Release 1.0.165

error: explicit call to `.into_iter()` in function argument accepting `IntoIterator`
       --> test_suite/tests/test_de.rs:202:12
        |
    202 |     .chain(vec![Token::MapEnd].into_iter())
        |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider removing the `.into_iter()`: `vec![Token::MapEnd]`
        |
    note: this parameter accepts any `IntoIterator`, so you don't need to call `.into_iter()`
       --> /home/david/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/iter/traits/iterator.rs:522:12
        |
    522 |         U: IntoIterator<Item = Self::Item>,
        |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#useless_conversion
        = note: `-D clippy::useless-conversion` implied by `-D clippy::all`

.gitattributes

@@ -1 +0,0 @@
-test_suite/tests/expand/*.expanded.rs linguist-generated

.github/workflows/ci.yml

@@ -3,6 +3,7 @@ name: CI
 on:
   push:
   pull_request:
+  workflow_dispatch:
   schedule: [cron: "40 1 * * *"]
 
 permissions:
@@ -108,12 +109,12 @@ jobs:
       - run: cd serde && cargo build
 
   derive:
-    name: Rust 1.31.0
+    name: Rust 1.56.0
     runs-on: ubuntu-latest
     timeout-minutes: 45
     steps:
       - uses: actions/checkout@v3
-      - uses: dtolnay/rust-toolchain@1.31.0
+      - uses: dtolnay/rust-toolchain@1.56.0
       - run: cd serde && cargo check --no-default-features
       - run: cd serde && cargo check
       - run: cd serde_derive && cargo check
@@ -149,6 +150,7 @@ jobs:
     steps:
       - uses: actions/checkout@v3
       - uses: dtolnay/rust-toolchain@miri
+      - run: cargo miri setup
       - run: cd serde && cargo miri test --features derive,rc,unstable
         env:
           MIRIFLAGS: -Zmiri-strict-provenance

README.md

@@ -1,13 +1,13 @@
-# Serde   [![Build Status]][actions] [![Latest Version]][crates.io] [![serde: rustc 1.19+]][Rust 1.19] [![serde_derive: rustc 1.31+]][Rust 1.31]
+# Serde   [![Build Status]][actions] [![Latest Version]][crates.io] [![serde: rustc 1.19+]][Rust 1.19] [![serde_derive: rustc 1.56+]][Rust 1.56]
 
 [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 1.19+]: https://img.shields.io/badge/serde-rustc_1.19+-lightgray.svg
-[serde_derive: rustc 1.31+]: https://img.shields.io/badge/serde_derive-rustc_1.31+-lightgray.svg
+[serde_derive: rustc 1.56+]: https://img.shields.io/badge/serde_derive-rustc_1.56+-lightgray.svg
 [Rust 1.19]: https://blog.rust-lang.org/2017/07/20/Rust-1.19.html
-[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
 
 **Serde is a framework for *ser*ializing and *de*serializing Rust data structures efficiently and generically.**
 

serde/.clippy.toml

@@ -1 +0,0 @@
-msrv = "1.13.0"

serde/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "serde"
-version = "1.0.154" # remember to update html_root_url and serde_derive dependency
+version = "1.0.165" # remember to update html_root_url and serde_derive dependency
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>", "David Tolnay <dtolnay@gmail.com>"]
 build = "build.rs"
 categories = ["encoding", "no-std"]
@@ -15,7 +15,7 @@ repository = "https://github.com/serde-rs/serde"
 rust-version = "1.19"
 
 [dependencies]
-serde_derive = { version = "=1.0.154", optional = true, path = "../serde_derive" }
+serde_derive = { version = "=1.0.165", optional = true, path = "../serde_derive" }
 
 [dev-dependencies]
 serde_derive = { version = "1.0", path = "../serde_derive" }
@@ -27,6 +27,7 @@ doc-scrape-examples = false
 features = ["derive", "rc"]
 
 [package.metadata.docs.rs]
+features = ["derive"]
 targets = ["x86_64-unknown-linux-gnu"]
 
 

serde/build.rs

@@ -78,11 +78,6 @@ fn main() {
         println!("cargo:rustc-cfg=no_num_nonzero");
     }
 
-    // Current minimum supported version of serde_derive crate is Rust 1.31.
-    if minor < 31 {
-        println!("cargo:rustc-cfg=no_serde_derive");
-    }
-
     // TryFrom, Atomic types, non-zero signed integers, and SystemTime::checked_add
     // stabilized in Rust 1.34:
     // https://blog.rust-lang.org/2019/04/11/Rust-1.34.0.html#tryfrom-and-tryinto
@@ -94,6 +89,11 @@ fn main() {
         println!("cargo:rustc-cfg=no_relaxed_trait_bounds");
     }
 
+    // Current minimum supported version of serde_derive crate is Rust 1.56.
+    if minor < 56 {
+        println!("cargo:rustc-cfg=no_serde_derive");
+    }
+
     // Support for #[cfg(target_has_atomic = "...")] stabilized in Rust 1.60.
     if minor < 60 {
         println!("cargo:rustc-cfg=no_target_has_atomic");
@@ -114,6 +114,12 @@ fn main() {
             println!("cargo:rustc-cfg=no_std_atomic");
         }
     }
+
+    // Support for core::ffi::CStr and alloc::ffi::CString stabilized in Rust 1.64.
+    // https://blog.rust-lang.org/2022/09/22/Rust-1.64.0.html#c-compatible-ffi-types-in-core-and-alloc
+    if minor < 64 {
+        println!("cargo:rustc-cfg=no_core_cstr");
+    }
 }
 
 fn rustc_minor_version() -> Option<u32> {

serde/src/de/impls.rs

@@ -666,10 +666,10 @@ impl<'de: 'a, 'a> Deserialize<'de> for &'a [u8] {
 
 ////////////////////////////////////////////////////////////////////////////////
 
-#[cfg(feature = "std")]
+#[cfg(any(feature = "std", all(not(no_core_cstr), feature = "alloc")))]
 struct CStringVisitor;
 
-#[cfg(feature = "std")]
+#[cfg(any(feature = "std", all(not(no_core_cstr), feature = "alloc")))]
 impl<'de> Visitor<'de> for CStringVisitor {
     type Value = CString;
 
@@ -720,7 +720,7 @@ impl<'de> Visitor<'de> for CStringVisitor {
     }
 }
 
-#[cfg(feature = "std")]
+#[cfg(any(feature = "std", all(not(no_core_cstr), feature = "alloc")))]
 impl<'de> Deserialize<'de> for CString {
     fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
     where
@@ -747,7 +747,10 @@ macro_rules! forwarded_impl {
     }
 }
 
-#[cfg(all(feature = "std", not(no_de_boxed_c_str)))]
+#[cfg(all(
+    any(feature = "std", all(not(no_core_cstr), feature = "alloc")),
+    not(no_de_boxed_c_str)
+))]
 forwarded_impl!((), Box<CStr>, CString::into_boxed_c_str);
 
 #[cfg(not(no_core_reverse))]
@@ -991,7 +994,8 @@ seq_impl!(
     HashSet::clear,
     HashSet::with_capacity_and_hasher(size_hint::cautious(seq.size_hint()), S::default()),
     HashSet::reserve,
-    HashSet::insert);
+    HashSet::insert
+);
 
 #[cfg(any(feature = "std", feature = "alloc"))]
 seq_impl!(
@@ -1406,16 +1410,14 @@ macro_rules! map_impl {
 }
 
 #[cfg(any(feature = "std", feature = "alloc"))]
-map_impl!(
+map_impl!(BTreeMap<K: Ord, V>, map, BTreeMap::new());
-    BTreeMap<K: Ord, V>,
-    map,
-    BTreeMap::new());
 
 #[cfg(feature = "std")]
 map_impl!(
     HashMap<K: Eq + Hash, V, S: BuildHasher + Default>,
     map,
-    HashMap::with_capacity_and_hasher(size_hint::cautious(map.size_hint()), S::default()));
+    HashMap::with_capacity_and_hasher(size_hint::cautious(map.size_hint()), S::default())
+);
 
 ////////////////////////////////////////////////////////////////////////////////
 
@@ -1585,7 +1587,7 @@ macro_rules! parse_socket_impl {
                 if deserializer.is_human_readable() {
                     deserializer.deserialize_str(FromStrVisitor::new($expecting))
                 } else {
-                    <(_, u16)>::deserialize(deserializer).map(|(ip, port)| $new(ip, port))
+                    <(_, u16)>::deserialize(deserializer).map($new)
                 }
             }
         }
@@ -1612,12 +1614,10 @@ impl<'de> Deserialize<'de> for net::SocketAddr {
 }
 
 #[cfg(feature = "std")]
-parse_socket_impl!("IPv4 socket address" net::SocketAddrV4, net::SocketAddrV4::new);
+parse_socket_impl!("IPv4 socket address" net::SocketAddrV4, |(ip, port)| net::SocketAddrV4::new(ip, port));
 
 #[cfg(feature = "std")]
-parse_socket_impl!("IPv6 socket address" net::SocketAddrV6, |ip, port| net::SocketAddrV6::new(
+parse_socket_impl!("IPv6 socket address" net::SocketAddrV6, |(ip, port)| net::SocketAddrV6::new(ip, port, 0, 0));
-    ip, port, 0, 0
-));
 
 ////////////////////////////////////////////////////////////////////////////////
 
@@ -2096,7 +2096,7 @@ impl<'de> Deserialize<'de> for Duration {
             }
         }
 
-        const FIELDS: &'static [&'static str] = &["secs", "nanos"];
+        const FIELDS: &[&str] = &["secs", "nanos"];
         deserializer.deserialize_struct("Duration", FIELDS, DurationVisitor)
     }
 }
@@ -2238,7 +2238,7 @@ impl<'de> Deserialize<'de> for SystemTime {
             }
         }
 
-        const FIELDS: &'static [&'static str] = &["secs_since_epoch", "nanos_since_epoch"];
+        const FIELDS: &[&str] = &["secs_since_epoch", "nanos_since_epoch"];
         let duration = try!(deserializer.deserialize_struct("SystemTime", FIELDS, DurationVisitor));
         #[cfg(not(no_systemtime_checked_add))]
         let ret = UNIX_EPOCH
@@ -2306,7 +2306,7 @@ mod range {
 
     use de::{Deserialize, Deserializer, Error, MapAccess, SeqAccess, Visitor};
 
-    pub const FIELDS: &'static [&'static str] = &["start", "end"];
+    pub const FIELDS: &[&str] = &["start", "end"];
 
     // If this were outside of the serde crate, it would just use:
     //
@@ -2532,7 +2532,7 @@ where
             }
         }
 
-        const VARIANTS: &'static [&'static str] = &["Unbounded", "Included", "Excluded"];
+        const VARIANTS: &[&str] = &["Unbounded", "Included", "Excluded"];
 
         deserializer.deserialize_enum("Bound", VARIANTS, BoundVisitor(PhantomData))
     }
@@ -2640,7 +2640,7 @@ where
             }
         }
 
-        const VARIANTS: &'static [&'static str] = &["Ok", "Err"];
+        const VARIANTS: &[&str] = &["Ok", "Err"];
 
         deserializer.deserialize_enum("Result", VARIANTS, ResultVisitor(PhantomData))
     }
@@ -2706,7 +2706,7 @@ struct FromStrVisitor<T> {
 impl<T> FromStrVisitor<T> {
     fn new(expecting: &'static str) -> Self {
         FromStrVisitor {
-            expecting: expecting,
+            expecting,
             ty: PhantomData,
         }
     }

serde/src/de/utf8.rs

@@ -31,7 +31,7 @@ pub fn encode(c: char) -> Encode {
         buf[3] = (code & 0x3F) as u8 | TAG_CONT;
         0
     };
-    Encode { buf: buf, pos: pos }
+    Encode { buf, pos }
 }
 
 pub struct Encode {

serde/src/de/value.rs

@@ -251,7 +251,7 @@ macro_rules! primitive_deserializer {
             #[allow(missing_docs)]
             pub fn new(value: $ty) -> Self {
                 $name {
-                    value: value,
+                    value,
                     marker: PhantomData,
                 }
             }
@@ -330,7 +330,7 @@ impl<E> U32Deserializer<E> {
     #[allow(missing_docs)]
     pub fn new(value: u32) -> Self {
         U32Deserializer {
-            value: value,
+            value,
             marker: PhantomData,
         }
     }
@@ -419,7 +419,7 @@ impl<'a, E> StrDeserializer<'a, E> {
     #[allow(missing_docs)]
     pub fn new(value: &'a str) -> Self {
         StrDeserializer {
-            value: value,
+            value,
             marker: PhantomData,
         }
     }
@@ -498,7 +498,7 @@ impl<'de, E> BorrowedStrDeserializer<'de, E> {
     /// Create a new borrowed deserializer from the given string.
     pub fn new(value: &'de str) -> BorrowedStrDeserializer<'de, E> {
         BorrowedStrDeserializer {
-            value: value,
+            value,
             marker: PhantomData,
         }
     }
@@ -598,7 +598,7 @@ impl<E> StringDeserializer<E> {
     #[allow(missing_docs)]
     pub fn new(value: String) -> Self {
         StringDeserializer {
-            value: value,
+            value,
             marker: PhantomData,
         }
     }
@@ -701,7 +701,7 @@ impl<'a, E> CowStrDeserializer<'a, E> {
     #[allow(missing_docs)]
     pub fn new(value: Cow<'a, str>) -> Self {
         CowStrDeserializer {
-            value: value,
+            value,
             marker: PhantomData,
         }
     }
@@ -783,7 +783,7 @@ impl<'a, E> BytesDeserializer<'a, E> {
     /// Create a new deserializer from the given bytes.
     pub fn new(value: &'a [u8]) -> Self {
         BytesDeserializer {
-            value: value,
+            value,
             marker: PhantomData,
         }
     }
@@ -842,7 +842,7 @@ impl<'de, E> BorrowedBytesDeserializer<'de, E> {
     /// Create a new borrowed deserializer from the given borrowed bytes.
     pub fn new(value: &'de [u8]) -> Self {
         BorrowedBytesDeserializer {
-            value: value,
+            value,
             marker: PhantomData,
         }
     }
@@ -1053,7 +1053,7 @@ pub struct SeqAccessDeserializer<A> {
 impl<A> SeqAccessDeserializer<A> {
     /// Construct a new `SeqAccessDeserializer<A>`.
     pub fn new(seq: A) -> Self {
-        SeqAccessDeserializer { seq: seq }
+        SeqAccessDeserializer { seq }
     }
 }
 
@@ -1454,7 +1454,7 @@ pub struct MapAccessDeserializer<A> {
 impl<A> MapAccessDeserializer<A> {
     /// Construct a new `MapAccessDeserializer<A>`.
     pub fn new(map: A) -> Self {
-        MapAccessDeserializer { map: map }
+        MapAccessDeserializer { map }
     }
 }
 
@@ -1519,7 +1519,7 @@ pub struct EnumAccessDeserializer<A> {
 impl<A> EnumAccessDeserializer<A> {
     /// Construct a new `EnumAccessDeserializer<A>`.
     pub fn new(access: A) -> Self {
-        EnumAccessDeserializer { access: access }
+        EnumAccessDeserializer { access }
     }
 }
 
@@ -1613,7 +1613,7 @@ mod private {
     }
 
     pub fn map_as_enum<A>(map: A) -> MapAsEnum<A> {
-        MapAsEnum { map: map }
+        MapAsEnum { map }
     }
 
     impl<'de, A> VariantAccess<'de> for MapAsEnum<A>
@@ -1637,10 +1637,7 @@ mod private {
         where
             V: Visitor<'de>,
         {
-            self.map.next_value_seed(SeedTupleVariant {
+            self.map.next_value_seed(SeedTupleVariant { len, visitor })
-                len: len,
-                visitor: visitor,
-            })
         }
 
         fn struct_variant<V>(
@@ -1651,8 +1648,7 @@ mod private {
         where
             V: Visitor<'de>,
         {
-            self.map
+            self.map.next_value_seed(SeedStructVariant { visitor })
-                .next_value_seed(SeedStructVariant { visitor: visitor })
         }
     }
 

serde/src/lib.rs

@@ -93,7 +93,7 @@
 ////////////////////////////////////////////////////////////////////////////////
 
 // Serde types in rustdoc of other crates get linked to here.
-#![doc(html_root_url = "https://docs.rs/serde/1.0.154")]
+#![doc(html_root_url = "https://docs.rs/serde/1.0.165")]
 // Support using Serde without the standard library!
 #![cfg_attr(not(feature = "std"), no_std)]
 // Unstable functionality only if the user asks for it. For tracking and
@@ -219,13 +219,23 @@ mod lib {
     #[cfg(feature = "std")]
     pub use std::collections::{BTreeMap, BTreeSet, BinaryHeap, LinkedList, VecDeque};
 
+    #[cfg(all(not(no_core_cstr), not(feature = "std")))]
+    pub use core::ffi::CStr;
+    #[cfg(feature = "std")]
+    pub use std::ffi::CStr;
+
+    #[cfg(all(not(no_core_cstr), feature = "alloc", not(feature = "std")))]
+    pub use alloc::ffi::CString;
+    #[cfg(feature = "std")]
+    pub use std::ffi::CString;
+
     #[cfg(feature = "std")]
     pub use std::{error, net};
 
     #[cfg(feature = "std")]
     pub use std::collections::{HashMap, HashSet};
     #[cfg(feature = "std")]
-    pub use std::ffi::{CStr, CString, OsStr, OsString};
+    pub use std::ffi::{OsStr, OsString};
     #[cfg(feature = "std")]
     pub use std::hash::{BuildHasher, Hash};
     #[cfg(feature = "std")]
@@ -328,9 +338,10 @@ mod std_error;
 #[allow(unused_imports)]
 #[macro_use]
 extern crate serde_derive;
+
+/// Derive macro available if serde is built with `features = ["derive"]`.
 #[cfg(feature = "serde_derive")]
-#[doc(hidden)]
+pub use serde_derive::{Deserialize, Serialize};
-pub use serde_derive::*;
 
 #[cfg(all(not(no_serde_derive), any(feature = "std", feature = "alloc")))]
 mod actually_private {

serde/src/private/de.rs

@@ -518,7 +518,7 @@ mod content {
     impl<'de> TagOrContentVisitor<'de> {
         fn new(name: &'static str) -> Self {
             TagOrContentVisitor {
-                name: name,
+                name,
                 value: PhantomData,
             }
         }
@@ -815,7 +815,7 @@ mod content {
         pub fn new(name: &'static str, expecting: &'static str) -> Self {
             TaggedContentVisitor {
                 tag_name: name,
-                expecting: expecting,
+                expecting,
                 value: PhantomData,
             }
         }
@@ -859,7 +859,7 @@ mod content {
             };
             let rest = de::value::SeqAccessDeserializer::new(seq);
             Ok(TaggedContent {
-                tag: tag,
+                tag,
                 content: try!(Content::deserialize(rest)),
             })
         }
@@ -887,7 +887,7 @@ mod content {
             match tag {
                 None => Err(de::Error::missing_field(self.tag_name)),
                 Some(tag) => Ok(TaggedContent {
-                    tag: tag,
+                    tag,
                     content: Content::Map(vec),
                 }),
             }
@@ -982,9 +982,16 @@ mod content {
         where
             E: de::Error,
         {
-            if field == self.tag {
+            self.visit_bytes(field.as_bytes())
+        }
+
+        fn visit_bytes<E>(self, field: &[u8]) -> Result<Self::Value, E>
+        where
+            E: de::Error,
+        {
+            if field == self.tag.as_bytes() {
                 Ok(TagContentOtherField::Tag)
-            } else if field == self.content {
+            } else if field == self.content.as_bytes() {
                 Ok(TagContentOtherField::Content)
             } else {
                 Ok(TagContentOtherField::Other)
@@ -1457,7 +1464,7 @@ mod content {
         /// private API, don't use
         pub fn new(content: Content<'de>) -> Self {
             ContentDeserializer {
-                content: content,
+                content,
                 err: PhantomData,
             }
         }
@@ -1478,8 +1485,8 @@ mod content {
     {
         pub fn new(variant: Content<'de>, value: Option<Content<'de>>) -> EnumDeserializer<'de, E> {
             EnumDeserializer {
-                variant: variant,
+                variant,
-                value: value,
+                value,
                 err: PhantomData,
             }
         }
@@ -2135,8 +2142,8 @@ mod content {
             };
 
             visitor.visit_enum(EnumRefDeserializer {
-                variant: variant,
+                variant,
-                value: value,
+                value,
                 err: PhantomData,
             })
         }
@@ -2180,12 +2187,20 @@ mod content {
         /// private API, don't use
         pub fn new(content: &'a Content<'de>) -> Self {
             ContentRefDeserializer {
-                content: content,
+                content,
                 err: PhantomData,
             }
         }
     }
 
+    impl<'a, 'de: 'a, E> Copy for ContentRefDeserializer<'a, 'de, E> {}
+
+    impl<'a, 'de: 'a, E> Clone for ContentRefDeserializer<'a, 'de, E> {
+        fn clone(&self) -> Self {
+            *self
+        }
+    }
+
     struct EnumRefDeserializer<'a, 'de: 'a, E>
     where
         E: de::Error,
@@ -2481,8 +2496,8 @@ mod content {
         /// Not public API.
         pub fn new(type_name: &'a str, variant_name: &'a str) -> Self {
             InternallyTaggedUnitVisitor {
-                type_name: type_name,
+                type_name,
-                variant_name: variant_name,
+                variant_name,
             }
         }
     }
@@ -2526,8 +2541,8 @@ mod content {
         /// Not public API.
         pub fn new(type_name: &'a str, variant_name: &'a str) -> Self {
             UntaggedUnitVisitor {
-                type_name: type_name,
+                type_name,
-                variant_name: variant_name,
+                variant_name,
             }
         }
     }
@@ -2731,11 +2746,7 @@ where
     where
         V: Visitor<'de>,
     {
-        visitor.visit_map(FlatInternallyTaggedAccess {
+        self.deserialize_map(visitor)
-            iter: self.0.iter_mut(),
-            pending: None,
-            _marker: PhantomData,
-        })
     }
 
     fn deserialize_enum<V>(
@@ -2747,17 +2758,8 @@ where
     where
         V: Visitor<'de>,
     {
-        for item in self.0.iter_mut() {
+        for entry in self.0 {
-            // items in the vector are nulled out when used.  So we can only use
+            if let Some((key, value)) = flat_map_take_entry(entry, variants) {
-            // an item if it's still filled in and if the field is one we care
-            // about.
-            let use_item = match *item {
-                None => false,
-                Some((ref c, _)) => c.as_str().map_or(false, |x| variants.contains(&x)),
-            };
-
-            if use_item {
-                let (key, value) = item.take().unwrap();
                 return visitor.visit_enum(EnumDeserializer::new(key, Some(value)));
             }
         }
@@ -2772,7 +2774,11 @@ where
     where
         V: Visitor<'de>,
     {
-        visitor.visit_map(FlatMapAccess::new(self.0.iter()))
+        visitor.visit_map(FlatMapAccess {
+            iter: self.0.iter(),
+            pending_content: None,
+            _marker: PhantomData,
+        })
     }
 
     fn deserialize_struct<V>(
@@ -2784,7 +2790,12 @@ where
     where
         V: Visitor<'de>,
     {
-        visitor.visit_map(FlatStructAccess::new(self.0.iter_mut(), fields))
+        visitor.visit_map(FlatStructAccess {
+            iter: self.0.iter_mut(),
+            pending_content: None,
+            fields,
+            _marker: PhantomData,
+        })
     }
 
     fn deserialize_newtype_struct<V>(self, _name: &str, visitor: V) -> Result<V::Value, Self::Error>
@@ -2838,25 +2849,12 @@ where
 }
 
 #[cfg(any(feature = "std", feature = "alloc"))]
-pub struct FlatMapAccess<'a, 'de: 'a, E> {
+struct FlatMapAccess<'a, 'de: 'a, E> {
     iter: slice::Iter<'a, Option<(Content<'de>, Content<'de>)>>,
     pending_content: Option<&'a Content<'de>>,
     _marker: PhantomData<E>,
 }
 
-#[cfg(any(feature = "std", feature = "alloc"))]
-impl<'a, 'de, E> FlatMapAccess<'a, 'de, E> {
-    fn new(
-        iter: slice::Iter<'a, Option<(Content<'de>, Content<'de>)>>,
-    ) -> FlatMapAccess<'a, 'de, E> {
-        FlatMapAccess {
-            iter: iter,
-            pending_content: None,
-            _marker: PhantomData,
-        }
-    }
-}
-
 #[cfg(any(feature = "std", feature = "alloc"))]
 impl<'a, 'de, E> MapAccess<'de> for FlatMapAccess<'a, 'de, E>
 where
@@ -2871,6 +2869,10 @@ where
         for item in &mut self.iter {
             // Items in the vector are nulled out when used by a struct.
             if let Some((ref key, ref content)) = *item {
+                // Do not take(), instead borrow this entry. The internally tagged
+                // enum does its own buffering so we can't tell whether this entry
+                // is going to be consumed. Borrowing here leaves the entry
+                // available for later flattened fields.
                 self.pending_content = Some(content);
                 return seed.deserialize(ContentRefDeserializer::new(key)).map(Some);
             }
@@ -2890,28 +2892,13 @@ where
 }
 
 #[cfg(any(feature = "std", feature = "alloc"))]
-pub struct FlatStructAccess<'a, 'de: 'a, E> {
+struct FlatStructAccess<'a, 'de: 'a, E> {
     iter: slice::IterMut<'a, Option<(Content<'de>, Content<'de>)>>,
     pending_content: Option<Content<'de>>,
     fields: &'static [&'static str],
     _marker: PhantomData<E>,
 }
 
-#[cfg(any(feature = "std", feature = "alloc"))]
-impl<'a, 'de, E> FlatStructAccess<'a, 'de, E> {
-    fn new(
-        iter: slice::IterMut<'a, Option<(Content<'de>, Content<'de>)>>,
-        fields: &'static [&'static str],
-    ) -> FlatStructAccess<'a, 'de, E> {
-        FlatStructAccess {
-            iter: iter,
-            pending_content: None,
-            fields: fields,
-            _marker: PhantomData,
-        }
-    }
-}
-
 #[cfg(any(feature = "std", feature = "alloc"))]
 impl<'a, 'de, E> MapAccess<'de> for FlatStructAccess<'a, 'de, E>
 where
@@ -2923,17 +2910,8 @@ where
     where
         T: DeserializeSeed<'de>,
     {
-        while let Some(item) = self.iter.next() {
+        for entry in self.iter.by_ref() {
-            // items in the vector are nulled out when used.  So we can only use
+            if let Some((key, content)) = flat_map_take_entry(entry, self.fields) {
-            // an item if it's still filled in and if the field is one we care
-            // about.  In case we do not know which fields we want, we take them all.
-            let use_item = match *item {
-                None => false,
-                Some((ref c, _)) => c.as_str().map_or(false, |key| self.fields.contains(&key)),
-            };
-
-            if use_item {
-                let (key, content) = item.take().unwrap();
                 self.pending_content = Some(content);
                 return seed.deserialize(ContentDeserializer::new(key)).map(Some);
             }
@@ -2952,44 +2930,24 @@ where
     }
 }
 
+/// Claims one key-value pair from a FlatMapDeserializer's field buffer if the
+/// field name matches any of the recognized ones.
 #[cfg(any(feature = "std", feature = "alloc"))]
-pub struct FlatInternallyTaggedAccess<'a, 'de: 'a, E> {
+fn flat_map_take_entry<'de>(
-    iter: slice::IterMut<'a, Option<(Content<'de>, Content<'de>)>>,
+    entry: &mut Option<(Content<'de>, Content<'de>)>,
-    pending: Option<&'a Content<'de>>,
+    recognized: &[&str],
-    _marker: PhantomData<E>,
+) -> Option<(Content<'de>, Content<'de>)> {
-}
+    // Entries in the FlatMapDeserializer buffer are nulled out as they get
+    // claimed for deserialization. We only use an entry if it is still present
+    // and if the field is one recognized by the current data structure.
+    let is_recognized = match entry {
+        None => false,
+        Some((k, _v)) => k.as_str().map_or(false, |name| recognized.contains(&name)),
+    };
 
-#[cfg(any(feature = "std", feature = "alloc"))]
+    if is_recognized {
-impl<'a, 'de, E> MapAccess<'de> for FlatInternallyTaggedAccess<'a, 'de, E>
+        entry.take()
-where
+    } else {
-    E: Error,
+        None
-{
-    type Error = E;
-
-    fn next_key_seed<T>(&mut self, seed: T) -> Result<Option<T::Value>, Self::Error>
-    where
-        T: DeserializeSeed<'de>,
-    {
-        for item in &mut self.iter {
-            if let Some((ref key, ref content)) = *item {
-                // Do not take(), instead borrow this entry. The internally tagged
-                // enum does its own buffering so we can't tell whether this entry
-                // is going to be consumed. Borrowing here leaves the entry
-                // available for later flattened fields.
-                self.pending = Some(content);
-                return seed.deserialize(ContentRefDeserializer::new(key)).map(Some);
-            }
-        }
-        Ok(None)
-    }
-
-    fn next_value_seed<T>(&mut self, seed: T) -> Result<T::Value, Self::Error>
-    where
-        T: DeserializeSeed<'de>,
-    {
-        match self.pending.take() {
-            Some(value) => seed.deserialize(ContentRefDeserializer::new(value)),
-            None => panic!("value is missing"),
-        }
     }
 }

serde/src/private/ser.rs

@@ -27,10 +27,10 @@ where
     T: Serialize,
 {
     value.serialize(TaggedSerializer {
-        type_ident: type_ident,
+        type_ident,
-        variant_ident: variant_ident,
+        variant_ident,
-        tag: tag,
+        tag,
-        variant_name: variant_name,
+        variant_name,
         delegate: serializer,
     })
 }
@@ -350,8 +350,8 @@ mod content {
     impl<M> SerializeTupleVariantAsMapValue<M> {
         pub fn new(map: M, name: &'static str, len: usize) -> Self {
             SerializeTupleVariantAsMapValue {
-                map: map,
+                map,
-                name: name,
+                name,
                 fields: Vec::with_capacity(len),
             }
         }
@@ -390,8 +390,8 @@ mod content {
     impl<M> SerializeStructVariantAsMapValue<M> {
         pub fn new(map: M, name: &'static str, len: usize) -> Self {
             SerializeStructVariantAsMapValue {
-                map: map,
+                map,
-                name: name,
+                name,
                 fields: Vec::with_capacity(len),
             }
         }
@@ -711,7 +711,7 @@ mod content {
             len: usize,
         ) -> Result<Self::SerializeTupleStruct, E> {
             Ok(SerializeTupleStruct {
-                name: name,
+                name,
                 fields: Vec::with_capacity(len),
                 error: PhantomData,
             })
@@ -725,9 +725,9 @@ mod content {
             len: usize,
         ) -> Result<Self::SerializeTupleVariant, E> {
             Ok(SerializeTupleVariant {
-                name: name,
+                name,
-                variant_index: variant_index,
+                variant_index,
-                variant: variant,
+                variant,
                 fields: Vec::with_capacity(len),
                 error: PhantomData,
             })
@@ -747,7 +747,7 @@ mod content {
             len: usize,
         ) -> Result<Self::SerializeStruct, E> {
             Ok(SerializeStruct {
-                name: name,
+                name,
                 fields: Vec::with_capacity(len),
                 error: PhantomData,
             })
@@ -761,9 +761,9 @@ mod content {
             len: usize,
         ) -> Result<Self::SerializeStructVariant, E> {
             Ok(SerializeStructVariant {
-                name: name,
+                name,
-                variant_index: variant_index,
+                variant_index,
-                variant: variant,
+                variant,
                 fields: Vec::with_capacity(len),
                 error: PhantomData,
             })
@@ -1273,8 +1273,8 @@ where
 {
     fn new(map: &'a mut M, name: &'static str) -> FlatMapSerializeStructVariantAsMapValue<'a, M> {
         FlatMapSerializeStructVariantAsMapValue {
-            map: map,
+            map,
-            name: name,
+            name,
             fields: Vec::new(),
         }
     }

serde/src/ser/impls.rs

@@ -72,7 +72,7 @@ impl<'a> Serialize for fmt::Arguments<'a> {
 
 ////////////////////////////////////////////////////////////////////////////////
 
-#[cfg(feature = "std")]
+#[cfg(any(feature = "std", not(no_core_cstr)))]
 impl Serialize for CStr {
     #[inline]
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
@@ -83,7 +83,7 @@ impl Serialize for CStr {
     }
 }
 
-#[cfg(feature = "std")]
+#[cfg(any(feature = "std", all(not(no_core_cstr), feature = "alloc")))]
 impl Serialize for CString {
     #[inline]
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
@@ -713,7 +713,7 @@ impl Serialize for net::IpAddr {
 }
 
 #[cfg(feature = "std")]
-const DEC_DIGITS_LUT: &'static [u8] = b"\
+const DEC_DIGITS_LUT: &[u8] = b"\
       0001020304050607080910111213141516171819\
       2021222324252627282930313233343536373839\
       4041424344454647484950515253545556575859\

serde_derive/.clippy.toml

@@ -1 +0,0 @@
-msrv = "1.31.0"

serde_derive/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "serde_derive"
-version = "1.0.154" # remember to update html_root_url
+version = "1.0.165" # remember to update html_root_url
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>", "David Tolnay <dtolnay@gmail.com>"]
 categories = ["no-std"]
 description = "Macros 1.1 implementation of #[derive(Serialize, Deserialize)]"
@@ -11,7 +11,7 @@ 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 = "1.31"
+rust-version = "1.56"
 
 [features]
 default = []
@@ -24,7 +24,7 @@ proc-macro = true
 [dependencies]
 proc-macro2 = "1.0"
 quote = "1.0"
-syn = "1.0.104"
+syn = "2.0.21"
 
 [dev-dependencies]
 serde = { version = "1.0", path = "../serde" }

serde_derive/build.rs

@@ -1,38 +0,0 @@
-use std::env;
-use std::process::Command;
-use std::str;
-
-// The rustc-cfg strings below are *not* public API. Please let us know by
-// opening a GitHub issue if your build environment requires some way to enable
-// these cfgs other than by executing our build script.
-fn main() {
-    println!("cargo:rerun-if-changed=build.rs");
-
-    let minor = match rustc_minor_version() {
-        Some(minor) => minor,
-        None => return,
-    };
-
-    // Underscore const names stabilized in Rust 1.37:
-    // https://blog.rust-lang.org/2019/08/15/Rust-1.37.0.html#using-unnamed-const-items-for-macros
-    if minor < 37 {
-        println!("cargo:rustc-cfg=no_underscore_consts");
-    }
-
-    // The ptr::addr_of! macro stabilized in Rust 1.51:
-    // https://blog.rust-lang.org/2021/03/25/Rust-1.51.0.html#stabilized-apis
-    if minor < 51 {
-        println!("cargo:rustc-cfg=no_ptr_addr_of");
-    }
-}
-
-fn rustc_minor_version() -> Option<u32> {
-    let rustc = env::var_os("RUSTC")?;
-    let output = Command::new(rustc).arg("--version").output().ok()?;
-    let version = str::from_utf8(&output.stdout).ok()?;
-    let mut pieces = version.split('.');
-    if pieces.next() != Some("rustc 1") {
-        return None;
-    }
-    pieces.next()?.parse().ok()
-}

serde_derive/src/bound.rs

@@ -200,10 +200,16 @@ pub fn with_bound(
                     for arg in &arguments.args {
                         match arg {
                             syn::GenericArgument::Type(arg) => self.visit_type(arg),
-                            syn::GenericArgument::Binding(arg) => self.visit_type(&arg.ty),
+                            syn::GenericArgument::AssocType(arg) => self.visit_type(&arg.ty),
                             syn::GenericArgument::Lifetime(_)
-                            | syn::GenericArgument::Constraint(_)
+                            | syn::GenericArgument::Const(_)
-                            | syn::GenericArgument::Const(_) => {}
+                            | syn::GenericArgument::AssocConst(_)
+                            | syn::GenericArgument::Constraint(_) => {}
+                            #[cfg_attr(
+                                all(test, exhaustive),
+                                deny(non_exhaustive_omitted_patterns)
+                            )]
+                            _ => {}
                         }
                     }
                 }
@@ -226,7 +232,9 @@ pub fn with_bound(
         fn visit_type_param_bound(&mut self, bound: &'ast syn::TypeParamBound) {
             match bound {
                 syn::TypeParamBound::Trait(bound) => self.visit_path(&bound.path),
-                syn::TypeParamBound::Lifetime(_) => {}
+                syn::TypeParamBound::Lifetime(_) | syn::TypeParamBound::Verbatim(_) => {}
+                #[cfg_attr(all(test, exhaustive), deny(non_exhaustive_omitted_patterns))]
+                _ => {}
             }
         }
 
@@ -251,7 +259,7 @@ pub fn with_bound(
     };
     match &cont.data {
         Data::Enum(variants) => {
-            for variant in variants.iter() {
+            for variant in variants {
                 let relevant_fields = variant
                     .fields
                     .iter()
@@ -334,7 +342,7 @@ pub fn with_self_bound(
 
 pub fn with_lifetime_bound(generics: &syn::Generics, lifetime: &str) -> syn::Generics {
     let bound = syn::Lifetime::new(lifetime, Span::call_site());
-    let def = syn::LifetimeDef {
+    let def = syn::LifetimeParam {
         attrs: Vec::new(),
         lifetime: bound.clone(),
         colon_token: None,

serde_derive/src/de.rs

@@ -15,9 +15,7 @@ use this;
 use std::collections::BTreeSet;
 use std::ptr;
 
-pub fn expand_derive_deserialize(
+pub fn expand_derive_deserialize(input: &mut syn::DeriveInput) -> syn::Result<TokenStream> {
-    input: &mut syn::DeriveInput,
-) -> Result<TokenStream, Vec<syn::Error>> {
     replace_receiver(input);
 
     let ctxt = Ctxt::new();
@@ -69,8 +67,6 @@ pub fn expand_derive_deserialize(
 
     Ok(dummy::wrap_in_const(
         cont.attrs.custom_serde_path(),
-        "DESERIALIZE",
-        ident,
         impl_block,
     ))
 }
@@ -244,9 +240,9 @@ impl BorrowedLifetimes {
         }
     }
 
-    fn de_lifetime_def(&self) -> Option<syn::LifetimeDef> {
+    fn de_lifetime_param(&self) -> Option<syn::LifetimeParam> {
         match self {
-            BorrowedLifetimes::Borrowed(bounds) => Some(syn::LifetimeDef {
+            BorrowedLifetimes::Borrowed(bounds) => Some(syn::LifetimeParam {
                 attrs: Vec::new(),
                 lifetime: syn::Lifetime::new("'de", Span::call_site()),
                 colon_token: None,
@@ -419,6 +415,7 @@ fn deserialize_unit_struct(params: &Parameters, cattrs: &attr::Container) -> Fra
     let expecting = cattrs.expecting().unwrap_or(&expecting);
 
     quote_block! {
+        #[doc(hidden)]
         struct __Visitor;
 
         impl<'de> _serde::de::Visitor<'de> for __Visitor {
@@ -448,14 +445,19 @@ fn deserialize_tuple(
     cattrs: &attr::Container,
     deserializer: Option<TokenStream>,
 ) -> Fragment {
+    assert!(!cattrs.has_flatten());
+
+    let field_count = fields
+        .iter()
+        .filter(|field| !field.attrs.skip_deserializing())
+        .count();
+
     let this_type = &params.this_type;
     let this_value = &params.this_value;
     let (de_impl_generics, de_ty_generics, ty_generics, where_clause) =
         split_with_de_lifetime(params);
     let delife = params.borrowed.de_lifetime();
 
-    assert!(!cattrs.has_flatten());
-
     // If there are getters (implying private fields), construct the local type
     // and use an `Into` conversion to get the remote type. If there are no
     // getters then construct the target type directly.
@@ -496,25 +498,25 @@ fn deserialize_tuple(
         }
     };
     let dispatch = if let Some(deserializer) = deserializer {
-        quote!(_serde::Deserializer::deserialize_tuple(#deserializer, #nfields, #visitor_expr))
+        quote!(_serde::Deserializer::deserialize_tuple(#deserializer, #field_count, #visitor_expr))
     } else if is_enum {
-        quote!(_serde::de::VariantAccess::tuple_variant(__variant, #nfields, #visitor_expr))
+        quote!(_serde::de::VariantAccess::tuple_variant(__variant, #field_count, #visitor_expr))
     } else if nfields == 1 {
         let type_name = cattrs.name().deserialize_name();
         quote!(_serde::Deserializer::deserialize_newtype_struct(__deserializer, #type_name, #visitor_expr))
     } else {
         let type_name = cattrs.name().deserialize_name();
-        quote!(_serde::Deserializer::deserialize_tuple_struct(__deserializer, #type_name, #nfields, #visitor_expr))
+        quote!(_serde::Deserializer::deserialize_tuple_struct(__deserializer, #type_name, #field_count, #visitor_expr))
     };
 
-    let all_skipped = fields.iter().all(|field| field.attrs.skip_deserializing());
+    let visitor_var = if field_count == 0 {
-    let visitor_var = if all_skipped {
         quote!(_)
     } else {
         quote!(mut __seq)
     };
 
     quote_block! {
+        #[doc(hidden)]
         struct __Visitor #de_impl_generics #where_clause {
             marker: _serde::__private::PhantomData<#this_type #ty_generics>,
             lifetime: _serde::__private::PhantomData<&#delife ()>,
@@ -550,13 +552,18 @@ fn deserialize_tuple_in_place(
     cattrs: &attr::Container,
     deserializer: Option<TokenStream>,
 ) -> Fragment {
+    assert!(!cattrs.has_flatten());
+
+    let field_count = fields
+        .iter()
+        .filter(|field| !field.attrs.skip_deserializing())
+        .count();
+
     let this_type = &params.this_type;
     let (de_impl_generics, de_ty_generics, ty_generics, where_clause) =
         split_with_de_lifetime(params);
     let delife = params.borrowed.de_lifetime();
 
-    assert!(!cattrs.has_flatten());
-
     let is_enum = variant_ident.is_some();
     let expecting = match variant_ident {
         Some(variant_ident) => format!("tuple variant {}::{}", params.type_name(), variant_ident),
@@ -582,19 +589,18 @@ fn deserialize_tuple_in_place(
     };
 
     let dispatch = if let Some(deserializer) = deserializer {
-        quote!(_serde::Deserializer::deserialize_tuple(#deserializer, #nfields, #visitor_expr))
+        quote!(_serde::Deserializer::deserialize_tuple(#deserializer, #field_count, #visitor_expr))
     } else if is_enum {
-        quote!(_serde::de::VariantAccess::tuple_variant(__variant, #nfields, #visitor_expr))
+        quote!(_serde::de::VariantAccess::tuple_variant(__variant, #field_count, #visitor_expr))
     } else if nfields == 1 {
         let type_name = cattrs.name().deserialize_name();
         quote!(_serde::Deserializer::deserialize_newtype_struct(__deserializer, #type_name, #visitor_expr))
     } else {
         let type_name = cattrs.name().deserialize_name();
-        quote!(_serde::Deserializer::deserialize_tuple_struct(__deserializer, #type_name, #nfields, #visitor_expr))
+        quote!(_serde::Deserializer::deserialize_tuple_struct(__deserializer, #type_name, #field_count, #visitor_expr))
     };
 
-    let all_skipped = fields.iter().all(|field| field.attrs.skip_deserializing());
+    let visitor_var = if field_count == 0 {
-    let visitor_var = if all_skipped {
         quote!(_)
     } else {
         quote!(mut __seq)
@@ -605,6 +611,7 @@ fn deserialize_tuple_in_place(
     let place_life = place_lifetime();
 
     quote_block! {
+        #[doc(hidden)]
         struct __Visitor #in_place_impl_generics #where_clause {
             place: &#place_life mut #this_type #ty_generics,
             lifetime: _serde::__private::PhantomData<&#delife ()>,
@@ -1020,6 +1027,7 @@ fn deserialize_struct(
     quote_block! {
         #field_visitor
 
+        #[doc(hidden)]
         struct __Visitor #de_impl_generics #where_clause {
             marker: _serde::__private::PhantomData<#this_type #ty_generics>,
             lifetime: _serde::__private::PhantomData<&#delife ()>,
@@ -1132,6 +1140,7 @@ fn deserialize_struct_in_place(
     Some(quote_block! {
         #field_visitor
 
+        #[doc(hidden)]
         struct __Visitor #in_place_impl_generics #where_clause {
             place: &#place_life mut #this_type #ty_generics,
             lifetime: _serde::__private::PhantomData<&#delife ()>,
@@ -1165,6 +1174,22 @@ fn deserialize_enum(
     params: &Parameters,
     variants: &[Variant],
     cattrs: &attr::Container,
+) -> Fragment {
+    // The variants have already been checked (in ast.rs) that all untagged variants appear at the end
+    match variants.iter().position(|var| var.attrs.untagged()) {
+        Some(variant_idx) => {
+            let (tagged, untagged) = variants.split_at(variant_idx);
+            let tagged_frag = Expr(deserialize_homogeneous_enum(params, tagged, cattrs));
+            deserialize_untagged_enum_after(params, untagged, cattrs, Some(tagged_frag))
+        }
+        None => deserialize_homogeneous_enum(params, variants, cattrs),
+    }
+}
+
+fn deserialize_homogeneous_enum(
+    params: &Parameters,
+    variants: &[Variant],
+    cattrs: &attr::Container,
 ) -> Fragment {
     match cattrs.tag() {
         attr::TagType::External => deserialize_externally_tagged_enum(params, variants, cattrs),
@@ -1203,6 +1228,7 @@ fn prepare_enum_variant_enum(
     let variants_stmt = {
         let variant_names = variant_names_idents.iter().map(|(name, _, _)| name);
         quote! {
+            #[doc(hidden)]
             const VARIANTS: &'static [&'static str] = &[ #(#variant_names),* ];
         }
     };
@@ -1275,6 +1301,7 @@ fn deserialize_externally_tagged_enum(
     quote_block! {
         #variant_visitor
 
+        #[doc(hidden)]
         struct __Visitor #de_impl_generics #where_clause {
             marker: _serde::__private::PhantomData<#this_type #ty_generics>,
             lifetime: _serde::__private::PhantomData<&#delife ()>,
@@ -1522,6 +1549,7 @@ fn deserialize_adjacently_tagged_enum(
 
         #variants_stmt
 
+        #[doc(hidden)]
         struct __Seed #de_impl_generics #where_clause {
             field: __Field,
             marker: _serde::__private::PhantomData<#this_type #ty_generics>,
@@ -1541,6 +1569,7 @@ fn deserialize_adjacently_tagged_enum(
             }
         }
 
+        #[doc(hidden)]
         struct __Visitor #de_impl_generics #where_clause {
             marker: _serde::__private::PhantomData<#this_type #ty_generics>,
             lifetime: _serde::__private::PhantomData<&#delife ()>,
@@ -1643,6 +1672,7 @@ fn deserialize_adjacently_tagged_enum(
             }
         }
 
+        #[doc(hidden)]
         const FIELDS: &'static [&'static str] = &[#tag, #content];
         _serde::Deserializer::deserialize_struct(
             __deserializer,
@@ -1660,6 +1690,16 @@ fn deserialize_untagged_enum(
     params: &Parameters,
     variants: &[Variant],
     cattrs: &attr::Container,
+) -> Fragment {
+    let first_attempt = None;
+    deserialize_untagged_enum_after(params, variants, cattrs, first_attempt)
+}
+
+fn deserialize_untagged_enum_after(
+    params: &Parameters,
+    variants: &[Variant],
+    cattrs: &attr::Container,
+    first_attempt: Option<Expr>,
 ) -> Fragment {
     let attempts = variants
         .iter()
@@ -1669,12 +1709,10 @@ fn deserialize_untagged_enum(
                 params,
                 variant,
                 cattrs,
-                quote!(
+                quote!(__deserializer),
-                    _serde::__private::de::ContentRefDeserializer::<__D::Error>::new(&__content)
-                ),
             ))
         });
-
+    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
@@ -1689,6 +1727,7 @@ fn deserialize_untagged_enum(
 
     quote_block! {
         let __content = try!(<_serde::__private::de::Content as _serde::Deserialize>::deserialize(__deserializer));
+        let __deserializer = _serde::__private::de::ContentRefDeserializer::<__D::Error>::new(&__content);
 
         #(
             if let _serde::__private::Ok(__ok) = #attempts {
@@ -1954,11 +1993,13 @@ fn deserialize_generated_identifier(
 
     quote_block! {
         #[allow(non_camel_case_types)]
+        #[doc(hidden)]
         enum __Field #lifetime {
             #(#field_idents,)*
             #ignore_variant
         }
 
+        #[doc(hidden)]
         struct __FieldVisitor;
 
         impl<'de> _serde::de::Visitor<'de> for __FieldVisitor {
@@ -2046,11 +2087,13 @@ fn deserialize_custom_identifier(
         None
     } else if is_variant {
         let variants = quote! {
+            #[doc(hidden)]
             const VARIANTS: &'static [&'static str] = &[ #(#names),* ];
         };
         Some(variants)
     } else {
         let fields = quote! {
+            #[doc(hidden)]
             const FIELDS: &'static [&'static str] = &[ #(#names),* ];
         };
         Some(fields)
@@ -2072,6 +2115,7 @@ fn deserialize_custom_identifier(
     quote_block! {
         #names_const
 
+        #[doc(hidden)]
         struct __FieldVisitor #de_impl_generics #where_clause {
             marker: _serde::__private::PhantomData<#this_type #ty_generics>,
             lifetime: _serde::__private::PhantomData<&#delife ()>,
@@ -2406,6 +2450,7 @@ fn deserialize_struct_as_struct_visitor(
             .flat_map(|(_, _, aliases)| aliases);
 
         quote_block! {
+            #[doc(hidden)]
             const FIELDS: &'static [&'static str] = &[ #(#field_names),* ];
         }
     };
@@ -2684,6 +2729,7 @@ fn deserialize_struct_as_struct_in_place_visitor(
     let fields_stmt = {
         let field_names = field_names_idents.iter().map(|(name, _, _)| name);
         quote_block! {
+            #[doc(hidden)]
             const FIELDS: &'static [&'static str] = &[ #(#field_names),* ];
         }
     };
@@ -2864,6 +2910,7 @@ fn wrap_deserialize_with(
     let delife = params.borrowed.de_lifetime();
 
     let wrapper = quote! {
+        #[doc(hidden)]
         struct __DeserializeWith #de_impl_generics #where_clause {
             value: #value_ty,
             phantom: _serde::__private::PhantomData<#this_type #ty_generics>,
@@ -3011,7 +3058,7 @@ struct InPlaceImplGenerics<'a>(&'a Parameters);
 impl<'a> ToTokens for DeImplGenerics<'a> {
     fn to_tokens(&self, tokens: &mut TokenStream) {
         let mut generics = self.0.generics.clone();
-        if let Some(de_lifetime) = self.0.borrowed.de_lifetime_def() {
+        if let Some(de_lifetime) = self.0.borrowed.de_lifetime_param() {
             generics.params = Some(syn::GenericParam::Lifetime(de_lifetime))
                 .into_iter()
                 .chain(generics.params)
@@ -3046,7 +3093,7 @@ impl<'a> ToTokens for InPlaceImplGenerics<'a> {
             .into_iter()
             .chain(generics.params)
             .collect();
-        if let Some(de_lifetime) = self.0.borrowed.de_lifetime_def() {
+        if let Some(de_lifetime) = self.0.borrowed.de_lifetime_param() {
             generics.params = Some(syn::GenericParam::Lifetime(de_lifetime))
                 .into_iter()
                 .chain(generics.params)
@@ -3068,23 +3115,31 @@ struct DeTypeGenerics<'a>(&'a Parameters);
 #[cfg(feature = "deserialize_in_place")]
 struct InPlaceTypeGenerics<'a>(&'a Parameters);
 
+fn de_type_generics_to_tokens(
+    mut generics: syn::Generics,
+    borrowed: &BorrowedLifetimes,
+    tokens: &mut TokenStream,
+) {
+    if borrowed.de_lifetime_param().is_some() {
+        let def = syn::LifetimeParam {
+            attrs: Vec::new(),
+            lifetime: syn::Lifetime::new("'de", Span::call_site()),
+            colon_token: None,
+            bounds: Punctuated::new(),
+        };
+        // Prepend 'de lifetime to list of generics
+        generics.params = Some(syn::GenericParam::Lifetime(def))
+            .into_iter()
+            .chain(generics.params)
+            .collect();
+    }
+    let (_, ty_generics, _) = generics.split_for_impl();
+    ty_generics.to_tokens(tokens);
+}
+
 impl<'a> ToTokens for DeTypeGenerics<'a> {
     fn to_tokens(&self, tokens: &mut TokenStream) {
-        let mut generics = self.0.generics.clone();
+        de_type_generics_to_tokens(self.0.generics.clone(), &self.0.borrowed, tokens);
-        if self.0.borrowed.de_lifetime_def().is_some() {
-            let def = syn::LifetimeDef {
-                attrs: Vec::new(),
-                lifetime: syn::Lifetime::new("'de", Span::call_site()),
-                colon_token: None,
-                bounds: Punctuated::new(),
-            };
-            generics.params = Some(syn::GenericParam::Lifetime(def))
-                .into_iter()
-                .chain(generics.params)
-                .collect();
-        }
-        let (_, ty_generics, _) = generics.split_for_impl();
-        ty_generics.to_tokens(tokens);
     }
 }
 
@@ -3097,20 +3152,7 @@ impl<'a> ToTokens for InPlaceTypeGenerics<'a> {
             .chain(generics.params)
             .collect();
 
-        if self.0.borrowed.de_lifetime_def().is_some() {
+        de_type_generics_to_tokens(generics, &self.0.borrowed, tokens);
-            let def = syn::LifetimeDef {
-                attrs: Vec::new(),
-                lifetime: syn::Lifetime::new("'de", Span::call_site()),
-                colon_token: None,
-                bounds: Punctuated::new(),
-            };
-            generics.params = Some(syn::GenericParam::Lifetime(def))
-                .into_iter()
-                .chain(generics.params)
-                .collect();
-        }
-        let (_, ty_generics, _) = generics.split_for_impl();
-        ty_generics.to_tokens(tokens);
     }
 }
 
@@ -3122,8 +3164,8 @@ impl<'a> DeTypeGenerics<'a> {
 }
 
 #[cfg(feature = "deserialize_in_place")]
-fn place_lifetime() -> syn::LifetimeDef {
+fn place_lifetime() -> syn::LifetimeParam {
-    syn::LifetimeDef {
+    syn::LifetimeParam {
         attrs: Vec::new(),
         lifetime: syn::Lifetime::new("'place", Span::call_site()),
         colon_token: None,

serde_derive/src/dummy.rs

@@ -1,23 +1,11 @@
-use proc_macro2::{Ident, TokenStream};
+use proc_macro2::TokenStream;
-use quote::format_ident;
 
 use syn;
 use try;
 
-pub fn wrap_in_const(
+pub fn wrap_in_const(serde_path: Option<&syn::Path>, code: TokenStream) -> TokenStream {
-    serde_path: Option<&syn::Path>,
-    trait_: &str,
-    ty: &Ident,
-    code: TokenStream,
-) -> TokenStream {
     let try_replacement = try::replacement();
 
-    let dummy_const = if cfg!(no_underscore_consts) {
-        format_ident!("_IMPL_{}_FOR_{}", trait_, unraw(ty))
-    } else {
-        format_ident!("_")
-    };
-
     let use_serde = match serde_path {
         Some(path) => quote! {
             use #path as _serde;
@@ -31,14 +19,10 @@ pub fn wrap_in_const(
     quote! {
         #[doc(hidden)]
         #[allow(non_upper_case_globals, unused_attributes, unused_qualifications)]
-        const #dummy_const: () = {
+        const _: () = {
             #use_serde
             #try_replacement
             #code
         };
     }
 }
-
-fn unraw(ident: &Ident) -> String {
-    ident.to_string().trim_start_matches("r#").to_owned()
-}

serde_derive/src/internals/ast.rs

@@ -140,7 +140,7 @@ fn enum_from_ast<'a>(
     variants: &'a Punctuated<syn::Variant, Token![,]>,
     container_default: &attr::Default,
 ) -> Vec<Variant<'a>> {
-    variants
+    let variants: Vec<Variant> = variants
         .iter()
         .map(|variant| {
             let attrs = attr::Variant::from_ast(cx, variant);
@@ -154,7 +154,20 @@ fn enum_from_ast<'a>(
                 original: variant,
             }
         })
-        .collect()
+        .collect();
+
+    let index_of_last_tagged_variant = variants
+        .iter()
+        .rposition(|variant| !variant.attrs.untagged());
+    if let Some(index_of_last_tagged_variant) = index_of_last_tagged_variant {
+        for variant in &variants[..index_of_last_tagged_variant] {
+            if variant.attrs.untagged() {
+                cx.error_spanned_by(&variant.ident, "all variants with the #[serde(untagged)] attribute must be placed at the end of the enum");
+            }
+        }
+    }
+
+    variants
 }
 
 fn struct_from_ast<'a>(

serde_derive/src/internals/check.rs

@@ -3,8 +3,8 @@ use internals::attr::{Identifier, TagType};
 use internals::{ungroup, Ctxt, Derive};
 use syn::{Member, Type};
 
-/// Cross-cutting checks that require looking at more than a single attrs
+// Cross-cutting checks that require looking at more than a single attrs object.
-/// object. Simpler checks should happen when parsing and building the attrs.
+// Simpler checks should happen when parsing and building the attrs.
 pub fn check(cx: &Ctxt, cont: &mut Container, derive: Derive) {
     check_remote_generic(cx, cont);
     check_getter(cx, cont);
@@ -17,18 +17,18 @@ pub fn check(cx: &Ctxt, cont: &mut Container, derive: Derive) {
     check_from_and_try_from(cx, cont);
 }
 
-/// Remote derive definition type must have either all of the generics of the
+// Remote derive definition type must have either all of the generics of the
-/// remote type:
+// remote type:
-///
+//
-///     #[serde(remote = "Generic")]
+//     #[serde(remote = "Generic")]
-///     struct Generic<T> {…}
+//     struct Generic<T> {…}
-///
+//
-/// or none of them, i.e. defining impls for one concrete instantiation of the
+// or none of them, i.e. defining impls for one concrete instantiation of the
-/// remote type only:
+// remote type only:
-///
+//
-///     #[serde(remote = "Generic<T>")]
+//     #[serde(remote = "Generic<T>")]
-///     struct ConcreteDef {…}
+//     struct ConcreteDef {…}
-///
+//
 fn check_remote_generic(cx: &Ctxt, cont: &Container) {
     if let Some(remote) = cont.attrs.remote() {
         let local_has_generic = !cont.generics.params.is_empty();
@@ -39,8 +39,8 @@ fn check_remote_generic(cx: &Ctxt, cont: &Container) {
     }
 }
 
-/// Getters are only allowed inside structs (not enums) with the `remote`
+// Getters are only allowed inside structs (not enums) with the `remote`
-/// attribute.
+// attribute.
 fn check_getter(cx: &Ctxt, cont: &Container) {
     match cont.data {
         Data::Enum(_) => {
@@ -62,7 +62,7 @@ fn check_getter(cx: &Ctxt, cont: &Container) {
     }
 }
 
-/// Flattening has some restrictions we can test.
+// Flattening has some restrictions we can test.
 fn check_flatten(cx: &Ctxt, cont: &Container) {
     match &cont.data {
         Data::Enum(variants) => {
@@ -101,18 +101,16 @@ fn check_flatten_field(cx: &Ctxt, style: Style, field: &Field) {
     }
 }
 
-/// The `other` attribute must be used at most once and it must be the last
+// The `other` attribute must be used at most once and it must be the last
-/// variant of an enum.
+// variant of an enum.
-///
+//
-/// Inside a `variant_identifier` all variants must be unit variants. Inside a
+// Inside a `variant_identifier` all variants must be unit variants. Inside a
-/// `field_identifier` all but possibly one variant must be unit variants. The
+// `field_identifier` all but possibly one variant must be unit variants. The
-/// last variant may be a newtype variant which is an implicit "other" case.
+// last variant may be a newtype variant which is an implicit "other" case.
 fn check_identifier(cx: &Ctxt, cont: &Container) {
     let variants = match &cont.data {
         Data::Enum(variants) => variants,
-        Data::Struct(_, _) => {
+        Data::Struct(_, _) => return,
-            return;
-        }
     };
 
     for (i, variant) in variants.iter().enumerate() {
@@ -189,17 +187,15 @@ fn check_identifier(cx: &Ctxt, cont: &Container) {
     }
 }
 
-/// Skip-(de)serializing attributes are not allowed on variants marked
+// Skip-(de)serializing attributes are not allowed on variants marked
-/// (de)serialize_with.
+// (de)serialize_with.
 fn check_variant_skip_attrs(cx: &Ctxt, cont: &Container) {
     let variants = match &cont.data {
         Data::Enum(variants) => variants,
-        Data::Struct(_, _) => {
+        Data::Struct(_, _) => return,
-            return;
-        }
     };
 
-    for variant in variants.iter() {
+    for variant in variants {
         if variant.attrs.serialize_with().is_some() {
             if variant.attrs.skip_serializing() {
                 cx.error_spanned_by(
@@ -264,10 +260,9 @@ fn check_variant_skip_attrs(cx: &Ctxt, cont: &Container) {
     }
 }
 
-/// The tag of an internally-tagged struct variant must not be
+// The tag of an internally-tagged struct variant must not be the same as either
-/// the same as either one of its fields, as this would result in
+// one of its fields, as this would result in duplicate keys in the serialized
-/// duplicate keys in the serialized output and/or ambiguity in
+// output and/or ambiguity in the to-be-deserialized input.
-/// the to-be-deserialized input.
 fn check_internal_tag_field_name_conflict(cx: &Ctxt, cont: &Container) {
     let variants = match &cont.data {
         Data::Enum(variants) => variants,
@@ -313,8 +308,8 @@ fn check_internal_tag_field_name_conflict(cx: &Ctxt, cont: &Container) {
     }
 }
 
-/// In the case of adjacently-tagged enums, the type and the
+// In the case of adjacently-tagged enums, the type and the contents tag must
-/// contents tag must differ, for the same reason.
+// differ, for the same reason.
 fn check_adjacent_tag_conflict(cx: &Ctxt, cont: &Container) {
     let (type_tag, content_tag) = match cont.attrs.tag() {
         TagType::Adjacent { tag, content } => (tag, content),
@@ -332,7 +327,7 @@ fn check_adjacent_tag_conflict(cx: &Ctxt, cont: &Container) {
     }
 }
 
-/// Enums and unit structs cannot be transparent.
+// Enums and unit structs cannot be transparent.
 fn check_transparent(cx: &Ctxt, cont: &mut Container, derive: Derive) {
     if !cont.attrs.transparent() {
         return;

serde_derive/src/internals/ctxt.rs

@@ -44,12 +44,19 @@ impl Ctxt {
     }
 
     /// Consume this object, producing a formatted error string if there are errors.
-    pub fn check(self) -> Result<(), Vec<syn::Error>> {
+    pub fn check(self) -> syn::Result<()> {
-        let errors = self.errors.borrow_mut().take().unwrap();
+        let mut errors = self.errors.borrow_mut().take().unwrap().into_iter();
-        match errors.len() {
+
-            0 => Ok(()),
+        let mut combined = match errors.next() {
-            _ => Err(errors),
+            Some(first) => first,
+            None => return Ok(()),
+        };
+
+        for rest in errors {
+            combined.combine(rest);
         }
+
+        Err(combined)
     }
 }
 

serde_derive/src/internals/receiver.rs

@@ -179,10 +179,13 @@ impl ReplaceReceiver<'_> {
                 for arg in &mut arguments.args {
                     match arg {
                         GenericArgument::Type(arg) => self.visit_type_mut(arg),
-                        GenericArgument::Binding(arg) => self.visit_type_mut(&mut arg.ty),
+                        GenericArgument::AssocType(arg) => self.visit_type_mut(&mut arg.ty),
                         GenericArgument::Lifetime(_)
-                        | GenericArgument::Constraint(_)
+                        | GenericArgument::Const(_)
-                        | GenericArgument::Const(_) => {}
+                        | GenericArgument::AssocConst(_)
+                        | GenericArgument::Constraint(_) => {}
+                        #[cfg_attr(all(test, exhaustive), deny(non_exhaustive_omitted_patterns))]
+                        _ => {}
                     }
                 }
             }
@@ -205,7 +208,9 @@ impl ReplaceReceiver<'_> {
     fn visit_type_param_bound_mut(&mut self, bound: &mut TypeParamBound) {
         match bound {
             TypeParamBound::Trait(bound) => self.visit_path_mut(&mut bound.path),
-            TypeParamBound::Lifetime(_) => {}
+            TypeParamBound::Lifetime(_) | TypeParamBound::Verbatim(_) => {}
+            #[cfg_attr(all(test, exhaustive), deny(non_exhaustive_omitted_patterns))]
+            _ => {}
         }
     }
 
@@ -229,7 +234,9 @@ impl ReplaceReceiver<'_> {
                             self.visit_type_param_bound_mut(bound);
                         }
                     }
-                    WherePredicate::Lifetime(_) | WherePredicate::Eq(_) => {}
+                    WherePredicate::Lifetime(_) => {}
+                    #[cfg_attr(all(test, exhaustive), deny(non_exhaustive_omitted_patterns))]
+                    _ => {}
                 }
             }
         }

serde_derive/src/internals/symbol.rs

@@ -13,6 +13,7 @@ pub const DEFAULT: Symbol = Symbol("default");
 pub const DENY_UNKNOWN_FIELDS: Symbol = Symbol("deny_unknown_fields");
 pub const DESERIALIZE: Symbol = Symbol("deserialize");
 pub const DESERIALIZE_WITH: Symbol = Symbol("deserialize_with");
+pub const EXPECTING: Symbol = Symbol("expecting");
 pub const FIELD_IDENTIFIER: Symbol = Symbol("field_identifier");
 pub const FLATTEN: Symbol = Symbol("flatten");
 pub const FROM: Symbol = Symbol("from");
@@ -22,6 +23,7 @@ pub const OTHER: Symbol = Symbol("other");
 pub const REMOTE: Symbol = Symbol("remote");
 pub const RENAME: Symbol = Symbol("rename");
 pub const RENAME_ALL: Symbol = Symbol("rename_all");
+pub const REPR: Symbol = Symbol("repr");
 pub const SERDE: Symbol = Symbol("serde");
 pub const SERIALIZE: Symbol = Symbol("serialize");
 pub const SERIALIZE_WITH: Symbol = Symbol("serialize_with");
@@ -35,7 +37,6 @@ pub const TRY_FROM: Symbol = Symbol("try_from");
 pub const UNTAGGED: Symbol = Symbol("untagged");
 pub const VARIANT_IDENTIFIER: Symbol = Symbol("variant_identifier");
 pub const WITH: Symbol = Symbol("with");
-pub const EXPECTING: Symbol = Symbol("expecting");
 
 impl PartialEq<Symbol> for Ident {
     fn eq(&self, word: &Symbol) -> bool {

serde_derive/src/lib.rs

@@ -13,7 +13,7 @@
 //!
 //! [https://serde.rs/derive.html]: https://serde.rs/derive.html
 
-#![doc(html_root_url = "https://docs.rs/serde_derive/1.0.154")]
+#![doc(html_root_url = "https://docs.rs/serde_derive/1.0.165")]
 #![allow(unknown_lints, bare_trait_objects)]
 // Ignored clippy lints
 #![allow(
@@ -92,7 +92,7 @@ mod try;
 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(to_compile_errors)
+        .unwrap_or_else(syn::Error::into_compile_error)
         .into()
 }
 
@@ -100,11 +100,6 @@ pub fn derive_serialize(input: TokenStream) -> TokenStream {
 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(to_compile_errors)
+        .unwrap_or_else(syn::Error::into_compile_error)
         .into()
 }
-
-fn to_compile_errors(errors: Vec<syn::Error>) -> proc_macro2::TokenStream {
-    let compile_errors = errors.iter().map(syn::Error::to_compile_error);
-    quote!(#(#compile_errors)*)
-}

serde_derive/src/pretend.rs

@@ -97,29 +97,14 @@ fn pretend_fields_used_struct_packed(cont: &Container, fields: &[Field]) -> Toke
 
     let members = fields.iter().map(|field| &field.member).collect::<Vec<_>>();
 
-    #[cfg(not(no_ptr_addr_of))]
+    quote! {
-    {
+        match _serde::__private::None::<&#type_ident #ty_generics> {
-        quote! {
+            _serde::__private::Some(__v @ #type_ident { #(#members: _),* }) => {
-            match _serde::__private::None::<&#type_ident #ty_generics> {
+                #(
-                _serde::__private::Some(__v @ #type_ident { #(#members: _),* }) => {
+                    let _ = _serde::__private::ptr::addr_of!(__v.#members);
-                    #(
+                )*
-                        let _ = _serde::__private::ptr::addr_of!(__v.#members);
-                    )*
-                }
-                _ => {}
-            }
-        }
-    }
-
-    #[cfg(no_ptr_addr_of)]
-    {
-        let placeholders = (0usize..).map(|i| format_ident!("__v{}", i));
-
-        quote! {
-            match _serde::__private::None::<#type_ident #ty_generics> {
-                _serde::__private::Some(#type_ident { #(#members: #placeholders),* }) => {}
-                _ => {}
             }
+            _ => {}
         }
     }
 }

serde_derive/src/ser.rs

@@ -10,9 +10,7 @@ use internals::{attr, replace_receiver, Ctxt, Derive};
 use pretend;
 use this;
 
-pub fn expand_derive_serialize(
+pub fn expand_derive_serialize(input: &mut syn::DeriveInput) -> syn::Result<TokenStream> {
-    input: &mut syn::DeriveInput,
-) -> Result<TokenStream, Vec<syn::Error>> {
     replace_receiver(input);
 
     let ctxt = Ctxt::new();
@@ -59,8 +57,6 @@ pub fn expand_derive_serialize(
 
     Ok(dummy::wrap_in_const(
         cont.attrs.custom_serde_path(),
-        "SERIALIZE",
-        ident,
         impl_block,
     ))
 }
@@ -477,17 +473,19 @@ fn serialize_variant(
             }
         };
 
-        let body = Match(match cattrs.tag() {
+        let body = Match(match (cattrs.tag(), variant.attrs.untagged()) {
-            attr::TagType::External => {
+            (attr::TagType::External, false) => {
                 serialize_externally_tagged_variant(params, variant, variant_index, cattrs)
             }
-            attr::TagType::Internal { tag } => {
+            (attr::TagType::Internal { tag }, false) => {
                 serialize_internally_tagged_variant(params, variant, cattrs, tag)
             }
-            attr::TagType::Adjacent { tag, content } => {
+            (attr::TagType::Adjacent { tag, content }, false) => {
                 serialize_adjacently_tagged_variant(params, variant, cattrs, tag, content)
             }
-            attr::TagType::None => serialize_untagged_variant(params, variant, cattrs),
+            (attr::TagType::None, _) | (_, true) => {
+                serialize_untagged_variant(params, variant, cattrs)
+            }
         });
 
         quote! {
@@ -719,6 +717,7 @@ fn serialize_adjacently_tagged_variant(
     let (wrapper_impl_generics, wrapper_ty_generics, _) = wrapper_generics.split_for_impl();
 
     quote_block! {
+        #[doc(hidden)]
         struct __AdjacentlyTagged #wrapper_generics #where_clause {
             data: (#(&'__a #fields_ty,)*),
             phantom: _serde::__private::PhantomData<#this_type #ty_generics>,
@@ -982,6 +981,7 @@ fn serialize_struct_variant_with_flatten(
             let (wrapper_impl_generics, wrapper_ty_generics, _) = wrapper_generics.split_for_impl();
 
             quote_block! {
+                #[doc(hidden)]
                 struct __EnumFlatten #wrapper_generics #where_clause {
                     data: (#(&'__a #fields_ty,)*),
                     phantom: _serde::__private::PhantomData<#this_type #ty_generics>,
@@ -1212,6 +1212,7 @@ fn wrap_serialize_with(
     });
 
     quote!({
+        #[doc(hidden)]
         struct __SerializeWith #wrapper_impl_generics #where_clause {
             values: (#(&'__a #field_tys, )*),
             phantom: _serde::__private::PhantomData<#this_type #ty_generics>,

serde_derive_internals/.clippy.toml

@@ -1 +0,0 @@
-msrv = "1.31.0"

serde_derive_internals/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "serde_derive_internals"
-version = "0.26.0" # remember to update html_root_url
+version = "0.28.0" # remember to update html_root_url
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>", "David Tolnay <dtolnay@gmail.com>"]
 description = "AST representation used by Serde derive macros. Unstable."
 documentation = "https://docs.rs/serde_derive_internals"
@@ -9,7 +9,7 @@ include = ["lib.rs", "src/**/*.rs", "LICENSE-APACHE", "LICENSE-MIT"]
 keywords = ["serde", "serialization"]
 license = "MIT OR Apache-2.0"
 repository = "https://github.com/serde-rs/serde"
-rust-version = "1.31"
+rust-version = "1.56"
 
 [lib]
 path = "lib.rs"
@@ -17,7 +17,7 @@ path = "lib.rs"
 [dependencies]
 proc-macro2 = "1.0"
 quote = "1.0"
-syn = { version = "1.0.104", default-features = false, features = ["derive", "parsing", "printing", "clone-impls"] }
+syn = { version = "2.0.21", default-features = false, features = ["derive", "parsing", "printing", "clone-impls"] }
 
 [package.metadata.docs.rs]
 targets = ["x86_64-unknown-linux-gnu"]

serde_derive_internals/lib.rs

@@ -1,4 +1,4 @@
-#![doc(html_root_url = "https://docs.rs/serde_derive_internals/0.26.0")]
+#![doc(html_root_url = "https://docs.rs/serde_derive_internals/0.28.0")]
 #![allow(unknown_lints, bare_trait_objects)]
 // Ignored clippy lints
 #![allow(
@@ -31,6 +31,7 @@
     clippy::module_name_repetitions,
     clippy::must_use_candidate,
     clippy::similar_names,
+    clippy::single_match_else,
     clippy::struct_excessive_bools,
     clippy::too_many_lines,
     clippy::unused_self,

serde_test/.clippy.toml

@@ -1 +0,0 @@
-msrv = "1.13.0"

serde_test/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "serde_test"
-version = "1.0.154" # remember to update html_root_url
+version = "1.0.165" # remember to update html_root_url
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>", "David Tolnay <dtolnay@gmail.com>"]
 build = "build.rs"
 categories = ["development-tools::testing"]

serde_test/src/de.rs

@@ -12,32 +12,29 @@ pub struct Deserializer<'de> {
     tokens: &'de [Token],
 }
 
-macro_rules! assert_next_token {
+fn assert_next_token(de: &mut Deserializer, expected: Token) -> Result<(), Error> {
-    ($de:expr, $expected:expr) => {
+    match de.next_token_opt() {
-        match $de.next_token_opt() {
+        Some(token) if token == expected => Ok(()),
-            Some(token) if token == $expected => {}
+        Some(other) => Err(de::Error::custom(format!(
-            Some(other) => panic!(
+            "expected Token::{} but deserialization wants Token::{}",
-                "expected Token::{} but deserialization wants Token::{}",
+            other, expected,
-                other, $expected
+        ))),
-            ),
+        None => Err(de::Error::custom(format!(
-            None => panic!(
+            "end of tokens but deserialization wants Token::{}",
-                "end of tokens but deserialization wants Token::{}",
+            expected,
-                $expected
+        ))),
-            ),
+    }
-        }
-    };
 }
 
-macro_rules! unexpected {
+fn unexpected(token: Token) -> Error {
-    ($token:expr) => {
+    de::Error::custom(format!(
-        panic!("deserialization did not expect this token: {}", $token)
+        "deserialization did not expect this token: {}",
-    };
+        token,
+    ))
 }
 
-macro_rules! end_of_tokens {
+fn end_of_tokens() -> Error {
-    () => {
+    de::Error::custom("ran out of tokens to deserialize")
-        panic!("ran out of tokens to deserialize")
-    };
 }
 
 impl<'de> Deserializer<'de> {
@@ -49,11 +46,8 @@ impl<'de> Deserializer<'de> {
         self.tokens.first().cloned()
     }
 
-    fn peek_token(&self) -> Token {
+    fn peek_token(&self) -> Result<Token, Error> {
-        match self.peek_token_opt() {
+        self.peek_token_opt().ok_or_else(end_of_tokens)
-            Some(token) => token,
-            None => end_of_tokens!(),
-        }
     }
 
     pub fn next_token_opt(&mut self) -> Option<Token> {
@@ -66,14 +60,10 @@ impl<'de> Deserializer<'de> {
         }
     }
 
-    fn next_token(&mut self) -> Token {
+    fn next_token(&mut self) -> Result<Token, Error> {
-        match self.tokens.split_first() {
+        let (&first, rest) = self.tokens.split_first().ok_or_else(end_of_tokens)?;
-            Some((&first, rest)) => {
+        self.tokens = rest;
-                self.tokens = rest;
+        Ok(first)
-                first
-            }
-            None => end_of_tokens!(),
-        }
     }
 
     pub fn remaining(&self) -> usize {
@@ -94,7 +84,7 @@ impl<'de> Deserializer<'de> {
             len: len,
             end: end,
         })?;
-        assert_next_token!(self, end);
+        assert_next_token(self, end)?;
         Ok(value)
     }
 
@@ -112,7 +102,7 @@ impl<'de> Deserializer<'de> {
             len: len,
             end: end,
         })?;
-        assert_next_token!(self, end);
+        assert_next_token(self, end)?;
         Ok(value)
     }
 }
@@ -129,7 +119,7 @@ impl<'de, 'a> de::Deserializer<'de> for &'a mut Deserializer<'de> {
     where
         V: Visitor<'de>,
     {
-        let token = self.next_token();
+        let token = self.next_token()?;
         match token {
             Token::Bool(v) => visitor.visit_bool(v),
             Token::I8(v) => visitor.visit_i8(v),
@@ -161,50 +151,50 @@ impl<'de, 'a> de::Deserializer<'de> for &'a mut Deserializer<'de> {
             Token::Map { len } => self.visit_map(len, Token::MapEnd, visitor),
             Token::Struct { len, .. } => self.visit_map(Some(len), Token::StructEnd, visitor),
             Token::Enum { .. } => {
-                let variant = self.next_token();
+                let variant = self.next_token()?;
-                let next = self.peek_token();
+                let next = self.peek_token()?;
                 match (variant, next) {
                     (Token::Str(variant), Token::Unit) => {
-                        self.next_token();
+                        self.next_token()?;
                         visitor.visit_str(variant)
                     }
                     (Token::BorrowedStr(variant), Token::Unit) => {
-                        self.next_token();
+                        self.next_token()?;
                         visitor.visit_borrowed_str(variant)
                     }
                     (Token::String(variant), Token::Unit) => {
-                        self.next_token();
+                        self.next_token()?;
                         visitor.visit_string(variant.to_string())
                     }
                     (Token::Bytes(variant), Token::Unit) => {
-                        self.next_token();
+                        self.next_token()?;
                         visitor.visit_bytes(variant)
                     }
                     (Token::BorrowedBytes(variant), Token::Unit) => {
-                        self.next_token();
+                        self.next_token()?;
                         visitor.visit_borrowed_bytes(variant)
                     }
                     (Token::ByteBuf(variant), Token::Unit) => {
-                        self.next_token();
+                        self.next_token()?;
                         visitor.visit_byte_buf(variant.to_vec())
                     }
                     (Token::U8(variant), Token::Unit) => {
-                        self.next_token();
+                        self.next_token()?;
                         visitor.visit_u8(variant)
                     }
                     (Token::U16(variant), Token::Unit) => {
-                        self.next_token();
+                        self.next_token()?;
                         visitor.visit_u16(variant)
                     }
                     (Token::U32(variant), Token::Unit) => {
-                        self.next_token();
+                        self.next_token()?;
                         visitor.visit_u32(variant)
                     }
                     (Token::U64(variant), Token::Unit) => {
-                        self.next_token();
+                        self.next_token()?;
                         visitor.visit_u64(variant)
                     }
-                    (variant, Token::Unit) => unexpected!(variant),
+                    (variant, Token::Unit) => Err(unexpected(variant)),
                     (variant, _) => {
                         visitor.visit_map(EnumMapVisitor::new(self, variant, EnumFormat::Any))
                     }
@@ -232,9 +222,7 @@ impl<'de, 'a> de::Deserializer<'de> for &'a mut Deserializer<'de> {
             | Token::MapEnd
             | Token::StructEnd
             | Token::TupleVariantEnd
-            | Token::StructVariantEnd => {
+            | Token::StructVariantEnd => Err(unexpected(token)),
-                unexpected!(token);
-            }
         }
     }
 
@@ -242,13 +230,13 @@ impl<'de, 'a> de::Deserializer<'de> for &'a mut Deserializer<'de> {
     where
         V: Visitor<'de>,
     {
-        match self.peek_token() {
+        match self.peek_token()? {
             Token::Unit | Token::None => {
-                self.next_token();
+                self.next_token()?;
                 visitor.visit_none()
             }
             Token::Some => {
-                self.next_token();
+                self.next_token()?;
                 visitor.visit_some(self)
             }
             _ => self.deserialize_any(visitor),
@@ -264,9 +252,9 @@ impl<'de, 'a> de::Deserializer<'de> for &'a mut Deserializer<'de> {
     where
         V: Visitor<'de>,
     {
-        match self.peek_token() {
+        match self.peek_token()? {
             Token::Enum { name: n } if name == n => {
-                self.next_token();
+                self.next_token()?;
 
                 visitor.visit_enum(DeserializerEnumVisitor { de: self })
             }
@@ -286,9 +274,9 @@ impl<'de, 'a> de::Deserializer<'de> for &'a mut Deserializer<'de> {
     where
         V: Visitor<'de>,
     {
-        match self.peek_token() {
+        match self.peek_token()? {
             Token::UnitStruct { .. } => {
-                assert_next_token!(self, Token::UnitStruct { name: name });
+                assert_next_token(self, Token::UnitStruct { name: name })?;
                 visitor.visit_unit()
             }
             _ => self.deserialize_any(visitor),
@@ -303,9 +291,9 @@ impl<'de, 'a> de::Deserializer<'de> for &'a mut Deserializer<'de> {
     where
         V: Visitor<'de>,
     {
-        match self.peek_token() {
+        match self.peek_token()? {
             Token::NewtypeStruct { .. } => {
-                assert_next_token!(self, Token::NewtypeStruct { name: name });
+                assert_next_token(self, Token::NewtypeStruct { name: name })?;
                 visitor.visit_newtype_struct(self)
             }
             _ => self.deserialize_any(visitor),
@@ -316,21 +304,21 @@ impl<'de, 'a> de::Deserializer<'de> for &'a mut Deserializer<'de> {
     where
         V: Visitor<'de>,
     {
-        match self.peek_token() {
+        match self.peek_token()? {
             Token::Unit | Token::UnitStruct { .. } => {
-                self.next_token();
+                self.next_token()?;
                 visitor.visit_unit()
             }
             Token::Seq { .. } => {
-                self.next_token();
+                self.next_token()?;
                 self.visit_seq(Some(len), Token::SeqEnd, visitor)
             }
             Token::Tuple { .. } => {
-                self.next_token();
+                self.next_token()?;
                 self.visit_seq(Some(len), Token::TupleEnd, visitor)
             }
             Token::TupleStruct { .. } => {
-                self.next_token();
+                self.next_token()?;
                 self.visit_seq(Some(len), Token::TupleStructEnd, visitor)
             }
             _ => self.deserialize_any(visitor),
@@ -346,25 +334,25 @@ impl<'de, 'a> de::Deserializer<'de> for &'a mut Deserializer<'de> {
     where
         V: Visitor<'de>,
     {
-        match self.peek_token() {
+        match self.peek_token()? {
             Token::Unit => {
-                self.next_token();
+                self.next_token()?;
                 visitor.visit_unit()
             }
             Token::UnitStruct { .. } => {
-                assert_next_token!(self, Token::UnitStruct { name: name });
+                assert_next_token(self, Token::UnitStruct { name: name })?;
                 visitor.visit_unit()
             }
             Token::Seq { .. } => {
-                self.next_token();
+                self.next_token()?;
                 self.visit_seq(Some(len), Token::SeqEnd, visitor)
             }
             Token::Tuple { .. } => {
-                self.next_token();
+                self.next_token()?;
                 self.visit_seq(Some(len), Token::TupleEnd, visitor)
             }
             Token::TupleStruct { len: n, .. } => {
-                assert_next_token!(self, Token::TupleStruct { name: name, len: n });
+                assert_next_token(self, Token::TupleStruct { name: name, len: n })?;
                 self.visit_seq(Some(len), Token::TupleStructEnd, visitor)
             }
             _ => self.deserialize_any(visitor),
@@ -380,13 +368,13 @@ impl<'de, 'a> de::Deserializer<'de> for &'a mut Deserializer<'de> {
     where
         V: Visitor<'de>,
     {
-        match self.peek_token() {
+        match self.peek_token()? {
             Token::Struct { len: n, .. } => {
-                assert_next_token!(self, Token::Struct { name: name, len: n });
+                assert_next_token(self, Token::Struct { name: name, len: n })?;
                 self.visit_map(Some(fields.len()), Token::StructEnd, visitor)
             }
             Token::Map { .. } => {
-                self.next_token();
+                self.next_token()?;
                 self.visit_map(Some(fields.len()), Token::MapEnd, visitor)
             }
             _ => self.deserialize_any(visitor),
@@ -476,7 +464,7 @@ impl<'de, 'a> EnumAccess<'de> for DeserializerEnumVisitor<'a, 'de> {
     where
         V: DeserializeSeed<'de>,
     {
-        match self.de.peek_token() {
+        match self.de.peek_token()? {
             Token::UnitVariant { variant: v, .. }
             | Token::NewtypeVariant { variant: v, .. }
             | Token::TupleVariant { variant: v, .. }
@@ -497,9 +485,9 @@ impl<'de, 'a> VariantAccess<'de> for DeserializerEnumVisitor<'a, 'de> {
     type Error = Error;
 
     fn unit_variant(self) -> Result<(), Error> {
-        match self.de.peek_token() {
+        match self.de.peek_token()? {
             Token::UnitVariant { .. } => {
-                self.de.next_token();
+                self.de.next_token()?;
                 Ok(())
             }
             _ => Deserialize::deserialize(self.de),
@@ -510,9 +498,9 @@ impl<'de, 'a> VariantAccess<'de> for DeserializerEnumVisitor<'a, 'de> {
     where
         T: DeserializeSeed<'de>,
     {
-        match self.de.peek_token() {
+        match self.de.peek_token()? {
             Token::NewtypeVariant { .. } => {
-                self.de.next_token();
+                self.de.next_token()?;
                 seed.deserialize(self.de)
             }
             _ => seed.deserialize(self.de),
@@ -523,26 +511,26 @@ impl<'de, 'a> VariantAccess<'de> for DeserializerEnumVisitor<'a, 'de> {
     where
         V: Visitor<'de>,
     {
-        match self.de.peek_token() {
+        match self.de.peek_token()? {
             Token::TupleVariant { len: enum_len, .. } => {
-                let token = self.de.next_token();
+                let token = self.de.next_token()?;
 
                 if len == enum_len {
                     self.de
                         .visit_seq(Some(len), Token::TupleVariantEnd, visitor)
                 } else {
-                    unexpected!(token);
+                    Err(unexpected(token))
                 }
             }
             Token::Seq {
                 len: Some(enum_len),
             } => {
-                let token = self.de.next_token();
+                let token = self.de.next_token()?;
 
                 if len == enum_len {
                     self.de.visit_seq(Some(len), Token::SeqEnd, visitor)
                 } else {
-                    unexpected!(token);
+                    Err(unexpected(token))
                 }
             }
             _ => de::Deserializer::deserialize_any(self.de, visitor),
@@ -557,27 +545,27 @@ impl<'de, 'a> VariantAccess<'de> for DeserializerEnumVisitor<'a, 'de> {
     where
         V: Visitor<'de>,
     {
-        match self.de.peek_token() {
+        match self.de.peek_token()? {
             Token::StructVariant { len: enum_len, .. } => {
-                let token = self.de.next_token();
+                let token = self.de.next_token()?;
 
                 if fields.len() == enum_len {
                     self.de
                         .visit_map(Some(fields.len()), Token::StructVariantEnd, visitor)
                 } else {
-                    unexpected!(token);
+                    Err(unexpected(token))
                 }
             }
             Token::Map {
                 len: Some(enum_len),
             } => {
-                let token = self.de.next_token();
+                let token = self.de.next_token()?;
 
                 if fields.len() == enum_len {
                     self.de
                         .visit_map(Some(fields.len()), Token::MapEnd, visitor)
                 } else {
-                    unexpected!(token);
+                    Err(unexpected(token))
                 }
             }
             _ => de::Deserializer::deserialize_any(self.de, visitor),
@@ -622,7 +610,7 @@ impl<'de, 'a> MapAccess<'de> for EnumMapVisitor<'a, 'de> {
                 .deserialize(BytesDeserializer { value: variant })
                 .map(Some),
             Some(Token::U32(variant)) => seed.deserialize(variant.into_deserializer()).map(Some),
-            Some(other) => unexpected!(other),
+            Some(other) => Err(unexpected(other)),
             None => Ok(None),
         }
     }
@@ -641,7 +629,7 @@ impl<'de, 'a> MapAccess<'de> for EnumMapVisitor<'a, 'de> {
                     };
                     seed.deserialize(SeqAccessDeserializer::new(visitor))?
                 };
-                assert_next_token!(self.de, Token::TupleVariantEnd);
+                assert_next_token(self.de, Token::TupleVariantEnd)?;
                 Ok(value)
             }
             EnumFormat::Map => {
@@ -653,7 +641,7 @@ impl<'de, 'a> MapAccess<'de> for EnumMapVisitor<'a, 'de> {
                     };
                     seed.deserialize(MapAccessDeserializer::new(visitor))?
                 };
-                assert_next_token!(self.de, Token::StructVariantEnd);
+                assert_next_token(self.de, Token::StructVariantEnd)?;
                 Ok(value)
             }
             EnumFormat::Any => seed.deserialize(&mut *self.de),

serde_test/src/lib.rs

@@ -140,7 +140,7 @@
 //! # }
 //! ```
 
-#![doc(html_root_url = "https://docs.rs/serde_test/1.0.154")]
+#![doc(html_root_url = "https://docs.rs/serde_test/1.0.165")]
 #![cfg_attr(feature = "cargo-clippy", allow(renamed_and_removed_lints))]
 // Ignored clippy lints
 #![cfg_attr(feature = "cargo-clippy", allow(float_cmp, needless_doctest_main))]
@@ -182,7 +182,3 @@ pub use assert::{
 pub use token::Token;
 
 pub use configure::{Compact, Configure, Readable};
-
-// Not public API.
-#[doc(hidden)]
-pub use de::Deserializer;

serde_test/src/ser.rs

@@ -63,14 +63,12 @@ macro_rules! assert_next_token {
     ($ser:expr, $actual:expr, $pat:pat, $guard:expr) => {
         match $ser.next_token() {
             Some($pat) if $guard => {}
-            Some(expected) => {
+            Some(expected) => return Err(ser::Error::custom(
-                panic!("expected Token::{} but serialized as {}",
+                format!("expected Token::{} but serialized as {}", expected, $actual)
-                       expected, $actual);
+            )),
-            }
+            None => return Err(ser::Error::custom(
-            None => {
+                format!("expected end of tokens, but {} was serialized", $actual)
-                panic!("expected end of tokens, but {} was serialized",
+            )),
-                       $actual);
-            }
         }
     };
 }

test_suite/Cargo.toml

@@ -12,6 +12,7 @@ unstable = ["serde/unstable"]
 serde = { path = "../serde" }
 
 [dev-dependencies]
+automod = "1.0"
 fnv = "1.0"
 rustversion = "1.0"
 serde = { path = "../serde", features = ["rc", "derive"] }

test_suite/tests/regression.rs

@@ -0,0 +1,3 @@
+mod regression {
+    automod::dir!("tests/regression");
+}

test_suite/tests/regression/issue2371.rs

@@ -0,0 +1,43 @@
+use serde::Deserialize;
+
+#[derive(Deserialize)]
+pub struct Nested;
+
+#[derive(Deserialize)]
+pub enum ExternallyTagged {
+    Flatten {
+        #[serde(flatten)]
+        nested: Nested,
+        string: &'static str,
+    },
+}
+
+#[derive(Deserialize)]
+#[serde(tag = "tag")]
+pub enum InternallyTagged {
+    Flatten {
+        #[serde(flatten)]
+        nested: Nested,
+        string: &'static str,
+    },
+}
+
+#[derive(Deserialize)]
+#[serde(tag = "tag", content = "content")]
+pub enum AdjacentlyTagged {
+    Flatten {
+        #[serde(flatten)]
+        nested: Nested,
+        string: &'static str,
+    },
+}
+
+#[derive(Deserialize)]
+#[serde(untagged)]
+pub enum UntaggedWorkaround {
+    Flatten {
+        #[serde(flatten)]
+        nested: Nested,
+        string: &'static str,
+    },
+}

test_suite/tests/regression/issue2409.rs

@@ -0,0 +1,11 @@
+use serde::Deserialize;
+
+macro_rules! bug {
+    ($serde_path:literal) => {
+        #[derive(Deserialize)]
+        #[serde(crate = $serde_path)]
+        pub struct Struct;
+    };
+}
+
+bug!("serde");

test_suite/tests/regression/issue2415.rs

@@ -0,0 +1,5 @@
+use serde_derive::Serialize;
+
+#[derive(Serialize)]
+#[serde()]
+pub struct S;

test_suite/tests/test_annotations.rs

@@ -1533,7 +1533,7 @@ fn test_invalid_length_enum() {
             Token::TupleVariant {
                 name: "InvalidLengthEnum",
                 variant: "B",
-                len: 3,
+                len: 2,
             },
             Token::I32(1),
             Token::TupleVariantEnd,
@@ -2317,6 +2317,53 @@ fn test_internally_tagged_enum_new_type_with_unit() {
     );
 }
 
+#[test]
+fn test_adjacently_tagged_enum_bytes() {
+    #[derive(Serialize, Deserialize, PartialEq, Debug)]
+    #[serde(tag = "t", content = "c")]
+    enum Data {
+        A { a: i32 },
+    }
+
+    let data = Data::A { a: 0 };
+
+    assert_tokens(
+        &data,
+        &[
+            Token::Struct {
+                name: "Data",
+                len: 2,
+            },
+            Token::Str("t"),
+            Token::Str("A"),
+            Token::Str("c"),
+            Token::Struct { name: "A", len: 1 },
+            Token::Str("a"),
+            Token::I32(0),
+            Token::StructEnd,
+            Token::StructEnd,
+        ],
+    );
+
+    assert_de_tokens(
+        &data,
+        &[
+            Token::Struct {
+                name: "Data",
+                len: 2,
+            },
+            Token::Bytes(b"t"),
+            Token::Str("A"),
+            Token::Bytes(b"c"),
+            Token::Struct { name: "A", len: 1 },
+            Token::Str("a"),
+            Token::I32(0),
+            Token::StructEnd,
+            Token::StructEnd,
+        ],
+    );
+}
+
 #[test]
 fn test_adjacently_tagged_enum_containing_flatten() {
     #[derive(Serialize, Deserialize, PartialEq, Debug)]
@@ -2395,6 +2442,162 @@ fn test_untagged_enum_containing_flatten() {
     );
 }
 
+#[test]
+fn test_partially_untagged_enum() {
+    #[derive(Serialize, Deserialize, PartialEq, Debug)]
+    enum Exp {
+        Lambda(u32, Box<Exp>),
+        #[serde(untagged)]
+        App(Box<Exp>, Box<Exp>),
+        #[serde(untagged)]
+        Var(u32),
+    }
+    use Exp::*;
+
+    let data = Lambda(0, Box::new(App(Box::new(Var(0)), Box::new(Var(0)))));
+    assert_tokens(
+        &data,
+        &[
+            Token::TupleVariant {
+                name: "Exp",
+                variant: "Lambda",
+                len: 2,
+            },
+            Token::U32(0),
+            Token::Tuple { len: 2 },
+            Token::U32(0),
+            Token::U32(0),
+            Token::TupleEnd,
+            Token::TupleVariantEnd,
+        ],
+    );
+}
+
+#[test]
+fn test_partially_untagged_enum_generic() {
+    trait Trait<T> {
+        type Assoc;
+        type Assoc2;
+    }
+
+    #[derive(Serialize, Deserialize, PartialEq, Debug)]
+    enum E<A, B, C>
+    where
+        A: Trait<C, Assoc2 = B>,
+    {
+        A(A::Assoc),
+        #[serde(untagged)]
+        B(A::Assoc2),
+    }
+
+    impl<T> Trait<T> for () {
+        type Assoc = T;
+        type Assoc2 = bool;
+    }
+
+    type MyE = E<(), bool, u32>;
+    use E::*;
+
+    assert_tokens::<MyE>(&B(true), &[Token::Bool(true)]);
+
+    assert_tokens::<MyE>(
+        &A(5),
+        &[
+            Token::NewtypeVariant {
+                name: "E",
+                variant: "A",
+            },
+            Token::U32(5),
+        ],
+    );
+}
+
+#[test]
+fn test_partially_untagged_enum_desugared() {
+    #[derive(Serialize, Deserialize, PartialEq, Debug)]
+    enum Test {
+        A(u32, u32),
+        B(u32),
+        #[serde(untagged)]
+        C(u32),
+        #[serde(untagged)]
+        D(u32, u32),
+    }
+    use Test::*;
+
+    mod desugared {
+        use super::*;
+        #[derive(Serialize, Deserialize, PartialEq, Debug)]
+        pub(super) enum Test {
+            A(u32, u32),
+            B(u32),
+        }
+    }
+    use desugared::Test as TestTagged;
+
+    #[derive(Serialize, Deserialize, PartialEq, Debug)]
+    #[serde(untagged)]
+    enum TestUntagged {
+        Tagged(TestTagged),
+        C(u32),
+        D(u32, u32),
+    }
+
+    impl From<Test> for TestUntagged {
+        fn from(test: Test) -> Self {
+            match test {
+                A(x, y) => TestUntagged::Tagged(TestTagged::A(x, y)),
+                B(x) => TestUntagged::Tagged(TestTagged::B(x)),
+                C(x) => TestUntagged::C(x),
+                D(x, y) => TestUntagged::D(x, y),
+            }
+        }
+    }
+
+    fn assert_tokens_desugared(value: Test, tokens: &[Token]) {
+        assert_tokens(&value, tokens);
+        let desugared: TestUntagged = value.into();
+        assert_tokens(&desugared, tokens);
+    }
+
+    assert_tokens_desugared(
+        A(0, 1),
+        &[
+            Token::TupleVariant {
+                name: "Test",
+                variant: "A",
+                len: 2,
+            },
+            Token::U32(0),
+            Token::U32(1),
+            Token::TupleVariantEnd,
+        ],
+    );
+
+    assert_tokens_desugared(
+        B(1),
+        &[
+            Token::NewtypeVariant {
+                name: "Test",
+                variant: "B",
+            },
+            Token::U32(1),
+        ],
+    );
+
+    assert_tokens_desugared(C(2), &[Token::U32(2)]);
+
+    assert_tokens_desugared(
+        D(3, 5),
+        &[
+            Token::Tuple { len: 2 },
+            Token::U32(3),
+            Token::U32(5),
+            Token::TupleEnd,
+        ],
+    );
+}
+
 #[test]
 fn test_flatten_untagged_enum() {
     #[derive(Serialize, Deserialize, PartialEq, Debug)]

test_suite/tests/test_borrow.rs

@@ -4,6 +4,8 @@
     clippy::used_underscore_binding
 )]
 
+use serde::de::value::{BorrowedStrDeserializer, MapDeserializer};
+use serde::de::IntoDeserializer;
 use serde::{Deserialize, Deserializer};
 use serde_test::{assert_de_tokens, assert_de_tokens_error, Token};
 
@@ -130,20 +132,22 @@ fn test_cow() {
         borrowed: Cow<'b, str>,
     }
 
-    let tokens = &[
+    struct BorrowedStr(&'static str);
-        Token::Struct {
-            name: "Cows",
-            len: 2,
-        },
-        Token::Str("copied"),
-        Token::BorrowedStr("copied"),
-        Token::Str("borrowed"),
-        Token::BorrowedStr("borrowed"),
-        Token::StructEnd,
-    ];
 
-    let mut de = serde_test::Deserializer::new(tokens);
+    impl<'de> IntoDeserializer<'de> for BorrowedStr {
-    let cows = Cows::deserialize(&mut de).unwrap();
+        type Deserializer = BorrowedStrDeserializer<'de, serde::de::value::Error>;
+
+        fn into_deserializer(self) -> Self::Deserializer {
+            BorrowedStrDeserializer::new(self.0)
+        }
+    }
+
+    let de = MapDeserializer::new(IntoIterator::into_iter([
+        ("copied", BorrowedStr("copied")),
+        ("borrowed", BorrowedStr("borrowed")),
+    ]));
+
+    let cows = Cows::deserialize(de).unwrap();
 
     match cows.copied {
         Cow::Owned(ref s) if s == "copied" => {}

test_suite/tests/test_de.rs

@@ -14,6 +14,7 @@ use std::collections::{BTreeMap, BTreeSet, HashMap, HashSet};
 use std::default::Default;
 use std::ffi::{CStr, CString, OsString};
 use std::fmt::Debug;
+use std::iter;
 use std::net;
 use std::num::{
     NonZeroI128, NonZeroI16, NonZeroI32, NonZeroI64, NonZeroI8, NonZeroIsize, NonZeroU128,
@@ -33,7 +34,7 @@ use std::time::{Duration, UNIX_EPOCH};
 use std::sync::atomic::{AtomicI64, AtomicU64};
 
 use fnv::FnvHasher;
-use serde::de::DeserializeOwned;
+use serde::de::{DeserializeOwned, IntoDeserializer};
 use serde::{Deserialize, Deserializer};
 use serde_test::{assert_de_tokens, Configure, Token};
 
@@ -199,12 +200,11 @@ fn assert_de_tokens_ignore(ignorable_tokens: &[Token]) {
     ]
     .into_iter()
     .chain(ignorable_tokens.iter().copied())
-    .chain(vec![Token::MapEnd].into_iter())
+    .chain(iter::once(Token::MapEnd))
     .collect();
 
-    let mut de = serde_test::Deserializer::new(&concated_tokens);
+    let expected = IgnoreBase { a: 1 };
-    let base = IgnoreBase::deserialize(&mut de).unwrap();
+    assert_de_tokens(&expected, &concated_tokens);
-    assert_eq!(base, IgnoreBase { a: 1 });
 }
 
 //////////////////////////////////////////////////////////////////////////
@@ -2245,39 +2245,34 @@ fn test_cstr() {
 
 #[test]
 fn test_atomics() {
-    fn test<L, A, T>(load: L, val: T, token: Token)
+    fn test<L, A, T>(load: L, val: T)
     where
         L: Fn(&A, Ordering) -> T,
         A: DeserializeOwned,
-        T: PartialEq + Debug,
+        T: PartialEq + Debug + Copy + for<'de> IntoDeserializer<'de>,
     {
-        let tokens = &[token];
+        match A::deserialize(val.into_deserializer()) {
-        let mut de = serde_test::Deserializer::new(tokens);
-        match A::deserialize(&mut de) {
             Ok(v) => {
                 let loaded = load(&v, Ordering::Relaxed);
                 assert_eq!(val, loaded);
             }
             Err(e) => panic!("tokens failed to deserialize: {}", e),
-        };
-        if de.remaining() > 0 {
-            panic!("{} remaining tokens", de.remaining());
         }
     }
 
-    test(AtomicBool::load, true, Token::Bool(true));
+    test(AtomicBool::load, true);
-    test(AtomicI8::load, -127, Token::I8(-127i8));
+    test(AtomicI8::load, -127i8);
-    test(AtomicI16::load, -510, Token::I16(-510i16));
+    test(AtomicI16::load, -510i16);
-    test(AtomicI32::load, -131072, Token::I32(-131072i32));
+    test(AtomicI32::load, -131072i32);
-    test(AtomicIsize::load, -131072isize, Token::I32(-131072));
+    test(AtomicIsize::load, -131072isize);
-    test(AtomicU8::load, 127, Token::U8(127u8));
+    test(AtomicU8::load, 127u8);
-    test(AtomicU16::load, 510u16, Token::U16(510u16));
+    test(AtomicU16::load, 510u16);
-    test(AtomicU32::load, 131072u32, Token::U32(131072u32));
+    test(AtomicU32::load, 131072u32);
-    test(AtomicUsize::load, 131072usize, Token::U32(131072));
+    test(AtomicUsize::load, 131072usize);
 
     #[cfg(target_arch = "x86_64")]
     {
-        test(AtomicI64::load, -8589934592, Token::I64(-8589934592));
+        test(AtomicI64::load, -8589934592i64);
-        test(AtomicU64::load, 8589934592u64, Token::U64(8589934592));
+        test(AtomicU64::load, 8589934592u64);
     }
 }

test_suite/tests/test_gen.rs

@@ -257,6 +257,16 @@ fn test_gen() {
     }
     assert::<VariantWithTraits2<X, X>>();
 
+    type PhantomDataAlias<T> = PhantomData<T>;
+
+    #[derive(Serialize, Deserialize)]
+    #[serde(bound = "")]
+    struct PhantomDataWrapper<T> {
+        #[serde(default)]
+        field: PhantomDataAlias<T>,
+    }
+    assert::<PhantomDataWrapper<X>>();
+
     #[derive(Serialize, Deserialize)]
     struct CowStr<'a>(Cow<'a, str>);
     assert::<CowStr>();
@@ -892,53 +902,3 @@ pub struct RemotePackedNonCopyDef {
 impl Drop for RemotePackedNonCopyDef {
     fn drop(&mut self) {}
 }
-
-//////////////////////////////////////////////////////////////////////////
-
-/// Regression tests for <https://github.com/serde-rs/serde/issues/2371>
-#[allow(dead_code)]
-mod static_and_flatten {
-    use super::*;
-
-    #[derive(Deserialize)]
-    struct Nested;
-
-    #[derive(Deserialize)]
-    enum ExternallyTagged {
-        Flatten {
-            #[serde(flatten)]
-            nested: Nested,
-            string: &'static str,
-        },
-    }
-
-    #[derive(Deserialize)]
-    #[serde(tag = "tag")]
-    enum InternallyTagged {
-        Flatten {
-            #[serde(flatten)]
-            nested: Nested,
-            string: &'static str,
-        },
-    }
-
-    #[derive(Deserialize)]
-    #[serde(tag = "tag", content = "content")]
-    enum AdjacentlyTagged {
-        Flatten {
-            #[serde(flatten)]
-            nested: Nested,
-            string: &'static str,
-        },
-    }
-
-    #[derive(Deserialize)]
-    #[serde(untagged)]
-    enum UntaggedWorkaround {
-        Flatten {
-            #[serde(flatten)]
-            nested: Nested,
-            string: &'static str,
-        },
-    }
-}

test_suite/tests/ui/borrow/duplicate_variant.stderr

@@ -1,5 +1,5 @@
 error: duplicate serde attribute `borrow`
- --> tests/ui/borrow/duplicate_variant.rs:8:13
+ --> tests/ui/borrow/duplicate_variant.rs:9:15
   |
-8 |     #[serde(borrow)]
+9 |     S(#[serde(borrow)] Str<'a>),
-  |             ^^^^^^
+  |               ^^^^^^

test_suite/tests/ui/borrow/empty_lifetimes.rs

@@ -3,6 +3,8 @@ use serde_derive::Deserialize;
 #[derive(Deserialize)]
 struct Test<'a> {
     #[serde(borrow = "")]
+    r: &'a str,
+    #[serde(borrow = "  ")]
     s: &'a str,
 }
 

test_suite/tests/ui/borrow/empty_lifetimes.stderr

@@ -3,3 +3,9 @@ error: at least one lifetime must be borrowed
   |
 5 |     #[serde(borrow = "")]
   |                      ^^
+
+error: at least one lifetime must be borrowed
+ --> tests/ui/borrow/empty_lifetimes.rs:7:22
+  |
+7 |     #[serde(borrow = "  ")]
+  |                      ^^^^

test_suite/tests/ui/enum-representation/partially_tagged_wrong_order.rs

@@ -0,0 +1,10 @@
+use serde_derive::Serialize;
+
+#[derive(Serialize)]
+enum E {
+    #[serde(untagged)]
+    A(u8),
+    B(String),
+}
+
+fn main() {}

test_suite/tests/ui/enum-representation/partially_tagged_wrong_order.stderr

@@ -0,0 +1,5 @@
+error: all variants with the #[serde(untagged)] attribute must be placed at the end of the enum
+ --> tests/ui/enum-representation/partially_tagged_wrong_order.rs:6:5
+  |
+6 |     A(u8),
+  |     ^

test_suite/tests/ui/malformed/cut_off.stderr

@@ -1,4 +1,4 @@
-error: unexpected end of input, expected literal
+error: unexpected end of input, expected an expression
  --> tests/ui/malformed/cut_off.rs:4:17
   |
 4 | #[serde(rename =)]

test_suite/tests/ui/malformed/not_list.stderr

@@ -1,11 +1,11 @@
-error: expected #[serde(...)]
+error: expected attribute arguments in parentheses: #[serde(...)]
  --> tests/ui/malformed/not_list.rs:4:3
   |
 4 | #[serde]
   |   ^^^^^
 
-error: expected #[serde(...)]
+error: expected parentheses: #[serde(...)]
- --> tests/ui/malformed/not_list.rs:5:3
+ --> tests/ui/malformed/not_list.rs:5:9
   |
 5 | #[serde = "?"]
-  |   ^^^^^^^^^^^
+  |         ^

test_suite/tests/ui/malformed/trailing_expr.rs

@@ -0,0 +1,9 @@
+use serde_derive::Serialize;
+
+#[derive(Serialize)]
+struct S {
+    #[serde(skip_serializing_if, x.is_empty())]
+    x: Vec<()>,
+}
+
+fn main() {}

test_suite/tests/ui/malformed/trailing_expr.stderr

@@ -0,0 +1,5 @@
+error: expected `=`
+ --> tests/ui/malformed/trailing_expr.rs:5:32
+  |
+5 |     #[serde(skip_serializing_if, x.is_empty())]
+  |                                ^

test_suite/tests/ui/unexpected-literal/container.stderr

@@ -1,4 +1,4 @@
-error: unexpected literal in serde container attribute
+error: unexpected literal in nested attribute, expected ident
  --> tests/ui/unexpected-literal/container.rs:4:9
   |
 4 | #[serde("literal")]

test_suite/tests/ui/unexpected-literal/field.stderr

@@ -1,4 +1,4 @@
-error: unexpected literal in serde field attribute
+error: unexpected literal in nested attribute, expected ident
  --> tests/ui/unexpected-literal/field.rs:5:13
   |
 5 |     #[serde("literal")]

test_suite/tests/ui/unexpected-literal/variant.stderr

@@ -1,4 +1,4 @@
-error: unexpected literal in serde variant attribute
+error: unexpected literal in nested attribute, expected ident
  --> tests/ui/unexpected-literal/variant.rs:5:13
   |
 5 |     #[serde("literal")]