_name, de_name, None),
             transparent: transparent.get(),
             deny_unknown_fields: deny_unknown_fields.get(),
             default: default.get().unwrap_or(Default::None),
@@ -583,14 +538,14 @@ impl Container {
             type_into: type_into.get(),
             remote: remote.get(),
             identifier: decide_identifier(cx, item, field_identifier, variant_identifier),
-            has_flatten: false,
             serde_path: serde_path.get(),
             is_packed,
             expecting: expecting.get(),
+            non_exhaustive,
         }
     }
 
-    pub fn name(&self) -> &Name {
+    pub fn name(&self) -> &MultiName {
         &self.name
     }
 
@@ -650,14 +605,6 @@ impl Container {
         self.identifier
     }
 
-    pub fn has_flatten(&self) -> bool {
-        self.has_flatten
-    }
-
-    pub fn mark_has_flatten(&mut self) {
-        self.has_flatten = true;
-    }
-
     pub fn custom_serde_path(&self) -> Option<&syn::Path> {
         self.serde_path.as_ref()
     }
@@ -672,6 +619,10 @@ impl Container {
     pub fn expecting(&self) -> Option<&str> {
         self.expecting.as_ref().map(String::as_ref)
     }
+
+    pub fn non_exhaustive(&self) -> bool {
+        self.non_exhaustive
+    }
 }
 
 fn decide_tag(
@@ -707,7 +658,7 @@ fn decide_tag(
             }
             TagType::Internal { tag }
         }
-        (Some((untagged_tokens, _)), Some((tag_tokens, _)), None) => {
+        (Some((untagged_tokens, ())), Some((tag_tokens, _)), None) => {
             let msg = "enum cannot be both untagged and internally tagged";
             cx.error_spanned_by(untagged_tokens, msg);
             cx.error_spanned_by(tag_tokens, msg);
@@ -718,14 +669,14 @@ fn decide_tag(
             cx.error_spanned_by(content_tokens, msg);
             TagType::External
         }
-        (Some((untagged_tokens, _)), None, Some((content_tokens, _))) => {
+        (Some((untagged_tokens, ())), None, Some((content_tokens, _))) => {
             let msg = "untagged enum cannot have #[serde(content = \"...\")]";
             cx.error_spanned_by(untagged_tokens, msg);
             cx.error_spanned_by(content_tokens, msg);
             TagType::External
         }
         (None, Some((_, tag)), Some((_, content))) => TagType::Adjacent { tag, content },
-        (Some((untagged_tokens, _)), Some((tag_tokens, _)), Some((content_tokens, _))) => {
+        (Some((untagged_tokens, ())), Some((tag_tokens, _)), Some((content_tokens, _))) => {
             let msg = "untagged enum cannot have #[serde(tag = \"...\", content = \"...\")]";
             cx.error_spanned_by(untagged_tokens, msg);
             cx.error_spanned_by(tag_tokens, msg);
@@ -747,7 +698,7 @@ fn decide_identifier(
         variant_identifier.0.get_with_tokens(),
     ) {
         (_, None, None) => Identifier::No,
-        (_, Some((field_identifier_tokens, _)), Some((variant_identifier_tokens, _))) => {
+        (_, Some((field_identifier_tokens, ())), Some((variant_identifier_tokens, ()))) => {
             let msg =
                 "#[serde(field_identifier)] and #[serde(variant_identifier)] cannot both be set";
             cx.error_spanned_by(field_identifier_tokens, msg);
@@ -781,7 +732,7 @@ fn decide_identifier(
 
 /// Represents variant attribute information
 pub struct Variant {
-    name: Name,
+    name: MultiName,
     rename_all_rules: RenameAllRules,
     ser_bound: Option<Vec<syn::WherePredicate>>,
     de_bound: Option<Vec<syn::WherePredicate>>,
@@ -832,15 +783,15 @@ impl Variant {
                     // #[serde(rename = "foo")]
                     // #[serde(rename(serialize = "foo", deserialize = "bar"))]
                     let (ser, de) = get_multiple_renames(cx, &meta)?;
-                    ser_name.set_opt(&meta.path, ser.as_ref().map(syn::LitStr::value));
+                    ser_name.set_opt(&meta.path, ser.as_ref().map(Name::from));
                     for de_value in de {
-                        de_name.set_if_none(de_value.value());
-                        de_aliases.insert(&meta.path, de_value.value());
+                        de_name.set_if_none(Name::from(&de_value));
+                        de_aliases.insert(&meta.path, Name::from(&de_value));
                     }
                 } else if meta.path == ALIAS {
                     // #[serde(alias = "foo")]
                     if let Some(s) = get_lit_str(cx, ALIAS, &meta)? {
-                        de_aliases.insert(&meta.path, s.value());
+                        de_aliases.insert(&meta.path, Name::from(&s));
                     }
                 } else if meta.path == RENAME_ALL {
                     // #[serde(rename_all = "foo")]
@@ -889,13 +840,13 @@ impl Variant {
                         ser_path
                             .path
                             .segments
-                            .push(Ident::new("serialize", Span::call_site()).into());
+                            .push(Ident::new("serialize", ser_path.span()).into());
                         serialize_with.set(&meta.path, ser_path);
                         let mut de_path = path;
                         de_path
                             .path
                             .segments
-                            .push(Ident::new("deserialize", Span::call_site()).into());
+                            .push(Ident::new("deserialize", de_path.span()).into());
                         deserialize_with.set(&meta.path, de_path);
                     }
                 } else if meta.path == SERIALIZE_WITH {
@@ -947,7 +898,12 @@ impl Variant {
         }
 
         Variant {
-            name: Name::from_attrs(unraw(&variant.ident), ser_name, de_name, Some(de_aliases)),
+            name: MultiName::from_attrs(
+                Name::from(&unraw(&variant.ident)),
+                ser_name,
+                de_name,
+                Some(de_aliases),
+            ),
             rename_all_rules: RenameAllRules {
                 serialize: rename_all_ser_rule.get().unwrap_or(RenameRule::None),
                 deserialize: rename_all_de_rule.get().unwrap_or(RenameRule::None),
@@ -964,20 +920,23 @@ impl Variant {
         }
     }
 
-    pub fn name(&self) -> &Name {
+    pub fn name(&self) -> &MultiName {
         &self.name
     }
 
-    pub fn aliases(&self) -> &BTreeSet<String> {
+    pub fn aliases(&self) -> &BTreeSet<Name> {
         self.name.deserialize_aliases()
     }
 
     pub fn rename_by_rules(&mut self, rules: RenameAllRules) {
         if !self.name.serialize_renamed {
-            self.name.serialize = rules.serialize.apply_to_variant(&self.name.serialize);
+            self.name.serialize.value =
+                rules.serialize.apply_to_variant(&self.name.serialize.value);
         }
         if !self.name.deserialize_renamed {
-            self.name.deserialize = rules.deserialize.apply_to_variant(&self.name.deserialize);
+            self.name.deserialize.value = rules
+                .deserialize
+                .apply_to_variant(&self.name.deserialize.value);
         }
         self.name
             .deserialize_aliases
@@ -1023,7 +982,7 @@ impl Variant {
 
 /// Represents field attribute information
 pub struct Field {
-    name: Name,
+    name: MultiName,
     skip_serializing: bool,
     skip_deserializing: bool,
     skip_serializing_if: Option<syn::ExprPath>,
@@ -1082,8 +1041,11 @@ impl Field {
         let mut flatten = BoolAttr::none(cx, FLATTEN);
 
         let ident = match &field.ident {
-            Some(ident) => unraw(ident),
-            None => index.to_string(),
+            Some(ident) => Name::from(&unraw(ident)),
+            None => Name {
+                value: index.to_string(),
+                span: Span::call_site(),
+            },
         };
 
         if let Some(borrow_attribute) = attrs.and_then(|variant| variant.borrow.as_ref()) {
@@ -1119,15 +1081,15 @@ impl Field {
                     // #[serde(rename = "foo")]
                     // #[serde(rename(serialize = "foo", deserialize = "bar"))]
                     let (ser, de) = get_multiple_renames(cx, &meta)?;
-                    ser_name.set_opt(&meta.path, ser.as_ref().map(syn::LitStr::value));
+                    ser_name.set_opt(&meta.path, ser.as_ref().map(Name::from));
                     for de_value in de {
-                        de_name.set_if_none(de_value.value());
-                        de_aliases.insert(&meta.path, de_value.value());
+                        de_name.set_if_none(Name::from(&de_value));
+                        de_aliases.insert(&meta.path, Name::from(&de_value));
                     }
                 } else if meta.path == ALIAS {
                     // #[serde(alias = "foo")]
                     if let Some(s) = get_lit_str(cx, ALIAS, &meta)? {
-                        de_aliases.insert(&meta.path, s.value());
+                        de_aliases.insert(&meta.path, Name::from(&s));
                     }
                 } else if meta.path == DEFAULT {
                     if meta.input.peek(Token![=]) {
@@ -1171,13 +1133,13 @@ impl Field {
                         ser_path
                             .path
                             .segments
-                            .push(Ident::new("serialize", Span::call_site()).into());
+                            .push(Ident::new("serialize", ser_path.span()).into());
                         serialize_with.set(&meta.path, ser_path);
                         let mut de_path = path;
                         de_path
                             .path
                             .segments
-                            .push(Ident::new("deserialize", Span::call_site()).into());
+                            .push(Ident::new("deserialize", de_path.span()).into());
                         deserialize_with.set(&meta.path, de_path);
                     }
                 } else if meta.path == BOUND {
@@ -1290,7 +1252,7 @@ impl Field {
         }
 
         Field {
-            name: Name::from_attrs(ident, ser_name, de_name, Some(de_aliases)),
+            name: MultiName::from_attrs(ident, ser_name, de_name, Some(de_aliases)),
             skip_serializing: skip_serializing.get(),
             skip_deserializing: skip_deserializing.get(),
             skip_serializing_if: skip_serializing_if.get(),
@@ -1306,20 +1268,22 @@ impl Field {
         }
     }
 
-    pub fn name(&self) -> &Name {
+    pub fn name(&self) -> &MultiName {
         &self.name
     }
 
-    pub fn aliases(&self) -> &BTreeSet<String> {
+    pub fn aliases(&self) -> &BTreeSet<Name> {
         self.name.deserialize_aliases()
     }
 
     pub fn rename_by_rules(&mut self, rules: RenameAllRules) {
         if !self.name.serialize_renamed {
-            self.name.serialize = rules.serialize.apply_to_field(&self.name.serialize);
+            self.name.serialize.value = rules.serialize.apply_to_field(&self.name.serialize.value);
         }
         if !self.name.deserialize_renamed {
-            self.name.deserialize = rules.deserialize.apply_to_field(&self.name.deserialize);
+            self.name.deserialize.value = rules
+                .deserialize
+                .apply_to_field(&self.name.deserialize.value);
         }
         self.name
             .deserialize_aliases
@@ -1769,7 +1733,7 @@ fn is_primitive_path(path: &syn::Path, primitive: &str) -> bool {
 // attribute on the field so there must be at least one borrowable lifetime.
 fn borrowable_lifetimes(
     cx: &Ctxt,
-    name: &str,
+    name: &Name,
     field: &syn::Field,
 ) -> Result<BTreeSet<syn::Lifetime>, ()> {
     let mut lifetimes = BTreeSet::new();
@@ -1785,6 +1749,7 @@ fn borrowable_lifetimes(
 
 fn collect_lifetimes(ty: &syn::Type, out: &mut BTreeSet<syn::Lifetime>) {
     match ty {
+        #![cfg_attr(all(test, exhaustive), deny(non_exhaustive_omitted_patterns))]
         syn::Type::Slice(ty) => {
             collect_lifetimes(&ty.elem, out);
         }
@@ -1820,7 +1785,10 @@ fn collect_lifetimes(ty: &syn::Type, out: &mut BTreeSet<syn::Lifetime>) {
                             syn::GenericArgument::AssocType(binding) => {
                                 collect_lifetimes(&binding.ty, out);
                             }
-                            _ => {}
+                            syn::GenericArgument::Const(_)
+                            | syn::GenericArgument::AssocConst(_)
+                            | syn::GenericArgument::Constraint(_)
+                            | _ => {}
                         }
                     }
                 }
@@ -1842,7 +1810,6 @@ fn collect_lifetimes(ty: &syn::Type, out: &mut BTreeSet<syn::Lifetime>) {
         | syn::Type::Infer(_)
         | syn::Type::Verbatim(_) => {}
 
-        #[cfg_attr(all(test, exhaustive), deny(non_exhaustive_omitted_patterns))]
         _ => {}
     }
 }

serde_derive/src/internals/check.rs

@@ -318,6 +318,9 @@ 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());
@@ -326,13 +329,13 @@ fn check_internal_tag_field_name_conflict(cx: &Ctxt, cont: &Container) {
                     let name = field.attrs.name();
                     let ser_name = name.serialize_name();
 
-                    if check_ser && ser_name == tag {
+                    if check_ser && ser_name.value == tag {
                         diagnose_conflict();
                         return;
                     }
 
                     for de_name in field.attrs.aliases() {
-                        if check_de && de_name == tag {
+                        if check_de && de_name.value == tag {
                             diagnose_conflict();
                             return;
                         }

serde_derive/src/internals/mod.rs

@@ -1,5 +1,6 @@
 pub mod ast;
 pub mod attr;
+pub mod name;
 
 mod case;
 mod check;

serde_derive/src/internals/name.rs

@@ -0,0 +1,113 @@
+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)
+    }
+}

serde_derive/src/internals/receiver.rs

@@ -84,7 +84,7 @@ impl ReplaceReceiver<'_> {
             self.visit_type_mut_impl(ty);
             return;
         };
-        *ty = self.self_ty(span).into();
+        *ty = Type::Path(self.self_ty(span));
     }
 
     // `Self::Assoc` -> `<Receiver>::Assoc`
@@ -107,6 +107,7 @@ 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);
@@ -147,7 +148,6 @@ impl ReplaceReceiver<'_> {
 
             Type::Infer(_) | Type::Never(_) | Type::Verbatim(_) => {}
 
-            #[cfg_attr(all(test, exhaustive), deny(non_exhaustive_omitted_patterns))]
             _ => {}
         }
     }
@@ -178,13 +178,13 @@ 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::Lifetime(_)
                         | GenericArgument::Const(_)
                         | GenericArgument::AssocConst(_)
                         | GenericArgument::Constraint(_) => {}
-                        #[cfg_attr(all(test, exhaustive), deny(non_exhaustive_omitted_patterns))]
                         _ => {}
                     }
                 }
@@ -207,9 +207,11 @@ 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::Verbatim(_) => {}
-            #[cfg_attr(all(test, exhaustive), deny(non_exhaustive_omitted_patterns))]
+            TypeParamBound::Lifetime(_)
+            | TypeParamBound::PreciseCapture(_)
+            | TypeParamBound::Verbatim(_) => {}
             _ => {}
         }
     }
@@ -228,6 +230,7 @@ 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 {
@@ -235,7 +238,6 @@ impl ReplaceReceiver<'_> {
                         }
                     }
                     WherePredicate::Lifetime(_) => {}
-                    #[cfg_attr(all(test, exhaustive), deny(non_exhaustive_omitted_patterns))]
                     _ => {}
                 }
             }

serde_derive/src/internals/symbol.rs

@@ -19,6 +19,7 @@ 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");
@@ -45,7 +46,7 @@ impl PartialEq<Symbol> for Ident {
     }
 }
 
-impl<'a> PartialEq<Symbol> for &'a Ident {
+impl PartialEq<Symbol> for &Ident {
     fn eq(&self, word: &Symbol) -> bool {
         *self == word.0
     }
@@ -57,7 +58,7 @@ impl PartialEq<Symbol> for Path {
     }
 }
 
-impl<'a> PartialEq<Symbol> for &'a Path {
+impl PartialEq<Symbol> for &Path {
     fn eq(&self, word: &Symbol) -> bool {
         self.is_ident(word.0)
     }

serde_derive/src/lib.rs

@@ -13,7 +13,8 @@
 //!
 //! [https://serde.rs/derive.html]: https://serde.rs/derive.html
 
-#![doc(html_root_url = "https://docs.rs/serde_derive/1.0.183")]
+#![doc(html_root_url = "https://docs.rs/serde_derive/1.0.215")]
+#![cfg_attr(not(check_cfg), allow(unexpected_cfgs))]
 // Ignored clippy lints
 #![allow(
     // clippy false positive: https://github.com/rust-lang/rust-clippy/issues/7054
@@ -26,6 +27,7 @@
     // 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,
@@ -50,11 +52,11 @@
     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,
@@ -66,17 +68,11 @@ extern crate proc_macro2;
 extern crate quote;
 extern crate syn;
 
-#[cfg(not(precompiled))]
 extern crate proc_macro;
-#[cfg(precompiled)]
-extern crate proc_macro2 as proc_macro;
 
 mod internals;
 
 use proc_macro::TokenStream;
-#[cfg(precompiled)]
-use std::sync::atomic::AtomicBool;
-#[cfg(not(precompiled))]
 use syn::parse_macro_input;
 use syn::DeriveInput;
 
@@ -91,20 +87,7 @@ mod pretend;
 mod ser;
 mod this;
 
-#[cfg(precompiled)]
-macro_rules! parse_macro_input {
-    ($tokenstream:ident as $ty:ty) => {
-        match syn::parse2::<$ty>($tokenstream) {
-            Ok(data) => data,
-            Err(err) => return err.to_compile_error(),
-        }
-    };
-}
-
-#[cfg(precompiled)]
-pub static DESERIALIZE_IN_PLACE: AtomicBool = AtomicBool::new(false);
-
-#[cfg_attr(not(precompiled), proc_macro_derive(Serialize, attributes(serde)))]
+#[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)
@@ -112,7 +95,7 @@ pub fn derive_serialize(input: TokenStream) -> TokenStream {
         .into()
 }
 
-#[cfg_attr(not(precompiled), proc_macro_derive(Deserialize, attributes(serde)))]
+#[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)

serde_derive/src/pretend.rs

@@ -64,14 +64,14 @@ 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, fields) => {
+        Data::Struct(Style::Struct | Style::Tuple | Style::Newtype, fields) => {
             if is_packed {
                 pretend_fields_used_struct_packed(cont, fields)
             } else {
                 pretend_fields_used_struct(cont, fields)
             }
         }
-        Data::Struct(_, _) => quote!(),
+        Data::Struct(Style::Unit, _) => quote!(),
     }
 }
 
@@ -115,13 +115,13 @@ fn pretend_fields_used_enum(cont: &Container, variants: &[Variant]) -> TokenStre
     let patterns = variants
         .iter()
         .filter_map(|variant| match variant.style {
-            Style::Struct => {
+            Style::Struct | Style::Tuple | Style::Newtype => {
                 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),* }))
             }
-            _ => None,
+            Style::Unit => None,
         })
         .collect::<Vec<_>>();
 

serde_derive/src/ser.rs

@@ -1,5 +1,6 @@
 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, this};
 use proc_macro2::{Span, TokenStream};
@@ -289,9 +290,18 @@ fn serialize_tuple_struct(
 }
 
 fn serialize_struct(params: &Parameters, fields: &[Field], cattrs: &attr::Container) -> Fragment {
-    assert!(fields.len() as u64 <= u64::from(u32::max_value()));
+    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,
+    );
 
-    if cattrs.has_flatten() {
+    let has_non_skipped_flatten = fields
+        .iter()
+        .any(|field| field.attrs.flatten() && !field.attrs.skip_serializing());
+    if has_non_skipped_flatten {
         serialize_struct_as_map(params, fields, cattrs)
     } else {
         serialize_struct_as_struct(params, fields, cattrs)
@@ -370,26 +380,8 @@ 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, #len)?;
+        let #let_mut __serde_state = _serde::Serializer::serialize_map(__serializer, _serde::__private::None)?;
         #tag_field
         #(#serialize_fields)*
         _serde::ser::SerializeMap::end(__serde_state)
@@ -397,11 +389,11 @@ 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_value()));
+    assert!(variants.len() as u64 <= u64::from(u32::MAX));
 
     let self_var = &params.self_var;
 
-    let arms: Vec<_> = variants
+    let mut arms: Vec<_> = variants
         .iter()
         .enumerate()
         .map(|(variant_index, variant)| {
@@ -409,6 +401,12 @@ 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)*
@@ -704,7 +702,7 @@ fn serialize_adjacently_tagged_variant(
     });
 
     let fields_ty = variant.fields.iter().map(|f| &f.ty);
-    let fields_ident: &Vec<_> = &match variant.style {
+    let fields_ident: &[_] = &match variant.style {
         Style::Unit => {
             if variant.attrs.serialize_with().is_some() {
                 vec![]
@@ -801,9 +799,9 @@ fn serialize_untagged_variant(
 
 enum TupleVariant<'a> {
     ExternallyTagged {
-        type_name: &'a str,
+        type_name: &'a Name,
         variant_index: u32,
-        variant_name: &'a str,
+        variant_name: &'a Name,
     },
     Untagged,
 }
@@ -870,11 +868,11 @@ fn serialize_tuple_variant(
 enum StructVariant<'a> {
     ExternallyTagged {
         variant_index: u32,
-        variant_name: &'a str,
+        variant_name: &'a Name,
     },
     InternallyTagged {
         tag: &'a str,
-        variant_name: &'a str,
+        variant_name: &'a Name,
     },
     Untagged,
 }
@@ -883,7 +881,7 @@ fn serialize_struct_variant(
     context: StructVariant,
     params: &Parameters,
     fields: &[Field],
-    name: &str,
+    name: &Name,
 ) -> Fragment {
     if fields.iter().any(|field| field.attrs.flatten()) {
         return serialize_struct_variant_with_flatten(context, params, fields, name);
@@ -967,7 +965,7 @@ fn serialize_struct_variant_with_flatten(
     context: StructVariant,
     params: &Parameters,
     fields: &[Field],
-    name: &str,
+    name: &Name,
 ) -> Fragment {
     let struct_trait = StructTrait::SerializeMap;
     let serialize_fields = serialize_struct_visitor(fields, params, true, &struct_trait);
@@ -1223,6 +1221,17 @@ 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)]
         struct __SerializeWith #wrapper_impl_generics #where_clause {
@@ -1231,11 +1240,11 @@ fn wrap_serialize_with(
         }
 
         impl #wrapper_impl_generics _serde::Serialize for __SerializeWith #wrapper_ty_generics #where_clause {
-            fn serialize<__S>(&self, __s: __S) -> _serde::__private::Result<__S::Ok, __S::Error>
+            fn serialize<__S>(&#self_var, #serializer_var: __S) -> _serde::__private::Result<__S::Ok, __S::Error>
             where
                 __S: _serde::Serializer,
             {
-                #serialize_with(#(self.values.#field_access, )* __s)
+                #wrapper_serialize
             }
         }
 

serde_derive_internals/Cargo.toml

@@ -1,23 +1,24 @@
 [package]
 name = "serde_derive_internals"
-version = "0.28.0" # remember to update html_root_url
+version = "0.29.1"
 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 = "2015"
 exclude = ["build.rs"]
 homepage = "https://serde.rs"
 keywords = ["serde", "serialization"]
 license = "MIT OR Apache-2.0"
 repository = "https://github.com/serde-rs/serde"
-rust-version = "1.56"
+rust-version = "1.61"
 
 [lib]
 path = "lib.rs"
 
 [dependencies]
-proc-macro2 = "1.0"
-quote = "1.0"
-syn = { version = "2.0.28", default-features = false, features = ["clone-impls", "derive", "parsing", "printing"] }
+proc-macro2 = { workspace = true }
+quote = { workspace = true }
+syn = { workspace = true, features = ["clone-impls", "derive", "parsing", "printing"] }
 
 [package.metadata.docs.rs]
 targets = ["x86_64-unknown-linux-gnu"]

serde_derive_internals/build.rs

@@ -1,9 +1,17 @@
 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

serde_derive_internals/lib.rs

@@ -1,4 +1,5 @@
-#![doc(html_root_url = "https://docs.rs/serde_derive_internals/0.28.0")]
+#![doc(html_root_url = "https://docs.rs/serde_derive_internals/0.29.1")]
+#![cfg_attr(not(check_cfg), allow(unexpected_cfgs))]
 // Ignored clippy lints
 #![allow(
     clippy::cognitive_complexity,
@@ -8,6 +9,7 @@
     // 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,
@@ -34,6 +36,7 @@
     clippy::single_match_else,
     clippy::struct_excessive_bools,
     clippy::too_many_lines,
+    clippy::uninlined_format_args,
     clippy::unused_self,
     clippy::wildcard_imports
 )]

test_suite/Cargo.toml

@@ -18,4 +18,4 @@ rustversion = "1.0"
 serde = { path = "../serde", features = ["rc"] }
 serde_derive = { path = "../serde_derive", features = ["deserialize_in_place"] }
 serde_test = "1.0.176"
-trybuild = { version = "1.0.66", features = ["diff"] }
+trybuild = { version = "1.0.97", features = ["diff"] }

test_suite/no_std/src/main.rs

@@ -23,21 +23,21 @@ fn panic(_info: &core::panic::PanicInfo) -> ! {
 use serde_derive::{Deserialize, Serialize};
 
 #[derive(Serialize, Deserialize)]
-struct Unit;
+pub struct Unit;
 
 #[derive(Serialize, Deserialize)]
-struct Newtype(u8);
+pub struct Newtype(u8);
 
 #[derive(Serialize, Deserialize)]
-struct Tuple(u8, u8);
+pub struct Tuple(u8, u8);
 
 #[derive(Serialize, Deserialize)]
-struct Struct {
+pub struct Struct {
     f: u8,
 }
 
 #[derive(Serialize, Deserialize)]
-enum Enum {
+pub enum Enum {
     Unit,
     Newtype(u8),
     Tuple(u8, u8),

test_suite/tests/compiletest.rs

@@ -1,6 +1,6 @@
-#[cfg_attr(target_os = "emscripten", ignore)]
-#[rustversion::attr(not(nightly), ignore)]
-#[cfg_attr(miri, ignore)]
+#[cfg_attr(target_os = "emscripten", ignore = "disabled on Emscripten")]
+#[rustversion::attr(not(nightly), ignore = "requires nightly")]
+#[cfg_attr(miri, ignore = "incompatible with miri")]
 #[allow(unused_attributes)]
 #[test]
 fn ui() {

test_suite/tests/regression/issue1904.rs

@@ -0,0 +1,66 @@
+#![allow(dead_code)] // we do not read enum fields
+
+use serde_derive::Deserialize;
+
+#[derive(Deserialize)]
+pub struct Nested;
+
+#[derive(Deserialize)]
+pub enum ExternallyTagged1 {
+    Tuple(f64, String),
+    Flatten {
+        #[serde(flatten)]
+        nested: Nested,
+    },
+}
+
+#[derive(Deserialize)]
+pub enum ExternallyTagged2 {
+    Flatten {
+        #[serde(flatten)]
+        nested: Nested,
+    },
+    Tuple(f64, String),
+}
+
+// Internally tagged enums cannot contain tuple variants so not tested here
+
+#[derive(Deserialize)]
+#[serde(tag = "tag", content = "content")]
+pub enum AdjacentlyTagged1 {
+    Tuple(f64, String),
+    Flatten {
+        #[serde(flatten)]
+        nested: Nested,
+    },
+}
+
+#[derive(Deserialize)]
+#[serde(tag = "tag", content = "content")]
+pub enum AdjacentlyTagged2 {
+    Flatten {
+        #[serde(flatten)]
+        nested: Nested,
+    },
+    Tuple(f64, String),
+}
+
+#[derive(Deserialize)]
+#[serde(untagged)]
+pub enum Untagged1 {
+    Tuple(f64, String),
+    Flatten {
+        #[serde(flatten)]
+        nested: Nested,
+    },
+}
+
+#[derive(Deserialize)]
+#[serde(untagged)]
+pub enum Untagged2 {
+    Flatten {
+        #[serde(flatten)]
+        nested: Nested,
+    },
+    Tuple(f64, String),
+}

test_suite/tests/regression/issue2371.rs

@@ -7,7 +7,9 @@ pub struct Nested;
 pub enum ExternallyTagged {
     Flatten {
         #[serde(flatten)]
+        #[allow(dead_code)]
         nested: Nested,
+        #[allow(dead_code)]
         string: &'static str,
     },
 }
@@ -17,7 +19,9 @@ pub enum ExternallyTagged {
 pub enum InternallyTagged {
     Flatten {
         #[serde(flatten)]
+        #[allow(dead_code)]
         nested: Nested,
+        #[allow(dead_code)]
         string: &'static str,
     },
 }
@@ -27,7 +31,9 @@ pub enum InternallyTagged {
 pub enum AdjacentlyTagged {
     Flatten {
         #[serde(flatten)]
+        #[allow(dead_code)]
         nested: Nested,
+        #[allow(dead_code)]
         string: &'static str,
     },
 }
@@ -37,7 +43,9 @@ pub enum AdjacentlyTagged {
 pub enum UntaggedWorkaround {
     Flatten {
         #[serde(flatten)]
+        #[allow(dead_code)]
         nested: Nested,
+        #[allow(dead_code)]
         string: &'static str,
     },
 }

test_suite/tests/regression/issue2565.rs

@@ -0,0 +1,48 @@
+use serde_derive::{Deserialize, Serialize};
+use serde_test::{assert_tokens, Token};
+
+#[derive(Serialize, Deserialize, Debug, PartialEq)]
+enum Enum {
+    Simple {
+        a: i32,
+    },
+    Flatten {
+        #[serde(flatten)]
+        flatten: (),
+        a: i32,
+    },
+}
+
+#[test]
+fn simple_variant() {
+    assert_tokens(
+        &Enum::Simple { a: 42 },
+        &[
+            Token::StructVariant {
+                name: "Enum",
+                variant: "Simple",
+                len: 1,
+            },
+            Token::Str("a"),
+            Token::I32(42),
+            Token::StructVariantEnd,
+        ],
+    );
+}
+
+#[test]
+fn flatten_variant() {
+    assert_tokens(
+        &Enum::Flatten { flatten: (), a: 42 },
+        &[
+            Token::NewtypeVariant {
+                name: "Enum",
+                variant: "Flatten",
+            },
+            Token::Map { len: None },
+            Token::Str("a"),
+            Token::I32(42),
+            Token::MapEnd,
+        ],
+    );
+}

test_suite/tests/regression/issue2792.rs

@@ -0,0 +1,18 @@
+#![allow(dead_code)] // we do not read enum fields
+
+use serde_derive::Deserialize;
+
+#[derive(Deserialize)]
+#[serde(deny_unknown_fields)]
+pub enum A {
+    B {
+        c: String,
+    },
+    D {
+        #[serde(flatten)]
+        e: E,
+    },
+}
+
+#[derive(Deserialize)]
+pub struct E {}

test_suite/tests/regression/issue2844.rs

@@ -0,0 +1,33 @@
+#![allow(clippy::trivially_copy_pass_by_ref)]
+
+use serde_derive::{Deserialize, Serialize};
+
+macro_rules! declare_in_macro {
+    ($with:literal) => {
+        #[derive(Serialize, Deserialize)]
+        pub struct S {
+            #[serde(with = $with)]
+            f: i32,
+        }
+    };
+}
+
+declare_in_macro!("with");
+
+mod with {
+    use serde::{Deserializer, Serializer};
+
+    pub fn serialize<S>(_: &i32, _: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        unimplemented!()
+    }
+
+    pub fn deserialize<'de, D>(_: D) -> Result<i32, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        unimplemented!()
+    }
+}

test_suite/tests/regression/issue2846.rs

@@ -0,0 +1,27 @@
+#![allow(clippy::trivially_copy_pass_by_ref)]
+
+use serde_derive::Deserialize;
+
+macro_rules! declare_in_macro {
+    ($with:literal) => {
+        #[derive(Deserialize)]
+        pub struct S(
+            #[serde(with = $with)]
+            #[allow(dead_code)]
+            i32,
+        );
+    };
+}
+
+declare_in_macro!("with");
+
+mod with {
+    use serde::Deserializer;
+
+    pub fn deserialize<'de, D>(_: D) -> Result<i32, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        unimplemented!()
+    }
+}

test_suite/tests/test_borrow.rs

@@ -162,7 +162,7 @@ fn test_cow() {
 #[test]
 fn test_lifetimes() {
     #[derive(Deserialize)]
-    struct Cows<'a, 'b> {
+    pub struct Cows<'a, 'b> {
         _copied: Cow<'a, str>,
 
         #[serde(borrow)]
@@ -178,7 +178,7 @@ fn test_lifetimes() {
     }
 
     #[derive(Deserialize)]
-    struct Wrap<'a, 'b> {
+    pub struct Wrap<'a, 'b> {
         #[serde(borrow = "'b")]
         _cows: Cows<'a, 'b>,
     }

test_suite/tests/test_de.rs

@@ -11,6 +11,7 @@
 #![cfg_attr(feature = "unstable", feature(never_type))]
 
 use fnv::FnvHasher;
+use serde::de::value::{F32Deserializer, F64Deserializer};
 use serde::de::{Deserialize, DeserializeOwned, Deserializer, IntoDeserializer};
 use serde_derive::Deserialize;
 use serde_test::{assert_de_tokens, Configure, Token};
@@ -22,7 +23,7 @@ use std::iter;
 use std::net;
 use std::num::{
     NonZeroI128, NonZeroI16, NonZeroI32, NonZeroI64, NonZeroI8, NonZeroIsize, NonZeroU128,
-    NonZeroU16, NonZeroU32, NonZeroU64, NonZeroU8, NonZeroUsize, Wrapping,
+    NonZeroU16, NonZeroU32, NonZeroU64, NonZeroU8, NonZeroUsize, Saturating, Wrapping,
 };
 use std::ops::Bound;
 use std::path::{Path, PathBuf};
@@ -92,7 +93,7 @@ struct StructSkipDefault {
 
 #[derive(PartialEq, Debug, Deserialize)]
 #[serde(default)]
-struct StructSkipDefaultGeneric<T> {
+pub struct StructSkipDefaultGeneric<T> {
     #[serde(skip_deserializing)]
     t: T,
 }
@@ -832,6 +833,26 @@ fn test_f64() {
     test(1.11, &[Token::F64(1.11)]);
 }
 
+#[test]
+fn test_nan() {
+    let f32_deserializer = F32Deserializer::<serde::de::value::Error>::new;
+    let f64_deserializer = F64Deserializer::<serde::de::value::Error>::new;
+
+    let pos_f32_nan = f32_deserializer(f32::NAN.copysign(1.0));
+    let pos_f64_nan = f64_deserializer(f64::NAN.copysign(1.0));
+    assert!(f32::deserialize(pos_f32_nan).unwrap().is_sign_positive());
+    assert!(f32::deserialize(pos_f64_nan).unwrap().is_sign_positive());
+    assert!(f64::deserialize(pos_f32_nan).unwrap().is_sign_positive());
+    assert!(f64::deserialize(pos_f64_nan).unwrap().is_sign_positive());
+
+    let neg_f32_nan = f32_deserializer(f32::NAN.copysign(-1.0));
+    let neg_f64_nan = f64_deserializer(f64::NAN.copysign(-1.0));
+    assert!(f32::deserialize(neg_f32_nan).unwrap().is_sign_negative());
+    assert!(f32::deserialize(neg_f64_nan).unwrap().is_sign_negative());
+    assert!(f64::deserialize(neg_f32_nan).unwrap().is_sign_negative());
+    assert!(f64::deserialize(neg_f64_nan).unwrap().is_sign_negative());
+}
+
 #[test]
 fn test_char() {
     test('a', &[Token::Char('a')]);
@@ -1877,6 +1898,46 @@ fn test_range_inclusive() {
     );
 }
 
+#[test]
+fn test_range_from() {
+    test(
+        1u32..,
+        &[
+            Token::Struct {
+                name: "RangeFrom",
+                len: 1,
+            },
+            Token::Str("start"),
+            Token::U32(1),
+            Token::StructEnd,
+        ],
+    );
+    test(
+        1u32..,
+        &[Token::Seq { len: Some(1) }, Token::U32(1), Token::SeqEnd],
+    );
+}
+
+#[test]
+fn test_range_to() {
+    test(
+        ..2u32,
+        &[
+            Token::Struct {
+                name: "RangeTo",
+                len: 1,
+            },
+            Token::Str("end"),
+            Token::U32(2),
+            Token::StructEnd,
+        ],
+    );
+    test(
+        ..2u32,
+        &[Token::Seq { len: Some(1) }, Token::U32(2), Token::SeqEnd],
+    );
+}
+
 #[test]
 fn test_bound() {
     test(
@@ -2004,6 +2065,43 @@ fn test_wrapping() {
     test(Wrapping(1usize), &[Token::U64(1)]);
 }
 
+#[test]
+fn test_saturating() {
+    test(Saturating(1usize), &[Token::U32(1)]);
+    test(Saturating(1usize), &[Token::U64(1)]);
+    test(Saturating(0u8), &[Token::I8(0)]);
+    test(Saturating(0u16), &[Token::I16(0)]);
+
+    // saturate input values at the minimum or maximum value
+    test(Saturating(u8::MAX), &[Token::U16(u16::MAX)]);
+    test(Saturating(u8::MAX), &[Token::U16(u8::MAX as u16 + 1)]);
+    test(Saturating(u16::MAX), &[Token::U32(u32::MAX)]);
+    test(Saturating(u32::MAX), &[Token::U64(u64::MAX)]);
+    test(Saturating(u8::MIN), &[Token::I8(i8::MIN)]);
+    test(Saturating(u16::MIN), &[Token::I16(i16::MIN)]);
+    test(Saturating(u32::MIN), &[Token::I32(i32::MIN)]);
+    test(Saturating(i8::MIN), &[Token::I16(i16::MIN)]);
+    test(Saturating(i16::MIN), &[Token::I32(i32::MIN)]);
+    test(Saturating(i32::MIN), &[Token::I64(i64::MIN)]);
+
+    test(Saturating(u8::MIN), &[Token::I8(-1)]);
+    test(Saturating(u16::MIN), &[Token::I16(-1)]);
+
+    #[cfg(target_pointer_width = "64")]
+    {
+        test(Saturating(usize::MIN), &[Token::U64(u64::MIN)]);
+        test(Saturating(usize::MAX), &[Token::U64(u64::MAX)]);
+        test(Saturating(isize::MIN), &[Token::I64(i64::MIN)]);
+        test(Saturating(isize::MAX), &[Token::I64(i64::MAX)]);
+        test(Saturating(0usize), &[Token::I64(i64::MIN)]);
+
+        test(
+            Saturating(9_223_372_036_854_775_807usize),
+            &[Token::I64(i64::MAX)],
+        );
+    }
+}
+
 #[test]
 fn test_rc_dst() {
     test(Rc::<str>::from("s"), &[Token::Str("s")]);

test_suite/tests/test_de_error.rs

@@ -1434,7 +1434,15 @@ fn test_number_from_string() {
 fn test_integer_from_float() {
     assert_de_tokens_error::<isize>(
         &[Token::F32(0.0)],
-        "invalid type: floating point `0`, expected isize",
+        "invalid type: floating point `0.0`, expected isize",
+    );
+}
+
+#[test]
+fn test_nan_no_decimal_point() {
+    assert_de_tokens_error::<isize>(
+        &[Token::F32(f32::NAN)],
+        "invalid type: floating point `NaN`, expected isize",
     );
 }
 
@@ -1459,7 +1467,7 @@ fn test_duration_overflow_seq() {
     assert_de_tokens_error::<Duration>(
         &[
             Token::Seq { len: Some(2) },
-            Token::U64(u64::max_value()),
+            Token::U64(u64::MAX),
             Token::U32(1_000_000_000),
             Token::SeqEnd,
         ],
@@ -1476,7 +1484,7 @@ fn test_duration_overflow_struct() {
                 len: 2,
             },
             Token::Str("secs"),
-            Token::U64(u64::max_value()),
+            Token::U64(u64::MAX),
             Token::Str("nanos"),
             Token::U32(1_000_000_000),
             Token::StructEnd,
@@ -1490,7 +1498,7 @@ fn test_systemtime_overflow_seq() {
     assert_de_tokens_error::<SystemTime>(
         &[
             Token::Seq { len: Some(2) },
-            Token::U64(u64::max_value()),
+            Token::U64(u64::MAX),
             Token::U32(1_000_000_000),
             Token::SeqEnd,
         ],
@@ -1507,7 +1515,7 @@ fn test_systemtime_overflow_struct() {
                 len: 2,
             },
             Token::Str("secs_since_epoch"),
-            Token::U64(u64::max_value()),
+            Token::U64(u64::MAX),
             Token::Str("nanos_since_epoch"),
             Token::U32(1_000_000_000),
             Token::StructEnd,
@@ -1516,13 +1524,12 @@ fn test_systemtime_overflow_struct() {
     );
 }
 
-#[cfg(systemtime_checked_add)]
 #[test]
 fn test_systemtime_overflow() {
     assert_de_tokens_error::<SystemTime>(
         &[
             Token::Seq { len: Some(2) },
-            Token::U64(u64::max_value()),
+            Token::U64(u64::MAX),
             Token::U32(0),
             Token::SeqEnd,
         ],

test_suite/tests/test_enum_adjacently_tagged.rs

@@ -0,0 +1,799 @@
+#![deny(trivial_numeric_casts)]
+#![allow(
+    clippy::derive_partial_eq_without_eq,
+    clippy::enum_variant_names,
+    clippy::redundant_field_names,
+    clippy::too_many_lines
+)]
+
+use serde_derive::{Deserialize, Serialize};
+use serde_test::{assert_de_tokens, assert_de_tokens_error, assert_tokens, Token};
+
+#[derive(Debug, PartialEq, Serialize, Deserialize)]
+#[serde(tag = "t", content = "c")]
+enum AdjacentlyTagged<T> {
+    Unit,
+    Newtype(T),
+    Tuple(u8, u8),
+    Struct { f: u8 },
+}
+
+mod unit {
+    use super::*;
+
+    #[test]
+    fn map_str_tag_only() {
+        // Map: tag only
+        assert_tokens(
+            &AdjacentlyTagged::Unit::<u8>,
+            &[
+                Token::Struct {
+                    name: "AdjacentlyTagged",
+                    len: 1,
+                },
+                Token::Str("t"),
+                Token::UnitVariant {
+                    name: "AdjacentlyTagged",
+                    variant: "Unit",
+                },
+                Token::StructEnd,
+            ],
+        );
+
+        // Map: tag only and incorrect hint for number of elements
+        assert_de_tokens(
+            &AdjacentlyTagged::Unit::<u8>,
+            &[
+                Token::Struct {
+                    name: "AdjacentlyTagged",
+                    len: 2,
+                },
+                Token::Str("t"),
+                Token::UnitVariant {
+                    name: "AdjacentlyTagged",
+                    variant: "Unit",
+                },
+                Token::StructEnd,
+            ],
+        );
+    }
+
+    #[test]
+    fn map_int_tag_only() {
+        // Map: tag (as number) only
+        assert_de_tokens(
+            &AdjacentlyTagged::Unit::<u8>,
+            &[
+                Token::Struct {
+                    name: "AdjacentlyTagged",
+                    len: 1,
+                },
+                Token::U16(0),
+                Token::UnitVariant {
+                    name: "AdjacentlyTagged",
+                    variant: "Unit",
+                },
+                Token::StructEnd,
+            ],
+        );
+    }
+
+    #[test]
+    fn map_bytes_tag_only() {
+        // Map: tag only
+        assert_de_tokens(
+            &AdjacentlyTagged::Unit::<u8>,
+            &[
+                Token::Struct {
+                    name: "AdjacentlyTagged",
+                    len: 1,
+                },
+                Token::Bytes(b"t"),
+                Token::UnitVariant {
+                    name: "AdjacentlyTagged",
+                    variant: "Unit",
+                },
+                Token::StructEnd,
+            ],
+        );
+
+        // Map: tag only
+        assert_de_tokens(
+            &AdjacentlyTagged::Unit::<u8>,
+            &[
+                Token::Struct {
+                    name: "AdjacentlyTagged",
+                    len: 1,
+                },
+                Token::BorrowedBytes(b"t"),
+                Token::UnitVariant {
+                    name: "AdjacentlyTagged",
+                    variant: "Unit",
+                },
+                Token::StructEnd,
+            ],
+        );
+    }
+
+    #[test]
+    fn map_str_tag_content() {
+        // Map: tag + content
+        assert_de_tokens(
+            &AdjacentlyTagged::Unit::<u8>,
+            &[
+                Token::Struct {
+                    name: "AdjacentlyTagged",
+                    len: 2,
+                },
+                Token::Str("t"),
+                Token::UnitVariant {
+                    name: "AdjacentlyTagged",
+                    variant: "Unit",
+                },
+                Token::Str("c"),
+                Token::Unit,
+                Token::StructEnd,
+            ],
+        );
+        // Map: content + tag
+        assert_de_tokens(
+            &AdjacentlyTagged::Unit::<u8>,
+            &[
+                Token::Struct {
+                    name: "AdjacentlyTagged",
+                    len: 2,
+                },
+                Token::Str("c"),
+                Token::Unit,
+                Token::Str("t"),
+                Token::UnitVariant {
+                    name: "AdjacentlyTagged",
+                    variant: "Unit",
+                },
+                Token::StructEnd,
+            ],
+        );
+
+        // Map: tag + content + excess fields (f, g, h)
+        assert_de_tokens(
+            &AdjacentlyTagged::Unit::<u8>,
+            &[
+                Token::Struct {
+                    name: "AdjacentlyTagged",
+                    len: 2,
+                },
+                Token::Str("f"),
+                Token::Unit,
+                Token::Str("t"),
+                Token::UnitVariant {
+                    name: "AdjacentlyTagged",
+                    variant: "Unit",
+                },
+                Token::Str("g"),
+                Token::Unit,
+                Token::Str("c"),
+                Token::Unit,
+                Token::Str("h"),
+                Token::Unit,
+                Token::StructEnd,
+            ],
+        );
+    }
+
+    #[test]
+    fn map_int_tag_content() {
+        // Map: tag (as number) + content (as number)
+        assert_de_tokens(
+            &AdjacentlyTagged::Unit::<u8>,
+            &[
+                Token::Struct {
+                    name: "AdjacentlyTagged",
+                    len: 2,
+                },
+                Token::U8(0),
+                Token::UnitVariant {
+                    name: "AdjacentlyTagged",
+                    variant: "Unit",
+                },
+                Token::U8(1),
+                Token::Unit,
+                Token::StructEnd,
+            ],
+        );
+
+        // Map: content (as number) + tag (as number)
+        assert_de_tokens(
+            &AdjacentlyTagged::Unit::<u8>,
+            &[
+                Token::Struct {
+                    name: "AdjacentlyTagged",
+                    len: 2,
+                },
+                Token::U64(1),
+                Token::Unit,
+                Token::U64(0),
+                Token::UnitVariant {
+                    name: "AdjacentlyTagged",
+                    variant: "Unit",
+                },
+                Token::StructEnd,
+            ],
+        );
+    }
+
+    #[test]
+    fn map_bytes_tag_content() {
+        // Map: tag + content
+        assert_de_tokens(
+            &AdjacentlyTagged::Unit::<u8>,
+            &[
+                Token::Struct {
+                    name: "AdjacentlyTagged",
+                    len: 2,
+                },
+                Token::BorrowedBytes(b"t"),
+                Token::UnitVariant {
+                    name: "AdjacentlyTagged",
+                    variant: "Unit",
+                },
+                Token::BorrowedBytes(b"c"),
+                Token::Unit,
+                Token::StructEnd,
+            ],
+        );
+
+        // Map: content + tag
+        assert_de_tokens(
+            &AdjacentlyTagged::Unit::<u8>,
+            &[
+                Token::Struct {
+                    name: "AdjacentlyTagged",
+                    len: 2,
+                },
+                Token::Bytes(b"c"),
+                Token::Unit,
+                Token::Bytes(b"t"),
+                Token::UnitVariant {
+                    name: "AdjacentlyTagged",
+                    variant: "Unit",
+                },
+                Token::StructEnd,
+            ],
+        );
+    }
+
+    #[test]
+    fn seq_tag_content() {
+        // Seq: tag and content
+        assert_de_tokens(
+            &AdjacentlyTagged::Unit::<u8>,
+            &[
+                Token::Seq { len: Some(2) },
+                Token::UnitVariant {
+                    name: "AdjacentlyTagged",
+                    variant: "Unit",
+                },
+                Token::Unit,
+                Token::SeqEnd,
+            ],
+        );
+
+        // Seq: tag (as string) and content
+        assert_de_tokens(
+            &AdjacentlyTagged::Unit::<u8>,
+            &[
+                Token::Seq { len: None },
+                Token::Str("Unit"), // tag
+                Token::Unit,        // content
+                Token::SeqEnd,
+            ],
+        );
+
+        // Seq: tag (as borrowed string) and content
+        assert_de_tokens(
+            &AdjacentlyTagged::Unit::<u8>,
+            &[
+                Token::Seq { len: None },
+                Token::BorrowedStr("Unit"), // tag
+                Token::Unit,                // content
+                Token::SeqEnd,
+            ],
+        );
+    }
+}
+
+mod newtype {
+    use super::*;
+
+    #[test]
+    fn map_tag_only() {
+        // optional newtype with no content field
+        assert_de_tokens(
+            &AdjacentlyTagged::Newtype::<Option<u8>>(None),
+            &[
+                Token::Struct {
+                    name: "AdjacentlyTagged",
+                    len: 1,
+                },
+                Token::Str("t"),
+                Token::UnitVariant {
+                    name: "AdjacentlyTagged",
+                    variant: "Newtype",
+                },
+                Token::StructEnd,
+            ],
+        );
+    }
+
+    #[test]
+    fn map_tag_content() {
+        let value = AdjacentlyTagged::Newtype::<u8>(1);
+
+        // Map: tag + content
+        assert_tokens(
+            &value,
+            &[
+                Token::Struct {
+                    name: "AdjacentlyTagged",
+                    len: 2,
+                },
+                Token::Str("t"),
+                Token::UnitVariant {
+                    name: "AdjacentlyTagged",
+                    variant: "Newtype",
+                },
+                Token::Str("c"),
+                Token::U8(1),
+                Token::StructEnd,
+            ],
+        );
+
+        // Map: content + tag
+        assert_de_tokens(
+            &value,
+            &[
+                Token::Struct {
+                    name: "AdjacentlyTagged",
+                    len: 2,
+                },
+                Token::Str("c"),
+                Token::U8(1),
+                Token::Str("t"),
+                Token::UnitVariant {
+                    name: "AdjacentlyTagged",
+                    variant: "Newtype",
+                },
+                Token::StructEnd,
+            ],
+        );
+    }
+
+    #[test]
+    fn seq() {
+        let value = AdjacentlyTagged::Newtype::<u8>(1);
+
+        // Seq: tag and content
+        assert_de_tokens(
+            &value,
+            &[
+                Token::Seq { len: Some(2) },
+                Token::UnitVariant {
+                    name: "AdjacentlyTagged",
+                    variant: "Newtype",
+                },
+                Token::U8(1),
+                Token::SeqEnd,
+            ],
+        );
+
+        // Seq: tag (as string) and content
+        assert_de_tokens(
+            &value,
+            &[
+                Token::Seq { len: None },
+                Token::Str("Newtype"), // tag
+                Token::U8(1),          // content
+                Token::SeqEnd,
+            ],
+        );
+
+        // Seq: tag (as borrowed string) and content
+        assert_de_tokens(
+            &value,
+            &[
+                Token::Seq { len: None },
+                Token::BorrowedStr("Newtype"), // tag
+                Token::U8(1),                  // content
+                Token::SeqEnd,
+            ],
+        );
+    }
+}
+
+#[test]
+fn newtype_with_newtype() {
+    #[derive(Debug, PartialEq, Serialize, Deserialize)]
+    struct NewtypeStruct(u32);
+
+    assert_de_tokens(
+        &AdjacentlyTagged::Newtype(NewtypeStruct(5)),
+        &[
+            Token::Struct {
+                name: "AdjacentlyTagged",
+                len: 2,
+            },
+            Token::Str("c"),
+            Token::NewtypeStruct {
+                name: "NewtypeStruct",
+            },
+            Token::U32(5),
+            Token::Str("t"),
+            Token::UnitVariant {
+                name: "AdjacentlyTagged",
+                variant: "Newtype",
+            },
+            Token::StructEnd,
+        ],
+    );
+}
+
+mod tuple {
+    use super::*;
+
+    #[test]
+    fn map() {
+        let value = AdjacentlyTagged::Tuple::<u8>(1, 1);
+
+        // Map: tag + content
+        assert_tokens(
+            &value,
+            &[
+                Token::Struct {
+                    name: "AdjacentlyTagged",
+                    len: 2,
+                },
+                Token::Str("t"),
+                Token::UnitVariant {
+                    name: "AdjacentlyTagged",
+                    variant: "Tuple",
+                },
+                Token::Str("c"),
+                Token::Tuple { len: 2 },
+                Token::U8(1),
+                Token::U8(1),
+                Token::TupleEnd,
+                Token::StructEnd,
+            ],
+        );
+
+        // Map: content + tag
+        assert_de_tokens(
+            &value,
+            &[
+                Token::Struct {
+                    name: "AdjacentlyTagged",
+                    len: 2,
+                },
+                Token::Str("c"),
+                Token::Tuple { len: 2 },
+                Token::U8(1),
+                Token::U8(1),
+                Token::TupleEnd,
+                Token::Str("t"),
+                Token::UnitVariant {
+                    name: "AdjacentlyTagged",
+                    variant: "Tuple",
+                },
+                Token::StructEnd,
+            ],
+        );
+    }
+
+    #[test]
+    fn seq() {
+        let value = AdjacentlyTagged::Tuple::<u8>(1, 1);
+
+        // Seq: tag + content
+        assert_de_tokens(
+            &value,
+            &[
+                Token::Seq { len: Some(2) },
+                Token::UnitVariant {
+                    name: "AdjacentlyTagged",
+                    variant: "Tuple",
+                },
+                Token::Tuple { len: 2 },
+                Token::U8(1),
+                Token::U8(1),
+                Token::TupleEnd,
+                Token::SeqEnd,
+            ],
+        );
+    }
+}
+
+mod struct_ {
+    use super::*;
+
+    #[test]
+    fn map() {
+        let value = AdjacentlyTagged::Struct::<u8> { f: 1 };
+
+        // Map: tag + content
+        assert_tokens(
+            &value,
+            &[
+                Token::Struct {
+                    name: "AdjacentlyTagged",
+                    len: 2,
+                },
+                Token::Str("t"),
+                Token::UnitVariant {
+                    name: "AdjacentlyTagged",
+                    variant: "Struct",
+                },
+                Token::Str("c"),
+                Token::Struct {
+                    name: "Struct",
+                    len: 1,
+                },
+                Token::Str("f"),
+                Token::U8(1),
+                Token::StructEnd,
+                Token::StructEnd,
+            ],
+        );
+
+        // Map: content + tag
+        assert_de_tokens(
+            &value,
+            &[
+                Token::Struct {
+                    name: "AdjacentlyTagged",
+                    len: 2,
+                },
+                Token::Str("c"),
+                Token::Struct {
+                    name: "Struct",
+                    len: 1,
+                },
+                Token::Str("f"),
+                Token::U8(1),
+                Token::StructEnd,
+                Token::Str("t"),
+                Token::UnitVariant {
+                    name: "AdjacentlyTagged",
+                    variant: "Struct",
+                },
+                Token::StructEnd,
+            ],
+        );
+    }
+
+    #[test]
+    fn seq() {
+        let value = AdjacentlyTagged::Struct::<u8> { f: 1 };
+
+        // Seq: tag + content
+        assert_de_tokens(
+            &value,
+            &[
+                Token::Seq { len: Some(2) },
+                Token::UnitVariant {
+                    name: "AdjacentlyTagged",
+                    variant: "Struct",
+                },
+                Token::Struct {
+                    name: "Struct",
+                    len: 1,
+                },
+                Token::Str("f"),
+                Token::U8(1),
+                Token::StructEnd,
+                Token::SeqEnd,
+            ],
+        );
+    }
+}
+
+#[test]
+fn struct_with_flatten() {
+    #[derive(Serialize, Deserialize, PartialEq, Debug)]
+    #[serde(tag = "t", content = "c")]
+    enum Data {
+        A {
+            a: i32,
+            #[serde(flatten)]
+            flat: Flat,
+        },
+    }
+
+    #[derive(Serialize, Deserialize, PartialEq, Debug)]
+    struct Flat {
+        b: i32,
+    }
+
+    let data = Data::A {
+        a: 0,
+        flat: Flat { b: 0 },
+    };
+
+    assert_tokens(
+        &data,
+        &[
+            Token::Struct {
+                name: "Data",
+                len: 2,
+            },
+            Token::Str("t"),
+            Token::UnitVariant {
+                name: "Data",
+                variant: "A",
+            },
+            Token::Str("c"),
+            Token::Map { len: None },
+            Token::Str("a"),
+            Token::I32(0),
+            Token::Str("b"),
+            Token::I32(0),
+            Token::MapEnd,
+            Token::StructEnd,
+        ],
+    );
+}
+
+#[test]
+fn expecting_message() {
+    #[derive(Deserialize)]
+    #[serde(tag = "tag", content = "content")]
+    #[serde(expecting = "something strange...")]
+    enum Enum {
+        AdjacentlyTagged,
+    }
+
+    assert_de_tokens_error::<Enum>(
+        &[Token::Str("AdjacentlyTagged")],
+        r#"invalid type: string "AdjacentlyTagged", expected something strange..."#,
+    );
+
+    assert_de_tokens_error::<Enum>(
+        &[Token::Map { len: None }, Token::Unit],
+        r#"invalid type: unit value, expected "tag", "content", or other ignored fields"#,
+    );
+
+    // Check that #[serde(expecting = "...")] doesn't affect variant identifier error message
+    assert_de_tokens_error::<Enum>(
+        &[Token::Map { len: None }, Token::Str("tag"), Token::Unit],
+        "invalid type: unit value, expected variant of enum Enum",
+    );
+}
+
+#[test]
+fn partially_untagged() {
+    #[derive(Serialize, Deserialize, PartialEq, Debug)]
+    #[serde(tag = "t", content = "c")]
+    enum Data {
+        A(u32),
+        B,
+        #[serde(untagged)]
+        Var(u32),
+    }
+
+    let data = Data::A(7);
+
+    assert_de_tokens(
+        &data,
+        &[
+            Token::Map { len: None },
+            Token::Str("t"),
+            Token::Str("A"),
+            Token::Str("c"),
+            Token::U32(7),
+            Token::MapEnd,
+        ],
+    );
+
+    let data = Data::Var(42);
+
+    assert_de_tokens(&data, &[Token::U32(42)]);
+
+    // TODO test error output
+}
+
+#[test]
+fn deny_unknown_fields() {
+    #[derive(Debug, PartialEq, Deserialize)]
+    #[serde(tag = "t", content = "c", deny_unknown_fields)]
+    enum AdjacentlyTagged {
+        Unit,
+    }
+
+    assert_de_tokens(
+        &AdjacentlyTagged::Unit,
+        &[
+            Token::Struct {
+                name: "AdjacentlyTagged",
+                len: 2,
+            },
+            Token::Str("t"),
+            Token::UnitVariant {
+                name: "AdjacentlyTagged",
+                variant: "Unit",
+            },
+            Token::Str("c"),
+            Token::Unit,
+            Token::StructEnd,
+        ],
+    );
+
+    assert_de_tokens_error::<AdjacentlyTagged>(
+        &[
+            Token::Struct {
+                name: "AdjacentlyTagged",
+                len: 2,
+            },
+            Token::Str("t"),
+            Token::UnitVariant {
+                name: "AdjacentlyTagged",
+                variant: "Unit",
+            },
+            Token::Str("c"),
+            Token::Unit,
+            Token::Str("h"),
+        ],
+        r#"invalid value: string "h", expected "t" or "c""#,
+    );
+
+    assert_de_tokens_error::<AdjacentlyTagged>(
+        &[
+            Token::Struct {
+                name: "AdjacentlyTagged",
+                len: 2,
+            },
+            Token::Str("h"),
+        ],
+        r#"invalid value: string "h", expected "t" or "c""#,
+    );
+
+    assert_de_tokens_error::<AdjacentlyTagged>(
+        &[
+            Token::Struct {
+                name: "AdjacentlyTagged",
+                len: 2,
+            },
+            Token::Str("c"),
+            Token::Unit,
+            Token::Str("h"),
+        ],
+        r#"invalid value: string "h", expected "t" or "c""#,
+    );
+
+    assert_de_tokens_error::<AdjacentlyTagged>(
+        &[
+            Token::Struct {
+                name: "AdjacentlyTagged",
+                len: 2,
+            },
+            Token::U64(0), // tag field
+            Token::UnitVariant {
+                name: "AdjacentlyTagged",
+                variant: "Unit",
+            },
+            Token::U64(3),
+        ],
+        r#"invalid value: integer `3`, expected "t" or "c""#,
+    );
+
+    assert_de_tokens_error::<AdjacentlyTagged>(
+        &[
+            Token::Struct {
+                name: "AdjacentlyTagged",
+                len: 2,
+            },
+            Token::Bytes(b"c"),
+            Token::Unit,
+            Token::Bytes(b"h"),
+        ],
+        r#"invalid value: byte array, expected "t" or "c""#,
+    );
+}

test_suite/tests/test_enum_untagged.rs

@@ -0,0 +1,583 @@
+#![deny(trivial_numeric_casts)]
+#![allow(
+    clippy::derive_partial_eq_without_eq,
+    clippy::enum_variant_names,
+    clippy::redundant_field_names,
+    clippy::too_many_lines
+)]
+
+mod bytes;
+
+use serde_derive::{Deserialize, Serialize};
+use serde_test::{assert_de_tokens, assert_de_tokens_error, assert_tokens, Token};
+use std::collections::BTreeMap;
+
+#[test]
+fn complex() {
+    #[derive(Debug, PartialEq, Serialize, Deserialize)]
+    #[serde(untagged)]
+    enum Untagged {
+        A { a: u8 },
+        B { b: u8 },
+        C,
+        D(u8),
+        E(String),
+        F(u8, u8),
+    }
+
+    assert_tokens(
+        &Untagged::A { a: 1 },
+        &[
+            Token::Struct {
+                name: "Untagged",
+                len: 1,
+            },
+            Token::Str("a"),
+            Token::U8(1),
+            Token::StructEnd,
+        ],
+    );
+
+    assert_tokens(
+        &Untagged::B { b: 2 },
+        &[
+            Token::Struct {
+                name: "Untagged",
+                len: 1,
+            },
+            Token::Str("b"),
+            Token::U8(2),
+            Token::StructEnd,
+        ],
+    );
+
+    // Serializes to unit, deserializes from either depending on format's
+    // preference.
+    assert_tokens(&Untagged::C, &[Token::Unit]);
+    assert_de_tokens(&Untagged::C, &[Token::None]);
+
+    assert_tokens(&Untagged::D(4), &[Token::U8(4)]);
+    assert_tokens(&Untagged::E("e".to_owned()), &[Token::Str("e")]);
+
+    assert_tokens(
+        &Untagged::F(1, 2),
+        &[
+            Token::Tuple { len: 2 },
+            Token::U8(1),
+            Token::U8(2),
+            Token::TupleEnd,
+        ],
+    );
+
+    assert_de_tokens_error::<Untagged>(
+        &[Token::Tuple { len: 1 }, Token::U8(1), Token::TupleEnd],
+        "data did not match any variant of untagged enum Untagged",
+    );
+
+    assert_de_tokens_error::<Untagged>(
+        &[
+            Token::Tuple { len: 3 },
+            Token::U8(1),
+            Token::U8(2),
+            Token::U8(3),
+            Token::TupleEnd,
+        ],
+        "data did not match any variant of untagged enum Untagged",
+    );
+}
+
+#[test]
+fn newtype_unit_and_empty_map() {
+    #[derive(Debug, PartialEq, Serialize, Deserialize)]
+    struct Unit;
+
+    #[derive(Debug, PartialEq, Serialize, Deserialize)]
+    #[serde(untagged)]
+    enum Message {
+        Unit(Unit),
+        Map(BTreeMap<String, String>),
+    }
+
+    assert_tokens(
+        &Message::Map(BTreeMap::new()),
+        &[Token::Map { len: Some(0) }, Token::MapEnd],
+    );
+}
+
+// Reaches crate::private::de::content::ContentRefDeserializer::deserialize_newtype_struct
+#[test]
+fn newtype_struct() {
+    #[derive(Debug, PartialEq, Serialize, Deserialize)]
+    struct NewtypeStruct(u32);
+
+    #[derive(Debug, PartialEq, Serialize, Deserialize)]
+    #[serde(untagged)]
+    enum E {
+        Newtype(NewtypeStruct),
+        Null,
+    }
+
+    let value = E::Newtype(NewtypeStruct(5));
+
+    // Content::Newtype case
+    assert_tokens(
+        &value,
+        &[
+            Token::NewtypeStruct {
+                name: "NewtypeStruct",
+            },
+            Token::U32(5),
+        ],
+    );
+
+    // _ case
+    assert_de_tokens(&value, &[Token::U32(5)]);
+}
+
+mod newtype_enum {
+    use super::*;
+
+    #[derive(Debug, PartialEq, Serialize, Deserialize)]
+    #[serde(untagged)]
+    enum Outer {
+        Inner(Inner),
+    }
+
+    #[derive(Debug, PartialEq, Serialize, Deserialize)]
+    enum Inner {
+        Unit,
+        Newtype(u8),
+        Tuple0(),
+        Tuple2(u8, u8),
+        Struct { f: u8 },
+        EmptyStruct {},
+    }
+
+    // Reaches crate::private::de::content::VariantRefDeserializer::unit_variant
+    #[test]
+    fn unit() {
+        assert_tokens(
+            &Outer::Inner(Inner::Unit),
+            &[Token::UnitVariant {
+                name: "Inner",
+                variant: "Unit",
+            }],
+        );
+    }
+
+    // Reaches crate::private::de::content::VariantRefDeserializer::newtype_variant_seed
+    #[test]
+    fn newtype() {
+        assert_tokens(
+            &Outer::Inner(Inner::Newtype(1)),
+            &[
+                Token::NewtypeVariant {
+                    name: "Inner",
+                    variant: "Newtype",
+                },
+                Token::U8(1),
+            ],
+        );
+    }
+
+    // Reaches crate::private::de::content::VariantRefDeserializer::tuple_variant
+    #[test]
+    fn tuple0() {
+        assert_tokens(
+            &Outer::Inner(Inner::Tuple0()),
+            &[
+                Token::TupleVariant {
+                    name: "Inner",
+                    variant: "Tuple0",
+                    len: 0,
+                },
+                Token::TupleVariantEnd,
+            ],
+        );
+    }
+
+    // Reaches crate::private::de::content::VariantRefDeserializer::tuple_variant
+    #[test]
+    fn tuple2() {
+        assert_tokens(
+            &Outer::Inner(Inner::Tuple2(1, 1)),
+            &[
+                Token::TupleVariant {
+                    name: "Inner",
+                    variant: "Tuple2",
+                    len: 2,
+                },
+                Token::U8(1),
+                Token::U8(1),
+                Token::TupleVariantEnd,
+            ],
+        );
+    }
+
+    // Reaches crate::private::de::content::VariantRefDeserializer::struct_variant
+    // Content::Map case
+    #[test]
+    fn struct_from_map() {
+        assert_tokens(
+            &Outer::Inner(Inner::Struct { f: 1 }),
+            &[
+                Token::StructVariant {
+                    name: "Inner",
+                    variant: "Struct",
+                    len: 1,
+                },
+                Token::Str("f"),
+                Token::U8(1),
+                Token::StructVariantEnd,
+            ],
+        );
+    }
+
+    // Reaches crate::private::de::content::VariantRefDeserializer::struct_variant
+    // Content::Seq case
+    #[test]
+    fn struct_from_seq() {
+        assert_de_tokens(
+            &Outer::Inner(Inner::Struct { f: 1 }),
+            &[
+                Token::Map { len: Some(1) },
+                // tag
+                Token::Str("Struct"),
+                // content
+                Token::Seq { len: Some(1) },
+                Token::U8(1),
+                Token::SeqEnd,
+                Token::MapEnd,
+            ],
+        );
+    }
+
+    // Reaches crate::private::de::content::VariantRefDeserializer::struct_variant
+    // Content::Map case
+    // Special case - empty map
+    #[test]
+    fn empty_struct_from_map() {
+        assert_de_tokens(
+            &Outer::Inner(Inner::EmptyStruct {}),
+            &[
+                Token::Map { len: Some(1) },
+                // tag
+                Token::Str("EmptyStruct"),
+                // content
+                Token::Map { len: Some(0) },
+                Token::MapEnd,
+                Token::MapEnd,
+            ],
+        );
+    }
+
+    // Reaches crate::private::de::content::VariantRefDeserializer::struct_variant
+    // Content::Seq case
+    // Special case - empty seq
+    #[test]
+    fn empty_struct_from_seq() {
+        assert_de_tokens(
+            &Outer::Inner(Inner::EmptyStruct {}),
+            &[
+                Token::Map { len: Some(1) },
+                // tag
+                Token::Str("EmptyStruct"),
+                // content
+                Token::Seq { len: Some(0) },
+                Token::SeqEnd,
+                Token::MapEnd,
+            ],
+        );
+    }
+}
+
+// Reaches crate::private::de::content::ContentRefDeserializer::deserialize_option
+mod with_optional_field {
+    use super::*;
+
+    #[derive(Debug, PartialEq, Serialize, Deserialize)]
+    #[serde(untagged)]
+    enum Enum {
+        Struct { optional: Option<u32> },
+        Null,
+    }
+
+    #[test]
+    fn some() {
+        assert_tokens(
+            &Enum::Struct { optional: Some(42) },
+            &[
+                Token::Struct {
+                    name: "Enum",
+                    len: 1,
+                },
+                Token::Str("optional"),
+                Token::Some,
+                Token::U32(42),
+                Token::StructEnd,
+            ],
+        );
+    }
+
+    #[test]
+    fn some_without_marker() {
+        assert_de_tokens(
+            &Enum::Struct { optional: Some(42) },
+            &[
+                Token::Struct {
+                    name: "Enum",
+                    len: 1,
+                },
+                Token::Str("optional"),
+                Token::U32(42),
+                Token::StructEnd,
+            ],
+        );
+    }
+
+    #[test]
+    fn none() {
+        assert_tokens(
+            &Enum::Struct { optional: None },
+            &[
+                Token::Struct {
+                    name: "Enum",
+                    len: 1,
+                },
+                Token::Str("optional"),
+                Token::None,
+                Token::StructEnd,
+            ],
+        );
+    }
+
+    #[test]
+    fn unit() {
+        assert_de_tokens(
+            &Enum::Struct { optional: None },
+            &[
+                Token::Map { len: None },
+                Token::Str("optional"),
+                Token::Unit,
+                Token::MapEnd,
+            ],
+        );
+    }
+}
+
+#[test]
+fn string_and_bytes() {
+    #[derive(Debug, PartialEq, Deserialize)]
+    #[serde(untagged)]
+    enum Untagged {
+        String {
+            string: String,
+        },
+        Bytes {
+            #[serde(with = "bytes")]
+            bytes: Vec<u8>,
+        },
+    }
+
+    assert_de_tokens(
+        &Untagged::String {
+            string: "\0".to_owned(),
+        },
+        &[
+            Token::Struct {
+                name: "Untagged",
+                len: 1,
+            },
+            Token::Str("string"),
+            Token::Str("\0"),
+            Token::StructEnd,
+        ],
+    );
+
+    assert_de_tokens(
+        &Untagged::String {
+            string: "\0".to_owned(),
+        },
+        &[
+            Token::Struct {
+                name: "Untagged",
+                len: 1,
+            },
+            Token::Str("string"),
+            Token::String("\0"),
+            Token::StructEnd,
+        ],
+    );
+
+    assert_de_tokens(
+        &Untagged::String {
+            string: "\0".to_owned(),
+        },
+        &[
+            Token::Struct {
+                name: "Untagged",
+                len: 1,
+            },
+            Token::Str("string"),
+            Token::Bytes(b"\0"),
+            Token::StructEnd,
+        ],
+    );
+
+    assert_de_tokens(
+        &Untagged::String {
+            string: "\0".to_owned(),
+        },
+        &[
+            Token::Struct {
+                name: "Untagged",
+                len: 1,
+            },
+            Token::Str("string"),
+            Token::ByteBuf(b"\0"),
+            Token::StructEnd,
+        ],
+    );
+
+    assert_de_tokens(
+        &Untagged::Bytes { bytes: vec![0] },
+        &[
+            Token::Struct {
+                name: "Untagged",
+                len: 1,
+            },
+            Token::Str("bytes"),
+            Token::Str("\0"),
+            Token::StructEnd,
+        ],
+    );
+
+    assert_de_tokens(
+        &Untagged::Bytes { bytes: vec![0] },
+        &[
+            Token::Struct {
+                name: "Untagged",
+                len: 1,
+            },
+            Token::Str("bytes"),
+            Token::String("\0"),
+            Token::StructEnd,
+        ],
+    );
+
+    assert_de_tokens(
+        &Untagged::Bytes { bytes: vec![0] },
+        &[
+            Token::Struct {
+                name: "Untagged",
+                len: 1,
+            },
+            Token::Str("bytes"),
+            Token::Bytes(b"\0"),
+            Token::StructEnd,
+        ],
+    );
+
+    assert_de_tokens(
+        &Untagged::Bytes { bytes: vec![0] },
+        &[
+            Token::Struct {
+                name: "Untagged",
+                len: 1,
+            },
+            Token::Str("bytes"),
+            Token::ByteBuf(b"\0"),
+            Token::StructEnd,
+        ],
+    );
+
+    assert_de_tokens(
+        &Untagged::Bytes { bytes: vec![0] },
+        &[
+            Token::Struct {
+                name: "Untagged",
+                len: 1,
+            },
+            Token::Str("bytes"),
+            Token::Seq { len: Some(1) },
+            Token::U8(0),
+            Token::SeqEnd,
+            Token::StructEnd,
+        ],
+    );
+}
+
+#[test]
+fn contains_flatten() {
+    #[derive(Serialize, Deserialize, PartialEq, Debug)]
+    #[serde(untagged)]
+    enum Data {
+        A {
+            a: i32,
+            #[serde(flatten)]
+            flat: Flat,
+        },
+    }
+
+    #[derive(Serialize, Deserialize, PartialEq, Debug)]
+    struct Flat {
+        b: i32,
+    }
+
+    let data = Data::A {
+        a: 0,
+        flat: Flat { b: 0 },
+    };
+
+    assert_tokens(
+        &data,
+        &[
+            Token::Map { len: None },
+            Token::Str("a"),
+            Token::I32(0),
+            Token::Str("b"),
+            Token::I32(0),
+            Token::MapEnd,
+        ],
+    );
+}
+
+#[test]
+fn contains_flatten_with_integer_key() {
+    #[derive(Debug, PartialEq, Serialize, Deserialize)]
+    #[serde(untagged)]
+    pub enum Untagged {
+        Variant {
+            #[serde(flatten)]
+            map: BTreeMap<u64, String>,
+        },
+    }
+
+    assert_tokens(
+        &Untagged::Variant {
+            map: {
+                let mut map = BTreeMap::new();
+                map.insert(100, "BTreeMap".to_owned());
+                map
+            },
+        },
+        &[
+            Token::Map { len: None },
+            Token::U64(100),
+            Token::Str("BTreeMap"),
+            Token::MapEnd,
+        ],
+    );
+}
+
+#[test]
+fn expecting_message() {
+    #[derive(Deserialize)]
+    #[serde(untagged)]
+    #[serde(expecting = "something strange...")]
+    enum Enum {
+        Untagged,
+    }
+
+    assert_de_tokens_error::<Enum>(&[Token::Str("Untagged")], "something strange...");
+}

test_suite/tests/test_gen.rs

@@ -4,6 +4,7 @@
 
 #![deny(warnings)]
 #![allow(
+    confusable_idents,
     unknown_lints,
     mixed_script_confusables,
     clippy::derive_partial_eq_without_eq,
@@ -19,6 +20,7 @@
     clippy::trivially_copy_pass_by_ref,
     clippy::type_repetition_in_bounds
 )]
+#![deny(clippy::collection_is_never_read)]
 
 use serde::de::{Deserialize, DeserializeOwned, Deserializer};
 use serde::ser::{Serialize, Serializer};
@@ -287,60 +289,60 @@ fn test_gen() {
     assert::<EmptyEnumVariant>();
 
     #[derive(Serialize, Deserialize)]
-    struct NonAsciiIdents {
+    pub struct NonAsciiIdents {
         σ: f64,
     }
 
     #[derive(Serialize, Deserialize)]
-    struct EmptyBraced {}
+    pub struct EmptyBraced {}
 
     #[derive(Serialize, Deserialize)]
     #[serde(deny_unknown_fields)]
-    struct EmptyBracedDenyUnknown {}
+    pub struct EmptyBracedDenyUnknown {}
 
     #[derive(Serialize, Deserialize)]
-    struct BracedSkipAll {
+    pub struct BracedSkipAll {
         #[serde(skip_deserializing)]
         f: u8,
     }
 
     #[derive(Serialize, Deserialize)]
     #[serde(deny_unknown_fields)]
-    struct BracedSkipAllDenyUnknown {
+    pub struct BracedSkipAllDenyUnknown {
         #[serde(skip_deserializing)]
         f: u8,
     }
 
     #[derive(Serialize, Deserialize)]
-    struct EmptyTuple();
+    pub struct EmptyTuple();
 
     #[derive(Serialize, Deserialize)]
     #[serde(deny_unknown_fields)]
-    struct EmptyTupleDenyUnknown();
+    pub struct EmptyTupleDenyUnknown();
 
     #[derive(Serialize, Deserialize)]
-    struct TupleSkipAll(#[serde(skip_deserializing)] u8);
+    pub struct TupleSkipAll(#[serde(skip_deserializing)] u8);
 
     #[derive(Serialize, Deserialize)]
     #[serde(deny_unknown_fields)]
-    struct TupleSkipAllDenyUnknown(#[serde(skip_deserializing)] u8);
+    pub struct TupleSkipAllDenyUnknown(#[serde(skip_deserializing)] u8);
 
     #[derive(Serialize, Deserialize)]
-    enum EmptyEnum {}
+    pub enum EmptyEnum {}
 
     #[derive(Serialize, Deserialize)]
     #[serde(deny_unknown_fields)]
-    enum EmptyEnumDenyUnknown {}
+    pub enum EmptyEnumDenyUnknown {}
 
     #[derive(Serialize, Deserialize)]
-    enum EnumSkipAll {
+    pub enum EnumSkipAll {
         #[serde(skip_deserializing)]
         #[allow(dead_code)]
         Variant,
     }
 
     #[derive(Serialize, Deserialize)]
-    enum EmptyVariants {
+    pub enum EmptyVariants {
         Braced {},
         Tuple(),
         BracedSkip {
@@ -352,7 +354,7 @@ fn test_gen() {
 
     #[derive(Serialize, Deserialize)]
     #[serde(deny_unknown_fields)]
-    enum EmptyVariantsDenyUnknown {
+    pub enum EmptyVariantsDenyUnknown {
         Braced {},
         Tuple(),
         BracedSkip {
@@ -364,21 +366,21 @@ fn test_gen() {
 
     #[derive(Serialize, Deserialize)]
     #[serde(deny_unknown_fields)]
-    struct UnitDenyUnknown;
+    pub struct UnitDenyUnknown;
 
     #[derive(Serialize, Deserialize)]
-    struct EmptyArray {
+    pub struct EmptyArray {
         empty: [X; 0],
     }
 
-    enum Or<A, B> {
+    pub enum Or<A, B> {
         A(A),
         B(B),
     }
 
     #[derive(Serialize, Deserialize)]
     #[serde(untagged, remote = "Or")]
-    enum OrDef<A, B> {
+    pub enum OrDef<A, B> {
         A(A),
         B(B),
     }
@@ -390,7 +392,7 @@ fn test_gen() {
     struct StrDef<'a>(&'a str);
 
     #[derive(Serialize, Deserialize)]
-    struct Remote<'a> {
+    pub struct Remote<'a> {
         #[serde(with = "OrDef")]
         or: Or<u8, bool>,
         #[serde(borrow, with = "StrDef")]
@@ -398,7 +400,7 @@ fn test_gen() {
     }
 
     #[derive(Serialize, Deserialize)]
-    enum BorrowVariant<'a> {
+    pub enum BorrowVariant<'a> {
         #[serde(borrow, with = "StrDef")]
         S(Str<'a>),
     }
@@ -415,14 +417,14 @@ fn test_gen() {
 
     // This would not work if SDef::serialize / deserialize are private.
     #[derive(Serialize, Deserialize)]
-    struct RemoteVisibility {
+    pub struct RemoteVisibility {
         #[serde(with = "vis::SDef")]
         s: vis::S,
     }
 
     #[derive(Serialize, Deserialize)]
     #[serde(remote = "Self")]
-    struct RemoteSelf;
+    pub struct RemoteSelf;
 
     #[derive(Serialize, Deserialize)]
     enum ExternallyTaggedVariantWith {
@@ -546,26 +548,45 @@ fn test_gen() {
     assert::<FlattenWith>();
 
     #[derive(Serialize, Deserialize)]
-    #[serde(deny_unknown_fields)]
-    struct FlattenDenyUnknown<T> {
+    pub struct Flatten<T> {
         #[serde(flatten)]
         t: T,
     }
 
     #[derive(Serialize, Deserialize)]
-    struct StaticStrStruct<'a> {
+    #[serde(deny_unknown_fields)]
+    pub struct FlattenDenyUnknown<T> {
+        #[serde(flatten)]
+        t: T,
+    }
+
+    #[derive(Serialize, Deserialize)]
+    pub struct SkipDeserializing<T> {
+        #[serde(skip_deserializing)]
+        flat: T,
+    }
+
+    #[derive(Serialize, Deserialize)]
+    #[serde(deny_unknown_fields)]
+    pub struct SkipDeserializingDenyUnknown<T> {
+        #[serde(skip_deserializing)]
+        flat: T,
+    }
+
+    #[derive(Serialize, Deserialize)]
+    pub struct StaticStrStruct<'a> {
         a: &'a str,
         b: &'static str,
     }
 
     #[derive(Serialize, Deserialize)]
-    struct StaticStrTupleStruct<'a>(&'a str, &'static str);
+    pub struct StaticStrTupleStruct<'a>(&'a str, &'static str);
 
     #[derive(Serialize, Deserialize)]
-    struct StaticStrNewtypeStruct(&'static str);
+    pub struct StaticStrNewtypeStruct(&'static str);
 
     #[derive(Serialize, Deserialize)]
-    enum StaticStrEnum<'a> {
+    pub enum StaticStrEnum<'a> {
         Struct { a: &'a str, b: &'static str },
         Tuple(&'a str, &'static str),
         Newtype(&'static str),
@@ -639,6 +660,7 @@ fn test_gen() {
             use serde_derive::{Deserialize, Serialize};
 
             #[derive(Serialize, Deserialize)]
+            #[allow(dead_code)]
             struct Restricted {
                 pub(super) a: usize,
                 pub(in super::inner) b: usize,
@@ -648,7 +670,7 @@ fn test_gen() {
 
     #[derive(Deserialize)]
     #[serde(tag = "t", content = "c")]
-    enum AdjacentlyTaggedVoid {}
+    pub enum AdjacentlyTaggedVoid {}
 
     #[derive(Serialize, Deserialize)]
     enum SkippedVariant<T> {
@@ -661,14 +683,13 @@ fn test_gen() {
     assert::<SkippedVariant<X>>();
 
     #[derive(Deserialize)]
-    struct ImplicitlyBorrowedOption<'a> {
-        #[allow(dead_code)]
+    pub struct ImplicitlyBorrowedOption<'a> {
         option: std::option::Option<&'a str>,
     }
 
     #[derive(Serialize, Deserialize)]
     #[serde(untagged)]
-    enum UntaggedNewtypeVariantWith {
+    pub enum UntaggedNewtypeVariantWith {
         Newtype(
             #[serde(serialize_with = "ser_x")]
             #[serde(deserialize_with = "de_x")]
@@ -678,7 +699,7 @@ fn test_gen() {
 
     #[derive(Serialize, Deserialize)]
     #[serde(transparent)]
-    struct TransparentWith {
+    pub struct TransparentWith {
         #[serde(serialize_with = "ser_x")]
         #[serde(deserialize_with = "de_x")]
         x: X,
@@ -686,41 +707,60 @@ fn test_gen() {
 
     #[derive(Deserialize)]
     #[serde(untagged)]
-    enum UntaggedWithBorrow<'a> {
-        Single(#[serde(borrow)] RelObject<'a>),
-        Many(#[serde(borrow)] Vec<RelObject<'a>>),
+    pub enum UntaggedWithBorrow<'a> {
+        Single(
+            #[serde(borrow)]
+            #[allow(dead_code)]
+            RelObject<'a>,
+        ),
+        Many(
+            #[serde(borrow)]
+            #[allow(dead_code)]
+            Vec<RelObject<'a>>,
+        ),
     }
 
     #[derive(Deserialize)]
-    struct RelObject<'a> {
-        #[allow(dead_code)]
+    pub struct RelObject<'a> {
         ty: &'a str,
-        #[allow(dead_code)]
         id: String,
     }
 
     #[derive(Serialize, Deserialize)]
-    struct FlattenSkipSerializing<T> {
+    pub struct FlattenSkipSerializing<T> {
         #[serde(flatten, skip_serializing)]
         #[allow(dead_code)]
         flat: T,
     }
 
     #[derive(Serialize, Deserialize)]
-    struct FlattenSkipSerializingIf<T> {
+    pub struct FlattenSkipSerializingIf<T> {
         #[serde(flatten, skip_serializing_if = "StdOption::is_none")]
         flat: StdOption<T>,
     }
 
     #[derive(Serialize, Deserialize)]
-    struct FlattenSkipDeserializing<T> {
+    pub struct FlattenSkipDeserializing<T> {
         #[serde(flatten, skip_deserializing)]
         flat: T,
     }
 
+    #[derive(Serialize, Deserialize)]
+    #[serde(untagged)]
+    pub enum Inner<T> {
+        Builder {
+            s: T,
+            #[serde(flatten)]
+            o: T,
+        },
+        Default {
+            s: T,
+        },
+    }
+
     // https://github.com/serde-rs/serde/issues/1804
     #[derive(Serialize, Deserialize)]
-    enum Message {
+    pub enum Message {
         #[serde(skip)]
         #[allow(dead_code)]
         String(String),
@@ -730,6 +770,7 @@ fn test_gen() {
 
     #[derive(Serialize)]
     #[repr(packed)]
+    #[allow(dead_code)]
     struct Packed {
         x: u8,
         y: u16,
@@ -738,8 +779,7 @@ fn test_gen() {
     macro_rules! deriving {
         ($field:ty) => {
             #[derive(Deserialize)]
-            struct MacroRules<'a> {
-                #[allow(dead_code)]
+            pub struct MacroRules<'a> {
                 field: $field,
             }
         };
@@ -754,21 +794,20 @@ fn test_gen() {
     }
 
     #[derive(Deserialize)]
-    struct BorrowLifetimeInsideMacro<'a> {
+    pub struct BorrowLifetimeInsideMacro<'a> {
         #[serde(borrow = "'a")]
-        #[allow(dead_code)]
-        f: mac!(Cow<'a, str>),
+        pub f: mac!(Cow<'a, str>),
     }
 
     #[derive(Serialize)]
-    struct Struct {
+    pub struct Struct {
         #[serde(serialize_with = "vec_first_element")]
-        vec: Vec<Self>,
+        pub vec: Vec<Self>,
     }
 
     #[derive(Deserialize)]
     #[serde(bound(deserialize = "[&'de str; N]: Copy"))]
-    struct GenericUnitStruct<const N: usize>;
+    pub struct GenericUnitStruct<const N: usize>;
 }
 
 //////////////////////////////////////////////////////////////////////////
@@ -843,7 +882,7 @@ pub fn is_zero(n: &u8) -> bool {
     *n == 0
 }
 
-fn vec_first_element<T, S>(vec: &Vec<T>, serializer: S) -> StdResult<S::Ok, S::Error>
+fn vec_first_element<T, S>(vec: &[T], serializer: S) -> StdResult<S::Ok, S::Error>
 where
     T: Serialize,
     S: Serializer,
@@ -855,7 +894,7 @@ where
 
 #[derive(Debug, PartialEq, Deserialize)]
 #[serde(tag = "tag")]
-enum InternallyTagged {
+pub enum InternallyTagged {
     #[serde(deserialize_with = "deserialize_generic")]
     Unit,
 

test_suite/tests/test_remote.rs

@@ -7,14 +7,17 @@ mod remote {
 
     pub struct PrimitivePriv(u8);
 
+    #[allow(dead_code)]
     pub struct PrimitivePub(pub u8);
 
     pub struct NewtypePriv(Unit);
 
+    #[allow(dead_code)]
     pub struct NewtypePub(pub Unit);
 
     pub struct TuplePriv(u8, Unit);
 
+    #[allow(dead_code)]
     pub struct TuplePub(pub u8, pub Unit);
 
     pub struct StructPriv {
@@ -22,6 +25,7 @@ mod remote {
         b: Unit,
     }
 
+    #[allow(dead_code)]
     pub struct StructPub {
         pub a: u8,
         pub b: Unit,
@@ -86,12 +90,14 @@ mod remote {
         }
     }
 
+    #[allow(dead_code)]
     pub enum EnumGeneric<T> {
         Variant(T),
     }
 }
 
 #[derive(Serialize, Deserialize)]
+#[allow(dead_code)]
 struct Test {
     #[serde(with = "UnitDef")]
     unit: remote::Unit,
@@ -125,10 +131,14 @@ struct Test {
 
     #[serde(with = "EnumConcrete")]
     enum_concrete: remote::EnumGeneric<u8>,
+
+    #[serde(with = "ErrorKindDef")]
+    io_error_kind: ErrorKind,
 }
 
 #[derive(Serialize, Deserialize)]
 #[serde(remote = "remote::Unit")]
+#[allow(dead_code)]
 struct UnitDef;
 
 #[derive(Serialize, Deserialize)]
@@ -137,6 +147,7 @@ struct PrimitivePrivDef(#[serde(getter = "remote::PrimitivePriv::get")] u8);
 
 #[derive(Serialize, Deserialize)]
 #[serde(remote = "remote::PrimitivePub")]
+#[allow(dead_code)]
 struct PrimitivePubDef(u8);
 
 #[derive(Serialize, Deserialize)]
@@ -145,6 +156,7 @@ struct NewtypePrivDef(#[serde(getter = "remote::NewtypePriv::get", with = "UnitD
 
 #[derive(Serialize, Deserialize)]
 #[serde(remote = "remote::NewtypePub")]
+#[allow(dead_code)]
 struct NewtypePubDef(#[serde(with = "UnitDef")] remote::Unit);
 
 #[derive(Serialize, Deserialize)]
@@ -156,6 +168,7 @@ struct TuplePrivDef(
 
 #[derive(Serialize, Deserialize)]
 #[serde(remote = "remote::TuplePub")]
+#[allow(dead_code)]
 struct TuplePubDef(u8, #[serde(with = "UnitDef")] remote::Unit);
 
 #[derive(Serialize, Deserialize)]
@@ -171,6 +184,7 @@ struct StructPrivDef {
 
 #[derive(Serialize, Deserialize)]
 #[serde(remote = "remote::StructPub")]
+#[allow(dead_code)]
 struct StructPubDef {
     a: u8,
 
@@ -187,16 +201,37 @@ struct StructGenericWithGetterDef<T> {
 
 #[derive(Serialize, Deserialize)]
 #[serde(remote = "remote::StructGeneric<u8>")]
+#[allow(dead_code)]
 struct StructConcrete {
     value: u8,
 }
 
 #[derive(Serialize, Deserialize)]
 #[serde(remote = "remote::EnumGeneric<u8>")]
+#[allow(dead_code)]
 enum EnumConcrete {
     Variant(u8),
 }
 
+#[derive(Debug)]
+#[allow(dead_code)]
+enum ErrorKind {
+    NotFound,
+    PermissionDenied,
+    #[allow(dead_code)]
+    ConnectionRefused,
+}
+
+#[derive(Serialize, Deserialize)]
+#[serde(remote = "ErrorKind")]
+#[non_exhaustive]
+#[allow(dead_code)]
+enum ErrorKindDef {
+    NotFound,
+    PermissionDenied,
+    // ...
+}
+
 impl From<PrimitivePrivDef> for remote::PrimitivePriv {
     fn from(def: PrimitivePrivDef) -> Self {
         remote::PrimitivePriv::new(def.0)

test_suite/tests/test_self.rs

@@ -41,7 +41,7 @@ fn test_self() {
     }
 
     #[derive(Deserialize, Serialize)]
-    struct Tuple(
+    pub struct Tuple(
         Box<Self>,
         Box<<Self as Trait>::Assoc>,
         [(); Self::ASSOC],
@@ -60,7 +60,7 @@ fn test_self() {
     }
 
     #[derive(Deserialize, Serialize)]
-    enum Enum {
+    pub enum Enum {
         Struct {
             _f1: Box<Self>,
             _f2: Box<<Self as Trait>::Assoc>,

test_suite/tests/test_ser.rs

@@ -8,7 +8,7 @@ use std::cell::RefCell;
 use std::collections::{BTreeMap, BTreeSet, HashMap, HashSet};
 use std::ffi::CString;
 use std::net;
-use std::num::Wrapping;
+use std::num::{Saturating, Wrapping};
 use std::ops::Bound;
 use std::path::{Path, PathBuf};
 use std::rc::{Rc, Weak as RcWeak};
@@ -500,6 +500,38 @@ fn test_range_inclusive() {
     );
 }
 
+#[test]
+fn test_range_from() {
+    assert_ser_tokens(
+        &(1u32..),
+        &[
+            Token::Struct {
+                name: "RangeFrom",
+                len: 1,
+            },
+            Token::Str("start"),
+            Token::U32(1),
+            Token::StructEnd,
+        ],
+    );
+}
+
+#[test]
+fn test_range_to() {
+    assert_ser_tokens(
+        &(..2u32),
+        &[
+            Token::Struct {
+                name: "RangeTo",
+                len: 1,
+            },
+            Token::Str("end"),
+            Token::U32(2),
+            Token::StructEnd,
+        ],
+    );
+}
+
 #[test]
 fn test_bound() {
     assert_ser_tokens(
@@ -592,6 +624,11 @@ fn test_wrapping() {
     assert_ser_tokens(&Wrapping(1usize), &[Token::U64(1)]);
 }
 
+#[test]
+fn test_saturating() {
+    assert_ser_tokens(&Saturating(1usize), &[Token::U64(1)]);
+}
+
 #[test]
 fn test_rc_dst() {
     assert_ser_tokens(&Rc::<str>::from("s"), &[Token::Str("s")]);

test_suite/tests/test_serde_path.rs

@@ -1,5 +1,6 @@
 #![allow(
     clippy::extra_unused_type_parameters,
+    clippy::needless_lifetimes,
     clippy::type_repetition_in_bounds
 )]
 
@@ -27,19 +28,21 @@ mod fake_serde {
     {
     }
 
+    #[allow(dead_code)]
     pub trait Serialize {
         fn serialize<S: Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error>;
     }
 
+    #[allow(dead_code)]
     pub trait Deserialize<'a>: Sized {
         fn deserialize<D: Deserializer<'a>>(deserializer: D) -> Result<Self, D::Error>;
     }
 }
 
-trait AssertNotSerdeSerialize {}
+pub trait AssertNotSerdeSerialize {}
 
 impl<T: serde::Serialize> AssertNotSerdeSerialize for T {}
 
-trait AssertNotSerdeDeserialize<'a> {}
+pub trait AssertNotSerdeDeserialize<'a> {}
 
 impl<'a, T: serde::Deserialize<'a>> AssertNotSerdeDeserialize<'a> for T {}

test_suite/tests/test_value.rs

@@ -63,7 +63,7 @@ fn test_map_access_to_enum() {
                 type Value = Potential;
 
                 fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
-                    write!(formatter, "a map")
+                    formatter.write_str("a map")
                 }
 
                 fn visit_map<A>(self, map: A) -> Result<Self::Value, A::Error>

test_suite/tests/ui/conflict/alias-enum.rs

@@ -0,0 +1,75 @@
+#![allow(non_camel_case_types)]
+
+use serde_derive::Deserialize;
+
+#[derive(Deserialize)]
+enum E {
+    S1 {
+        #[serde(alias = "a", alias = "b", alias = "c")]
+        a: (),
+
+        // Warning on "c" and "b"
+        #[serde(alias = "c")]
+        b: (),
+
+        #[serde(skip_deserializing)]
+        c: (),
+    },
+
+    S2 {
+        #[serde(alias = "b", alias = "c")]
+        a: (),
+
+        // Warning on "c"
+        #[serde(rename = "c")]
+        b: (),
+    },
+
+    #[serde(rename_all = "UPPERCASE")]
+    S3 {
+        #[serde(alias = "B", alias = "c")]
+        a: (),
+
+        // Warning on "b" because this collides with the "B" above after
+        // applying rename rules
+        b: (),
+    },
+}
+
+#[derive(Deserialize)]
+enum E1 {
+    #[serde(alias = "a", alias = "b", alias = "c")]
+    a,
+
+    // Warning on "c" and "b"
+    #[serde(alias = "c")]
+    b,
+
+    #[serde(skip_deserializing)]
+    c,
+}
+
+#[derive(Deserialize)]
+enum E2 {
+    #[serde(alias = "b", alias = "c")]
+    a,
+
+    // Warning on "c"
+    #[serde(rename = "c")]
+    b,
+}
+
+#[derive(Deserialize)]
+#[serde(rename_all = "UPPERCASE")]
+enum E3 {
+    #[serde(alias = "B", alias = "c")]
+    a,
+
+    // Warning on "b" because this collides with the "B" above after applying
+    // rename rules
+    b,
+}
+
+fn main() {
+    __FAIL__;
+}

test_suite/tests/ui/conflict/alias-enum.stderr

@@ -0,0 +1,79 @@
+error[E0425]: cannot find value `__FAIL__` in this scope
+  --> tests/ui/conflict/alias-enum.rs:74:5
+   |
+74 |     __FAIL__;
+   |     ^^^^^^^^ not found in this scope
+
+warning: unreachable pattern
+  --> tests/ui/conflict/alias-enum.rs:13:9
+   |
+8  |         #[serde(alias = "a", alias = "b", alias = "c")]
+   |                                      --- matches all the relevant values
+...
+13 |         b: (),
+   |         ^ no value can reach this
+   |
+   = note: `#[warn(unreachable_patterns)]` on by default
+
+warning: unreachable pattern
+  --> tests/ui/conflict/alias-enum.rs:12:25
+   |
+8  |         #[serde(alias = "a", alias = "b", alias = "c")]
+   |                                                   --- matches all the relevant values
+...
+12 |         #[serde(alias = "c")]
+   |                         ^^^ no value can reach this
+
+warning: unreachable pattern
+  --> tests/ui/conflict/alias-enum.rs:24:26
+   |
+20 |         #[serde(alias = "b", alias = "c")]
+   |                                      --- matches all the relevant values
+...
+24 |         #[serde(rename = "c")]
+   |                          ^^^ no value can reach this
+
+warning: unreachable pattern
+  --> tests/ui/conflict/alias-enum.rs:35:9
+   |
+30 |         #[serde(alias = "B", alias = "c")]
+   |                         --- matches all the relevant values
+...
+35 |         b: (),
+   |         ^ no value can reach this
+
+warning: unreachable pattern
+  --> tests/ui/conflict/alias-enum.rs:46:5
+   |
+41 |     #[serde(alias = "a", alias = "b", alias = "c")]
+   |                                  --- matches all the relevant values
+...
+46 |     b,
+   |     ^ no value can reach this
+
+warning: unreachable pattern
+  --> tests/ui/conflict/alias-enum.rs:45:21
+   |
+41 |     #[serde(alias = "a", alias = "b", alias = "c")]
+   |                                               --- matches all the relevant values
+...
+45 |     #[serde(alias = "c")]
+   |                     ^^^ no value can reach this
+
+warning: unreachable pattern
+  --> tests/ui/conflict/alias-enum.rs:58:22
+   |
+54 |     #[serde(alias = "b", alias = "c")]
+   |                                  --- matches all the relevant values
+...
+58 |     #[serde(rename = "c")]
+   |                      ^^^ no value can reach this
+
+warning: unreachable pattern
+  --> tests/ui/conflict/alias-enum.rs:70:5
+   |
+65 |     #[serde(alias = "B", alias = "c")]
+   |                     --- matches all the relevant values
+...
+70 |     b,
+   |     ^ no value can reach this

test_suite/tests/ui/conflict/alias.rs

@@ -0,0 +1,39 @@
+use serde_derive::Deserialize;
+
+#[derive(Deserialize)]
+struct S1 {
+    #[serde(alias = "a", alias = "b", alias = "c")]
+    a: (),
+
+    // Warning on "c" and "b"
+    #[serde(alias = "c")]
+    b: (),
+
+    #[serde(skip_deserializing)]
+    c: (),
+}
+
+#[derive(Deserialize)]
+struct S2 {
+    #[serde(alias = "b", alias = "c")]
+    a: (),
+
+    // Warning on "c"
+    #[serde(rename = "c")]
+    b: (),
+}
+
+#[derive(Deserialize)]
+#[serde(rename_all = "UPPERCASE")]
+struct S3 {
+    #[serde(alias = "B", alias = "c")]
+    a: (),
+
+    // Warning on "b" because this collides with the "B" above after applying
+    // rename rules
+    b: (),
+}
+
+fn main() {
+    __FAIL__;
+}

test_suite/tests/ui/conflict/alias.stderr

@@ -0,0 +1,43 @@
+error[E0425]: cannot find value `__FAIL__` in this scope
+  --> tests/ui/conflict/alias.rs:38:5
+   |
+38 |     __FAIL__;
+   |     ^^^^^^^^ not found in this scope
+
+warning: unreachable pattern
+  --> tests/ui/conflict/alias.rs:10:5
+   |
+5  |     #[serde(alias = "a", alias = "b", alias = "c")]
+   |                                  --- matches all the relevant values
+...
+10 |     b: (),
+   |     ^ no value can reach this
+   |
+   = note: `#[warn(unreachable_patterns)]` on by default
+
+warning: unreachable pattern
+ --> tests/ui/conflict/alias.rs:9:21
+  |
+5 |     #[serde(alias = "a", alias = "b", alias = "c")]
+  |                                               --- matches all the relevant values
+...
+9 |     #[serde(alias = "c")]
+  |                     ^^^ no value can reach this
+
+warning: unreachable pattern
+  --> tests/ui/conflict/alias.rs:22:22
+   |
+18 |     #[serde(alias = "b", alias = "c")]
+   |                                  --- matches all the relevant values
+...
+22 |     #[serde(rename = "c")]
+   |                      ^^^ no value can reach this
+
+warning: unreachable pattern
+  --> tests/ui/conflict/alias.rs:34:5
+   |
+29 |     #[serde(alias = "B", alias = "c")]
+   |                     --- matches all the relevant values
+...
+34 |     b: (),
+   |     ^ no value can reach this

test_suite/tests/ui/default-attribute/incorrect_type_enum_adjacently_tagged.rs

@@ -0,0 +1,20 @@
+// Tests that type error points to the path in attribute
+
+use serde_derive::Deserialize;
+
+#[derive(Deserialize)]
+#[serde(tag = "tag", content = "content")]
+enum Enum {
+    // Newtype variants do not use the provided path, so it is forbidden here
+    // Newtype(#[serde(default = "main")] u8),
+    Tuple(u8, #[serde(default = "main")] i8),
+    Struct {
+        #[serde(default = "main")]
+        f1: u8,
+        f2: u8,
+        #[serde(default = "main")]
+        f3: i8,
+    },
+}
+
+fn main() {}

test_suite/tests/ui/default-attribute/incorrect_type_enum_adjacently_tagged.stderr

@@ -0,0 +1,35 @@
+error[E0308]: `match` arms have incompatible types
+  --> tests/ui/default-attribute/incorrect_type_enum_adjacently_tagged.rs:10:33
+   |
+5  | #[derive(Deserialize)]
+   |          -----------
+   |          |
+   |          this is found to be of type `i8`
+   |          `match` arms have incompatible types
+...
+10 |     Tuple(u8, #[serde(default = "main")] i8),
+   |                                 ^^^^^^ expected `i8`, found `()`
+
+error[E0308]: `match` arms have incompatible types
+  --> tests/ui/default-attribute/incorrect_type_enum_adjacently_tagged.rs:12:27
+   |
+5  | #[derive(Deserialize)]
+   |          -----------
+   |          |
+   |          this is found to be of type `u8`
+   |          `match` arms have incompatible types
+...
+12 |         #[serde(default = "main")]
+   |                           ^^^^^^ expected `u8`, found `()`
+
+error[E0308]: `match` arms have incompatible types
+  --> tests/ui/default-attribute/incorrect_type_enum_adjacently_tagged.rs:15:27
+   |
+5  | #[derive(Deserialize)]
+   |          -----------
+   |          |
+   |          this is found to be of type `i8`
+   |          `match` arms have incompatible types
+...
+15 |         #[serde(default = "main")]
+   |                           ^^^^^^ expected `i8`, found `()`

test_suite/tests/ui/default-attribute/incorrect_type_enum_externally_tagged.rs

@@ -0,0 +1,19 @@
+// Tests that type error points to the path in attribute
+
+use serde_derive::Deserialize;
+
+#[derive(Deserialize)]
+enum Enum {
+    // Newtype variants do not use the provided path, so it is forbidden here
+    // Newtype(#[serde(default = "main")] u8),
+    Tuple(u8, #[serde(default = "main")] i8),
+    Struct {
+        #[serde(default = "main")]
+        f1: u8,
+        f2: u8,
+        #[serde(default = "main")]
+        f3: i8,
+    },
+}
+
+fn main() {}