Release 1.0.227

Inline serde_core into serde in docsrs mode

.github/workflows/ci.yml

@@ -133,6 +133,7 @@ jobs:
       - uses: dtolnay/rust-toolchain@nightly
       - uses: dtolnay/install@cargo-docs-rs
       - run: cargo docs-rs -p serde
+      - run: cargo docs-rs -p serde_core
       - run: cargo docs-rs -p serde_derive
       - run: cargo docs-rs -p serde_derive_internals
 

serde/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "serde"
-version = "1.0.226"
+version = "1.0.227"
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>", "David Tolnay <dtolnay@gmail.com>"]
 build = "build.rs"
 categories = ["encoding", "no-std", "no-std::no-alloc"]
@@ -15,7 +15,7 @@ repository = "https://github.com/serde-rs/serde"
 rust-version = "1.56"
 
 [dependencies]
-serde_core = { version = "=1.0.226", path = "../serde_core", default-features = false, features = ["result"] }
+serde_core = { version = "=1.0.227", path = "../serde_core", default-features = false, features = ["result"] }
 serde_derive = { version = "1", optional = true, path = "../serde_derive" }
 
 [package.metadata.playground]

serde/build.rs

@@ -19,6 +19,10 @@ use serde_core::__private$$ as serde_core_private;
 fn main() {
     println!("cargo:rerun-if-changed=build.rs");
 
+    if env::var_os("DOCS_RS").is_some() {
+        println!("cargo:rustc-cfg=no_serde_core");
+    }
+
     let out_dir = PathBuf::from(env::var_os("OUT_DIR").unwrap());
     let patch_version = env::var("CARGO_PKG_VERSION_PATCH").unwrap();
     let module = PRIVATE.replace("$$", &patch_version);
@@ -30,8 +34,17 @@ fn main() {
     };
 
     if minor >= 77 {
+        println!("cargo:rustc-check-cfg=cfg(feature, values(\"result\"))");
+        println!("cargo:rustc-check-cfg=cfg(no_core_cstr)");
+        println!("cargo:rustc-check-cfg=cfg(no_core_error)");
+        println!("cargo:rustc-check-cfg=cfg(no_core_net)");
+        println!("cargo:rustc-check-cfg=cfg(no_core_num_saturating)");
         println!("cargo:rustc-check-cfg=cfg(no_diagnostic_namespace)");
+        println!("cargo:rustc-check-cfg=cfg(no_serde_core)");
         println!("cargo:rustc-check-cfg=cfg(no_serde_derive)");
+        println!("cargo:rustc-check-cfg=cfg(no_std_atomic)");
+        println!("cargo:rustc-check-cfg=cfg(no_std_atomic64)");
+        println!("cargo:rustc-check-cfg=cfg(no_target_has_atomic)");
     }
 
     // Current minimum supported version of serde_derive crate is Rust 1.61.

serde/src/core

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

serde/src/lib.rs

@@ -95,7 +95,7 @@
 ////////////////////////////////////////////////////////////////////////////////
 
 // Serde types in rustdoc of other crates get linked to here.
-#![doc(html_root_url = "https://docs.rs/serde/1.0.226")]
+#![doc(html_root_url = "https://docs.rs/serde/1.0.227")]
 // Support using Serde without the standard library!
 #![cfg_attr(not(feature = "std"), no_std)]
 // Show which crate feature enables conditionally compiled APIs in documentation.
@@ -168,81 +168,103 @@
 #[cfg(feature = "alloc")]
 extern crate alloc;
 
-/// A facade around all the types we need from the `std`, `core`, and `alloc`
-/// crates. This avoids elaborate import wrangling having to happen in every
-/// module.
-mod lib {
-    mod core {
-        #[cfg(not(feature = "std"))]
-        pub use core::*;
-        #[cfg(feature = "std")]
-        pub use std::*;
-    }
+// Rustdoc has a lot of shortcomings related to cross-crate re-exports that make
+// the rendered documentation of serde_core traits in serde more challenging to
+// understand than the equivalent documentation of the same items in serde_core.
+// https://github.com/rust-lang/rust/labels/A-cross-crate-reexports
+// So, just for the purpose of docs.rs documentation, we inline the contents of
+// serde_core into serde. This sidesteps all the cross-crate rustdoc bugs.
+#[cfg(docsrs)]
+#[macro_use]
+#[path = "core/crate_root.rs"]
+mod crate_root;
 
-    pub use self::core::{f32, f64};
-    pub use self::core::{ptr, str};
+#[cfg(docsrs)]
+#[macro_use]
+#[path = "core/macros.rs"]
+mod macros;
 
-    #[cfg(any(feature = "std", feature = "alloc"))]
-    pub use self::core::slice;
+#[cfg(not(docsrs))]
+macro_rules! crate_root {
+    () => {
+        /// A facade around all the types we need from the `std`, `core`, and `alloc`
+        /// crates. This avoids elaborate import wrangling having to happen in every
+        /// module.
+        mod lib {
+            mod core {
+                #[cfg(not(feature = "std"))]
+                pub use core::*;
+                #[cfg(feature = "std")]
+                pub use std::*;
+            }
 
-    pub use self::core::clone;
-    pub use self::core::convert;
-    pub use self::core::default;
-    pub use self::core::fmt::{self, Debug, Display, Write as FmtWrite};
-    pub use self::core::marker::{self, PhantomData};
-    pub use self::core::option;
-    pub use self::core::result;
+            pub use self::core::{f32, f64};
+            pub use self::core::{ptr, str};
 
-    #[cfg(all(feature = "alloc", not(feature = "std")))]
-    pub use alloc::borrow::{Cow, ToOwned};
-    #[cfg(feature = "std")]
-    pub use std::borrow::{Cow, ToOwned};
+            #[cfg(any(feature = "std", feature = "alloc"))]
+            pub use self::core::slice;
 
-    #[cfg(all(feature = "alloc", not(feature = "std")))]
-    pub use alloc::string::{String, ToString};
-    #[cfg(feature = "std")]
-    pub use std::string::{String, ToString};
+            pub use self::core::clone;
+            pub use self::core::convert;
+            pub use self::core::default;
+            pub use self::core::fmt::{self, Debug, Display, Write as FmtWrite};
+            pub use self::core::marker::{self, PhantomData};
+            pub use self::core::option;
+            pub use self::core::result;
 
-    #[cfg(all(feature = "alloc", not(feature = "std")))]
-    pub use alloc::vec::Vec;
-    #[cfg(feature = "std")]
-    pub use std::vec::Vec;
+            #[cfg(all(feature = "alloc", not(feature = "std")))]
+            pub use alloc::borrow::{Cow, ToOwned};
+            #[cfg(feature = "std")]
+            pub use std::borrow::{Cow, ToOwned};
 
-    #[cfg(all(feature = "alloc", not(feature = "std")))]
-    pub use alloc::boxed::Box;
-    #[cfg(feature = "std")]
-    pub use std::boxed::Box;
-}
+            #[cfg(all(feature = "alloc", not(feature = "std")))]
+            pub use alloc::string::{String, ToString};
+            #[cfg(feature = "std")]
+            pub use std::string::{String, ToString};
 
-// None of this crate's error handling needs the `From::from` error conversion
-// performed implicitly by the `?` operator or the standard library's `try!`
-// macro. This simplified macro gives a 5.5% improvement in compile time
-// compared to standard `try!`, and 9% improvement compared to `?`.
-#[cfg(not(no_serde_derive))]
-macro_rules! tri {
-    ($expr:expr) => {
-        match $expr {
-            Ok(val) => val,
-            Err(err) => return Err(err),
+            #[cfg(all(feature = "alloc", not(feature = "std")))]
+            pub use alloc::vec::Vec;
+            #[cfg(feature = "std")]
+            pub use std::vec::Vec;
+
+            #[cfg(all(feature = "alloc", not(feature = "std")))]
+            pub use alloc::boxed::Box;
+            #[cfg(feature = "std")]
+            pub use std::boxed::Box;
         }
+
+        // None of this crate's error handling needs the `From::from` error conversion
+        // performed implicitly by the `?` operator or the standard library's `try!`
+        // macro. This simplified macro gives a 5.5% improvement in compile time
+        // compared to standard `try!`, and 9% improvement compared to `?`.
+        #[cfg(not(no_serde_derive))]
+        macro_rules! tri {
+            ($expr:expr) => {
+                match $expr {
+                    Ok(val) => val,
+                    Err(err) => return Err(err),
+                }
+            };
+        }
+
+        ////////////////////////////////////////////////////////////////////////////////
+
+        pub use serde_core::{
+            de, forward_to_deserialize_any, ser, Deserialize, Deserializer, Serialize, Serializer,
+        };
+
+        // Used by generated code and doc tests. Not public API.
+        #[doc(hidden)]
+        mod private;
+
+        include!(concat!(env!("OUT_DIR"), "/private.rs"));
     };
 }
 
-////////////////////////////////////////////////////////////////////////////////
+crate_root!();
 
-pub use serde_core::{
-    de, forward_to_deserialize_any, ser, Deserialize, Deserializer, Serialize, Serializer,
-};
-
-#[macro_use]
 mod integer128;
 
-// Used by generated code and doc tests. Not public API.
-#[doc(hidden)]
-mod private;
-
-include!(concat!(env!("OUT_DIR"), "/private.rs"));
-
 // Re-export #[derive(Serialize, Deserialize)].
 //
 // The reason re-exporting is not enabled by default is that disabling it would

serde_core/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "serde_core"
-version = "1.0.226"
+version = "1.0.227"
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>", "David Tolnay <dtolnay@gmail.com>"]
 build = "build.rs"
 categories = ["encoding", "no-std", "no-std::no-alloc"]
@@ -37,7 +37,7 @@ rustdoc-args = [
 # is compatible with exactly one serde release because the generated code
 # involves nonpublic APIs which are not bound by semver.
 [target.'cfg(any())'.dependencies]
-serde_derive = { version = "=1.0.226", path = "../serde_derive" }
+serde_derive = { version = "=1.0.227", path = "../serde_derive" }
 
 
 ### FEATURES #################################################################

serde_core/build.rs

@@ -34,6 +34,7 @@ fn main() {
         println!("cargo:rustc-check-cfg=cfg(no_core_net)");
         println!("cargo:rustc-check-cfg=cfg(no_core_num_saturating)");
         println!("cargo:rustc-check-cfg=cfg(no_diagnostic_namespace)");
+        println!("cargo:rustc-check-cfg=cfg(no_serde_core)");
         println!("cargo:rustc-check-cfg=cfg(no_serde_derive)");
         println!("cargo:rustc-check-cfg=cfg(no_std_atomic)");
         println!("cargo:rustc-check-cfg=cfg(no_std_atomic64)");

serde_core/src/crate_root.rs

@@ -0,0 +1,168 @@
+macro_rules! crate_root {
+    () => {
+        /// A facade around all the types we need from the `std`, `core`, and `alloc`
+        /// crates. This avoids elaborate import wrangling having to happen in every
+        /// module.
+        mod lib {
+            mod core {
+                #[cfg(not(feature = "std"))]
+                pub use core::*;
+                #[cfg(feature = "std")]
+                pub use std::*;
+            }
+
+            pub use self::core::{f32, f64};
+            pub use self::core::{iter, num, str};
+
+            #[cfg(any(feature = "std", feature = "alloc"))]
+            pub use self::core::{cmp, mem};
+
+            pub use self::core::cell::{Cell, RefCell};
+            pub use self::core::cmp::Reverse;
+            pub use self::core::fmt::{self, Debug, Display, Write as FmtWrite};
+            pub use self::core::marker::PhantomData;
+            pub use self::core::num::Wrapping;
+            pub use self::core::ops::{Bound, Range, RangeFrom, RangeInclusive, RangeTo};
+            pub use self::core::result;
+            pub use self::core::time::Duration;
+
+            #[cfg(all(feature = "alloc", not(feature = "std")))]
+            pub use alloc::borrow::{Cow, ToOwned};
+            #[cfg(feature = "std")]
+            pub use std::borrow::{Cow, ToOwned};
+
+            #[cfg(all(feature = "alloc", not(feature = "std")))]
+            pub use alloc::string::{String, ToString};
+            #[cfg(feature = "std")]
+            pub use std::string::{String, ToString};
+
+            #[cfg(all(feature = "alloc", not(feature = "std")))]
+            pub use alloc::vec::Vec;
+            #[cfg(feature = "std")]
+            pub use std::vec::Vec;
+
+            #[cfg(all(feature = "alloc", not(feature = "std")))]
+            pub use alloc::boxed::Box;
+            #[cfg(feature = "std")]
+            pub use std::boxed::Box;
+
+            #[cfg(all(feature = "rc", feature = "alloc", not(feature = "std")))]
+            pub use alloc::rc::{Rc, Weak as RcWeak};
+            #[cfg(all(feature = "rc", feature = "std"))]
+            pub use std::rc::{Rc, Weak as RcWeak};
+
+            #[cfg(all(feature = "rc", feature = "alloc", not(feature = "std")))]
+            pub use alloc::sync::{Arc, Weak as ArcWeak};
+            #[cfg(all(feature = "rc", feature = "std"))]
+            pub use std::sync::{Arc, Weak as ArcWeak};
+
+            #[cfg(all(feature = "alloc", not(feature = "std")))]
+            pub use alloc::collections::{BTreeMap, BTreeSet, BinaryHeap, LinkedList, VecDeque};
+            #[cfg(feature = "std")]
+            pub use std::collections::{BTreeMap, BTreeSet, BinaryHeap, LinkedList, VecDeque};
+
+            #[cfg(all(not(no_core_cstr), not(feature = "std")))]
+            pub use self::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(all(not(no_core_net), not(feature = "std")))]
+            pub use self::core::net;
+            #[cfg(feature = "std")]
+            pub use std::net;
+
+            #[cfg(feature = "std")]
+            pub use std::error;
+
+            #[cfg(feature = "std")]
+            pub use std::collections::{HashMap, HashSet};
+            #[cfg(feature = "std")]
+            pub use std::ffi::{OsStr, OsString};
+            #[cfg(feature = "std")]
+            pub use std::hash::{BuildHasher, Hash};
+            #[cfg(feature = "std")]
+            pub use std::io::Write;
+            #[cfg(feature = "std")]
+            pub use std::path::{Path, PathBuf};
+            #[cfg(feature = "std")]
+            pub use std::sync::{Mutex, RwLock};
+            #[cfg(feature = "std")]
+            pub use std::time::{SystemTime, UNIX_EPOCH};
+
+            #[cfg(all(feature = "std", no_target_has_atomic, not(no_std_atomic)))]
+            pub use std::sync::atomic::{
+                AtomicBool, AtomicI16, AtomicI32, AtomicI8, AtomicIsize, AtomicU16, AtomicU32,
+                AtomicU8, AtomicUsize, Ordering,
+            };
+            #[cfg(all(feature = "std", no_target_has_atomic, not(no_std_atomic64)))]
+            pub use std::sync::atomic::{AtomicI64, AtomicU64};
+
+            #[cfg(all(feature = "std", not(no_target_has_atomic)))]
+            pub use std::sync::atomic::Ordering;
+            #[cfg(all(feature = "std", not(no_target_has_atomic), target_has_atomic = "8"))]
+            pub use std::sync::atomic::{AtomicBool, AtomicI8, AtomicU8};
+            #[cfg(all(feature = "std", not(no_target_has_atomic), target_has_atomic = "16"))]
+            pub use std::sync::atomic::{AtomicI16, AtomicU16};
+            #[cfg(all(feature = "std", not(no_target_has_atomic), target_has_atomic = "32"))]
+            pub use std::sync::atomic::{AtomicI32, AtomicU32};
+            #[cfg(all(feature = "std", not(no_target_has_atomic), target_has_atomic = "64"))]
+            pub use std::sync::atomic::{AtomicI64, AtomicU64};
+            #[cfg(all(feature = "std", not(no_target_has_atomic), target_has_atomic = "ptr"))]
+            pub use std::sync::atomic::{AtomicIsize, AtomicUsize};
+
+            #[cfg(not(no_core_num_saturating))]
+            pub use self::core::num::Saturating;
+        }
+
+        // None of this crate's error handling needs the `From::from` error conversion
+        // performed implicitly by the `?` operator or the standard library's `try!`
+        // macro. This simplified macro gives a 5.5% improvement in compile time
+        // compared to standard `try!`, and 9% improvement compared to `?`.
+        macro_rules! tri {
+            ($expr:expr) => {
+                match $expr {
+                    Ok(val) => val,
+                    Err(err) => return Err(err),
+                }
+            };
+        }
+
+        #[cfg_attr(no_serde_core, path = "core/de/mod.rs")]
+        pub mod de;
+        #[cfg_attr(no_serde_core, path = "core/ser/mod.rs")]
+        pub mod ser;
+
+        #[cfg_attr(no_serde_core, path = "core/format.rs")]
+        mod format;
+
+        #[doc(inline)]
+        pub use crate::de::{Deserialize, Deserializer};
+        #[doc(inline)]
+        pub use crate::ser::{Serialize, Serializer};
+
+        // Used by generated code. Not public API.
+        #[doc(hidden)]
+        #[cfg_attr(no_serde_core, path = "core/private/mod.rs")]
+        mod private;
+
+        // Used by declarative macro generated code. Not public API.
+        #[doc(hidden)]
+        pub mod __private {
+            #[doc(hidden)]
+            pub use crate::private::doc;
+            #[doc(hidden)]
+            pub use core::result::Result;
+        }
+
+        include!(concat!(env!("OUT_DIR"), "/private.rs"));
+
+        #[cfg(all(not(feature = "std"), no_core_error))]
+        #[cfg_attr(no_serde_core, path = "core/std_error.rs")]
+        mod std_error;
+    };
+}

serde_core/src/de/mod.rs

@@ -122,7 +122,6 @@ mod ignored_any;
 mod impls;
 
 pub use self::ignored_any::IgnoredAny;
-pub use crate::private::InPlaceSeed;
 #[cfg(all(not(feature = "std"), no_core_error))]
 #[doc(no_inline)]
 pub use crate::std_error::Error as StdError;

serde_core/src/lib.rs

@@ -35,7 +35,7 @@
 ////////////////////////////////////////////////////////////////////////////////
 
 // Serde types in rustdoc of other crates get linked to here.
-#![doc(html_root_url = "https://docs.rs/serde_core/1.0.226")]
+#![doc(html_root_url = "https://docs.rs/serde_core/1.0.227")]
 // Support using Serde without the standard library!
 #![cfg_attr(not(feature = "std"), no_std)]
 // Show which crate feature enables conditionally compiled APIs in documentation.
@@ -103,170 +103,12 @@
 #[cfg(feature = "alloc")]
 extern crate alloc;
 
-/// A facade around all the types we need from the `std`, `core`, and `alloc`
-/// crates. This avoids elaborate import wrangling having to happen in every
-/// module.
-mod lib {
-    mod core {
-        #[cfg(not(feature = "std"))]
-        pub use core::*;
-        #[cfg(feature = "std")]
-        pub use std::*;
-    }
-
-    pub use self::core::{f32, f64};
-    pub use self::core::{iter, num, str};
-
-    #[cfg(any(feature = "std", feature = "alloc"))]
-    pub use self::core::{cmp, mem};
-
-    pub use self::core::cell::{Cell, RefCell};
-    pub use self::core::cmp::Reverse;
-    pub use self::core::fmt::{self, Debug, Display, Write as FmtWrite};
-    pub use self::core::marker::PhantomData;
-    pub use self::core::num::Wrapping;
-    pub use self::core::ops::{Bound, Range, RangeFrom, RangeInclusive, RangeTo};
-    pub use self::core::result;
-    pub use self::core::time::Duration;
-
-    #[cfg(all(feature = "alloc", not(feature = "std")))]
-    pub use alloc::borrow::{Cow, ToOwned};
-    #[cfg(feature = "std")]
-    pub use std::borrow::{Cow, ToOwned};
-
-    #[cfg(all(feature = "alloc", not(feature = "std")))]
-    pub use alloc::string::{String, ToString};
-    #[cfg(feature = "std")]
-    pub use std::string::{String, ToString};
-
-    #[cfg(all(feature = "alloc", not(feature = "std")))]
-    pub use alloc::vec::Vec;
-    #[cfg(feature = "std")]
-    pub use std::vec::Vec;
-
-    #[cfg(all(feature = "alloc", not(feature = "std")))]
-    pub use alloc::boxed::Box;
-    #[cfg(feature = "std")]
-    pub use std::boxed::Box;
-
-    #[cfg(all(feature = "rc", feature = "alloc", not(feature = "std")))]
-    pub use alloc::rc::{Rc, Weak as RcWeak};
-    #[cfg(all(feature = "rc", feature = "std"))]
-    pub use std::rc::{Rc, Weak as RcWeak};
-
-    #[cfg(all(feature = "rc", feature = "alloc", not(feature = "std")))]
-    pub use alloc::sync::{Arc, Weak as ArcWeak};
-    #[cfg(all(feature = "rc", feature = "std"))]
-    pub use std::sync::{Arc, Weak as ArcWeak};
-
-    #[cfg(all(feature = "alloc", not(feature = "std")))]
-    pub use alloc::collections::{BTreeMap, BTreeSet, BinaryHeap, LinkedList, VecDeque};
-    #[cfg(feature = "std")]
-    pub use std::collections::{BTreeMap, BTreeSet, BinaryHeap, LinkedList, VecDeque};
-
-    #[cfg(all(not(no_core_cstr), not(feature = "std")))]
-    pub use self::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(all(not(no_core_net), not(feature = "std")))]
-    pub use self::core::net;
-    #[cfg(feature = "std")]
-    pub use std::net;
-
-    #[cfg(feature = "std")]
-    pub use std::error;
-
-    #[cfg(feature = "std")]
-    pub use std::collections::{HashMap, HashSet};
-    #[cfg(feature = "std")]
-    pub use std::ffi::{OsStr, OsString};
-    #[cfg(feature = "std")]
-    pub use std::hash::{BuildHasher, Hash};
-    #[cfg(feature = "std")]
-    pub use std::io::Write;
-    #[cfg(feature = "std")]
-    pub use std::path::{Path, PathBuf};
-    #[cfg(feature = "std")]
-    pub use std::sync::{Mutex, RwLock};
-    #[cfg(feature = "std")]
-    pub use std::time::{SystemTime, UNIX_EPOCH};
-
-    #[cfg(all(feature = "std", no_target_has_atomic, not(no_std_atomic)))]
-    pub use std::sync::atomic::{
-        AtomicBool, AtomicI16, AtomicI32, AtomicI8, AtomicIsize, AtomicU16, AtomicU32, AtomicU8,
-        AtomicUsize, Ordering,
-    };
-    #[cfg(all(feature = "std", no_target_has_atomic, not(no_std_atomic64)))]
-    pub use std::sync::atomic::{AtomicI64, AtomicU64};
-
-    #[cfg(all(feature = "std", not(no_target_has_atomic)))]
-    pub use std::sync::atomic::Ordering;
-    #[cfg(all(feature = "std", not(no_target_has_atomic), target_has_atomic = "8"))]
-    pub use std::sync::atomic::{AtomicBool, AtomicI8, AtomicU8};
-    #[cfg(all(feature = "std", not(no_target_has_atomic), target_has_atomic = "16"))]
-    pub use std::sync::atomic::{AtomicI16, AtomicU16};
-    #[cfg(all(feature = "std", not(no_target_has_atomic), target_has_atomic = "32"))]
-    pub use std::sync::atomic::{AtomicI32, AtomicU32};
-    #[cfg(all(feature = "std", not(no_target_has_atomic), target_has_atomic = "64"))]
-    pub use std::sync::atomic::{AtomicI64, AtomicU64};
-    #[cfg(all(feature = "std", not(no_target_has_atomic), target_has_atomic = "ptr"))]
-    pub use std::sync::atomic::{AtomicIsize, AtomicUsize};
-
-    #[cfg(not(no_core_num_saturating))]
-    pub use self::core::num::Saturating;
-}
-
-// None of this crate's error handling needs the `From::from` error conversion
-// performed implicitly by the `?` operator or the standard library's `try!`
-// macro. This simplified macro gives a 5.5% improvement in compile time
-// compared to standard `try!`, and 9% improvement compared to `?`.
-macro_rules! tri {
-    ($expr:expr) => {
-        match $expr {
-            Ok(val) => val,
-            Err(err) => return Err(err),
-        }
-    };
-}
-
-////////////////////////////////////////////////////////////////////////////////
-
+#[macro_use]
+mod crate_root;
 #[macro_use]
 mod macros;
 
-pub mod de;
-pub mod ser;
-
-mod format;
-
-#[doc(inline)]
-pub use crate::de::{Deserialize, Deserializer};
-#[doc(inline)]
-pub use crate::ser::{Serialize, Serializer};
-
-// Used by generated code. Not public API.
-#[doc(hidden)]
-mod private;
-
-// Used by declarative macro generated code. Not public API.
-#[doc(hidden)]
-pub mod __private {
-    #[doc(hidden)]
-    pub use crate::private::doc;
-    #[doc(hidden)]
-    pub use core::result::Result;
-}
-
-include!(concat!(env!("OUT_DIR"), "/private.rs"));
-
-#[cfg(all(not(feature = "std"), no_core_error))]
-mod std_error;
+crate_root!();
 
 #[macro_export]
 #[doc(hidden)]

serde_derive/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "serde_derive"
-version = "1.0.226"
+version = "1.0.227"
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>", "David Tolnay <dtolnay@gmail.com>"]
 categories = ["no-std", "no-std::no-alloc"]
 description = "Macros 1.1 implementation of #[derive(Serialize, Deserialize)]"

serde_derive/src/de/enum_.rs

@@ -0,0 +1,96 @@
+use crate::de::enum_adjacently;
+use crate::de::enum_externally;
+use crate::de::enum_internally;
+use crate::de::enum_untagged;
+use crate::de::identifier;
+use crate::de::{field_i, FieldWithAliases, Parameters};
+use crate::fragment::{Expr, Fragment, Stmts};
+use crate::internals::ast::Variant;
+use crate::internals::attr;
+use crate::private;
+use proc_macro2::TokenStream;
+use quote::quote;
+
+/// Generates `Deserialize::deserialize` body for an `enum Enum {...}`
+pub(super) fn deserialize(
+    params: &Parameters,
+    variants: &[Variant],
+    cattrs: &attr::Container,
+) -> Fragment {
+    // The variants have already been checked (in ast.rs) that all untagged variants appear at the end
+    match variants.iter().position(|var| var.attrs.untagged()) {
+        Some(variant_idx) => {
+            let (tagged, untagged) = variants.split_at(variant_idx);
+            let tagged_frag = Expr(deserialize_homogeneous_enum(params, tagged, cattrs));
+            // Ignore any error associated with non-untagged deserialization so that we
+            // can fall through to the untagged variants. This may be infallible so we
+            // need to provide the error type.
+            let first_attempt = quote! {
+                if let _serde::#private::Result::<_, __D::Error>::Ok(__ok) = (|| #tagged_frag)() {
+                    return _serde::#private::Ok(__ok);
+                }
+            };
+            enum_untagged::deserialize(params, untagged, cattrs, Some(first_attempt))
+        }
+        None => deserialize_homogeneous_enum(params, variants, cattrs),
+    }
+}
+
+fn deserialize_homogeneous_enum(
+    params: &Parameters,
+    variants: &[Variant],
+    cattrs: &attr::Container,
+) -> Fragment {
+    match cattrs.tag() {
+        attr::TagType::External => enum_externally::deserialize(params, variants, cattrs),
+        attr::TagType::Internal { tag } => {
+            enum_internally::deserialize(params, variants, cattrs, tag)
+        }
+        attr::TagType::Adjacent { tag, content } => {
+            enum_adjacently::deserialize(params, variants, cattrs, tag, content)
+        }
+        attr::TagType::None => enum_untagged::deserialize(params, variants, cattrs, None),
+    }
+}
+
+pub fn prepare_enum_variant_enum(variants: &[Variant]) -> (TokenStream, Stmts) {
+    let deserialized_variants = variants
+        .iter()
+        .enumerate()
+        .filter(|&(_i, variant)| !variant.attrs.skip_deserializing());
+
+    let fallthrough = deserialized_variants
+        .clone()
+        .find(|(_i, variant)| variant.attrs.other())
+        .map(|(i, _variant)| {
+            let ignore_variant = field_i(i);
+            quote!(_serde::#private::Ok(__Field::#ignore_variant))
+        });
+
+    let variants_stmt = {
+        let variant_names = deserialized_variants
+            .clone()
+            .flat_map(|(_i, variant)| variant.attrs.aliases());
+        quote! {
+            #[doc(hidden)]
+            const VARIANTS: &'static [&'static str] = &[ #(#variant_names),* ];
+        }
+    };
+
+    let deserialized_variants: Vec<_> = deserialized_variants
+        .map(|(i, variant)| FieldWithAliases {
+            ident: field_i(i),
+            aliases: variant.attrs.aliases(),
+        })
+        .collect();
+
+    let variant_visitor = Stmts(identifier::deserialize_generated(
+        &deserialized_variants,
+        false, // variant identifiers do not depend on the presence of flatten fields
+        true,
+        None,
+        fallthrough,
+    ));
+
+    (variants_stmt, variant_visitor)
+}

serde_derive/src/de/enum_adjacently.rs

@@ -0,0 +1,323 @@
+//! Deserialization for adjacently tagged enums:
+//!
+//! ```ignore
+//! #[serde(tag = "...", content = "...")]
+//! enum Enum {}
+//! ```
+
+use crate::de::enum_;
+use crate::de::enum_untagged;
+use crate::de::{field_i, Parameters};
+use crate::fragment::{Fragment, Match};
+use crate::internals::ast::{Style, Variant};
+use crate::internals::attr;
+use crate::private;
+use quote::{quote, quote_spanned};
+use syn::spanned::Spanned;
+
+/// Generates `Deserialize::deserialize` body for an `enum Enum {...}` with `#[serde(tag, content)]` attributes
+pub(super) fn deserialize(
+    params: &Parameters,
+    variants: &[Variant],
+    cattrs: &attr::Container,
+    tag: &str,
+    content: &str,
+) -> Fragment {
+    let this_type = &params.this_type;
+    let this_value = &params.this_value;
+    let (de_impl_generics, de_ty_generics, ty_generics, where_clause) =
+        params.generics_with_de_lifetime();
+    let delife = params.borrowed.de_lifetime();
+
+    let (variants_stmt, variant_visitor) = enum_::prepare_enum_variant_enum(variants);
+
+    let variant_arms: &Vec<_> = &variants
+        .iter()
+        .enumerate()
+        .filter(|&(_, variant)| !variant.attrs.skip_deserializing())
+        .map(|(i, variant)| {
+            let variant_index = field_i(i);
+
+            let block = Match(enum_untagged::deserialize_variant(params, variant, cattrs));
+
+            quote! {
+                __Field::#variant_index => #block
+            }
+        })
+        .collect();
+
+    let rust_name = params.type_name();
+    let expecting = format!("adjacently tagged enum {}", rust_name);
+    let expecting = cattrs.expecting().unwrap_or(&expecting);
+    let type_name = cattrs.name().deserialize_name();
+    let deny_unknown_fields = cattrs.deny_unknown_fields();
+
+    // If unknown fields are allowed, we pick the visitor that can step over
+    // those. Otherwise we pick the visitor that fails on unknown keys.
+    let field_visitor_ty = if deny_unknown_fields {
+        quote! { _serde::#private::de::TagOrContentFieldVisitor }
+    } else {
+        quote! { _serde::#private::de::TagContentOtherFieldVisitor }
+    };
+
+    let mut missing_content = quote! {
+        _serde::#private::Err(<__A::Error as _serde::de::Error>::missing_field(#content))
+    };
+    let mut missing_content_fallthrough = quote!();
+    let missing_content_arms = variants
+        .iter()
+        .enumerate()
+        .filter(|&(_, variant)| !variant.attrs.skip_deserializing())
+        .filter_map(|(i, variant)| {
+            let variant_index = field_i(i);
+            let variant_ident = &variant.ident;
+
+            let arm = match variant.style {
+                Style::Unit => quote! {
+                    _serde::#private::Ok(#this_value::#variant_ident)
+                },
+                Style::Newtype if variant.attrs.deserialize_with().is_none() => {
+                    let span = variant.original.span();
+                    let func = quote_spanned!(span=> _serde::#private::de::missing_field);
+                    quote! {
+                        #func(#content).map(#this_value::#variant_ident)
+                    }
+                }
+                _ => {
+                    missing_content_fallthrough = quote!(_ => #missing_content);
+                    return None;
+                }
+            };
+            Some(quote! {
+                __Field::#variant_index => #arm,
+            })
+        })
+        .collect::<Vec<_>>();
+    if !missing_content_arms.is_empty() {
+        missing_content = quote! {
+            match __field {
+                #(#missing_content_arms)*
+                #missing_content_fallthrough
+            }
+        };
+    }
+
+    // Advance the map by one key, returning early in case of error.
+    let next_key = quote! {
+        _serde::de::MapAccess::next_key_seed(&mut __map, #field_visitor_ty {
+            tag: #tag,
+            content: #content,
+        })?
+    };
+
+    let variant_from_map = quote! {
+        _serde::de::MapAccess::next_value_seed(&mut __map, _serde::#private::de::AdjacentlyTaggedEnumVariantSeed::<__Field> {
+            enum_name: #rust_name,
+            variants: VARIANTS,
+            fields_enum: _serde::#private::PhantomData
+        })?
+    };
+
+    // When allowing unknown fields, we want to transparently step through keys
+    // we don't care about until we find `tag`, `content`, or run out of keys.
+    let next_relevant_key = if deny_unknown_fields {
+        next_key
+    } else {
+        quote!({
+            let mut __rk : _serde::#private::Option<_serde::#private::de::TagOrContentField> = _serde::#private::None;
+            while let _serde::#private::Some(__k) = #next_key {
+                match __k {
+                    _serde::#private::de::TagContentOtherField::Other => {
+                        let _ = _serde::de::MapAccess::next_value::<_serde::de::IgnoredAny>(&mut __map)?;
+                        continue;
+                    },
+                    _serde::#private::de::TagContentOtherField::Tag => {
+                        __rk = _serde::#private::Some(_serde::#private::de::TagOrContentField::Tag);
+                        break;
+                    }
+                    _serde::#private::de::TagContentOtherField::Content => {
+                        __rk = _serde::#private::Some(_serde::#private::de::TagOrContentField::Content);
+                        break;
+                    }
+                }
+            }
+
+            __rk
+        })
+    };
+
+    // Step through remaining keys, looking for duplicates of previously-seen
+    // keys. When unknown fields are denied, any key that isn't a duplicate will
+    // at this point immediately produce an error.
+    let visit_remaining_keys = quote! {
+        match #next_relevant_key {
+            _serde::#private::Some(_serde::#private::de::TagOrContentField::Tag) => {
+                _serde::#private::Err(<__A::Error as _serde::de::Error>::duplicate_field(#tag))
+            }
+            _serde::#private::Some(_serde::#private::de::TagOrContentField::Content) => {
+                _serde::#private::Err(<__A::Error as _serde::de::Error>::duplicate_field(#content))
+            }
+            _serde::#private::None => _serde::#private::Ok(__ret),
+        }
+    };
+
+    let finish_content_then_tag = if variant_arms.is_empty() {
+        quote! {
+            match #variant_from_map {}
+        }
+    } else {
+        quote! {
+            let __seed = __Seed {
+                variant: #variant_from_map,
+                marker: _serde::#private::PhantomData,
+                lifetime: _serde::#private::PhantomData,
+            };
+            let __deserializer = _serde::#private::de::ContentDeserializer::<__A::Error>::new(__content);
+            let __ret = _serde::de::DeserializeSeed::deserialize(__seed, __deserializer)?;
+            // Visit remaining keys, looking for duplicates.
+            #visit_remaining_keys
+        }
+    };
+
+    quote_block! {
+        #variant_visitor
+
+        #variants_stmt
+
+        #[doc(hidden)]
+        struct __Seed #de_impl_generics #where_clause {
+            variant: __Field,
+            marker: _serde::#private::PhantomData<#this_type #ty_generics>,
+            lifetime: _serde::#private::PhantomData<&#delife ()>,
+        }
+
+        #[automatically_derived]
+        impl #de_impl_generics _serde::de::DeserializeSeed<#delife> for __Seed #de_ty_generics #where_clause {
+            type Value = #this_type #ty_generics;
+
+            fn deserialize<__D>(self, __deserializer: __D) -> _serde::#private::Result<Self::Value, __D::Error>
+            where
+                __D: _serde::Deserializer<#delife>,
+            {
+                match self.variant {
+                    #(#variant_arms)*
+                }
+            }
+        }
+
+        #[doc(hidden)]
+        struct __Visitor #de_impl_generics #where_clause {
+            marker: _serde::#private::PhantomData<#this_type #ty_generics>,
+            lifetime: _serde::#private::PhantomData<&#delife ()>,
+        }
+
+        #[automatically_derived]
+        impl #de_impl_generics _serde::de::Visitor<#delife> for __Visitor #de_ty_generics #where_clause {
+            type Value = #this_type #ty_generics;
+
+            fn expecting(&self, __formatter: &mut _serde::#private::Formatter) -> _serde::#private::fmt::Result {
+                _serde::#private::Formatter::write_str(__formatter, #expecting)
+            }
+
+            fn visit_map<__A>(self, mut __map: __A) -> _serde::#private::Result<Self::Value, __A::Error>
+            where
+                __A: _serde::de::MapAccess<#delife>,
+            {
+                // Visit the first relevant key.
+                match #next_relevant_key {
+                    // First key is the tag.
+                    _serde::#private::Some(_serde::#private::de::TagOrContentField::Tag) => {
+                        // Parse the tag.
+                        let __field = #variant_from_map;
+                        // Visit the second key.
+                        match #next_relevant_key {
+                            // Second key is a duplicate of the tag.
+                            _serde::#private::Some(_serde::#private::de::TagOrContentField::Tag) => {
+                                _serde::#private::Err(<__A::Error as _serde::de::Error>::duplicate_field(#tag))
+                            }
+                            // Second key is the content.
+                            _serde::#private::Some(_serde::#private::de::TagOrContentField::Content) => {
+                                let __ret = _serde::de::MapAccess::next_value_seed(&mut __map,
+                                    __Seed {
+                                        variant: __field,
+                                        marker: _serde::#private::PhantomData,
+                                        lifetime: _serde::#private::PhantomData,
+                                    })?;
+                                // Visit remaining keys, looking for duplicates.
+                                #visit_remaining_keys
+                            }
+                            // There is no second key; might be okay if the we have a unit variant.
+                            _serde::#private::None => #missing_content
+                        }
+                    }
+                    // First key is the content.
+                    _serde::#private::Some(_serde::#private::de::TagOrContentField::Content) => {
+                        // Buffer up the content.
+                        let __content = _serde::de::MapAccess::next_value_seed(&mut __map, _serde::#private::de::ContentVisitor::new())?;
+                        // Visit the second key.
+                        match #next_relevant_key {
+                            // Second key is the tag.
+                            _serde::#private::Some(_serde::#private::de::TagOrContentField::Tag) => {
+                                #finish_content_then_tag
+                            }
+                            // Second key is a duplicate of the content.
+                            _serde::#private::Some(_serde::#private::de::TagOrContentField::Content) => {
+                                _serde::#private::Err(<__A::Error as _serde::de::Error>::duplicate_field(#content))
+                            }
+                            // There is no second key.
+                            _serde::#private::None => {
+                                _serde::#private::Err(<__A::Error as _serde::de::Error>::missing_field(#tag))
+                            }
+                        }
+                    }
+                    // There is no first key.
+                    _serde::#private::None => {
+                        _serde::#private::Err(<__A::Error as _serde::de::Error>::missing_field(#tag))
+                    }
+                }
+            }
+
+            fn visit_seq<__A>(self, mut __seq: __A) -> _serde::#private::Result<Self::Value, __A::Error>
+            where
+                __A: _serde::de::SeqAccess<#delife>,
+            {
+                // Visit the first element - the tag.
+                match _serde::de::SeqAccess::next_element(&mut __seq)? {
+                    _serde::#private::Some(__variant) => {
+                        // Visit the second element - the content.
+                        match _serde::de::SeqAccess::next_element_seed(
+                            &mut __seq,
+                            __Seed {
+                                variant: __variant,
+                                marker: _serde::#private::PhantomData,
+                                lifetime: _serde::#private::PhantomData,
+                            },
+                        )? {
+                            _serde::#private::Some(__ret) => _serde::#private::Ok(__ret),
+                            // There is no second element.
+                            _serde::#private::None => {
+                                _serde::#private::Err(_serde::de::Error::invalid_length(1, &self))
+                            }
+                        }
+                    }
+                    // There is no first element.
+                    _serde::#private::None => {
+                        _serde::#private::Err(_serde::de::Error::invalid_length(0, &self))
+                    }
+                }
+            }
+        }
+
+        #[doc(hidden)]
+        const FIELDS: &'static [&'static str] = &[#tag, #content];
+        _serde::Deserializer::deserialize_struct(
+            __deserializer,
+            #type_name,
+            FIELDS,
+            __Visitor {
+                marker: _serde::#private::PhantomData::<#this_type #ty_generics>,
+                lifetime: _serde::#private::PhantomData,
+            },
+        )
+    }
+}

serde_derive/src/de/enum_externally.rs

@@ -0,0 +1,212 @@
+//! Deserialization for externally tagged enums:
+//!
+//! ```ignore
+//! enum Enum {}
+//! ```
+
+use crate::de::enum_;
+use crate::de::struct_;
+use crate::de::tuple;
+use crate::de::{
+    expr_is_missing, field_i, unwrap_to_variant_closure, wrap_deserialize_field_with,
+    wrap_deserialize_with, Parameters, StructForm, TupleForm,
+};
+use crate::fragment::{Expr, Fragment, Match};
+use crate::internals::ast::{Field, Style, Variant};
+use crate::internals::attr;
+use crate::private;
+use proc_macro2::TokenStream;
+use quote::{quote, quote_spanned};
+use syn::spanned::Spanned;
+
+/// Generates `Deserialize::deserialize` body for an `enum Enum {...}` without additional attributes
+pub(super) fn deserialize(
+    params: &Parameters,
+    variants: &[Variant],
+    cattrs: &attr::Container,
+) -> Fragment {
+    let this_type = &params.this_type;
+    let (de_impl_generics, de_ty_generics, ty_generics, where_clause) =
+        params.generics_with_de_lifetime();
+    let delife = params.borrowed.de_lifetime();
+
+    let type_name = cattrs.name().deserialize_name();
+    let expecting = format!("enum {}", params.type_name());
+    let expecting = cattrs.expecting().unwrap_or(&expecting);
+
+    let (variants_stmt, variant_visitor) = enum_::prepare_enum_variant_enum(variants);
+
+    // Match arms to extract a variant from a string
+    let variant_arms = variants
+        .iter()
+        .enumerate()
+        .filter(|&(_, variant)| !variant.attrs.skip_deserializing())
+        .map(|(i, variant)| {
+            let variant_name = field_i(i);
+
+            let block = Match(deserialize_externally_tagged_variant(
+                params, variant, cattrs,
+            ));
+
+            quote! {
+                (__Field::#variant_name, __variant) => #block
+            }
+        });
+
+    let all_skipped = variants
+        .iter()
+        .all(|variant| variant.attrs.skip_deserializing());
+    let match_variant = if all_skipped {
+        // This is an empty enum like `enum Impossible {}` or an enum in which
+        // all variants have `#[serde(skip_deserializing)]`.
+        quote! {
+            // FIXME: Once feature(exhaustive_patterns) is stable:
+            // let _serde::#private::Err(__err) = _serde::de::EnumAccess::variant::<__Field>(__data);
+            // _serde::#private::Err(__err)
+            _serde::#private::Result::map(
+                _serde::de::EnumAccess::variant::<__Field>(__data),
+                |(__impossible, _)| match __impossible {})
+        }
+    } else {
+        quote! {
+            match _serde::de::EnumAccess::variant(__data)? {
+                #(#variant_arms)*
+            }
+        }
+    };
+
+    quote_block! {
+        #variant_visitor
+
+        #[doc(hidden)]
+        struct __Visitor #de_impl_generics #where_clause {
+            marker: _serde::#private::PhantomData<#this_type #ty_generics>,
+            lifetime: _serde::#private::PhantomData<&#delife ()>,
+        }
+
+        #[automatically_derived]
+        impl #de_impl_generics _serde::de::Visitor<#delife> for __Visitor #de_ty_generics #where_clause {
+            type Value = #this_type #ty_generics;
+
+            fn expecting(&self, __formatter: &mut _serde::#private::Formatter) -> _serde::#private::fmt::Result {
+                _serde::#private::Formatter::write_str(__formatter, #expecting)
+            }
+
+            fn visit_enum<__A>(self, __data: __A) -> _serde::#private::Result<Self::Value, __A::Error>
+            where
+                __A: _serde::de::EnumAccess<#delife>,
+            {
+                #match_variant
+            }
+        }
+
+        #variants_stmt
+
+        _serde::Deserializer::deserialize_enum(
+            __deserializer,
+            #type_name,
+            VARIANTS,
+            __Visitor {
+                marker: _serde::#private::PhantomData::<#this_type #ty_generics>,
+                lifetime: _serde::#private::PhantomData,
+            },
+        )
+    }
+}
+
+fn deserialize_externally_tagged_variant(
+    params: &Parameters,
+    variant: &Variant,
+    cattrs: &attr::Container,
+) -> Fragment {
+    if let Some(path) = variant.attrs.deserialize_with() {
+        let (wrapper, wrapper_ty, unwrap_fn) = wrap_deserialize_variant_with(params, variant, path);
+        return quote_block! {
+            #wrapper
+            _serde::#private::Result::map(
+                _serde::de::VariantAccess::newtype_variant::<#wrapper_ty>(__variant), #unwrap_fn)
+        };
+    }
+
+    let variant_ident = &variant.ident;
+
+    match variant.style {
+        Style::Unit => {
+            let this_value = &params.this_value;
+            quote_block! {
+                _serde::de::VariantAccess::unit_variant(__variant)?;
+                _serde::#private::Ok(#this_value::#variant_ident)
+            }
+        }
+        Style::Newtype => deserialize_externally_tagged_newtype_variant(
+            variant_ident,
+            params,
+            &variant.fields[0],
+            cattrs,
+        ),
+        Style::Tuple => tuple::deserialize(
+            params,
+            &variant.fields,
+            cattrs,
+            TupleForm::ExternallyTagged(variant_ident),
+        ),
+        Style::Struct => struct_::deserialize(
+            params,
+            &variant.fields,
+            cattrs,
+            StructForm::ExternallyTagged(variant_ident),
+        ),
+    }
+}
+
+fn wrap_deserialize_variant_with(
+    params: &Parameters,
+    variant: &Variant,
+    deserialize_with: &syn::ExprPath,
+) -> (TokenStream, TokenStream, TokenStream) {
+    let field_tys = variant.fields.iter().map(|field| field.ty);
+    let (wrapper, wrapper_ty) =
+        wrap_deserialize_with(params, &quote!((#(#field_tys),*)), deserialize_with);
+
+    let unwrap_fn = unwrap_to_variant_closure(params, variant, true);
+
+    (wrapper, wrapper_ty, unwrap_fn)
+}
+
+fn deserialize_externally_tagged_newtype_variant(
+    variant_ident: &syn::Ident,
+    params: &Parameters,
+    field: &Field,
+    cattrs: &attr::Container,
+) -> Fragment {
+    let this_value = &params.this_value;
+
+    if field.attrs.skip_deserializing() {
+        let default = Expr(expr_is_missing(field, cattrs));
+        return quote_block! {
+            _serde::de::VariantAccess::unit_variant(__variant)?;
+            _serde::#private::Ok(#this_value::#variant_ident(#default))
+        };
+    }
+
+    match field.attrs.deserialize_with() {
+        None => {
+            let field_ty = field.ty;
+            let span = field.original.span();
+            let func =
+                quote_spanned!(span=> _serde::de::VariantAccess::newtype_variant::<#field_ty>);
+            quote_expr! {
+                _serde::#private::Result::map(#func(__variant), #this_value::#variant_ident)
+            }
+        }
+        Some(path) => {
+            let (wrapper, wrapper_ty) = wrap_deserialize_field_with(params, field.ty, path);
+            quote_block! {
+                #wrapper
+                _serde::#private::Result::map(
+                    _serde::de::VariantAccess::newtype_variant::<#wrapper_ty>(__variant),
+                    |__wrapper| #this_value::#variant_ident(__wrapper.value))
+            }
+        }
+    }
+}

serde_derive/src/de/enum_internally.rs

@@ -0,0 +1,106 @@
+//! Deserialization for internally tagged enums:
+//!
+//! ```ignore
+//! #[serde(tag = "...")]
+//! enum Enum {}
+//! ```
+
+use crate::de::enum_;
+use crate::de::enum_untagged;
+use crate::de::struct_;
+use crate::de::{
+    effective_style, expr_is_missing, field_i, unwrap_to_variant_closure, Parameters, StructForm,
+};
+use crate::fragment::{Expr, Fragment, Match};
+use crate::internals::ast::{Style, Variant};
+use crate::internals::attr;
+use crate::private;
+use quote::quote;
+
+/// Generates `Deserialize::deserialize` body for an `enum Enum {...}` with `#[serde(tag)]` attribute
+pub(super) fn deserialize(
+    params: &Parameters,
+    variants: &[Variant],
+    cattrs: &attr::Container,
+    tag: &str,
+) -> Fragment {
+    let (variants_stmt, variant_visitor) = enum_::prepare_enum_variant_enum(variants);
+
+    // Match arms to extract a variant from a string
+    let variant_arms = variants
+        .iter()
+        .enumerate()
+        .filter(|&(_, variant)| !variant.attrs.skip_deserializing())
+        .map(|(i, variant)| {
+            let variant_name = field_i(i);
+
+            let block = Match(deserialize_internally_tagged_variant(
+                params, variant, cattrs,
+            ));
+
+            quote! {
+                __Field::#variant_name => #block
+            }
+        });
+
+    let expecting = format!("internally tagged enum {}", params.type_name());
+    let expecting = cattrs.expecting().unwrap_or(&expecting);
+
+    quote_block! {
+        #variant_visitor
+
+        #variants_stmt
+
+        let (__tag, __content) = _serde::Deserializer::deserialize_any(
+            __deserializer,
+            _serde::#private::de::TaggedContentVisitor::<__Field>::new(#tag, #expecting))?;
+        let __deserializer = _serde::#private::de::ContentDeserializer::<__D::Error>::new(__content);
+
+        match __tag {
+            #(#variant_arms)*
+        }
+    }
+}
+
+// Generates significant part of the visit_seq and visit_map bodies of visitors
+// for the variants of internally tagged enum.
+fn deserialize_internally_tagged_variant(
+    params: &Parameters,
+    variant: &Variant,
+    cattrs: &attr::Container,
+) -> Fragment {
+    if let Some(path) = variant.attrs.deserialize_with() {
+        let unwrap_fn = unwrap_to_variant_closure(params, variant, false);
+        return quote_block! {
+            _serde::#private::Result::map(#path(__deserializer), #unwrap_fn)
+        };
+    }
+
+    let variant_ident = &variant.ident;
+
+    match effective_style(variant) {
+        Style::Unit => {
+            let this_value = &params.this_value;
+            let type_name = params.type_name();
+            let variant_name = variant.ident.to_string();
+            let default = variant.fields.first().map(|field| {
+                let default = Expr(expr_is_missing(field, cattrs));
+                quote!((#default))
+            });
+            quote_block! {
+                _serde::Deserializer::deserialize_any(__deserializer, _serde::#private::de::InternallyTaggedUnitVisitor::new(#type_name, #variant_name))?;
+                _serde::#private::Ok(#this_value::#variant_ident #default)
+            }
+        }
+        Style::Newtype => {
+            enum_untagged::deserialize_newtype_variant(variant_ident, params, &variant.fields[0])
+        }
+        Style::Struct => struct_::deserialize(
+            params,
+            &variant.fields,
+            cattrs,
+            StructForm::InternallyTagged(variant_ident),
+        ),
+        Style::Tuple => unreachable!("checked in serde_derive_internals"),
+    }
+}

serde_derive/src/de/enum_untagged.rs

@@ -0,0 +1,135 @@
+//! Deserialization for untagged enums:
+//!
+//! ```ignore
+//! #[serde(untagged)]
+//! enum Enum {}
+//! ```
+
+use crate::de::struct_;
+use crate::de::tuple;
+use crate::de::{
+    effective_style, expr_is_missing, unwrap_to_variant_closure, Parameters, StructForm, TupleForm,
+};
+use crate::fragment::{Expr, Fragment};
+use crate::internals::ast::{Field, Style, Variant};
+use crate::internals::attr;
+use crate::private;
+use proc_macro2::TokenStream;
+use quote::{quote, quote_spanned};
+use syn::spanned::Spanned;
+
+/// Generates `Deserialize::deserialize` body for an `enum Enum {...}` with `#[serde(untagged)]` attribute
+pub(super) fn deserialize(
+    params: &Parameters,
+    variants: &[Variant],
+    cattrs: &attr::Container,
+    first_attempt: Option<TokenStream>,
+) -> Fragment {
+    let attempts = variants
+        .iter()
+        .filter(|variant| !variant.attrs.skip_deserializing())
+        .map(|variant| Expr(deserialize_variant(params, variant, cattrs)));
+    // TODO this message could be better by saving the errors from the failed
+    // attempts. The heuristic used by TOML was to count the number of fields
+    // processed before an error, and use the error that happened after the
+    // largest number of fields. I'm not sure I like that. Maybe it would be
+    // better to save all the errors and combine them into one message that
+    // explains why none of the variants matched.
+    let fallthrough_msg = format!(
+        "data did not match any variant of untagged enum {}",
+        params.type_name()
+    );
+    let fallthrough_msg = cattrs.expecting().unwrap_or(&fallthrough_msg);
+
+    let private2 = private;
+    quote_block! {
+        let __content = _serde::de::DeserializeSeed::deserialize(_serde::#private::de::ContentVisitor::new(), __deserializer)?;
+        let __deserializer = _serde::#private::de::ContentRefDeserializer::<__D::Error>::new(&__content);
+
+        #first_attempt
+
+        #(
+            if let _serde::#private2::Ok(__ok) = #attempts {
+                return _serde::#private2::Ok(__ok);
+            }
+        )*
+
+        _serde::#private::Err(_serde::de::Error::custom(#fallthrough_msg))
+    }
+}
+
+// Also used by adjacently tagged enums
+pub(super) fn deserialize_variant(
+    params: &Parameters,
+    variant: &Variant,
+    cattrs: &attr::Container,
+) -> Fragment {
+    if let Some(path) = variant.attrs.deserialize_with() {
+        let unwrap_fn = unwrap_to_variant_closure(params, variant, false);
+        return quote_block! {
+            _serde::#private::Result::map(#path(__deserializer), #unwrap_fn)
+        };
+    }
+
+    let variant_ident = &variant.ident;
+
+    match effective_style(variant) {
+        Style::Unit => {
+            let this_value = &params.this_value;
+            let type_name = params.type_name();
+            let variant_name = variant.ident.to_string();
+            let default = variant.fields.first().map(|field| {
+                let default = Expr(expr_is_missing(field, cattrs));
+                quote!((#default))
+            });
+            quote_expr! {
+                match _serde::Deserializer::deserialize_any(
+                    __deserializer,
+                    _serde::#private::de::UntaggedUnitVisitor::new(#type_name, #variant_name)
+                ) {
+                    _serde::#private::Ok(()) => _serde::#private::Ok(#this_value::#variant_ident #default),
+                    _serde::#private::Err(__err) => _serde::#private::Err(__err),
+                }
+            }
+        }
+        Style::Newtype => deserialize_newtype_variant(variant_ident, params, &variant.fields[0]),
+        Style::Tuple => tuple::deserialize(
+            params,
+            &variant.fields,
+            cattrs,
+            TupleForm::Untagged(variant_ident),
+        ),
+        Style::Struct => struct_::deserialize(
+            params,
+            &variant.fields,
+            cattrs,
+            StructForm::Untagged(variant_ident),
+        ),
+    }
+}
+
+// Also used by internally tagged enums
+// Implicitly (via `generate_variant`) used by adjacently tagged enums
+pub(super) fn deserialize_newtype_variant(
+    variant_ident: &syn::Ident,
+    params: &Parameters,
+    field: &Field,
+) -> Fragment {
+    let this_value = &params.this_value;
+    let field_ty = field.ty;
+    match field.attrs.deserialize_with() {
+        None => {
+            let span = field.original.span();
+            let func = quote_spanned!(span=> <#field_ty as _serde::Deserialize>::deserialize);
+            quote_expr! {
+                _serde::#private::Result::map(#func(__deserializer), #this_value::#variant_ident)
+            }
+        }
+        Some(path) => {
+            quote_block! {
+                let __value: _serde::#private::Result<#field_ty, _> = #path(__deserializer);
+                _serde::#private::Result::map(__value, #this_value::#variant_ident)
+            }
+        }
+    }
+}

serde_derive/src/de/identifier.rs

@@ -0,0 +1,477 @@
+//! Deserialization of struct field identifiers and enum variant identifiers by
+//! way of a Rust enum.
+
+use crate::de::{FieldWithAliases, Parameters};
+use crate::fragment::{Fragment, Stmts};
+use crate::internals::ast::{Style, Variant};
+use crate::internals::attr;
+use crate::private;
+use proc_macro2::{Literal, TokenStream};
+use quote::{quote, ToTokens};
+
+// Generates `Deserialize::deserialize` body for an enum with
+// `serde(field_identifier)` or `serde(variant_identifier)` attribute.
+pub(super) fn deserialize_custom(
+    params: &Parameters,
+    variants: &[Variant],
+    cattrs: &attr::Container,
+) -> Fragment {
+    let is_variant = match cattrs.identifier() {
+        attr::Identifier::Variant => true,
+        attr::Identifier::Field => false,
+        attr::Identifier::No => unreachable!(),
+    };
+
+    let this_type = params.this_type.to_token_stream();
+    let this_value = params.this_value.to_token_stream();
+
+    let (ordinary, fallthrough, fallthrough_borrowed) = if let Some(last) = variants.last() {
+        let last_ident = &last.ident;
+        if last.attrs.other() {
+            // Process `serde(other)` attribute. It would always be found on the
+            // last variant (checked in `check_identifier`), so all preceding
+            // are ordinary variants.
+            let ordinary = &variants[..variants.len() - 1];
+            let fallthrough = quote!(_serde::#private::Ok(#this_value::#last_ident));
+            (ordinary, Some(fallthrough), None)
+        } else if let Style::Newtype = last.style {
+            let ordinary = &variants[..variants.len() - 1];
+            let fallthrough = |value| {
+                quote! {
+                    _serde::#private::Result::map(
+                        _serde::Deserialize::deserialize(
+                            _serde::#private::de::IdentifierDeserializer::from(#value)
+                        ),
+                        #this_value::#last_ident)
+                }
+            };
+            (
+                ordinary,
+                Some(fallthrough(quote!(__value))),
+                Some(fallthrough(quote!(_serde::#private::de::Borrowed(
+                    __value
+                )))),
+            )
+        } else {
+            (variants, None, None)
+        }
+    } else {
+        (variants, None, None)
+    };
+
+    let idents_aliases: Vec<_> = ordinary
+        .iter()
+        .map(|variant| FieldWithAliases {
+            ident: variant.ident.clone(),
+            aliases: variant.attrs.aliases(),
+        })
+        .collect();
+
+    let names = idents_aliases.iter().flat_map(|variant| variant.aliases);
+
+    let names_const = if fallthrough.is_some() {
+        None
+    } else if is_variant {
+        let variants = quote! {
+            #[doc(hidden)]
+            const VARIANTS: &'static [&'static str] = &[ #(#names),* ];
+        };
+        Some(variants)
+    } else {
+        let fields = quote! {
+            #[doc(hidden)]
+            const FIELDS: &'static [&'static str] = &[ #(#names),* ];
+        };
+        Some(fields)
+    };
+
+    let (de_impl_generics, de_ty_generics, ty_generics, where_clause) =
+        params.generics_with_de_lifetime();
+    let delife = params.borrowed.de_lifetime();
+    let visitor_impl = Stmts(deserialize_identifier(
+        &this_value,
+        &idents_aliases,
+        is_variant,
+        fallthrough,
+        fallthrough_borrowed,
+        false,
+        cattrs.expecting(),
+    ));
+
+    quote_block! {
+        #names_const
+
+        #[doc(hidden)]
+        struct __FieldVisitor #de_impl_generics #where_clause {
+            marker: _serde::#private::PhantomData<#this_type #ty_generics>,
+            lifetime: _serde::#private::PhantomData<&#delife ()>,
+        }
+
+        #[automatically_derived]
+        impl #de_impl_generics _serde::de::Visitor<#delife> for __FieldVisitor #de_ty_generics #where_clause {
+            type Value = #this_type #ty_generics;
+
+            #visitor_impl
+        }
+
+        let __visitor = __FieldVisitor {
+            marker: _serde::#private::PhantomData::<#this_type #ty_generics>,
+            lifetime: _serde::#private::PhantomData,
+        };
+        _serde::Deserializer::deserialize_identifier(__deserializer, __visitor)
+    }
+}
+
+pub(super) fn deserialize_generated(
+    deserialized_fields: &[FieldWithAliases],
+    has_flatten: bool,
+    is_variant: bool,
+    ignore_variant: Option<TokenStream>,
+    fallthrough: Option<TokenStream>,
+) -> Fragment {
+    let this_value = quote!(__Field);
+    let field_idents: &Vec<_> = &deserialized_fields
+        .iter()
+        .map(|field| &field.ident)
+        .collect();
+
+    let visitor_impl = Stmts(deserialize_identifier(
+        &this_value,
+        deserialized_fields,
+        is_variant,
+        fallthrough,
+        None,
+        !is_variant && has_flatten,
+        None,
+    ));
+
+    let lifetime = if !is_variant && has_flatten {
+        Some(quote!(<'de>))
+    } else {
+        None
+    };
+
+    quote_block! {
+        #[allow(non_camel_case_types)]
+        #[doc(hidden)]
+        enum __Field #lifetime {
+            #(#field_idents,)*
+            #ignore_variant
+        }
+
+        #[doc(hidden)]
+        struct __FieldVisitor;
+
+        #[automatically_derived]
+        impl<'de> _serde::de::Visitor<'de> for __FieldVisitor {
+            type Value = __Field #lifetime;
+
+            #visitor_impl
+        }
+
+        #[automatically_derived]
+        impl<'de> _serde::Deserialize<'de> for __Field #lifetime {
+            #[inline]
+            fn deserialize<__D>(__deserializer: __D) -> _serde::#private::Result<Self, __D::Error>
+            where
+                __D: _serde::Deserializer<'de>,
+            {
+                _serde::Deserializer::deserialize_identifier(__deserializer, __FieldVisitor)
+            }
+        }
+    }
+}
+
+fn deserialize_identifier(
+    this_value: &TokenStream,
+    deserialized_fields: &[FieldWithAliases],
+    is_variant: bool,
+    fallthrough: Option<TokenStream>,
+    fallthrough_borrowed: Option<TokenStream>,
+    collect_other_fields: bool,
+    expecting: Option<&str>,
+) -> Fragment {
+    let str_mapping = deserialized_fields.iter().map(|field| {
+        let ident = &field.ident;
+        let aliases = field.aliases;
+        let private2 = private;
+        // `aliases` also contains a main name
+        quote! {
+            #(
+                #aliases => _serde::#private2::Ok(#this_value::#ident),
+            )*
+        }
+    });
+    let bytes_mapping = deserialized_fields.iter().map(|field| {
+        let ident = &field.ident;
+        // `aliases` also contains a main name
+        let aliases = field
+            .aliases
+            .iter()
+            .map(|alias| Literal::byte_string(alias.value.as_bytes()));
+        let private2 = private;
+        quote! {
+            #(
+                #aliases => _serde::#private2::Ok(#this_value::#ident),
+            )*
+        }
+    });
+
+    let expecting = expecting.unwrap_or(if is_variant {
+        "variant identifier"
+    } else {
+        "field identifier"
+    });
+
+    let bytes_to_str = if fallthrough.is_some() || collect_other_fields {
+        None
+    } else {
+        Some(quote! {
+            let __value = &_serde::#private::from_utf8_lossy(__value);
+        })
+    };
+
+    let (
+        value_as_str_content,
+        value_as_borrowed_str_content,
+        value_as_bytes_content,
+        value_as_borrowed_bytes_content,
+    ) = if collect_other_fields {
+        (
+            Some(quote! {
+                let __value = _serde::#private::de::Content::String(_serde::#private::ToString::to_string(__value));
+            }),
+            Some(quote! {
+                let __value = _serde::#private::de::Content::Str(__value);
+            }),
+            Some(quote! {
+                let __value = _serde::#private::de::Content::ByteBuf(__value.to_vec());
+            }),
+            Some(quote! {
+                let __value = _serde::#private::de::Content::Bytes(__value);
+            }),
+        )
+    } else {
+        (None, None, None, None)
+    };
+
+    let fallthrough_arm_tokens;
+    let fallthrough_arm = if let Some(fallthrough) = &fallthrough {
+        fallthrough
+    } else if is_variant {
+        fallthrough_arm_tokens = quote! {
+            _serde::#private::Err(_serde::de::Error::unknown_variant(__value, VARIANTS))
+        };
+        &fallthrough_arm_tokens
+    } else {
+        fallthrough_arm_tokens = quote! {
+            _serde::#private::Err(_serde::de::Error::unknown_field(__value, FIELDS))
+        };
+        &fallthrough_arm_tokens
+    };
+
+    let visit_other = if collect_other_fields {
+        quote! {
+            fn visit_bool<__E>(self, __value: bool) -> _serde::#private::Result<Self::Value, __E>
+            where
+                __E: _serde::de::Error,
+            {
+                _serde::#private::Ok(__Field::__other(_serde::#private::de::Content::Bool(__value)))
+            }
+
+            fn visit_i8<__E>(self, __value: i8) -> _serde::#private::Result<Self::Value, __E>
+            where
+                __E: _serde::de::Error,
+            {
+                _serde::#private::Ok(__Field::__other(_serde::#private::de::Content::I8(__value)))
+            }
+
+            fn visit_i16<__E>(self, __value: i16) -> _serde::#private::Result<Self::Value, __E>
+            where
+                __E: _serde::de::Error,
+            {
+                _serde::#private::Ok(__Field::__other(_serde::#private::de::Content::I16(__value)))
+            }
+
+            fn visit_i32<__E>(self, __value: i32) -> _serde::#private::Result<Self::Value, __E>
+            where
+                __E: _serde::de::Error,
+            {
+                _serde::#private::Ok(__Field::__other(_serde::#private::de::Content::I32(__value)))
+            }
+
+            fn visit_i64<__E>(self, __value: i64) -> _serde::#private::Result<Self::Value, __E>
+            where
+                __E: _serde::de::Error,
+            {
+                _serde::#private::Ok(__Field::__other(_serde::#private::de::Content::I64(__value)))
+            }
+
+            fn visit_u8<__E>(self, __value: u8) -> _serde::#private::Result<Self::Value, __E>
+            where
+                __E: _serde::de::Error,
+            {
+                _serde::#private::Ok(__Field::__other(_serde::#private::de::Content::U8(__value)))
+            }
+
+            fn visit_u16<__E>(self, __value: u16) -> _serde::#private::Result<Self::Value, __E>
+            where
+                __E: _serde::de::Error,
+            {
+                _serde::#private::Ok(__Field::__other(_serde::#private::de::Content::U16(__value)))
+            }
+
+            fn visit_u32<__E>(self, __value: u32) -> _serde::#private::Result<Self::Value, __E>
+            where
+                __E: _serde::de::Error,
+            {
+                _serde::#private::Ok(__Field::__other(_serde::#private::de::Content::U32(__value)))
+            }
+
+            fn visit_u64<__E>(self, __value: u64) -> _serde::#private::Result<Self::Value, __E>
+            where
+                __E: _serde::de::Error,
+            {
+                _serde::#private::Ok(__Field::__other(_serde::#private::de::Content::U64(__value)))
+            }
+
+            fn visit_f32<__E>(self, __value: f32) -> _serde::#private::Result<Self::Value, __E>
+            where
+                __E: _serde::de::Error,
+            {
+                _serde::#private::Ok(__Field::__other(_serde::#private::de::Content::F32(__value)))
+            }
+
+            fn visit_f64<__E>(self, __value: f64) -> _serde::#private::Result<Self::Value, __E>
+            where
+                __E: _serde::de::Error,
+            {
+                _serde::#private::Ok(__Field::__other(_serde::#private::de::Content::F64(__value)))
+            }
+
+            fn visit_char<__E>(self, __value: char) -> _serde::#private::Result<Self::Value, __E>
+            where
+                __E: _serde::de::Error,
+            {
+                _serde::#private::Ok(__Field::__other(_serde::#private::de::Content::Char(__value)))
+            }
+
+            fn visit_unit<__E>(self) -> _serde::#private::Result<Self::Value, __E>
+            where
+                __E: _serde::de::Error,
+            {
+                _serde::#private::Ok(__Field::__other(_serde::#private::de::Content::Unit))
+            }
+        }
+    } else {
+        let u64_mapping = deserialized_fields.iter().enumerate().map(|(i, field)| {
+            let i = i as u64;
+            let ident = &field.ident;
+            quote!(#i => _serde::#private::Ok(#this_value::#ident))
+        });
+
+        let u64_fallthrough_arm_tokens;
+        let u64_fallthrough_arm = if let Some(fallthrough) = &fallthrough {
+            fallthrough
+        } else {
+            let index_expecting = if is_variant { "variant" } else { "field" };
+            let fallthrough_msg = format!(
+                "{} index 0 <= i < {}",
+                index_expecting,
+                deserialized_fields.len(),
+            );
+            u64_fallthrough_arm_tokens = quote! {
+                _serde::#private::Err(_serde::de::Error::invalid_value(
+                    _serde::de::Unexpected::Unsigned(__value),
+                    &#fallthrough_msg,
+                ))
+            };
+            &u64_fallthrough_arm_tokens
+        };
+
+        quote! {
+            fn visit_u64<__E>(self, __value: u64) -> _serde::#private::Result<Self::Value, __E>
+            where
+                __E: _serde::de::Error,
+            {
+                match __value {
+                    #(#u64_mapping,)*
+                    _ => #u64_fallthrough_arm,
+                }
+            }
+        }
+    };
+
+    let visit_borrowed = if fallthrough_borrowed.is_some() || collect_other_fields {
+        let str_mapping = str_mapping.clone();
+        let bytes_mapping = bytes_mapping.clone();
+        let fallthrough_borrowed_arm = fallthrough_borrowed.as_ref().unwrap_or(fallthrough_arm);
+        Some(quote! {
+            fn visit_borrowed_str<__E>(self, __value: &'de str) -> _serde::#private::Result<Self::Value, __E>
+            where
+                __E: _serde::de::Error,
+            {
+                match __value {
+                    #(#str_mapping)*
+                    _ => {
+                        #value_as_borrowed_str_content
+                        #fallthrough_borrowed_arm
+                    }
+                }
+            }
+
+            fn visit_borrowed_bytes<__E>(self, __value: &'de [u8]) -> _serde::#private::Result<Self::Value, __E>
+            where
+                __E: _serde::de::Error,
+            {
+                match __value {
+                    #(#bytes_mapping)*
+                    _ => {
+                        #bytes_to_str
+                        #value_as_borrowed_bytes_content
+                        #fallthrough_borrowed_arm
+                    }
+                }
+            }
+        })
+    } else {
+        None
+    };
+
+    quote_block! {
+        fn expecting(&self, __formatter: &mut _serde::#private::Formatter) -> _serde::#private::fmt::Result {
+            _serde::#private::Formatter::write_str(__formatter, #expecting)
+        }
+
+        #visit_other
+
+        fn visit_str<__E>(self, __value: &str) -> _serde::#private::Result<Self::Value, __E>
+        where
+            __E: _serde::de::Error,
+        {
+            match __value {
+                #(#str_mapping)*
+                _ => {
+                    #value_as_str_content
+                    #fallthrough_arm
+                }
+            }
+        }
+
+        fn visit_bytes<__E>(self, __value: &[u8]) -> _serde::#private::Result<Self::Value, __E>
+        where
+            __E: _serde::de::Error,
+        {
+            match __value {
+                #(#bytes_mapping)*
+                _ => {
+                    #bytes_to_str
+                    #value_as_bytes_content
+                    #fallthrough_arm
+                }
+            }
+        }
+
+        #visit_borrowed
+    }
+}

serde_derive/src/de/struct_.rs

@@ -0,0 +1,697 @@
+use crate::de::identifier;
+use crate::de::{
+    deserialize_seq, expr_is_missing, field_i, has_flatten, wrap_deserialize_field_with,
+    FieldWithAliases, Parameters, StructForm,
+};
+#[cfg(feature = "deserialize_in_place")]
+use crate::de::{deserialize_seq_in_place, place_lifetime};
+use crate::fragment::{Expr, Fragment, Match, Stmts};
+use crate::internals::ast::Field;
+use crate::internals::attr;
+use crate::private;
+use proc_macro2::TokenStream;
+use quote::{quote, quote_spanned};
+use syn::spanned::Spanned;
+
+/// Generates `Deserialize::deserialize` body for a `struct Struct {...}`
+pub(super) fn deserialize(
+    params: &Parameters,
+    fields: &[Field],
+    cattrs: &attr::Container,
+    form: StructForm,
+) -> Fragment {
+    let this_type = &params.this_type;
+    let this_value = &params.this_value;
+    let (de_impl_generics, de_ty_generics, ty_generics, where_clause) =
+        params.generics_with_de_lifetime();
+    let delife = params.borrowed.de_lifetime();
+
+    // If there are getters (implying private fields), construct the local type
+    // and use an `Into` conversion to get the remote type. If there are no
+    // getters then construct the target type directly.
+    let construct = if params.has_getter {
+        let local = &params.local;
+        quote!(#local)
+    } else {
+        quote!(#this_value)
+    };
+
+    let type_path = match form {
+        StructForm::Struct => construct,
+        StructForm::ExternallyTagged(variant_ident)
+        | StructForm::InternallyTagged(variant_ident)
+        | StructForm::Untagged(variant_ident) => quote!(#construct::#variant_ident),
+    };
+    let expecting = match form {
+        StructForm::Struct => format!("struct {}", params.type_name()),
+        StructForm::ExternallyTagged(variant_ident)
+        | StructForm::InternallyTagged(variant_ident)
+        | StructForm::Untagged(variant_ident) => {
+            format!("struct variant {}::{}", params.type_name(), variant_ident)
+        }
+    };
+    let expecting = cattrs.expecting().unwrap_or(&expecting);
+
+    let deserialized_fields: Vec<_> = fields
+        .iter()
+        .enumerate()
+        // Skip fields that shouldn't be deserialized or that were flattened,
+        // so they don't appear in the storage in their literal form
+        .filter(|&(_, field)| !field.attrs.skip_deserializing() && !field.attrs.flatten())
+        .map(|(i, field)| FieldWithAliases {
+            ident: field_i(i),
+            aliases: field.attrs.aliases(),
+        })
+        .collect();
+
+    let has_flatten = has_flatten(fields);
+    let field_visitor = deserialize_field_identifier(&deserialized_fields, cattrs, has_flatten);
+
+    // untagged struct variants do not get a visit_seq method. The same applies to
+    // structs that only have a map representation.
+    let visit_seq = match form {
+        StructForm::Untagged(_) => None,
+        _ if has_flatten => None,
+        _ => {
+            let mut_seq = if deserialized_fields.is_empty() {
+                quote!(_)
+            } else {
+                quote!(mut __seq)
+            };
+
+            let visit_seq = Stmts(deserialize_seq(
+                &type_path, params, fields, true, cattrs, expecting,
+            ));
+
+            Some(quote! {
+                #[inline]
+                fn visit_seq<__A>(self, #mut_seq: __A) -> _serde::#private::Result<Self::Value, __A::Error>
+                where
+                    __A: _serde::de::SeqAccess<#delife>,
+                {
+                    #visit_seq
+                }
+            })
+        }
+    };
+    let visit_map = Stmts(deserialize_map(
+        &type_path,
+        params,
+        fields,
+        cattrs,
+        has_flatten,
+    ));
+
+    let visitor_seed = match form {
+        StructForm::ExternallyTagged(..) if has_flatten => Some(quote! {
+            #[automatically_derived]
+            impl #de_impl_generics _serde::de::DeserializeSeed<#delife> for __Visitor #de_ty_generics #where_clause {
+                type Value = #this_type #ty_generics;
+
+                fn deserialize<__D>(self, __deserializer: __D) -> _serde::#private::Result<Self::Value, __D::Error>
+                where
+                    __D: _serde::Deserializer<#delife>,
+                {
+                    _serde::Deserializer::deserialize_map(__deserializer, self)
+                }
+            }
+        }),
+        _ => None,
+    };
+
+    let fields_stmt = if has_flatten {
+        None
+    } else {
+        let field_names = deserialized_fields.iter().flat_map(|field| field.aliases);
+
+        Some(quote! {
+            #[doc(hidden)]
+            const FIELDS: &'static [&'static str] = &[ #(#field_names),* ];
+        })
+    };
+
+    let visitor_expr = quote! {
+        __Visitor {
+            marker: _serde::#private::PhantomData::<#this_type #ty_generics>,
+            lifetime: _serde::#private::PhantomData,
+        }
+    };
+    let dispatch = match form {
+        StructForm::Struct if has_flatten => quote! {
+            _serde::Deserializer::deserialize_map(__deserializer, #visitor_expr)
+        },
+        StructForm::Struct => {
+            let type_name = cattrs.name().deserialize_name();
+            quote! {
+                _serde::Deserializer::deserialize_struct(__deserializer, #type_name, FIELDS, #visitor_expr)
+            }
+        }
+        StructForm::ExternallyTagged(_) if has_flatten => quote! {
+            _serde::de::VariantAccess::newtype_variant_seed(__variant, #visitor_expr)
+        },
+        StructForm::ExternallyTagged(_) => quote! {
+            _serde::de::VariantAccess::struct_variant(__variant, FIELDS, #visitor_expr)
+        },
+        StructForm::InternallyTagged(_) => quote! {
+            _serde::Deserializer::deserialize_any(__deserializer, #visitor_expr)
+        },
+        StructForm::Untagged(_) => quote! {
+            _serde::Deserializer::deserialize_any(__deserializer, #visitor_expr)
+        },
+    };
+
+    quote_block! {
+        #field_visitor
+
+        #[doc(hidden)]
+        struct __Visitor #de_impl_generics #where_clause {
+            marker: _serde::#private::PhantomData<#this_type #ty_generics>,
+            lifetime: _serde::#private::PhantomData<&#delife ()>,
+        }
+
+        #[automatically_derived]
+        impl #de_impl_generics _serde::de::Visitor<#delife> for __Visitor #de_ty_generics #where_clause {
+            type Value = #this_type #ty_generics;
+
+            fn expecting(&self, __formatter: &mut _serde::#private::Formatter) -> _serde::#private::fmt::Result {
+                _serde::#private::Formatter::write_str(__formatter, #expecting)
+            }
+
+            #visit_seq
+
+            #[inline]
+            fn visit_map<__A>(self, mut __map: __A) -> _serde::#private::Result<Self::Value, __A::Error>
+            where
+                __A: _serde::de::MapAccess<#delife>,
+            {
+                #visit_map
+            }
+        }
+
+        #visitor_seed
+
+        #fields_stmt
+
+        #dispatch
+    }
+}
+
+fn deserialize_map(
+    struct_path: &TokenStream,
+    params: &Parameters,
+    fields: &[Field],
+    cattrs: &attr::Container,
+    has_flatten: bool,
+) -> Fragment {
+    // Create the field names for the fields.
+    let fields_names: Vec<_> = fields
+        .iter()
+        .enumerate()
+        .map(|(i, field)| (field, field_i(i)))
+        .collect();
+
+    // Declare each field that will be deserialized.
+    let let_values = fields_names
+        .iter()
+        .filter(|&&(field, _)| !field.attrs.skip_deserializing() && !field.attrs.flatten())
+        .map(|(field, name)| {
+            let field_ty = field.ty;
+            quote! {
+                let mut #name: _serde::#private::Option<#field_ty> = _serde::#private::None;
+            }
+        });
+
+    // Collect contents for flatten fields into a buffer
+    let let_collect = if has_flatten {
+        Some(quote! {
+            let mut __collect = _serde::#private::Vec::<_serde::#private::Option<(
+                _serde::#private::de::Content,
+                _serde::#private::de::Content
+            )>>::new();
+        })
+    } else {
+        None
+    };
+
+    // Match arms to extract a value for a field.
+    let value_arms = fields_names
+        .iter()
+        .filter(|&&(field, _)| !field.attrs.skip_deserializing() && !field.attrs.flatten())
+        .map(|(field, name)| {
+            let deser_name = field.attrs.name().deserialize_name();
+
+            let visit = match field.attrs.deserialize_with() {
+                None => {
+                    let field_ty = field.ty;
+                    let span = field.original.span();
+                    let func =
+                        quote_spanned!(span=> _serde::de::MapAccess::next_value::<#field_ty>);
+                    quote! {
+                        #func(&mut __map)?
+                    }
+                }
+                Some(path) => {
+                    let (wrapper, wrapper_ty) = wrap_deserialize_field_with(params, field.ty, path);
+                    quote!({
+                        #wrapper
+                        match _serde::de::MapAccess::next_value::<#wrapper_ty>(&mut __map) {
+                            _serde::#private::Ok(__wrapper) => __wrapper.value,
+                            _serde::#private::Err(__err) => {
+                                return _serde::#private::Err(__err);
+                            }
+                        }
+                    })
+                }
+            };
+            quote! {
+                __Field::#name => {
+                    if _serde::#private::Option::is_some(&#name) {
+                        return _serde::#private::Err(<__A::Error as _serde::de::Error>::duplicate_field(#deser_name));
+                    }
+                    #name = _serde::#private::Some(#visit);
+                }
+            }
+        });
+
+    // Visit ignored values to consume them
+    let ignored_arm = if has_flatten {
+        Some(quote! {
+            __Field::__other(__name) => {
+                __collect.push(_serde::#private::Some((
+                    __name,
+                    _serde::de::MapAccess::next_value_seed(&mut __map, _serde::#private::de::ContentVisitor::new())?)));
+            }
+        })
+    } else if cattrs.deny_unknown_fields() {
+        None
+    } else {
+        Some(quote! {
+            _ => { let _ = _serde::de::MapAccess::next_value::<_serde::de::IgnoredAny>(&mut __map)?; }
+        })
+    };
+
+    let all_skipped = fields.iter().all(|field| field.attrs.skip_deserializing());
+    let match_keys = if cattrs.deny_unknown_fields() && all_skipped {
+        quote! {
+            // FIXME: Once feature(exhaustive_patterns) is stable:
+            // let _serde::#private::None::<__Field> = _serde::de::MapAccess::next_key(&mut __map)?;
+            _serde::#private::Option::map(
+                _serde::de::MapAccess::next_key::<__Field>(&mut __map)?,
+                |__impossible| match __impossible {});
+        }
+    } else {
+        quote! {
+            while let _serde::#private::Some(__key) = _serde::de::MapAccess::next_key::<__Field>(&mut __map)? {
+                match __key {
+                    #(#value_arms)*
+                    #ignored_arm
+                }
+            }
+        }
+    };
+
+    let extract_values = fields_names
+        .iter()
+        .filter(|&&(field, _)| !field.attrs.skip_deserializing() && !field.attrs.flatten())
+        .map(|(field, name)| {
+            let missing_expr = Match(expr_is_missing(field, cattrs));
+
+            quote! {
+                let #name = match #name {
+                    _serde::#private::Some(#name) => #name,
+                    _serde::#private::None => #missing_expr
+                };
+            }
+        });
+
+    let extract_collected = fields_names
+        .iter()
+        .filter(|&&(field, _)| field.attrs.flatten() && !field.attrs.skip_deserializing())
+        .map(|(field, name)| {
+            let field_ty = field.ty;
+            let func = match field.attrs.deserialize_with() {
+                None => {
+                    let span = field.original.span();
+                    quote_spanned!(span=> _serde::de::Deserialize::deserialize)
+                }
+                Some(path) => quote!(#path),
+            };
+            quote! {
+                let #name: #field_ty = #func(
+                    _serde::#private::de::FlatMapDeserializer(
+                        &mut __collect,
+                        _serde::#private::PhantomData))?;
+            }
+        });
+
+    let collected_deny_unknown_fields = if has_flatten && cattrs.deny_unknown_fields() {
+        Some(quote! {
+            if let _serde::#private::Some(_serde::#private::Some((__key, _))) =
+                __collect.into_iter().filter(_serde::#private::Option::is_some).next()
+            {
+                if let _serde::#private::Some(__key) = _serde::#private::de::content_as_str(&__key) {
+                    return _serde::#private::Err(
+                        _serde::de::Error::custom(format_args!("unknown field `{}`", &__key)));
+                } else {
+                    return _serde::#private::Err(
+                        _serde::de::Error::custom(format_args!("unexpected map key")));
+                }
+            }
+        })
+    } else {
+        None
+    };
+
+    let result = fields_names.iter().map(|(field, name)| {
+        let member = &field.member;
+        if field.attrs.skip_deserializing() {
+            let value = Expr(expr_is_missing(field, cattrs));
+            quote!(#member: #value)
+        } else {
+            quote!(#member: #name)
+        }
+    });
+
+    let let_default = match cattrs.default() {
+        attr::Default::Default => Some(quote!(
+            let __default: Self::Value = _serde::#private::Default::default();
+        )),
+        // If #path returns wrong type, error will be reported here (^^^^^).
+        // We attach span of the path to the function so it will be reported
+        // on the #[serde(default = "...")]
+        //                          ^^^^^
+        attr::Default::Path(path) => Some(quote_spanned!(path.span()=>
+            let __default: Self::Value = #path();
+        )),
+        attr::Default::None => {
+            // We don't need the default value, to prevent an unused variable warning
+            // we'll leave the line empty.
+            None
+        }
+    };
+
+    let mut result = quote!(#struct_path { #(#result),* });
+    if params.has_getter {
+        let this_type = &params.this_type;
+        let (_, ty_generics, _) = params.generics.split_for_impl();
+        result = quote! {
+            _serde::#private::Into::<#this_type #ty_generics>::into(#result)
+        };
+    }
+
+    quote_block! {
+        #(#let_values)*
+
+        #let_collect
+
+        #match_keys
+
+        #let_default
+
+        #(#extract_values)*
+
+        #(#extract_collected)*
+
+        #collected_deny_unknown_fields
+
+        _serde::#private::Ok(#result)
+    }
+}
+
+/// Generates `Deserialize::deserialize_in_place` body for a `struct Struct {...}`
+#[cfg(feature = "deserialize_in_place")]
+pub(super) fn deserialize_in_place(
+    params: &Parameters,
+    fields: &[Field],
+    cattrs: &attr::Container,
+) -> Option<Fragment> {
+    // for now we do not support in_place deserialization for structs that
+    // are represented as map.
+    if has_flatten(fields) {
+        return None;
+    }
+
+    let this_type = &params.this_type;
+    let (de_impl_generics, de_ty_generics, ty_generics, where_clause) =
+        params.generics_with_de_lifetime();
+    let delife = params.borrowed.de_lifetime();
+
+    let expecting = format!("struct {}", params.type_name());
+    let expecting = cattrs.expecting().unwrap_or(&expecting);
+
+    let deserialized_fields: Vec<_> = fields
+        .iter()
+        .enumerate()
+        .filter(|&(_, field)| !field.attrs.skip_deserializing())
+        .map(|(i, field)| FieldWithAliases {
+            ident: field_i(i),
+            aliases: field.attrs.aliases(),
+        })
+        .collect();
+
+    let field_visitor = deserialize_field_identifier(&deserialized_fields, cattrs, false);
+
+    let mut_seq = if deserialized_fields.is_empty() {
+        quote!(_)
+    } else {
+        quote!(mut __seq)
+    };
+    let visit_seq = Stmts(deserialize_seq_in_place(params, fields, cattrs, expecting));
+    let visit_map = Stmts(deserialize_map_in_place(params, fields, cattrs));
+    let field_names = deserialized_fields.iter().flat_map(|field| field.aliases);
+    let type_name = cattrs.name().deserialize_name();
+
+    let in_place_impl_generics = de_impl_generics.in_place();
+    let in_place_ty_generics = de_ty_generics.in_place();
+    let place_life = place_lifetime();
+
+    Some(quote_block! {
+        #field_visitor
+
+        #[doc(hidden)]
+        struct __Visitor #in_place_impl_generics #where_clause {
+            place: &#place_life mut #this_type #ty_generics,
+            lifetime: _serde::#private::PhantomData<&#delife ()>,
+        }
+
+        #[automatically_derived]
+        impl #in_place_impl_generics _serde::de::Visitor<#delife> for __Visitor #in_place_ty_generics #where_clause {
+            type Value = ();
+
+            fn expecting(&self, __formatter: &mut _serde::#private::Formatter) -> _serde::#private::fmt::Result {
+                _serde::#private::Formatter::write_str(__formatter, #expecting)
+            }
+
+            #[inline]
+            fn visit_seq<__A>(self, #mut_seq: __A) -> _serde::#private::Result<Self::Value, __A::Error>
+            where
+                __A: _serde::de::SeqAccess<#delife>,
+            {
+                #visit_seq
+            }
+
+            #[inline]
+            fn visit_map<__A>(self, mut __map: __A) -> _serde::#private::Result<Self::Value, __A::Error>
+            where
+                __A: _serde::de::MapAccess<#delife>,
+            {
+                #visit_map
+            }
+        }
+
+        #[doc(hidden)]
+        const FIELDS: &'static [&'static str] = &[ #(#field_names),* ];
+
+        _serde::Deserializer::deserialize_struct(__deserializer, #type_name, FIELDS, __Visitor {
+            place: __place,
+            lifetime: _serde::#private::PhantomData,
+        })
+    })
+}
+
+#[cfg(feature = "deserialize_in_place")]
+fn deserialize_map_in_place(
+    params: &Parameters,
+    fields: &[Field],
+    cattrs: &attr::Container,
+) -> Fragment {
+    assert!(
+        !has_flatten(fields),
+        "inplace deserialization of maps does not support flatten fields"
+    );
+
+    // Create the field names for the fields.
+    let fields_names: Vec<_> = fields
+        .iter()
+        .enumerate()
+        .map(|(i, field)| (field, field_i(i)))
+        .collect();
+
+    // For deserialize_in_place, declare booleans for each field that will be
+    // deserialized.
+    let let_flags = fields_names
+        .iter()
+        .filter(|&&(field, _)| !field.attrs.skip_deserializing())
+        .map(|(_, name)| {
+            quote! {
+                let mut #name: bool = false;
+            }
+        });
+
+    // Match arms to extract a value for a field.
+    let value_arms_from = fields_names
+        .iter()
+        .filter(|&&(field, _)| !field.attrs.skip_deserializing())
+        .map(|(field, name)| {
+            let deser_name = field.attrs.name().deserialize_name();
+            let member = &field.member;
+
+            let visit = match field.attrs.deserialize_with() {
+                None => {
+                    quote! {
+                        _serde::de::MapAccess::next_value_seed(&mut __map, _serde::#private::de::InPlaceSeed(&mut self.place.#member))?
+                    }
+                }
+                Some(path) => {
+                    let (wrapper, wrapper_ty) = wrap_deserialize_field_with(params, field.ty, path);
+                    quote!({
+                        #wrapper
+                        self.place.#member = match _serde::de::MapAccess::next_value::<#wrapper_ty>(&mut __map) {
+                            _serde::#private::Ok(__wrapper) => __wrapper.value,
+                            _serde::#private::Err(__err) => {
+                                return _serde::#private::Err(__err);
+                            }
+                        };
+                    })
+                }
+            };
+            quote! {
+                __Field::#name => {
+                    if #name {
+                        return _serde::#private::Err(<__A::Error as _serde::de::Error>::duplicate_field(#deser_name));
+                    }
+                    #visit;
+                    #name = true;
+                }
+            }
+        });
+
+    // Visit ignored values to consume them
+    let ignored_arm = if cattrs.deny_unknown_fields() {
+        None
+    } else {
+        Some(quote! {
+            _ => { let _ = _serde::de::MapAccess::next_value::<_serde::de::IgnoredAny>(&mut __map)?; }
+        })
+    };
+
+    let all_skipped = fields.iter().all(|field| field.attrs.skip_deserializing());
+
+    let match_keys = if cattrs.deny_unknown_fields() && all_skipped {
+        quote! {
+            // FIXME: Once feature(exhaustive_patterns) is stable:
+            // let _serde::#private::None::<__Field> = _serde::de::MapAccess::next_key(&mut __map)?;
+            _serde::#private::Option::map(
+                _serde::de::MapAccess::next_key::<__Field>(&mut __map)?,
+                |__impossible| match __impossible {});
+        }
+    } else {
+        quote! {
+            while let _serde::#private::Some(__key) = _serde::de::MapAccess::next_key::<__Field>(&mut __map)? {
+                match __key {
+                    #(#value_arms_from)*
+                    #ignored_arm
+                }
+            }
+        }
+    };
+
+    let check_flags = fields_names
+        .iter()
+        .filter(|&&(field, _)| !field.attrs.skip_deserializing())
+        .map(|(field, name)| {
+            let missing_expr = expr_is_missing(field, cattrs);
+            // If missing_expr unconditionally returns an error, don't try
+            // to assign its value to self.place.
+            if field.attrs.default().is_none()
+                && cattrs.default().is_none()
+                && field.attrs.deserialize_with().is_some()
+            {
+                let missing_expr = Stmts(missing_expr);
+                quote! {
+                    if !#name {
+                        #missing_expr;
+                    }
+                }
+            } else {
+                let member = &field.member;
+                let missing_expr = Expr(missing_expr);
+                quote! {
+                    if !#name {
+                        self.place.#member = #missing_expr;
+                    };
+                }
+            }
+        });
+
+    let this_type = &params.this_type;
+    let (_, ty_generics, _) = params.generics.split_for_impl();
+
+    let let_default = match cattrs.default() {
+        attr::Default::Default => Some(quote!(
+            let __default: #this_type #ty_generics = _serde::#private::Default::default();
+        )),
+        // If #path returns wrong type, error will be reported here (^^^^^).
+        // We attach span of the path to the function so it will be reported
+        // on the #[serde(default = "...")]
+        //                          ^^^^^
+        attr::Default::Path(path) => Some(quote_spanned!(path.span()=>
+            let __default: #this_type #ty_generics = #path();
+        )),
+        attr::Default::None => {
+            // We don't need the default value, to prevent an unused variable warning
+            // we'll leave the line empty.
+            None
+        }
+    };
+
+    quote_block! {
+        #(#let_flags)*
+
+        #match_keys
+
+        #let_default
+
+        #(#check_flags)*
+
+        _serde::#private::Ok(())
+    }
+}
+
+/// Generates enum and its `Deserialize` implementation that represents each
+/// non-skipped field of the struct
+fn deserialize_field_identifier(
+    deserialized_fields: &[FieldWithAliases],
+    cattrs: &attr::Container,
+    has_flatten: bool,
+) -> Stmts {
+    let (ignore_variant, fallthrough) = if has_flatten {
+        let ignore_variant = quote!(__other(_serde::#private::de::Content<'de>),);
+        let fallthrough = quote!(_serde::#private::Ok(__Field::__other(__value)));
+        (Some(ignore_variant), Some(fallthrough))
+    } else if cattrs.deny_unknown_fields() {
+        (None, None)
+    } else {
+        let ignore_variant = quote!(__ignore,);
+        let fallthrough = quote!(_serde::#private::Ok(__Field::__ignore));
+        (Some(ignore_variant), Some(fallthrough))
+    };
+
+    Stmts(identifier::deserialize_generated(
+        deserialized_fields,
+        has_flatten,
+        false,
+        ignore_variant,
+        fallthrough,
+    ))
+}

serde_derive/src/de/tuple.rs

@@ -0,0 +1,283 @@
+use crate::de::{deserialize_seq, has_flatten, Parameters, TupleForm};
+#[cfg(feature = "deserialize_in_place")]
+use crate::de::{deserialize_seq_in_place, place_lifetime};
+use crate::fragment::{Fragment, Stmts};
+use crate::internals::ast::Field;
+use crate::internals::attr;
+use crate::private;
+use proc_macro2::TokenStream;
+use quote::{quote, quote_spanned};
+use syn::spanned::Spanned;
+
+/// Generates `Deserialize::deserialize` body for a `struct Tuple(...);` including `struct Newtype(T);`
+pub(super) fn deserialize(
+    params: &Parameters,
+    fields: &[Field],
+    cattrs: &attr::Container,
+    form: TupleForm,
+) -> Fragment {
+    assert!(
+        !has_flatten(fields),
+        "tuples and tuple variants cannot have flatten fields"
+    );
+
+    let field_count = fields
+        .iter()
+        .filter(|field| !field.attrs.skip_deserializing())
+        .count();
+
+    let this_type = &params.this_type;
+    let this_value = &params.this_value;
+    let (de_impl_generics, de_ty_generics, ty_generics, where_clause) =
+        params.generics_with_de_lifetime();
+    let delife = params.borrowed.de_lifetime();
+
+    // If there are getters (implying private fields), construct the local type
+    // and use an `Into` conversion to get the remote type. If there are no
+    // getters then construct the target type directly.
+    let construct = if params.has_getter {
+        let local = &params.local;
+        quote!(#local)
+    } else {
+        quote!(#this_value)
+    };
+
+    let type_path = match form {
+        TupleForm::Tuple => construct,
+        TupleForm::ExternallyTagged(variant_ident) | TupleForm::Untagged(variant_ident) => {
+            quote!(#construct::#variant_ident)
+        }
+    };
+    let expecting = match form {
+        TupleForm::Tuple => format!("tuple struct {}", params.type_name()),
+        TupleForm::ExternallyTagged(variant_ident) | TupleForm::Untagged(variant_ident) => {
+            format!("tuple variant {}::{}", params.type_name(), variant_ident)
+        }
+    };
+    let expecting = cattrs.expecting().unwrap_or(&expecting);
+
+    let nfields = fields.len();
+
+    let visit_newtype_struct = match form {
+        TupleForm::Tuple if nfields == 1 => {
+            Some(deserialize_newtype_struct(&type_path, params, &fields[0]))
+        }
+        _ => None,
+    };
+
+    let visit_seq = Stmts(deserialize_seq(
+        &type_path, params, fields, false, cattrs, expecting,
+    ));
+
+    let visitor_expr = quote! {
+        __Visitor {
+            marker: _serde::#private::PhantomData::<#this_type #ty_generics>,
+            lifetime: _serde::#private::PhantomData,
+        }
+    };
+    let dispatch = match form {
+        TupleForm::Tuple if nfields == 1 => {
+            let type_name = cattrs.name().deserialize_name();
+            quote! {
+                _serde::Deserializer::deserialize_newtype_struct(__deserializer, #type_name, #visitor_expr)
+            }
+        }
+        TupleForm::Tuple => {
+            let type_name = cattrs.name().deserialize_name();
+            quote! {
+                _serde::Deserializer::deserialize_tuple_struct(__deserializer, #type_name, #field_count, #visitor_expr)
+            }
+        }
+        TupleForm::ExternallyTagged(_) => quote! {
+            _serde::de::VariantAccess::tuple_variant(__variant, #field_count, #visitor_expr)
+        },
+        TupleForm::Untagged(_) => quote! {
+            _serde::Deserializer::deserialize_tuple(__deserializer, #field_count, #visitor_expr)
+        },
+    };
+
+    let visitor_var = if field_count == 0 {
+        quote!(_)
+    } else {
+        quote!(mut __seq)
+    };
+
+    quote_block! {
+        #[doc(hidden)]
+        struct __Visitor #de_impl_generics #where_clause {
+            marker: _serde::#private::PhantomData<#this_type #ty_generics>,
+            lifetime: _serde::#private::PhantomData<&#delife ()>,
+        }
+
+        #[automatically_derived]
+        impl #de_impl_generics _serde::de::Visitor<#delife> for __Visitor #de_ty_generics #where_clause {
+            type Value = #this_type #ty_generics;
+
+            fn expecting(&self, __formatter: &mut _serde::#private::Formatter) -> _serde::#private::fmt::Result {
+                _serde::#private::Formatter::write_str(__formatter, #expecting)
+            }
+
+            #visit_newtype_struct
+
+            #[inline]
+            fn visit_seq<__A>(self, #visitor_var: __A) -> _serde::#private::Result<Self::Value, __A::Error>
+            where
+                __A: _serde::de::SeqAccess<#delife>,
+            {
+                #visit_seq
+            }
+        }
+
+        #dispatch
+    }
+}
+
+fn deserialize_newtype_struct(
+    type_path: &TokenStream,
+    params: &Parameters,
+    field: &Field,
+) -> TokenStream {
+    let delife = params.borrowed.de_lifetime();
+    let field_ty = field.ty;
+    let deserializer_var = quote!(__e);
+
+    let value = match field.attrs.deserialize_with() {
+        None => {
+            let span = field.original.span();
+            let func = quote_spanned!(span=> <#field_ty as _serde::Deserialize>::deserialize);
+            quote! {
+                #func(#deserializer_var)?
+            }
+        }
+        Some(path) => {
+            // If #path returns wrong type, error will be reported here (^^^^^).
+            // We attach span of the path to the function so it will be reported
+            // on the #[serde(with = "...")]
+            //                       ^^^^^
+            quote_spanned! {path.span()=>
+                #path(#deserializer_var)?
+            }
+        }
+    };
+
+    let mut result = quote!(#type_path(__field0));
+    if params.has_getter {
+        let this_type = &params.this_type;
+        let (_, ty_generics, _) = params.generics.split_for_impl();
+        result = quote! {
+            _serde::#private::Into::<#this_type #ty_generics>::into(#result)
+        };
+    }
+
+    quote! {
+        #[inline]
+        fn visit_newtype_struct<__E>(self, #deserializer_var: __E) -> _serde::#private::Result<Self::Value, __E::Error>
+        where
+            __E: _serde::Deserializer<#delife>,
+        {
+            let __field0: #field_ty = #value;
+            _serde::#private::Ok(#result)
+        }
+    }
+}
+
+/// Generates `Deserialize::deserialize_in_place` body for a `struct Tuple(...);` including `struct Newtype(T);`
+#[cfg(feature = "deserialize_in_place")]
+pub(super) fn deserialize_in_place(
+    params: &Parameters,
+    fields: &[Field],
+    cattrs: &attr::Container,
+) -> Fragment {
+    assert!(
+        !has_flatten(fields),
+        "tuples and tuple variants cannot have flatten fields"
+    );
+
+    let field_count = fields
+        .iter()
+        .filter(|field| !field.attrs.skip_deserializing())
+        .count();
+
+    let this_type = &params.this_type;
+    let (de_impl_generics, de_ty_generics, ty_generics, where_clause) =
+        params.generics_with_de_lifetime();
+    let delife = params.borrowed.de_lifetime();
+
+    let expecting = format!("tuple struct {}", params.type_name());
+    let expecting = cattrs.expecting().unwrap_or(&expecting);
+
+    let nfields = fields.len();
+
+    let visit_newtype_struct = if nfields == 1 {
+        // We do not generate deserialize_in_place if every field has a
+        // deserialize_with.
+        assert!(fields[0].attrs.deserialize_with().is_none());
+
+        Some(quote! {
+            #[inline]
+            fn visit_newtype_struct<__E>(self, __e: __E) -> _serde::#private::Result<Self::Value, __E::Error>
+            where
+                __E: _serde::Deserializer<#delife>,
+            {
+                _serde::Deserialize::deserialize_in_place(__e, &mut self.place.0)
+            }
+        })
+    } else {
+        None
+    };
+
+    let visit_seq = Stmts(deserialize_seq_in_place(params, fields, cattrs, expecting));
+
+    let visitor_expr = quote! {
+        __Visitor {
+            place: __place,
+            lifetime: _serde::#private::PhantomData,
+        }
+    };
+
+    let type_name = cattrs.name().deserialize_name();
+    let dispatch = if nfields == 1 {
+        quote!(_serde::Deserializer::deserialize_newtype_struct(__deserializer, #type_name, #visitor_expr))
+    } else {
+        quote!(_serde::Deserializer::deserialize_tuple_struct(__deserializer, #type_name, #field_count, #visitor_expr))
+    };
+
+    let visitor_var = if field_count == 0 {
+        quote!(_)
+    } else {
+        quote!(mut __seq)
+    };
+
+    let in_place_impl_generics = de_impl_generics.in_place();
+    let in_place_ty_generics = de_ty_generics.in_place();
+    let place_life = place_lifetime();
+
+    quote_block! {
+        #[doc(hidden)]
+        struct __Visitor #in_place_impl_generics #where_clause {
+            place: &#place_life mut #this_type #ty_generics,
+            lifetime: _serde::#private::PhantomData<&#delife ()>,
+        }
+
+        #[automatically_derived]
+        impl #in_place_impl_generics _serde::de::Visitor<#delife> for __Visitor #in_place_ty_generics #where_clause {
+            type Value = ();
+
+            fn expecting(&self, __formatter: &mut _serde::#private::Formatter) -> _serde::#private::fmt::Result {
+                _serde::#private::Formatter::write_str(__formatter, #expecting)
+            }
+
+            #visit_newtype_struct
+
+            #[inline]
+            fn visit_seq<__A>(self, #visitor_var: __A) -> _serde::#private::Result<Self::Value, __A::Error>
+            where
+                __A: _serde::de::SeqAccess<#delife>,
+            {
+                #visit_seq
+            }
+        }
+
+        #dispatch
+    }
+}

serde_derive/src/de/unit.rs

@@ -0,0 +1,52 @@
+use crate::de::Parameters;
+use crate::fragment::Fragment;
+use crate::internals::attr;
+use crate::private;
+use quote::quote;
+
+/// Generates `Deserialize::deserialize` body for a `struct Unit;`
+pub(super) fn deserialize(params: &Parameters, cattrs: &attr::Container) -> Fragment {
+    let this_type = &params.this_type;
+    let this_value = &params.this_value;
+    let type_name = cattrs.name().deserialize_name();
+    let (de_impl_generics, de_ty_generics, ty_generics, where_clause) =
+        params.generics_with_de_lifetime();
+    let delife = params.borrowed.de_lifetime();
+
+    let expecting = format!("unit struct {}", params.type_name());
+    let expecting = cattrs.expecting().unwrap_or(&expecting);
+
+    quote_block! {
+        #[doc(hidden)]
+        struct __Visitor #de_impl_generics #where_clause {
+            marker: _serde::#private::PhantomData<#this_type #ty_generics>,
+            lifetime: _serde::#private::PhantomData<&#delife ()>,
+        }
+
+        #[automatically_derived]
+        impl #de_impl_generics _serde::de::Visitor<#delife> for __Visitor #de_ty_generics #where_clause {
+            type Value = #this_type #ty_generics;
+
+            fn expecting(&self, __formatter: &mut _serde::#private::Formatter) -> _serde::#private::fmt::Result {
+                _serde::#private::Formatter::write_str(__formatter, #expecting)
+            }
+
+            #[inline]
+            fn visit_unit<__E>(self) -> _serde::#private::Result<Self::Value, __E>
+            where
+                __E: _serde::de::Error,
+            {
+                _serde::#private::Ok(#this_value)
+            }
+        }
+
+        _serde::Deserializer::deserialize_unit_struct(
+            __deserializer,
+            #type_name,
+            __Visitor {
+                marker: _serde::#private::PhantomData::<#this_type #ty_generics>,
+                lifetime: _serde::#private::PhantomData,
+            },
+        )
+    }
+}

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/1.0.226")]
+#![doc(html_root_url = "https://docs.rs/serde_derive/1.0.227")]
 #![cfg_attr(not(check_cfg), allow(unexpected_cfgs))]
 // Ignored clippy lints
 #![allow(