Release 0.9.0-rc1

Enforce correct use of Serialize trait

.travis.yml

@@ -1,8 +1,8 @@
 sudo: false
 language: rust
 rust:
-- 1.10.0
-- 1.11.0
+- 1.12.0
+- 1.13.0
 - stable
 - beta
 - nightly
@@ -19,8 +19,8 @@ script:
 - (cd testing && travis-cargo --skip nightly test)
 - (cd testing && travis-cargo --only nightly test -- --features unstable-testing)
 - (cd serde_derive && travis-cargo --only nightly test)
-- (cd examples/serde-syntex-example && travis-cargo --skip nightly run)
-- (cd examples/serde-syntex-example && travis-cargo --only nightly run -- --no-default-features --features unstable)
+#- (cd examples/serde-syntex-example && travis-cargo --skip nightly run)
+#- (cd examples/serde-syntex-example && travis-cargo --only nightly run -- --no-default-features --features unstable)
 - (cd serde && travis-cargo --only stable doc)
 env:
   global:

README.md

@@ -11,12 +11,11 @@ You may be looking for:
 - [Setting up `#[derive(Serialize, Deserialize)]`](https://serde.rs/codegen.html)
 - [Examples](https://serde.rs/examples.html)
 - [API documentation](https://docs.serde.rs/serde/)
+- [Release notes](https://github.com/serde-rs/serde/releases)
 
 ## Serde in action
 
 ```rust
-#![feature(proc_macro)]
-
 #[macro_use]
 extern crate serde_derive;
 
@@ -50,8 +49,9 @@ fn main() {
 Serde developers live in the #serde channel on
 [`irc.mozilla.org`](https://wiki.mozilla.org/IRC). The #rust channel is also a
 good resource with generally faster response time but less specific knowledge
-about Serde. If IRC is not your thing, we are happy to respond to [GitHub
-issues](https://github.com/serde-rs/serde/issues/new) as well.
+about Serde. If IRC is not your thing or you don't get a good response, we are
+happy to respond to [GitHub issues](https://github.com/serde-rs/serde/issues/new)
+as well.
 
 ## License
 

examples/serde-syntex-example/Cargo.toml

@@ -3,6 +3,7 @@ name = "serde-syntex-example"
 version = "0.1.0"
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>"]
 build = "build.rs"
+publish = false
 
 [features]
 default = ["serde_codegen"]

examples/serde-syntex-example/src/main.rs

@@ -1,5 +1,3 @@
-#![cfg_attr(feature = "serde_derive", feature(proc_macro))]
-
 #[cfg(feature = "serde_derive")]
 #[macro_use]
 extern crate serde_derive;

serde/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "serde"
-version = "0.8.17"
+version = "0.9.0-rc1"
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>"]
 license = "MIT/Apache-2.0"
 description = "A generic serialization/deserialization framework"

serde/src/bytes.rs

@@ -65,7 +65,7 @@ impl<'a> ops::Deref for Bytes<'a> {
 
 impl<'a> ser::Serialize for Bytes<'a> {
     #[inline]
-    fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
         where S: ser::Serializer
     {
         serializer.serialize_bytes(self.bytes)
@@ -84,7 +84,7 @@ mod bytebuf {
     use de;
 
     #[cfg(feature = "collections")]
-    use collections::Vec;
+    use collections::{String, Vec};
 
     /// `ByteBuf` wraps a `Vec<u8>` and serializes as a byte array.
     #[derive(Clone, Default, Eq, Hash, PartialEq, PartialOrd, Ord)]
@@ -168,7 +168,7 @@ mod bytebuf {
     }
 
     impl ser::Serialize for ByteBuf {
-        fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
+        fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
             where S: ser::Serializer
         {
             serializer.serialize_bytes(self)
@@ -182,14 +182,14 @@ mod bytebuf {
         type Value = ByteBuf;
 
         #[inline]
-        fn visit_unit<E>(&mut self) -> Result<ByteBuf, E>
+        fn visit_unit<E>(self) -> Result<ByteBuf, E>
             where E: de::Error,
         {
             Ok(ByteBuf::new())
         }
 
         #[inline]
-        fn visit_seq<V>(&mut self, mut visitor: V) -> Result<ByteBuf, V::Error>
+        fn visit_seq<V>(self, mut visitor: V) -> Result<ByteBuf, V::Error>
             where V: de::SeqVisitor,
         {
             let (len, _) = visitor.size_hint();
@@ -199,20 +199,30 @@ mod bytebuf {
                 values.push(value);
             }
 
-            try!(visitor.end());
-
             Ok(ByteBuf::from(values))
         }
 
         #[inline]
-        fn visit_bytes<E>(&mut self, v: &[u8]) -> Result<ByteBuf, E>
+        fn visit_bytes<E>(self, v: &[u8]) -> Result<ByteBuf, E>
             where E: de::Error,
         {
-            self.visit_byte_buf(v.to_vec())
+            Ok(ByteBuf::from(v))
         }
 
         #[inline]
-        fn visit_byte_buf<E>(&mut self, v: Vec<u8>) -> Result<ByteBuf, E>
+        fn visit_byte_buf<E>(self, v: Vec<u8>) -> Result<ByteBuf, E>
+            where E: de::Error,
+        {
+            Ok(ByteBuf::from(v))
+        }
+
+        fn visit_str<E>(self, v: &str) -> Result<ByteBuf, E>
+            where E: de::Error,
+        {
+            Ok(ByteBuf::from(v))
+        }
+
+        fn visit_string<E>(self, v: String) -> Result<ByteBuf, E>
             where E: de::Error,
         {
             Ok(ByteBuf::from(v))
@@ -221,7 +231,7 @@ mod bytebuf {
 
     impl de::Deserialize for ByteBuf {
         #[inline]
-        fn deserialize<D>(deserializer: &mut D) -> Result<ByteBuf, D::Error>
+        fn deserialize<D>(deserializer: D) -> Result<ByteBuf, D::Error>
             where D: de::Deserializer
         {
             deserializer.deserialize_bytes(ByteBufVisitor)

serde/src/de/impls.rs

@@ -83,21 +83,21 @@ pub struct UnitVisitor;
 impl Visitor for UnitVisitor {
     type Value = ();
 
-    fn visit_unit<E>(&mut self) -> Result<(), E>
+    fn visit_unit<E>(self) -> Result<(), E>
         where E: Error,
     {
         Ok(())
     }
 
-    fn visit_seq<V>(&mut self, mut visitor: V) -> Result<(), V::Error>
+    fn visit_seq<V>(self, _: V) -> Result<(), V::Error>
         where V: SeqVisitor,
     {
-        visitor.end()
+        Ok(())
     }
 }
 
 impl Deserialize for () {
-    fn deserialize<D>(deserializer: &mut D) -> Result<(), D::Error>
+    fn deserialize<D>(deserializer: D) -> Result<(), D::Error>
         where D: Deserializer,
     {
         deserializer.deserialize_unit(UnitVisitor)
@@ -112,13 +112,13 @@ pub struct BoolVisitor;
 impl Visitor for BoolVisitor {
     type Value = bool;
 
-    fn visit_bool<E>(&mut self, v: bool) -> Result<bool, E>
+    fn visit_bool<E>(self, v: bool) -> Result<bool, E>
         where E: Error,
     {
         Ok(v)
     }
 
-    fn visit_str<E>(&mut self, s: &str) -> Result<bool, E>
+    fn visit_str<E>(self, s: &str) -> Result<bool, E>
         where E: Error,
     {
         match s.trim_matches(::utils::Pattern_White_Space) {
@@ -130,7 +130,7 @@ impl Visitor for BoolVisitor {
 }
 
 impl Deserialize for bool {
-    fn deserialize<D>(deserializer: &mut D) -> Result<bool, D::Error>
+    fn deserialize<D>(deserializer: D) -> Result<bool, D::Error>
         where D: Deserializer,
     {
         deserializer.deserialize_bool(BoolVisitor)
@@ -142,7 +142,7 @@ impl Deserialize for bool {
 macro_rules! impl_deserialize_num_method {
     ($src_ty:ty, $method:ident, $from_method:ident, $ty:expr) => {
         #[inline]
-        fn $method<E>(&mut self, v: $src_ty) -> Result<T, E>
+        fn $method<E>(self, v: $src_ty) -> Result<T, E>
             where E: Error,
         {
             match FromPrimitive::$from_method(v) {
@@ -187,7 +187,7 @@ impl<T> Visitor for PrimitiveVisitor<T>
     impl_deserialize_num_method!(f64, visit_f64, from_f64, Type::F64);
 
     #[inline]
-    fn visit_str<E>(&mut self, s: &str) -> Result<T, E>
+    fn visit_str<E>(self, s: &str) -> Result<T, E>
         where E: Error,
     {
         str::FromStr::from_str(s.trim_matches(::utils::Pattern_White_Space)).or_else(|_| {
@@ -200,7 +200,7 @@ macro_rules! impl_deserialize_num {
     ($ty:ty, $method:ident) => {
         impl Deserialize for $ty {
             #[inline]
-            fn deserialize<D>(deserializer: &mut D) -> Result<$ty, D::Error>
+            fn deserialize<D>(deserializer: D) -> Result<$ty, D::Error>
                 where D: Deserializer,
             {
                 deserializer.$method(PrimitiveVisitor::new())
@@ -230,14 +230,14 @@ impl Visitor for CharVisitor {
     type Value = char;
 
     #[inline]
-    fn visit_char<E>(&mut self, v: char) -> Result<char, E>
+    fn visit_char<E>(self, v: char) -> Result<char, E>
         where E: Error,
     {
         Ok(v)
     }
 
     #[inline]
-    fn visit_str<E>(&mut self, v: &str) -> Result<char, E>
+    fn visit_str<E>(self, v: &str) -> Result<char, E>
         where E: Error,
     {
         let mut iter = v.chars();
@@ -255,7 +255,7 @@ impl Visitor for CharVisitor {
 
 impl Deserialize for char {
     #[inline]
-    fn deserialize<D>(deserializer: &mut D) -> Result<char, D::Error>
+    fn deserialize<D>(deserializer: D) -> Result<char, D::Error>
         where D: Deserializer,
     {
         deserializer.deserialize_char(CharVisitor)
@@ -271,19 +271,25 @@ struct StringVisitor;
 impl Visitor for StringVisitor {
     type Value = String;
 
-    fn visit_str<E>(&mut self, v: &str) -> Result<String, E>
+    fn visit_str<E>(self, v: &str) -> Result<String, E>
         where E: Error,
     {
         Ok(v.to_owned())
     }
 
-    fn visit_string<E>(&mut self, v: String) -> Result<String, E>
+    fn visit_string<E>(self, v: String) -> Result<String, E>
         where E: Error,
     {
         Ok(v)
     }
 
-    fn visit_bytes<E>(&mut self, v: &[u8]) -> Result<String, E>
+    fn visit_unit<E>(self) -> Result<String, E>
+        where E: Error,
+    {
+        Ok(String::new())
+    }
+
+    fn visit_bytes<E>(self, v: &[u8]) -> Result<String, E>
         where E: Error,
     {
         match str::from_utf8(v) {
@@ -292,7 +298,7 @@ impl Visitor for StringVisitor {
         }
     }
 
-    fn visit_byte_buf<E>(&mut self, v: Vec<u8>) -> Result<String, E>
+    fn visit_byte_buf<E>(self, v: Vec<u8>) -> Result<String, E>
         where E: Error,
     {
         match String::from_utf8(v) {
@@ -304,7 +310,7 @@ impl Visitor for StringVisitor {
 
 #[cfg(any(feature = "std", feature = "collections"))]
 impl Deserialize for String {
-    fn deserialize<D>(deserializer: &mut D) -> Result<String, D::Error>
+    fn deserialize<D>(deserializer: D) -> Result<String, D::Error>
         where D: Deserializer,
     {
         deserializer.deserialize_string(StringVisitor)
@@ -323,21 +329,21 @@ impl<
     type Value = Option<T>;
 
     #[inline]
-    fn visit_unit<E>(&mut self) -> Result<Option<T>, E>
+    fn visit_unit<E>(self) -> Result<Option<T>, E>
         where E: Error,
     {
         Ok(None)
     }
 
     #[inline]
-    fn visit_none<E>(&mut self) -> Result<Option<T>, E>
+    fn visit_none<E>(self) -> Result<Option<T>, E>
         where E: Error,
     {
         Ok(None)
     }
 
     #[inline]
-    fn visit_some<D>(&mut self, deserializer: &mut D) -> Result<Option<T>, D::Error>
+    fn visit_some<D>(self, deserializer: D) -> Result<Option<T>, D::Error>
         where D: Deserializer,
     {
         Ok(Some(try!(Deserialize::deserialize(deserializer))))
@@ -345,7 +351,7 @@ impl<
 }
 
 impl<T> Deserialize for Option<T> where T: Deserialize {
-    fn deserialize<D>(deserializer: &mut D) -> Result<Option<T>, D::Error>
+    fn deserialize<D>(deserializer: D) -> Result<Option<T>, D::Error>
         where D: Deserializer,
     {
         deserializer.deserialize_option(OptionVisitor { marker: PhantomData })
@@ -363,7 +369,7 @@ impl<T> Visitor for PhantomDataVisitor<T> {
     type Value = PhantomData<T>;
 
     #[inline]
-    fn visit_unit<E>(&mut self) -> Result<PhantomData<T>, E>
+    fn visit_unit<E>(self) -> Result<PhantomData<T>, E>
         where E: Error,
     {
         Ok(PhantomData)
@@ -371,7 +377,7 @@ impl<T> Visitor for PhantomDataVisitor<T> {
 }
 
 impl<T> Deserialize for PhantomData<T> {
-    fn deserialize<D>(deserializer: &mut D) -> Result<PhantomData<T>, D::Error>
+    fn deserialize<D>(deserializer: D) -> Result<PhantomData<T>, D::Error>
         where D: Deserializer,
     {
         let visitor = PhantomDataVisitor { marker: PhantomData };
@@ -412,14 +418,14 @@ macro_rules! seq_impl {
             type Value = $ty;
 
             #[inline]
-            fn visit_unit<E>(&mut self) -> Result<$ty, E>
+            fn visit_unit<E>(self) -> Result<$ty, E>
                 where E: Error,
             {
                 Ok($ctor)
             }
 
             #[inline]
-            fn visit_seq<V>(&mut self, mut $visitor: V) -> Result<$ty, V::Error>
+            fn visit_seq<V>(self, mut $visitor: V) -> Result<$ty, V::Error>
                 where V: SeqVisitor,
             {
                 let mut values = $with_capacity;
@@ -428,8 +434,6 @@ macro_rules! seq_impl {
                     $insert(&mut values, value);
                 }
 
-                try!($visitor.end());
-
                 Ok(values)
             }
         }
@@ -437,7 +441,7 @@ macro_rules! seq_impl {
         impl<$($typaram),*> Deserialize for $ty
             where $($typaram: $bound1 $(+ $bound2)*),*
         {
-            fn deserialize<D>(deserializer: &mut D) -> Result<$ty, D::Error>
+            fn deserialize<D>(deserializer: D) -> Result<$ty, D::Error>
                 where D: Deserializer,
             {
                 deserializer.deserialize_seq($visitor_ty::new())
@@ -528,17 +532,16 @@ impl<T> Visitor for ArrayVisitor<[T; 0]> where T: Deserialize {
     type Value = [T; 0];
 
     #[inline]
-    fn visit_unit<E>(&mut self) -> Result<[T; 0], E>
+    fn visit_unit<E>(self) -> Result<[T; 0], E>
         where E: Error,
     {
         Ok([])
     }
 
     #[inline]
-    fn visit_seq<V>(&mut self, mut visitor: V) -> Result<[T; 0], V::Error>
+    fn visit_seq<V>(self, _: V) -> Result<[T; 0], V::Error>
         where V: SeqVisitor,
     {
-        try!(visitor.end());
         Ok([])
     }
 }
@@ -546,7 +549,7 @@ impl<T> Visitor for ArrayVisitor<[T; 0]> where T: Deserialize {
 impl<T> Deserialize for [T; 0]
     where T: Deserialize
 {
-    fn deserialize<D>(deserializer: &mut D) -> Result<[T; 0], D::Error>
+    fn deserialize<D>(deserializer: D) -> Result<[T; 0], D::Error>
         where D: Deserializer,
     {
         deserializer.deserialize_seq_fixed_size(0, ArrayVisitor::<[T; 0]>::new())
@@ -560,7 +563,7 @@ macro_rules! array_impls {
                 type Value = [T; $len];
 
                 #[inline]
-                fn visit_seq<V>(&mut self, mut visitor: V) -> Result<[T; $len], V::Error>
+                fn visit_seq<V>(self, mut visitor: V) -> Result<[T; $len], V::Error>
                     where V: SeqVisitor,
                 {
                     $(
@@ -570,8 +573,6 @@ macro_rules! array_impls {
                         };
                     )+
 
-                    try!(visitor.end());
-
                     Ok([$($name),+])
                 }
             }
@@ -579,7 +580,7 @@ macro_rules! array_impls {
             impl<T> Deserialize for [T; $len]
                 where T: Deserialize,
             {
-                fn deserialize<D>(deserializer: &mut D) -> Result<[T; $len], D::Error>
+                fn deserialize<D>(deserializer: D) -> Result<[T; $len], D::Error>
                     where D: Deserializer,
                 {
                     deserializer.deserialize_seq_fixed_size($len, ArrayVisitor::<[T; $len]>::new())
@@ -646,7 +647,7 @@ macro_rules! tuple_impls {
 
                 #[inline]
                 #[allow(non_snake_case)]
-                fn visit_seq<V>(&mut self, mut visitor: V) -> Result<($($name,)+), V::Error>
+                fn visit_seq<V>(self, mut visitor: V) -> Result<($($name,)+), V::Error>
                     where V: SeqVisitor,
                 {
                     $(
@@ -656,15 +657,13 @@ macro_rules! tuple_impls {
                         };
                     )+
 
-                    try!(visitor.end());
-
                     Ok(($($name,)+))
                 }
             }
 
             impl<$($name: Deserialize),+> Deserialize for ($($name,)+) {
                 #[inline]
-                fn deserialize<D>(deserializer: &mut D) -> Result<($($name,)+), D::Error>
+                fn deserialize<D>(deserializer: D) -> Result<($($name,)+), D::Error>
                     where D: Deserializer,
                 {
                     deserializer.deserialize_tuple($len, $visitor::new())
@@ -725,14 +724,14 @@ macro_rules! map_impl {
             type Value = $ty;
 
             #[inline]
-            fn visit_unit<E>(&mut self) -> Result<$ty, E>
+            fn visit_unit<E>(self) -> Result<$ty, E>
                 where E: Error,
             {
                 Ok($ctor)
             }
 
             #[inline]
-            fn visit_map<Visitor>(&mut self, mut $visitor: Visitor) -> Result<$ty, Visitor::Error>
+            fn visit_map<Visitor>(self, mut $visitor: Visitor) -> Result<$ty, Visitor::Error>
                 where Visitor: MapVisitor,
             {
                 let mut values = $with_capacity;
@@ -741,8 +740,6 @@ macro_rules! map_impl {
                     values.insert(key, value);
                 }
 
-                try!($visitor.end());
-
                 Ok(values)
             }
         }
@@ -750,7 +747,7 @@ macro_rules! map_impl {
         impl<$($typaram),*> Deserialize for $ty
             where $($typaram: $bound1 $(+ $bound2)*),*
         {
-            fn deserialize<D>(deserializer: &mut D) -> Result<$ty, D::Error>
+            fn deserialize<D>(deserializer: D) -> Result<$ty, D::Error>
                 where D: Deserializer,
             {
                 deserializer.deserialize_map($visitor_ty::new())
@@ -782,7 +779,7 @@ map_impl!(
 
 #[cfg(feature = "std")]
 impl Deserialize for net::IpAddr {
-    fn deserialize<D>(deserializer: &mut D) -> Result<Self, D::Error>
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
         where D: Deserializer,
     {
         let s = try!(String::deserialize(deserializer));
@@ -795,7 +792,7 @@ impl Deserialize for net::IpAddr {
 
 #[cfg(feature = "std")]
 impl Deserialize for net::Ipv4Addr {
-    fn deserialize<D>(deserializer: &mut D) -> Result<Self, D::Error>
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
         where D: Deserializer,
     {
         let s = try!(String::deserialize(deserializer));
@@ -808,7 +805,7 @@ impl Deserialize for net::Ipv4Addr {
 
 #[cfg(feature = "std")]
 impl Deserialize for net::Ipv6Addr {
-    fn deserialize<D>(deserializer: &mut D) -> Result<Self, D::Error>
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
         where D: Deserializer,
     {
         let s = try!(String::deserialize(deserializer));
@@ -823,7 +820,7 @@ impl Deserialize for net::Ipv6Addr {
 
 #[cfg(feature = "std")]
 impl Deserialize for net::SocketAddr {
-    fn deserialize<D>(deserializer: &mut D) -> Result<Self, D::Error>
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
         where D: Deserializer,
     {
         let s = try!(String::deserialize(deserializer));
@@ -836,7 +833,7 @@ impl Deserialize for net::SocketAddr {
 
 #[cfg(feature = "std")]
 impl Deserialize for net::SocketAddrV4 {
-    fn deserialize<D>(deserializer: &mut D) -> Result<Self, D::Error>
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
         where D: Deserializer,
     {
         let s = try!(String::deserialize(deserializer));
@@ -849,7 +846,7 @@ impl Deserialize for net::SocketAddrV4 {
 
 #[cfg(feature = "std")]
 impl Deserialize for net::SocketAddrV6 {
-    fn deserialize<D>(deserializer: &mut D) -> Result<Self, D::Error>
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
         where D: Deserializer,
     {
         let s = try!(String::deserialize(deserializer));
@@ -869,13 +866,13 @@ struct PathBufVisitor;
 impl Visitor for PathBufVisitor {
     type Value = path::PathBuf;
 
-    fn visit_str<E>(&mut self, v: &str) -> Result<path::PathBuf, E>
+    fn visit_str<E>(self, v: &str) -> Result<path::PathBuf, E>
         where E: Error,
     {
         Ok(From::from(v))
     }
 
-    fn visit_string<E>(&mut self, v: String) -> Result<path::PathBuf, E>
+    fn visit_string<E>(self, v: String) -> Result<path::PathBuf, E>
         where E: Error,
     {
         self.visit_str(&v)
@@ -884,7 +881,7 @@ impl Visitor for PathBufVisitor {
 
 #[cfg(feature = "std")]
 impl Deserialize for path::PathBuf {
-    fn deserialize<D>(deserializer: &mut D) -> Result<path::PathBuf, D::Error>
+    fn deserialize<D>(deserializer: D) -> Result<path::PathBuf, D::Error>
         where D: Deserializer,
     {
         deserializer.deserialize_string(PathBufVisitor)
@@ -895,7 +892,7 @@ impl Deserialize for path::PathBuf {
 
 #[cfg(any(feature = "std", feature = "alloc"))]
 impl<T: Deserialize> Deserialize for Box<T> {
-    fn deserialize<D>(deserializer: &mut D) -> Result<Box<T>, D::Error>
+    fn deserialize<D>(deserializer: D) -> Result<Box<T>, D::Error>
         where D: Deserializer,
     {
         let val = try!(Deserialize::deserialize(deserializer));
@@ -905,7 +902,7 @@ impl<T: Deserialize> Deserialize for Box<T> {
 
 #[cfg(any(feature = "std", feature = "collections"))]
 impl<T: Deserialize> Deserialize for Box<[T]> {
-    fn deserialize<D>(deserializer: &mut D) -> Result<Box<[T]>, D::Error>
+    fn deserialize<D>(deserializer: D) -> Result<Box<[T]>, D::Error>
         where D: Deserializer,
     {
         let v: Vec<T> = try!(Deserialize::deserialize(deserializer));
@@ -915,7 +912,7 @@ impl<T: Deserialize> Deserialize for Box<[T]> {
 
 #[cfg(any(feature = "std", feature = "collections"))]
 impl Deserialize for Box<str> {
-    fn deserialize<D>(deserializer: &mut D) -> Result<Self, D::Error>
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
         where D: Deserializer
     {
         let s = try!(String::deserialize(deserializer));
@@ -925,7 +922,7 @@ impl Deserialize for Box<str> {
 
 #[cfg(any(feature = "std", feature = "alloc"))]
 impl<T: Deserialize> Deserialize for Arc<T> {
-    fn deserialize<D>(deserializer: &mut D) -> Result<Arc<T>, D::Error>
+    fn deserialize<D>(deserializer: D) -> Result<Arc<T>, D::Error>
         where D: Deserializer,
     {
         let val = try!(Deserialize::deserialize(deserializer));
@@ -935,7 +932,7 @@ impl<T: Deserialize> Deserialize for Arc<T> {
 
 #[cfg(any(feature = "std", feature = "alloc"))]
 impl<T: Deserialize> Deserialize for Rc<T> {
-    fn deserialize<D>(deserializer: &mut D) -> Result<Rc<T>, D::Error>
+    fn deserialize<D>(deserializer: D) -> Result<Rc<T>, D::Error>
         where D: Deserializer,
     {
         let val = try!(Deserialize::deserialize(deserializer));
@@ -946,7 +943,7 @@ impl<T: Deserialize> Deserialize for Rc<T> {
 #[cfg(any(feature = "std", feature = "collections"))]
 impl<'a, T: ?Sized> Deserialize for Cow<'a, T> where T: ToOwned, T::Owned: Deserialize, {
     #[inline]
-    fn deserialize<D>(deserializer: &mut D) -> Result<Cow<'a, T>, D::Error>
+    fn deserialize<D>(deserializer: D) -> Result<Cow<'a, T>, D::Error>
         where D: Deserializer,
     {
         let val = try!(Deserialize::deserialize(deserializer));
@@ -966,13 +963,13 @@ impl<'a, T: ?Sized> Deserialize for Cow<'a, T> where T: ToOwned, T::Owned: Deser
 //     }
 #[cfg(feature = "std")]
 impl Deserialize for Duration {
-    fn deserialize<D>(deserializer: &mut D) -> Result<Self, D::Error>
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
         where D: Deserializer,
     {
         enum Field { Secs, Nanos };
 
         impl Deserialize for Field {
-            fn deserialize<D>(deserializer: &mut D) -> Result<Field, D::Error>
+            fn deserialize<D>(deserializer: D) -> Result<Field, D::Error>
                 where D: Deserializer,
             {
                 struct FieldVisitor;
@@ -980,7 +977,7 @@ impl Deserialize for Duration {
                 impl Visitor for FieldVisitor {
                     type Value = Field;
 
-                    fn visit_usize<E>(&mut self, value: usize) -> Result<Field, E>
+                    fn visit_usize<E>(self, value: usize) -> Result<Field, E>
                         where E: Error,
                     {
                         match value {
@@ -990,7 +987,7 @@ impl Deserialize for Duration {
                         }
                     }
 
-                    fn visit_str<E>(&mut self, value: &str) -> Result<Field, E>
+                    fn visit_str<E>(self, value: &str) -> Result<Field, E>
                         where E: Error,
                     {
                         match value {
@@ -1000,7 +997,7 @@ impl Deserialize for Duration {
                         }
                     }
 
-                    fn visit_bytes<E>(&mut self, value: &[u8]) -> Result<Field, E>
+                    fn visit_bytes<E>(self, value: &[u8]) -> Result<Field, E>
                         where E: Error,
                     {
                         match value {
@@ -1023,28 +1020,25 @@ impl Deserialize for Duration {
         impl Visitor for DurationVisitor {
             type Value = Duration;
 
-            fn visit_seq<V>(&mut self, mut visitor: V) -> Result<Duration, V::Error>
+            fn visit_seq<V>(self, mut visitor: V) -> Result<Duration, V::Error>
                 where V: SeqVisitor,
             {
                 let secs: u64 = match try!(visitor.visit()) {
                     Some(value) => value,
                     None => {
-                        try!(visitor.end());
                         return Err(Error::invalid_length(0));
                     }
                 };
                 let nanos: u32 = match try!(visitor.visit()) {
                     Some(value) => value,
                     None => {
-                        try!(visitor.end());
                         return Err(Error::invalid_length(1));
                     }
                 };
-                try!(visitor.end());
                 Ok(Duration::new(secs, nanos))
             }
 
-            fn visit_map<V>(&mut self, mut visitor: V) -> Result<Duration, V::Error>
+            fn visit_map<V>(self, mut visitor: V) -> Result<Duration, V::Error>
                 where V: MapVisitor,
             {
                 let mut secs: Option<u64> = None;
@@ -1065,7 +1059,6 @@ impl Deserialize for Duration {
                         }
                     }
                 }
-                try!(visitor.end());
                 let secs = match secs {
                     Some(secs) => secs,
                     None => try!(visitor.missing_field("secs")),
@@ -1087,7 +1080,7 @@ impl Deserialize for Duration {
 
 #[cfg(feature = "unstable")]
 impl<T> Deserialize for NonZero<T> where T: Deserialize + PartialEq + Zeroable + Zero {
-    fn deserialize<D>(deserializer: &mut D) -> Result<NonZero<T>, D::Error> where D: Deserializer {
+    fn deserialize<D>(deserializer: D) -> Result<NonZero<T>, D::Error> where D: Deserializer {
         let value = try!(Deserialize::deserialize(deserializer));
         if value == Zero::zero() {
             return Err(Error::invalid_value("expected a non-zero value"))
@@ -1102,7 +1095,7 @@ impl<T> Deserialize for NonZero<T> where T: Deserialize + PartialEq + Zeroable +
 
 
 impl<T, E> Deserialize for Result<T, E> where T: Deserialize, E: Deserialize {
-    fn deserialize<D>(deserializer: &mut D) -> Result<Result<T, E>, D::Error>
+    fn deserialize<D>(deserializer: D) -> Result<Result<T, E>, D::Error>
                       where D: Deserializer {
         enum Field {
             Ok,
@@ -1111,16 +1104,16 @@ impl<T, E> Deserialize for Result<T, E> where T: Deserialize, E: Deserialize {
 
         impl Deserialize for Field {
             #[inline]
-            fn deserialize<D>(deserializer: &mut D) -> Result<Field, D::Error>
+            fn deserialize<D>(deserializer: D) -> Result<Field, D::Error>
                 where D: Deserializer
             {
                 struct FieldVisitor;
 
-                impl ::de::Visitor for FieldVisitor {
+                impl Visitor for FieldVisitor {
                     type Value = Field;
 
                     #[cfg(any(feature = "std", feature = "collections"))]
-                    fn visit_usize<E>(&mut self, value: usize) -> Result<Field, E> where E: Error {
+                    fn visit_usize<E>(self, value: usize) -> Result<Field, E> where E: Error {
                         #[cfg(feature = "collections")]
                         use collections::string::ToString;
                         match value {
@@ -1131,7 +1124,7 @@ impl<T, E> Deserialize for Result<T, E> where T: Deserialize, E: Deserialize {
                     }
 
                     #[cfg(all(not(feature = "std"), not(feature = "collections")))]
-                    fn visit_usize<E>(&mut self, value: usize) -> Result<Field, E> where E: Error {
+                    fn visit_usize<E>(self, value: usize) -> Result<Field, E> where E: Error {
                         match value {
                             0 => Ok(Field::Ok),
                             1 => Ok(Field::Err),
@@ -1139,7 +1132,7 @@ impl<T, E> Deserialize for Result<T, E> where T: Deserialize, E: Deserialize {
                         }
                     }
 
-                    fn visit_str<E>(&mut self, value: &str) -> Result<Field, E> where E: Error {
+                    fn visit_str<E>(self, value: &str) -> Result<Field, E> where E: Error {
                         match value {
                             "Ok" => Ok(Field::Ok),
                             "Err" => Ok(Field::Err),
@@ -1147,7 +1140,7 @@ impl<T, E> Deserialize for Result<T, E> where T: Deserialize, E: Deserialize {
                         }
                     }
 
-                    fn visit_bytes<E>(&mut self, value: &[u8]) -> Result<Field, E> where E: Error {
+                    fn visit_bytes<E>(self, value: &[u8]) -> Result<Field, E> where E: Error {
                         match value {
                             b"Ok" => Ok(Field::Ok),
                             b"Err" => Ok(Field::Err),
@@ -1165,33 +1158,27 @@ impl<T, E> Deserialize for Result<T, E> where T: Deserialize, E: Deserialize {
             }
         }
 
-        struct Visitor<T, E>(PhantomData<Result<T, E>>);
+        struct ResultVisitor<T, E>(PhantomData<Result<T, E>>);
 
-        impl<T, E> EnumVisitor for Visitor<T, E>
+        impl<T, E> Visitor for ResultVisitor<T, E>
             where T: Deserialize,
                   E: Deserialize
         {
             type Value = Result<T, E>;
 
-            fn visit<V>(&mut self, mut visitor: V) -> Result<Result<T, E>, V::Error>
-                where V: VariantVisitor
+            fn visit_enum<V>(self, visitor: V) -> Result<Result<T, E>, V::Error>
+                where V: EnumVisitor
             {
                 match try!(visitor.visit_variant()) {
-                    Field::Ok => {
-                        let value = try!(visitor.visit_newtype());
-                        Ok(Ok(value))
-                    }
-                    Field::Err => {
-                        let value = try!(visitor.visit_newtype());
-                        Ok(Err(value))
-                    }
+                    (Field::Ok, variant) => variant.visit_newtype().map(Ok),
+                    (Field::Err, variant) => variant.visit_newtype().map(Err),
                 }
             }
         }
 
         const VARIANTS: &'static [&'static str] = &["Ok", "Err"];
 
-        deserializer.deserialize_enum("Result", VARIANTS, Visitor(PhantomData))
+        deserializer.deserialize_enum("Result", VARIANTS, ResultVisitor(PhantomData))
     }
 }
 
@@ -1203,7 +1190,7 @@ pub struct IgnoredAny;
 
 impl Deserialize for IgnoredAny {
     #[inline]
-    fn deserialize<D>(deserializer: &mut D) -> Result<IgnoredAny, D::Error>
+    fn deserialize<D>(deserializer: D) -> Result<IgnoredAny, D::Error>
         where D: Deserializer,
     {
         struct IgnoredAnyVisitor;
@@ -1212,82 +1199,78 @@ impl Deserialize for IgnoredAny {
             type Value = IgnoredAny;
 
             #[inline]
-            fn visit_bool<E>(&mut self, _: bool) -> Result<IgnoredAny, E> {
+            fn visit_bool<E>(self, _: bool) -> Result<IgnoredAny, E> {
                 Ok(IgnoredAny)
             }
 
             #[inline]
-            fn visit_i64<E>(&mut self, _: i64) -> Result<IgnoredAny, E> {
+            fn visit_i64<E>(self, _: i64) -> Result<IgnoredAny, E> {
                 Ok(IgnoredAny)
             }
 
             #[inline]
-            fn visit_u64<E>(&mut self, _: u64) -> Result<IgnoredAny, E> {
+            fn visit_u64<E>(self, _: u64) -> Result<IgnoredAny, E> {
                 Ok(IgnoredAny)
             }
 
             #[inline]
-            fn visit_f64<E>(&mut self, _: f64) -> Result<IgnoredAny, E> {
+            fn visit_f64<E>(self, _: f64) -> Result<IgnoredAny, E> {
                 Ok(IgnoredAny)
             }
 
             #[inline]
-            fn visit_str<E>(&mut self, _: &str) -> Result<IgnoredAny, E>
+            fn visit_str<E>(self, _: &str) -> Result<IgnoredAny, E>
                 where E: Error,
             {
                 Ok(IgnoredAny)
             }
 
             #[inline]
-            fn visit_none<E>(&mut self) -> Result<IgnoredAny, E> {
+            fn visit_none<E>(self) -> Result<IgnoredAny, E> {
                 Ok(IgnoredAny)
             }
 
             #[inline]
-            fn visit_some<D>(&mut self, _: &mut D) -> Result<IgnoredAny, D::Error>
+            fn visit_some<D>(self, _: D) -> Result<IgnoredAny, D::Error>
                 where D: Deserializer,
             {
                 Ok(IgnoredAny)
             }
 
             #[inline]
-            fn visit_newtype_struct<D>(&mut self, _: &mut D) -> Result<IgnoredAny, D::Error>
+            fn visit_newtype_struct<D>(self, _: D) -> Result<IgnoredAny, D::Error>
                 where D: Deserializer,
             {
                 Ok(IgnoredAny)
             }
 
             #[inline]
-            fn visit_unit<E>(&mut self) -> Result<IgnoredAny, E> {
+            fn visit_unit<E>(self) -> Result<IgnoredAny, E> {
                 Ok(IgnoredAny)
             }
 
             #[inline]
-            fn visit_seq<V>(&mut self, mut visitor: V) -> Result<IgnoredAny, V::Error>
+            fn visit_seq<V>(self, mut visitor: V) -> Result<IgnoredAny, V::Error>
                 where V: SeqVisitor,
             {
                 while let Some(_) = try!(visitor.visit::<IgnoredAny>()) {
                     // Gobble
                 }
-
-                try!(visitor.end());
                 Ok(IgnoredAny)
             }
 
             #[inline]
-            fn visit_map<V>(&mut self, mut visitor: V) -> Result<IgnoredAny, V::Error>
+            fn visit_map<V>(self, mut visitor: V) -> Result<IgnoredAny, V::Error>
                 where V: MapVisitor,
             {
                 while let Some((_, _)) = try!(visitor.visit::<IgnoredAny, IgnoredAny>()) {
                     // Gobble
                 }
-
-                try!(visitor.end());
                 Ok(IgnoredAny)
             }
 
             #[inline]
-            fn visit_bytes<E>(&mut self, _: &[u8]) -> Result<IgnoredAny, E>
+            fn visit_bytes<E>(self, _: &[u8]) -> Result<IgnoredAny, E>
                 where E: Error,
             {
                 Ok(IgnoredAny)

serde/src/de/mod.rs

@@ -169,6 +169,9 @@ pub enum Type {
     /// Represents a unit variant.
     UnitVariant,
 
+    /// Represents a newtype variant.
+    NewtypeVariant,
+
     /// Represents a `&[u8]` type.
     Bytes,
 }
@@ -176,38 +179,39 @@ pub enum Type {
 impl fmt::Display for Type {
     fn fmt(&self, formatter: &mut fmt::Formatter) -> Result<(), fmt::Error> {
         let display = match *self {
-            Type::Bool          => "bool",
-            Type::Usize         => "usize",
-            Type::U8            => "u8",
-            Type::U16           => "u16",
-            Type::U32           => "u32",
-            Type::U64           => "u64",
-            Type::Isize         => "isize",
-            Type::I8            => "i8",
-            Type::I16           => "i16",
-            Type::I32           => "i32",
-            Type::I64           => "i64",
-            Type::F32           => "f32",
-            Type::F64           => "f64",
-            Type::Char          => "char",
-            Type::Str           => "str",
-            Type::String        => "string",
-            Type::Unit          => "unit",
-            Type::Option        => "option",
-            Type::Seq           => "seq",
-            Type::Map           => "map",
-            Type::UnitStruct    => "unit struct",
-            Type::NewtypeStruct => "newtype struct",
-            Type::TupleStruct   => "tuple struct",
-            Type::Struct        => "struct",
-            Type::FieldName     => "field name",
-            Type::Tuple         => "tuple",
-            Type::Enum          => "enum",
-            Type::VariantName   => "variant name",
-            Type::StructVariant => "struct variant",
-            Type::TupleVariant  => "tuple variant",
-            Type::UnitVariant   => "unit variant",
-            Type::Bytes         => "bytes",
+            Type::Bool           => "bool",
+            Type::Usize          => "usize",
+            Type::U8             => "u8",
+            Type::U16            => "u16",
+            Type::U32            => "u32",
+            Type::U64            => "u64",
+            Type::Isize          => "isize",
+            Type::I8             => "i8",
+            Type::I16            => "i16",
+            Type::I32            => "i32",
+            Type::I64            => "i64",
+            Type::F32            => "f32",
+            Type::F64            => "f64",
+            Type::Char           => "char",
+            Type::Str            => "str",
+            Type::String         => "string",
+            Type::Unit           => "unit",
+            Type::Option         => "option",
+            Type::Seq            => "seq",
+            Type::Map            => "map",
+            Type::UnitStruct     => "unit struct",
+            Type::NewtypeStruct  => "newtype struct",
+            Type::TupleStruct    => "tuple struct",
+            Type::Struct         => "struct",
+            Type::FieldName      => "field name",
+            Type::Tuple          => "tuple",
+            Type::Enum           => "enum",
+            Type::VariantName    => "variant name",
+            Type::StructVariant  => "struct variant",
+            Type::TupleVariant   => "tuple variant",
+            Type::UnitVariant    => "unit variant",
+            Type::NewtypeVariant => "newtype variant",
+            Type::Bytes          => "bytes",
         };
         display.fmt(formatter)
     }
@@ -218,7 +222,7 @@ impl fmt::Display for Type {
 /// `Deserialize` represents a type that can be deserialized.
 pub trait Deserialize: Sized {
     /// Deserialize this value given this `Deserializer`.
-    fn deserialize<D>(deserializer: &mut D) -> Result<Self, D::Error>
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
         where D: Deserializer;
 }
 
@@ -241,100 +245,100 @@ pub trait Deserializer {
     type Error: Error;
 
     /// This method walks a visitor through a value as it is being deserialized.
-    fn deserialize<V>(&mut self, visitor: V) -> Result<V::Value, Self::Error>
+    fn deserialize<V>(self, visitor: V) -> Result<V::Value, Self::Error>
         where V: Visitor;
 
     /// This method hints that the `Deserialize` type is expecting a `bool` value.
-    fn deserialize_bool<V>(&mut self, visitor: V) -> Result<V::Value, Self::Error>
+    fn deserialize_bool<V>(self, visitor: V) -> Result<V::Value, Self::Error>
         where V: Visitor;
 
     /// This method hints that the `Deserialize` type is expecting an `usize` value.
     /// A reasonable default is to forward to `deserialize_u64`.
-    fn deserialize_usize<V>(&mut self, visitor: V) -> Result<V::Value, Self::Error>
+    fn deserialize_usize<V>(self, visitor: V) -> Result<V::Value, Self::Error>
         where V: Visitor;
 
     /// This method hints that the `Deserialize` type is expecting an `u8` value.
     /// A reasonable default is to forward to `deserialize_u64`.
-    fn deserialize_u8<V>(&mut self, visitor: V) -> Result<V::Value, Self::Error>
+    fn deserialize_u8<V>(self, visitor: V) -> Result<V::Value, Self::Error>
         where V: Visitor;
 
     /// This method hints that the `Deserialize` type is expecting an `u16` value.
     /// A reasonable default is to forward to `deserialize_u64`.
-    fn deserialize_u16<V>(&mut self, visitor: V) -> Result<V::Value, Self::Error>
+    fn deserialize_u16<V>(self, visitor: V) -> Result<V::Value, Self::Error>
         where V: Visitor;
 
     /// This method hints that the `Deserialize` type is expecting an `u32` value.
     /// A reasonable default is to forward to `deserialize_u64`.
-    fn deserialize_u32<V>(&mut self, visitor: V) -> Result<V::Value, Self::Error>
+    fn deserialize_u32<V>(self, visitor: V) -> Result<V::Value, Self::Error>
         where V: Visitor;
 
     /// This method hints that the `Deserialize` type is expecting an `u64` value.
-    fn deserialize_u64<V>(&mut self, visitor: V) -> Result<V::Value, Self::Error>
+    fn deserialize_u64<V>(self, visitor: V) -> Result<V::Value, Self::Error>
         where V: Visitor;
 
     /// This method hints that the `Deserialize` type is expecting an `isize` value.
     /// A reasonable default is to forward to `deserialize_i64`.
-    fn deserialize_isize<V>(&mut self, visitor: V) -> Result<V::Value, Self::Error>
+    fn deserialize_isize<V>(self, visitor: V) -> Result<V::Value, Self::Error>
         where V: Visitor;
 
     /// This method hints that the `Deserialize` type is expecting an `i8` value.
     /// A reasonable default is to forward to `deserialize_i64`.
-    fn deserialize_i8<V>(&mut self, visitor: V) -> Result<V::Value, Self::Error>
+    fn deserialize_i8<V>(self, visitor: V) -> Result<V::Value, Self::Error>
         where V: Visitor;
 
     /// This method hints that the `Deserialize` type is expecting an `i16` value.
     /// A reasonable default is to forward to `deserialize_i64`.
-    fn deserialize_i16<V>(&mut self, visitor: V) -> Result<V::Value, Self::Error>
+    fn deserialize_i16<V>(self, visitor: V) -> Result<V::Value, Self::Error>
         where V: Visitor;
 
     /// This method hints that the `Deserialize` type is expecting an `i32` value.
     /// A reasonable default is to forward to `deserialize_i64`.
-    fn deserialize_i32<V>(&mut self, visitor: V) -> Result<V::Value, Self::Error>
+    fn deserialize_i32<V>(self, visitor: V) -> Result<V::Value, Self::Error>
         where V: Visitor;
 
     /// This method hints that the `Deserialize` type is expecting an `i64` value.
-    fn deserialize_i64<V>(&mut self, visitor: V) -> Result<V::Value, Self::Error>
+    fn deserialize_i64<V>(self, visitor: V) -> Result<V::Value, Self::Error>
         where V: Visitor;
 
     /// This method hints that the `Deserialize` type is expecting a `f32` value.
     /// A reasonable default is to forward to `deserialize_f64`.
-    fn deserialize_f32<V>(&mut self, visitor: V) -> Result<V::Value, Self::Error>
+    fn deserialize_f32<V>(self, visitor: V) -> Result<V::Value, Self::Error>
         where V: Visitor;
 
     /// This method hints that the `Deserialize` type is expecting a `f64` value.
-    fn deserialize_f64<V>(&mut self, visitor: V) -> Result<V::Value, Self::Error>
+    fn deserialize_f64<V>(self, visitor: V) -> Result<V::Value, Self::Error>
         where V: Visitor;
 
     /// This method hints that the `Deserialize` type is expecting a `char` value.
-    fn deserialize_char<V>(&mut self, visitor: V) -> Result<V::Value, Self::Error>
+    fn deserialize_char<V>(self, visitor: V) -> Result<V::Value, Self::Error>
         where V: Visitor;
 
     /// This method hints that the `Deserialize` type is expecting a `&str` value.
-    fn deserialize_str<V>(&mut self, visitor: V) -> Result<V::Value, Self::Error>
+    fn deserialize_str<V>(self, visitor: V) -> Result<V::Value, Self::Error>
         where V: Visitor;
 
     /// This method hints that the `Deserialize` type is expecting a `String` value.
-    fn deserialize_string<V>(&mut self, visitor: V) -> Result<V::Value, Self::Error>
+    fn deserialize_string<V>(self, visitor: V) -> Result<V::Value, Self::Error>
         where V: Visitor;
 
     /// This method hints that the `Deserialize` type is expecting an `unit` value.
-    fn deserialize_unit<V>(&mut self, visitor: V) -> Result<V::Value, Self::Error>
+    fn deserialize_unit<V>(self, visitor: V) -> Result<V::Value, Self::Error>
         where V: Visitor;
 
     /// This method hints that the `Deserialize` type is expecting an `Option` value. This allows
     /// deserializers that encode an optional value as a nullable value to convert the null value
     /// into a `None`, and a regular value as `Some(value)`.
-    fn deserialize_option<V>(&mut self, visitor: V) -> Result<V::Value, Self::Error>
+    fn deserialize_option<V>(self, visitor: V) -> Result<V::Value, Self::Error>
         where V: Visitor;
 
     /// This method hints that the `Deserialize` type is expecting a sequence value. This allows
     /// deserializers to parse sequences that aren't tagged as sequences.
-    fn deserialize_seq<V>(&mut self, visitor: V) -> Result<V::Value, Self::Error>
+    fn deserialize_seq<V>(self, visitor: V) -> Result<V::Value, Self::Error>
         where V: Visitor;
 
     /// This method hints that the `Deserialize` type is expecting a fixed size array. This allows
     /// deserializers to parse arrays that aren't tagged as arrays.
-    fn deserialize_seq_fixed_size<V>(&mut self,
+    fn deserialize_seq_fixed_size<V>(self,
                                      len: usize,
                                      visitor: V) -> Result<V::Value, Self::Error>
         where V: Visitor;
@@ -342,17 +346,17 @@ pub trait Deserializer {
     /// This method hints that the `Deserialize` type is expecting a `Vec<u8>`. This allows
     /// deserializers that provide a custom byte vector serialization to properly deserialize the
     /// type.
-    fn deserialize_bytes<V>(&mut self, visitor: V) -> Result<V::Value, Self::Error>
+    fn deserialize_bytes<V>(self, visitor: V) -> Result<V::Value, Self::Error>
         where V: Visitor;
 
     /// This method hints that the `Deserialize` type is expecting a map of values. This allows
     /// deserializers to parse sequences that aren't tagged as maps.
-    fn deserialize_map<V>(&mut self, visitor: V) -> Result<V::Value, Self::Error>
+    fn deserialize_map<V>(self, visitor: V) -> Result<V::Value, Self::Error>
         where V: Visitor;
 
     /// This method hints that the `Deserialize` type is expecting a unit struct. This allows
     /// deserializers to a unit struct that aren't tagged as a unit struct.
-    fn deserialize_unit_struct<V>(&mut self,
+    fn deserialize_unit_struct<V>(self,
                                   name: &'static str,
                                   visitor: V) -> Result<V::Value, Self::Error>
         where V: Visitor;
@@ -360,14 +364,14 @@ pub trait Deserializer {
     /// This method hints that the `Deserialize` type is expecting a newtype struct. This allows
     /// deserializers to a newtype struct that aren't tagged as a newtype struct.
     /// A reasonable default is to simply deserialize the expected value directly.
-    fn deserialize_newtype_struct<V>(&mut self,
+    fn deserialize_newtype_struct<V>(self,
                                      name: &'static str,
                                      visitor: V) -> Result<V::Value, Self::Error>
         where V: Visitor;
 
     /// This method hints that the `Deserialize` type is expecting a tuple struct. This allows
     /// deserializers to parse sequences that aren't tagged as sequences.
-    fn deserialize_tuple_struct<V>(&mut self,
+    fn deserialize_tuple_struct<V>(self,
                                    name: &'static str,
                                    len: usize,
                                    visitor: V) -> Result<V::Value, Self::Error>
@@ -375,7 +379,7 @@ pub trait Deserializer {
 
     /// This method hints that the `Deserialize` type is expecting a struct. This allows
     /// deserializers to parse sequences that aren't tagged as maps.
-    fn deserialize_struct<V>(&mut self,
+    fn deserialize_struct<V>(self,
                              name: &'static str,
                              fields: &'static [&'static str],
                              visitor: V) -> Result<V::Value, Self::Error>
@@ -384,38 +388,38 @@ pub trait Deserializer {
     /// This method hints that the `Deserialize` type is expecting some sort of struct field
     /// name.  This allows deserializers to choose between &str, usize, or &[u8] to properly
     /// deserialize a struct field.
-    fn deserialize_struct_field<V>(&mut self, visitor: V) -> Result<V::Value, Self::Error>
+    fn deserialize_struct_field<V>(self, visitor: V) -> Result<V::Value, Self::Error>
         where V: Visitor;
 
     /// This method hints that the `Deserialize` type is expecting a tuple value. This allows
     /// deserializers that provide a custom tuple serialization to properly deserialize the type.
-    fn deserialize_tuple<V>(&mut self, len: usize, visitor: V) -> Result<V::Value, Self::Error>
+    fn deserialize_tuple<V>(self, len: usize, visitor: V) -> Result<V::Value, Self::Error>
         where V: Visitor;
 
     /// This method hints that the `Deserialize` type is expecting an enum value. This allows
     /// deserializers that provide a custom enumeration serialization to properly deserialize the
     /// type.
-    fn deserialize_enum<V>(&mut self,
+    fn deserialize_enum<V>(self,
                            name: &'static str,
                            variants: &'static [&'static str],
                            visitor: V) -> Result<V::Value, Self::Error>
-        where V: EnumVisitor;
+        where V: Visitor;
 
     /// This method hints that the `Deserialize` type needs to deserialize a value whose type
     /// doesn't matter because it is ignored.
-    fn deserialize_ignored_any<V>(&mut self, visitor: V) -> Result<V::Value, Self::Error>
+    fn deserialize_ignored_any<V>(self, visitor: V) -> Result<V::Value, Self::Error>
         where V: Visitor;
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 
 /// This trait represents a visitor that walks through a deserializer.
-pub trait Visitor {
+pub trait Visitor: Sized {
     /// The value produced by this visitor.
-    type Value: Deserialize;
+    type Value;
 
     /// `visit_bool` deserializes a `bool` into a `Value`.
-    fn visit_bool<E>(&mut self, v: bool) -> Result<Self::Value, E>
+    fn visit_bool<E>(self, v: bool) -> Result<Self::Value, E>
         where E: Error,
     {
         let _ = v;
@@ -423,35 +427,35 @@ pub trait Visitor {
     }
 
     /// `visit_isize` deserializes a `isize` into a `Value`.
-    fn visit_isize<E>(&mut self, v: isize) -> Result<Self::Value, E>
+    fn visit_isize<E>(self, v: isize) -> Result<Self::Value, E>
         where E: Error,
     {
         self.visit_i64(v as i64)
     }
 
     /// `visit_i8` deserializes a `i8` into a `Value`.
-    fn visit_i8<E>(&mut self, v: i8) -> Result<Self::Value, E>
+    fn visit_i8<E>(self, v: i8) -> Result<Self::Value, E>
         where E: Error,
     {
         self.visit_i64(v as i64)
     }
 
     /// `visit_i16` deserializes a `i16` into a `Value`.
-    fn visit_i16<E>(&mut self, v: i16) -> Result<Self::Value, E>
+    fn visit_i16<E>(self, v: i16) -> Result<Self::Value, E>
         where E: Error,
     {
         self.visit_i64(v as i64)
     }
 
     /// `visit_i32` deserializes a `i32` into a `Value`.
-    fn visit_i32<E>(&mut self, v: i32) -> Result<Self::Value, E>
+    fn visit_i32<E>(self, v: i32) -> Result<Self::Value, E>
         where E: Error,
     {
         self.visit_i64(v as i64)
     }
 
     /// `visit_i64` deserializes a `i64` into a `Value`.
-    fn visit_i64<E>(&mut self, v: i64) -> Result<Self::Value, E>
+    fn visit_i64<E>(self, v: i64) -> Result<Self::Value, E>
         where E: Error,
     {
         let _ = v;
@@ -459,35 +463,35 @@ pub trait Visitor {
     }
 
     /// `visit_usize` deserializes a `usize` into a `Value`.
-    fn visit_usize<E>(&mut self, v: usize) -> Result<Self::Value, E>
+    fn visit_usize<E>(self, v: usize) -> Result<Self::Value, E>
         where E: Error,
     {
         self.visit_u64(v as u64)
     }
 
     /// `visit_u8` deserializes a `u8` into a `Value`.
-    fn visit_u8<E>(&mut self, v: u8) -> Result<Self::Value, E>
+    fn visit_u8<E>(self, v: u8) -> Result<Self::Value, E>
         where E: Error,
     {
         self.visit_u64(v as u64)
     }
 
     /// `visit_u16` deserializes a `u16` into a `Value`.
-    fn visit_u16<E>(&mut self, v: u16) -> Result<Self::Value, E>
+    fn visit_u16<E>(self, v: u16) -> Result<Self::Value, E>
         where E: Error,
     {
         self.visit_u64(v as u64)
     }
 
     /// `visit_u32` deserializes a `u32` into a `Value`.
-    fn visit_u32<E>(&mut self, v: u32) -> Result<Self::Value, E>
+    fn visit_u32<E>(self, v: u32) -> Result<Self::Value, E>
         where E: Error,
     {
         self.visit_u64(v as u64)
     }
 
     /// `visit_u64` deserializes a `u64` into a `Value`.
-    fn visit_u64<E>(&mut self, v: u64) -> Result<Self::Value, E>
+    fn visit_u64<E>(self, v: u64) -> Result<Self::Value, E>
         where E: Error,
     {
         let _ = v;
@@ -495,14 +499,14 @@ pub trait Visitor {
     }
 
     /// `visit_f32` deserializes a `f32` into a `Value`.
-    fn visit_f32<E>(&mut self, v: f32) -> Result<Self::Value, E>
+    fn visit_f32<E>(self, v: f32) -> Result<Self::Value, E>
         where E: Error,
     {
         self.visit_f64(v as f64)
     }
 
     /// `visit_f64` deserializes a `f64` into a `Value`.
-    fn visit_f64<E>(&mut self, v: f64) -> Result<Self::Value, E>
+    fn visit_f64<E>(self, v: f64) -> Result<Self::Value, E>
         where E: Error,
     {
         let _ = v;
@@ -511,14 +515,14 @@ pub trait Visitor {
 
     /// `visit_char` deserializes a `char` into a `Value`.
     #[inline]
-    fn visit_char<E>(&mut self, v: char) -> Result<Self::Value, E>
+    fn visit_char<E>(self, v: char) -> Result<Self::Value, E>
         where E: Error,
     {
         self.visit_str(::utils::encode_utf8(v).as_str())
     }
 
     /// `visit_str` deserializes a `&str` into a `Value`.
-    fn visit_str<E>(&mut self, v: &str) -> Result<Self::Value, E>
+    fn visit_str<E>(self, v: &str) -> Result<Self::Value, E>
         where E: Error,
     {
         let _ = v;
@@ -530,14 +534,14 @@ pub trait Visitor {
     /// to the `visit_str` method.
     #[inline]
     #[cfg(any(feature = "std", feature = "collections"))]
-    fn visit_string<E>(&mut self, v: String) -> Result<Self::Value, E>
+    fn visit_string<E>(self, v: String) -> Result<Self::Value, E>
         where E: Error,
     {
         self.visit_str(&v)
     }
 
     /// `visit_unit` deserializes a `()` into a `Value`.
-    fn visit_unit<E>(&mut self) -> Result<Self::Value, E>
+    fn visit_unit<E>(self) -> Result<Self::Value, E>
         where E: Error,
     {
         Err(Error::invalid_type(Type::Unit))
@@ -545,7 +549,7 @@ pub trait Visitor {
 
     /// `visit_unit_struct` deserializes a unit struct into a `Value`.
     #[inline]
-    fn visit_unit_struct<E>(&mut self, name: &'static str) -> Result<Self::Value, E>
+    fn visit_unit_struct<E>(self, name: &'static str) -> Result<Self::Value, E>
         where E: Error,
     {
         let _ = name;
@@ -553,14 +557,14 @@ pub trait Visitor {
     }
 
     /// `visit_none` deserializes a none value into a `Value`.
-    fn visit_none<E>(&mut self) -> Result<Self::Value, E>
+    fn visit_none<E>(self) -> Result<Self::Value, E>
         where E: Error,
     {
         Err(Error::invalid_type(Type::Option))
     }
 
     /// `visit_some` deserializes a value into a `Value`.
-    fn visit_some<D>(&mut self, deserializer: &mut D) -> Result<Self::Value, D::Error>
+    fn visit_some<D>(self, deserializer: D) -> Result<Self::Value, D::Error>
         where D: Deserializer,
     {
         let _ = deserializer;
@@ -568,7 +572,7 @@ pub trait Visitor {
     }
 
     /// `visit_newtype_struct` deserializes a value into a `Value`.
-    fn visit_newtype_struct<D>(&mut self, deserializer: &mut D) -> Result<Self::Value, D::Error>
+    fn visit_newtype_struct<D>(self, deserializer: D) -> Result<Self::Value, D::Error>
         where D: Deserializer,
     {
         let _ = deserializer;
@@ -576,7 +580,7 @@ pub trait Visitor {
     }
 
     /// `visit_seq` deserializes a `SeqVisitor` into a `Value`.
-    fn visit_seq<V>(&mut self, visitor: V) -> Result<Self::Value, V::Error>
+    fn visit_seq<V>(self, visitor: V) -> Result<Self::Value, V::Error>
         where V: SeqVisitor,
     {
         let _ = visitor;
@@ -584,15 +588,23 @@ pub trait Visitor {
     }
 
     /// `visit_map` deserializes a `MapVisitor` into a `Value`.
-    fn visit_map<V>(&mut self, visitor: V) -> Result<Self::Value, V::Error>
+    fn visit_map<V>(self, visitor: V) -> Result<Self::Value, V::Error>
         where V: MapVisitor,
     {
         let _ = visitor;
         Err(Error::invalid_type(Type::Map))
     }
 
+    /// `visit_enum` deserializes a `EnumVisitor` into a `Value`.
+    fn visit_enum<V>(self, visitor: V) -> Result<Self::Value, V::Error>
+        where V: EnumVisitor,
+    {
+        let _ = visitor;
+        Err(Error::invalid_type(Type::Enum))
+    }
+
     /// `visit_bytes` deserializes a `&[u8]` into a `Value`.
-    fn visit_bytes<E>(&mut self, v: &[u8]) -> Result<Self::Value, E>
+    fn visit_bytes<E>(self, v: &[u8]) -> Result<Self::Value, E>
         where E: Error,
     {
         let _ = v;
@@ -601,7 +613,7 @@ pub trait Visitor {
 
     /// `visit_byte_buf` deserializes a `Vec<u8>` into a `Value`.
     #[cfg(any(feature = "std", feature = "collections"))]
-    fn visit_byte_buf<E>(&mut self, v: Vec<u8>) -> Result<Self::Value, E>
+    fn visit_byte_buf<E>(self, v: Vec<u8>) -> Result<Self::Value, E>
         where E: Error,
     {
         self.visit_bytes(&v)
@@ -623,9 +635,6 @@ pub trait SeqVisitor {
     fn visit<T>(&mut self) -> Result<Option<T>, Self::Error>
         where T: Deserialize;
 
-    /// This signals to the `SeqVisitor` that the `Visitor` does not expect any more items.
-    fn end(&mut self) -> Result<(), Self::Error>;
-
     /// Return the lower and upper bound of items remaining in the sequence.
     #[inline]
     fn size_hint(&self) -> (usize, Option<usize>) {
@@ -643,11 +652,6 @@ impl<'a, V> SeqVisitor for &'a mut V where V: SeqVisitor {
         (**self).visit()
     }
 
-    #[inline]
-    fn end(&mut self) -> Result<(), V::Error> {
-        (**self).end()
-    }
-
     #[inline]
     fn size_hint(&self) -> (usize, Option<usize>) {
         (**self).size_hint()
@@ -688,9 +692,6 @@ pub trait MapVisitor {
     fn visit_value<V>(&mut self) -> Result<V, Self::Error>
         where V: Deserialize;
 
-    /// This signals to the `MapVisitor` that the `Visitor` does not expect any more items.
-    fn end(&mut self) -> Result<(), Self::Error>;
-
     /// Return the lower and upper bound of items remaining in the sequence.
     #[inline]
     fn size_hint(&self) -> (usize, Option<usize>) {
@@ -730,56 +731,55 @@ impl<'a, V_> MapVisitor for &'a mut V_ where V_: MapVisitor {
         (**self).visit_value()
     }
 
-    #[inline]
-    fn end(&mut self) -> Result<(), V_::Error> {
-        (**self).end()
-    }
-
     #[inline]
     fn size_hint(&self) -> (usize, Option<usize>) {
         (**self).size_hint()
     }
+
+    #[inline]
+    fn missing_field<V>(&mut self, field: &'static str) -> Result<V, Self::Error>
+        where V: Deserialize
+    {
+        (**self).missing_field(field)
+    }
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 
-/// `EnumVisitor` is a visitor that is created by the `Deserialize` and passed to the
-/// `Deserializer` in order to deserialize enums.
+/// `EnumVisitor` is a visitor that is created by the `Deserializer` and passed
+/// to the `Deserialize` in order to identify which variant of an enum to
+/// deserialize.
 pub trait EnumVisitor {
-    /// The value produced by this visitor.
-    type Value;
+    /// The error type that can be returned if some error occurs during deserialization.
+    type Error: Error;
+    /// The `Visitor` that will be used to deserialize the content of the enum
+    /// variant.
+    type Variant: VariantVisitor<Error=Self::Error>;
 
-    /// Visit the specific variant with the `VariantVisitor`.
-    fn visit<V>(&mut self, visitor: V) -> Result<Self::Value, V::Error>
-        where V: VariantVisitor;
+    /// `visit_variant` is called to identify which variant to deserialize.
+    fn visit_variant<V>(self) -> Result<(V, Self::Variant), Self::Error>
+        where V: Deserialize;
 }
 
-///////////////////////////////////////////////////////////////////////////////
-
-/// `VariantVisitor` is a visitor that is created by the `Deserializer` and passed to the
-/// `Deserialize` in order to deserialize a specific enum variant.
+/// `VariantVisitor` is a visitor that is created by the `Deserializer` and
+/// passed to the `Deserialize` to deserialize the content of a particular enum
+/// variant.
 pub trait VariantVisitor {
     /// The error type that can be returned if some error occurs during deserialization.
     type Error: Error;
 
-    /// `visit_variant` is called to identify which variant to deserialize.
-    fn visit_variant<V>(&mut self) -> Result<V, Self::Error>
-        where V: Deserialize;
-
     /// `visit_unit` is called when deserializing a variant with no values.
-    fn visit_unit(&mut self) -> Result<(), Self::Error> {
-        Err(Error::invalid_type(Type::UnitVariant))
-    }
+    fn visit_unit(self) -> Result<(), Self::Error>;
 
     /// `visit_newtype` is called when deserializing a variant with a single value.
     /// A good default is often to use the `visit_tuple` method to deserialize a `(value,)`.
-    fn visit_newtype<T>(&mut self) -> Result<T, Self::Error>
+    fn visit_newtype<T>(self) -> Result<T, Self::Error>
         where T: Deserialize;
 
     /// `visit_tuple` is called when deserializing a tuple-like variant.
     /// If no tuple variants are expected, yield a
     /// `Err(serde::de::Error::invalid_type(serde::de::Type::TupleVariant))`
-    fn visit_tuple<V>(&mut self,
+    fn visit_tuple<V>(self,
                       len: usize,
                       visitor: V) -> Result<V::Value, Self::Error>
         where V: Visitor;
@@ -787,44 +787,8 @@ pub trait VariantVisitor {
     /// `visit_struct` is called when deserializing a struct-like variant.
     /// If no struct variants are expected, yield a
     /// `Err(serde::de::Error::invalid_type(serde::de::Type::StructVariant))`
-    fn visit_struct<V>(&mut self,
+    fn visit_struct<V>(self,
                        fields: &'static [&'static str],
                        visitor: V) -> Result<V::Value, Self::Error>
         where V: Visitor;
 }
-
-impl<'a, T> VariantVisitor for &'a mut T where T: VariantVisitor {
-    type Error = T::Error;
-
-    fn visit_variant<V>(&mut self) -> Result<V, T::Error>
-        where V: Deserialize
-    {
-        (**self).visit_variant()
-    }
-
-    fn visit_unit(&mut self) -> Result<(), T::Error> {
-        (**self).visit_unit()
-    }
-
-    fn visit_newtype<D>(&mut self) -> Result<D, T::Error>
-        where D: Deserialize,
-    {
-        (**self).visit_newtype()
-    }
-
-    fn visit_tuple<V>(&mut self,
-                      len: usize,
-                      visitor: V) -> Result<V::Value, T::Error>
-        where V: Visitor,
-    {
-        (**self).visit_tuple(len, visitor)
-    }
-
-    fn visit_struct<V>(&mut self,
-                       fields: &'static [&'static str],
-                       visitor: V) -> Result<V::Value, T::Error>
-        where V: Visitor,
-    {
-        (**self).visit_struct(fields, visitor)
-    }
-}

serde/src/de/value.rs

@@ -41,7 +41,7 @@ use error;
 use core::fmt;
 use core::marker::PhantomData;
 
-use de;
+use de::{self, SeqVisitor};
 use bytes;
 
 ///////////////////////////////////////////////////////////////////////////////
@@ -184,13 +184,13 @@ impl<E> de::Deserializer for UnitDeserializer<E>
         tuple_struct struct struct_field tuple enum ignored_any
     }
 
-    fn deserialize<V>(&mut self, mut visitor: V) -> Result<V::Value, Self::Error>
+    fn deserialize<V>(self, visitor: V) -> Result<V::Value, Self::Error>
         where V: de::Visitor,
     {
         visitor.visit_unit()
     }
 
-    fn deserialize_option<V>(&mut self, mut visitor: V) -> Result<V::Value, Self::Error>
+    fn deserialize_option<V>(self, visitor: V) -> Result<V::Value, Self::Error>
         where V: de::Visitor,
     {
         visitor.visit_none()
@@ -202,7 +202,7 @@ impl<E> de::Deserializer for UnitDeserializer<E>
 macro_rules! primitive_deserializer {
     ($ty:ty, $name:ident, $method:ident) => {
         /// A helper deserializer that deserializes a number.
-        pub struct $name<E>(Option<$ty>, PhantomData<E>);
+        pub struct $name<E>($ty, PhantomData<E>);
 
         impl<E> ValueDeserializer<E> for $ty
             where E: de::Error,
@@ -210,7 +210,7 @@ macro_rules! primitive_deserializer {
             type Deserializer = $name<E>;
 
             fn into_deserializer(self) -> $name<E> {
-                $name(Some(self), PhantomData)
+                $name(self, PhantomData)
             }
         }
 
@@ -226,13 +226,10 @@ macro_rules! primitive_deserializer {
                 ignored_any
             }
 
-            fn deserialize<V>(&mut self, mut visitor: V) -> Result<V::Value, Self::Error>
+            fn deserialize<V>(self, visitor: V) -> Result<V::Value, Self::Error>
                 where V: de::Visitor,
             {
-                match self.0.take() {
-                    Some(v) => visitor.$method(v),
-                    None => Err(de::Error::end_of_stream()),
-                }
+                visitor.$method(self.0)
             }
         }
     }
@@ -256,7 +253,7 @@ primitive_deserializer!(char, CharDeserializer, visit_char);
 ///////////////////////////////////////////////////////////////////////////////
 
 /// A helper deserializer that deserializes a `&str`.
-pub struct StrDeserializer<'a, E>(Option<&'a str>, PhantomData<E>);
+pub struct StrDeserializer<'a, E>(&'a str, PhantomData<E>);
 
 impl<'a, E> ValueDeserializer<E> for &'a str
     where E: de::Error,
@@ -264,7 +261,7 @@ impl<'a, E> ValueDeserializer<E> for &'a str
     type Deserializer = StrDeserializer<'a, E>;
 
     fn into_deserializer(self) -> StrDeserializer<'a, E> {
-        StrDeserializer(Some(self), PhantomData)
+        StrDeserializer(self, PhantomData)
     }
 }
 
@@ -273,22 +270,19 @@ impl<'a, E> de::Deserializer for StrDeserializer<'a, E>
 {
     type Error = E;
 
-    fn deserialize<V>(&mut self, mut visitor: V) -> Result<V::Value, Self::Error>
+    fn deserialize<V>(self, visitor: V) -> Result<V::Value, Self::Error>
         where V: de::Visitor,
     {
-        match self.0.take() {
-            Some(v) => visitor.visit_str(v),
-            None => Err(de::Error::end_of_stream()),
-        }
+        visitor.visit_str(self.0)
     }
 
-    fn deserialize_enum<V>(&mut self,
+    fn deserialize_enum<V>(self,
                      _name: &str,
                      _variants: &'static [&'static str],
-                     mut visitor: V) -> Result<V::Value, Self::Error>
-        where V: de::EnumVisitor,
+                     visitor: V) -> Result<V::Value, Self::Error>
+        where V: de::Visitor,
     {
-        visitor.visit(self)
+        visitor.visit_enum(self)
     }
 
     forward_to_deserialize! {
@@ -298,42 +292,16 @@ impl<'a, E> de::Deserializer for StrDeserializer<'a, E>
     }
 }
 
-impl<'a, E> de::VariantVisitor for StrDeserializer<'a, E>
+impl<'a, E> de::EnumVisitor for StrDeserializer<'a, E>
     where E: de::Error,
 {
     type Error = E;
+    type Variant = private::UnitOnly<E>;
 
-    fn visit_variant<T>(&mut self) -> Result<T, Self::Error>
+    fn visit_variant<T>(self) -> Result<(T, Self::Variant), Self::Error>
         where T: de::Deserialize,
     {
-        de::Deserialize::deserialize(self)
-    }
-
-    fn visit_unit(&mut self) -> Result<(), Self::Error> {
-        Ok(())
-    }
-
-    fn visit_newtype<T>(&mut self) -> Result<T, Self::Error>
-        where T: super::Deserialize,
-    {
-        let (value,) = try!(self.visit_tuple(1, super::impls::TupleVisitor1::new()));
-        Ok(value)
-    }
-
-    fn visit_tuple<V>(&mut self,
-                      _len: usize,
-                      _visitor: V) -> Result<V::Value, Self::Error>
-        where V: super::Visitor
-    {
-        Err(super::Error::invalid_type(super::Type::TupleVariant))
-    }
-
-    fn visit_struct<V>(&mut self,
-                       _fields: &'static [&'static str],
-                       _visitor: V) -> Result<V::Value, Self::Error>
-        where V: super::Visitor
-    {
-        Err(super::Error::invalid_type(super::Type::StructVariant))
+        de::Deserialize::deserialize(self).map(private::unit_only)
     }
 }
 
@@ -341,7 +309,7 @@ impl<'a, E> de::VariantVisitor for StrDeserializer<'a, E>
 
 /// A helper deserializer that deserializes a `String`.
 #[cfg(any(feature = "std", feature = "collections"))]
-pub struct StringDeserializer<E>(Option<String>, PhantomData<E>);
+pub struct StringDeserializer<E>(String, PhantomData<E>);
 
 #[cfg(any(feature = "std", feature = "collections"))]
 impl<E> ValueDeserializer<E> for String
@@ -350,7 +318,7 @@ impl<E> ValueDeserializer<E> for String
     type Deserializer = StringDeserializer<E>;
 
     fn into_deserializer(self) -> StringDeserializer<E> {
-        StringDeserializer(Some(self), PhantomData)
+        StringDeserializer(self, PhantomData)
     }
 }
 
@@ -360,22 +328,19 @@ impl<E> de::Deserializer for StringDeserializer<E>
 {
     type Error = E;
 
-    fn deserialize<V>(&mut self, mut visitor: V) -> Result<V::Value, Self::Error>
+    fn deserialize<V>(self, visitor: V) -> Result<V::Value, Self::Error>
         where V: de::Visitor,
     {
-        match self.0.take() {
-            Some(string) => visitor.visit_string(string),
-            None => Err(de::Error::end_of_stream()),
-        }
+        visitor.visit_string(self.0)
     }
 
-    fn deserialize_enum<V>(&mut self,
+    fn deserialize_enum<V>(self,
                      _name: &str,
                      _variants: &'static [&'static str],
-                     mut visitor: V) -> Result<V::Value, Self::Error>
-        where V: de::EnumVisitor,
+                     visitor: V) -> Result<V::Value, Self::Error>
+        where V: de::Visitor,
     {
-        visitor.visit(self)
+        visitor.visit_enum(self)
     }
 
     forward_to_deserialize! {
@@ -386,42 +351,16 @@ impl<E> de::Deserializer for StringDeserializer<E>
 }
 
 #[cfg(any(feature = "std", feature = "collections"))]
-impl<'a, E> de::VariantVisitor for StringDeserializer<E>
+impl<'a, E> de::EnumVisitor for StringDeserializer<E>
     where E: de::Error,
 {
     type Error = E;
+    type Variant = private::UnitOnly<E>;
 
-    fn visit_variant<T>(&mut self) -> Result<T, Self::Error>
+    fn visit_variant<T>(self) -> Result<(T, Self::Variant), Self::Error>
         where T: de::Deserialize,
     {
-        de::Deserialize::deserialize(self)
-    }
-
-    fn visit_unit(&mut self) -> Result<(), Self::Error> {
-        Ok(())
-    }
-
-    fn visit_newtype<T>(&mut self) -> Result<T, Self::Error>
-        where T: super::Deserialize,
-    {
-        let (value,) = try!(self.visit_tuple(1, super::impls::TupleVisitor1::new()));
-        Ok(value)
-    }
-
-    fn visit_tuple<V>(&mut self,
-                      _len: usize,
-                      _visitor: V) -> Result<V::Value, Self::Error>
-        where V: super::Visitor
-    {
-        Err(super::Error::invalid_type(super::Type::TupleVariant))
-    }
-
-    fn visit_struct<V>(&mut self,
-                       _fields: &'static [&'static str],
-                       _visitor: V) -> Result<V::Value, Self::Error>
-        where V: super::Visitor
-    {
-        Err(super::Error::invalid_type(super::Type::StructVariant))
+        de::Deserialize::deserialize(self).map(private::unit_only)
     }
 }
 
@@ -429,7 +368,7 @@ impl<'a, E> de::VariantVisitor for StringDeserializer<E>
 
 /// A helper deserializer that deserializes a `String`.
 #[cfg(any(feature = "std", feature = "collections"))]
-pub struct CowStrDeserializer<'a, E>(Option<Cow<'a, str>>, PhantomData<E>);
+pub struct CowStrDeserializer<'a, E>(Cow<'a, str>, PhantomData<E>);
 
 #[cfg(any(feature = "std", feature = "collections"))]
 impl<'a, E> ValueDeserializer<E> for Cow<'a, str>
@@ -438,7 +377,7 @@ impl<'a, E> ValueDeserializer<E> for Cow<'a, str>
     type Deserializer = CowStrDeserializer<'a, E>;
 
     fn into_deserializer(self) -> CowStrDeserializer<'a, E> {
-        CowStrDeserializer(Some(self), PhantomData)
+        CowStrDeserializer(self, PhantomData)
     }
 }
 
@@ -448,23 +387,22 @@ impl<'a, E> de::Deserializer for CowStrDeserializer<'a, E>
 {
     type Error = E;
 
-    fn deserialize<V>(&mut self, mut visitor: V) -> Result<V::Value, Self::Error>
+    fn deserialize<V>(self, visitor: V) -> Result<V::Value, Self::Error>
         where V: de::Visitor,
     {
-        match self.0.take() {
-            Some(Cow::Borrowed(string)) => visitor.visit_str(string),
-            Some(Cow::Owned(string)) => visitor.visit_string(string),
-            None => Err(de::Error::end_of_stream()),
+        match self.0 {
+            Cow::Borrowed(string) => visitor.visit_str(string),
+            Cow::Owned(string) => visitor.visit_string(string),
         }
     }
 
-    fn deserialize_enum<V>(&mut self,
+    fn deserialize_enum<V>(self,
                      _name: &str,
                      _variants: &'static [&'static str],
-                     mut visitor: V) -> Result<V::Value, Self::Error>
-        where V: de::EnumVisitor,
+                     visitor: V) -> Result<V::Value, Self::Error>
+        where V: de::Visitor,
     {
-        visitor.visit(self)
+        visitor.visit_enum(self)
     }
 
     forward_to_deserialize! {
@@ -475,42 +413,16 @@ impl<'a, E> de::Deserializer for CowStrDeserializer<'a, E>
 }
 
 #[cfg(any(feature = "std", feature = "collections"))]
-impl<'a, E> de::VariantVisitor for CowStrDeserializer<'a, E>
+impl<'a, E> de::EnumVisitor for CowStrDeserializer<'a, E>
     where E: de::Error,
 {
     type Error = E;
+    type Variant = private::UnitOnly<E>;
 
-    fn visit_variant<T>(&mut self) -> Result<T, Self::Error>
+    fn visit_variant<T>(self) -> Result<(T, Self::Variant), Self::Error>
         where T: de::Deserialize,
     {
-        de::Deserialize::deserialize(self)
-    }
-
-    fn visit_unit(&mut self) -> Result<(), Self::Error> {
-        Ok(())
-    }
-
-    fn visit_newtype<T>(&mut self) -> Result<T, Self::Error>
-        where T: super::Deserialize,
-    {
-        let (value,) = try!(self.visit_tuple(1, super::impls::TupleVisitor1::new()));
-        Ok(value)
-    }
-
-    fn visit_tuple<V>(&mut self,
-                      _len: usize,
-                      _visitor: V) -> Result<V::Value, Self::Error>
-        where V: super::Visitor
-    {
-        Err(super::Error::invalid_type(super::Type::TupleVariant))
-    }
-
-    fn visit_struct<V>(&mut self,
-                       _fields: &'static [&'static str],
-                       _visitor: V) -> Result<V::Value, Self::Error>
-        where V: super::Visitor
-    {
-        Err(super::Error::invalid_type(super::Type::StructVariant))
+        de::Deserialize::deserialize(self).map(private::unit_only)
     }
 }
 
@@ -543,10 +455,15 @@ impl<I, T, E> de::Deserializer for SeqDeserializer<I, E>
 {
     type Error = E;
 
-    fn deserialize<V>(&mut self, mut visitor: V) -> Result<V::Value, Self::Error>
+    fn deserialize<V>(mut self, visitor: V) -> Result<V::Value, Self::Error>
         where V: de::Visitor,
     {
-        visitor.visit_seq(self)
+        let v = try!(visitor.visit_seq(&mut self));
+        if self.len == 0 {
+            Ok(v)
+        } else {
+            Err(de::Error::invalid_length(self.len))
+        }
     }
 
     forward_to_deserialize! {
@@ -569,21 +486,12 @@ impl<I, T, E> de::SeqVisitor for SeqDeserializer<I, E>
         match self.iter.next() {
             Some(value) => {
                 self.len -= 1;
-                let mut de = value.into_deserializer();
-                Ok(Some(try!(de::Deserialize::deserialize(&mut de))))
+                de::Deserialize::deserialize(value.into_deserializer()).map(Some)
             }
             None => Ok(None),
         }
     }
 
-    fn end(&mut self) -> Result<(), Self::Error> {
-        if self.len == 0 {
-            Ok(())
-        } else {
-            Err(de::Error::invalid_length(self.len))
-        }
-    }
-
     fn size_hint(&self) -> (usize, Option<usize>) {
         (self.len, Some(self.len))
     }
@@ -657,8 +565,8 @@ impl<V_, E> de::Deserializer for SeqVisitorDeserializer<V_, E>
 {
     type Error = E;
 
-    fn deserialize<V: de::Visitor>(&mut self, mut visitor: V) -> Result<V::Value, Self::Error> {
-        visitor.visit_seq(&mut self.visitor)
+    fn deserialize<V: de::Visitor>(self, visitor: V) -> Result<V::Value, Self::Error> {
+        visitor.visit_seq(self.visitor)
     }
 
     forward_to_deserialize! {
@@ -718,6 +626,13 @@ impl<I, K, V, E> MapDeserializer<I, K, V, E>
             (k, v)
         })
     }
+
+    fn end(&mut self) -> Result<(), E> {
+        match self.len {
+            Some(len) if len > 0 => Err(de::Error::invalid_length(len)),
+            _ => Ok(())
+        }
+    }
 }
 
 impl<I, K, V, E> de::Deserializer for MapDeserializer<I, K, V, E>
@@ -728,25 +643,32 @@ impl<I, K, V, E> de::Deserializer for MapDeserializer<I, K, V, E>
 {
     type Error = E;
 
-    fn deserialize<V_>(&mut self, mut visitor: V_) -> Result<V_::Value, Self::Error>
+    fn deserialize<V_>(mut self, visitor: V_) -> Result<V_::Value, Self::Error>
         where V_: de::Visitor,
     {
-        visitor.visit_map(self)
+        let value = try!(visitor.visit_map(&mut self));
+        try!(self.end());
+        Ok(value)
     }
 
-    fn deserialize_seq<V_>(&mut self, mut visitor: V_) -> Result<V_::Value, Self::Error>
+    fn deserialize_seq<V_>(mut self, visitor: V_) -> Result<V_::Value, Self::Error>
         where V_: de::Visitor,
     {
-        visitor.visit_seq(self)
+        let value = try!(visitor.visit_seq(&mut self));
+        try!(self.end());
+        Ok(value)
     }
 
-    fn deserialize_seq_fixed_size<V_>(&mut self, len: usize, mut visitor: V_) -> Result<V_::Value, Self::Error>
+    fn deserialize_seq_fixed_size<V_>(mut self, len: usize, visitor: V_) -> Result<V_::Value, Self::Error>
         where V_: de::Visitor,
     {
         match self.len {
-            Some(map_len) if map_len == len => visitor.visit_seq(self),
-            Some(_) => Err(de::Error::invalid_length(len)),
-            None => visitor.visit_seq(self),
+            Some(map_len) if map_len != len => Err(de::Error::invalid_length(len)),
+            _ => {
+                let value = try!(visitor.visit_seq(&mut self));
+                try!(self.end());
+                Ok(value)
+            }
         }
     }
 
@@ -771,8 +693,7 @@ impl<I, K, V, E> de::MapVisitor for MapDeserializer<I, K, V, E>
         match self.next() {
             Some((key, value)) => {
                 self.value = Some(value);
-                let mut de = key.into_deserializer();
-                de::Deserialize::deserialize(&mut de).map(Some)
+                de::Deserialize::deserialize(key.into_deserializer()).map(Some)
             }
             None => Ok(None),
         }
@@ -783,8 +704,7 @@ impl<I, K, V, E> de::MapVisitor for MapDeserializer<I, K, V, E>
     {
         match self.value.take() {
             Some(value) => {
-                let mut de = value.into_deserializer();
-                de::Deserialize::deserialize(&mut de)
+                de::Deserialize::deserialize(value.into_deserializer())
             }
             None => {
                 Err(de::Error::end_of_stream())
@@ -792,10 +712,17 @@ impl<I, K, V, E> de::MapVisitor for MapDeserializer<I, K, V, E>
         }
     }
 
-    fn end(&mut self) -> Result<(), Self::Error> {
-        match self.len {
-            Some(len) if len > 0 => Err(de::Error::invalid_length(len)),
-            _ => Ok(())
+    fn visit<TK, TV>(&mut self) -> Result<Option<(TK, TV)>, Self::Error>
+        where TK: de::Deserialize,
+              TV: de::Deserialize
+    {
+        match self.next() {
+            Some((key, value)) => {
+                let key = try!(de::Deserialize::deserialize(key.into_deserializer()));
+                let value = try!(de::Deserialize::deserialize(value.into_deserializer()));
+                Ok(Some((key, value)))
+            }
+            None => Ok(None)
         }
     }
 
@@ -818,18 +745,14 @@ impl<I, K, V, E> de::SeqVisitor for MapDeserializer<I, K, V, E>
         where T: de::Deserialize,
     {
         match self.next() {
-            Some(kv) => {
-                let mut de = PairDeserializer(Some(kv), PhantomData);
-                de::Deserialize::deserialize(&mut de).map(Some)
+            Some((k, v)) => {
+                let de = PairDeserializer(k, v, PhantomData);
+                de::Deserialize::deserialize(de).map(Some)
             }
             None => Ok(None),
         }
     }
 
-    fn end(&mut self) -> Result<(), Self::Error> {
-        de::MapVisitor::end(self)
-    }
-
     fn size_hint(&self) -> (usize, Option<usize>) {
         de::MapVisitor::size_hint(self)
     }
@@ -837,7 +760,7 @@ impl<I, K, V, E> de::SeqVisitor for MapDeserializer<I, K, V, E>
 
 // Used in the `impl SeqVisitor for MapDeserializer` to visit the map as a
 // sequence of pairs.
-struct PairDeserializer<A, B, E>(Option<(A, B)>, PhantomData<E>);
+struct PairDeserializer<A, B, E>(A, B, PhantomData<E>);
 
 impl<A, B, E> de::Deserializer for PairDeserializer<A, B, E>
     where A: ValueDeserializer<E>,
@@ -852,24 +775,25 @@ impl<A, B, E> de::Deserializer for PairDeserializer<A, B, E>
         struct_field tuple enum ignored_any
     }
 
-    fn deserialize<V>(&mut self, visitor: V) -> Result<V::Value, Self::Error>
+    fn deserialize<V>(self, visitor: V) -> Result<V::Value, Self::Error>
         where V: de::Visitor,
     {
         self.deserialize_seq(visitor)
     }
 
-    fn deserialize_seq<V>(&mut self, mut visitor: V) -> Result<V::Value, Self::Error>
+    fn deserialize_seq<V>(self, visitor: V) -> Result<V::Value, Self::Error>
         where V: de::Visitor,
     {
-        match self.0.take() {
-            Some((k, v)) => {
-                visitor.visit_seq(PairVisitor(Some(k), Some(v), PhantomData))
-            }
-            None => Err(de::Error::end_of_stream()),
+        let mut pair_visitor = PairVisitor(Some(self.0), Some(self.1), PhantomData);
+        let pair = try!(visitor.visit_seq(&mut pair_visitor));
+        if pair_visitor.1.is_none() {
+            Ok(pair)
+        } else {
+            Err(de::Error::invalid_length(pair_visitor.size_hint().0))
         }
     }
 
-    fn deserialize_seq_fixed_size<V>(&mut self, len: usize, visitor: V) -> Result<V::Value, Self::Error>
+    fn deserialize_seq_fixed_size<V>(self, len: usize, visitor: V) -> Result<V::Value, Self::Error>
         where V: de::Visitor,
     {
         if len == 2 {
@@ -893,24 +817,14 @@ impl<A, B, E> de::SeqVisitor for PairVisitor<A, B, E>
         where T: de::Deserialize,
     {
         if let Some(k) = self.0.take() {
-            let mut de = k.into_deserializer();
-            de::Deserialize::deserialize(&mut de).map(Some)
+            de::Deserialize::deserialize(k.into_deserializer()).map(Some)
         } else if let Some(v) = self.1.take() {
-            let mut de = v.into_deserializer();
-            de::Deserialize::deserialize(&mut de).map(Some)
+            de::Deserialize::deserialize(v.into_deserializer()).map(Some)
         } else {
             Ok(None)
         }
     }
 
-    fn end(&mut self) -> Result<(), Self::Error> {
-        if self.1.is_none() {
-            Ok(())
-        } else {
-            Err(de::Error::invalid_length(self.size_hint().0))
-        }
-    }
-
     fn size_hint(&self) -> (usize, Option<usize>) {
         let len = if self.0.is_some() {
             2
@@ -980,8 +894,8 @@ impl<V_, E> de::Deserializer for MapVisitorDeserializer<V_, E>
 {
     type Error = E;
 
-    fn deserialize<V: de::Visitor>(&mut self, mut visitor: V) -> Result<V::Value, Self::Error> {
-        visitor.visit_map(&mut self.visitor)
+    fn deserialize<V: de::Visitor>(self, visitor: V) -> Result<V::Value, Self::Error> {
+        visitor.visit_map(self.visitor)
     }
 
     forward_to_deserialize! {
@@ -999,25 +913,22 @@ impl<'a, E> ValueDeserializer<E> for bytes::Bytes<'a>
     type Deserializer = BytesDeserializer<'a, E>;
 
     fn into_deserializer(self) -> BytesDeserializer<'a, E> {
-        BytesDeserializer(Some(self.into()), PhantomData)
+        BytesDeserializer(self.into(), PhantomData)
     }
 }
 
 /// A helper deserializer that deserializes a `&[u8]`.
-pub struct BytesDeserializer<'a, E> (Option<&'a [u8]>, PhantomData<E>);
+pub struct BytesDeserializer<'a, E>(&'a [u8], PhantomData<E>);
 
 impl<'a, E> de::Deserializer for BytesDeserializer<'a, E>
     where E: de::Error
 {
     type Error = E;
 
-    fn deserialize<V>(&mut self, mut visitor: V) -> Result<V::Value, Self::Error>
+    fn deserialize<V>(self, visitor: V) -> Result<V::Value, Self::Error>
         where V: de::Visitor,
     {
-        match self.0.take() {
-            Some(bytes) => visitor.visit_bytes(bytes),
-            None => Err(de::Error::end_of_stream()),
-        }
+        visitor.visit_bytes(self.0)
     }
 
     forward_to_deserialize! {
@@ -1036,13 +947,13 @@ impl<E> ValueDeserializer<E> for bytes::ByteBuf
     type Deserializer = ByteBufDeserializer<E>;
 
     fn into_deserializer(self) -> Self::Deserializer {
-        ByteBufDeserializer(Some(self.into()), PhantomData)
+        ByteBufDeserializer(self.into(), PhantomData)
     }
 }
 
 /// A helper deserializer that deserializes a `Vec<u8>`.
 #[cfg(any(feature = "std", feature = "collections"))]
-pub struct ByteBufDeserializer<E>(Option<Vec<u8>>, PhantomData<E>);
+pub struct ByteBufDeserializer<E>(Vec<u8>, PhantomData<E>);
 
 #[cfg(any(feature = "std", feature = "collections"))]
 impl<E> de::Deserializer for ByteBufDeserializer<E>
@@ -1050,13 +961,10 @@ impl<E> de::Deserializer for ByteBufDeserializer<E>
 {
     type Error = E;
 
-    fn deserialize<V>(&mut self, mut visitor: V) -> Result<V::Value, Self::Error>
+    fn deserialize<V>(self, visitor: V) -> Result<V::Value, Self::Error>
         where V: de::Visitor,
     {
-        match self.0.take() {
-            Some(bytes) => visitor.visit_byte_buf(bytes),
-            None => Err(de::Error::end_of_stream()),
-        }
+        visitor.visit_byte_buf(self.0)
     }
 
     forward_to_deserialize! {
@@ -1065,3 +973,48 @@ impl<E> de::Deserializer for ByteBufDeserializer<E>
         tuple_struct struct struct_field tuple enum ignored_any
     }
 }
+
+///////////////////////////////////////////////////////////////////////////////
+
+mod private {
+    use de;
+    use core::marker::PhantomData;
+
+    pub struct UnitOnly<E>(PhantomData<E>);
+
+    pub fn unit_only<T, E>(t: T) -> (T, UnitOnly<E>) {
+        (t, UnitOnly(PhantomData))
+    }
+
+    impl<E> de::VariantVisitor for UnitOnly<E>
+        where E: de::Error
+    {
+        type Error = E;
+
+        fn visit_unit(self) -> Result<(), Self::Error> {
+            Ok(())
+        }
+
+        fn visit_newtype<T>(self) -> Result<T, Self::Error>
+            where T: de::Deserialize,
+        {
+            Err(de::Error::invalid_type(de::Type::NewtypeVariant))
+        }
+
+        fn visit_tuple<V>(self,
+                        _len: usize,
+                        _visitor: V) -> Result<V::Value, Self::Error>
+            where V: de::Visitor
+        {
+            Err(de::Error::invalid_type(de::Type::TupleVariant))
+        }
+
+        fn visit_struct<V>(self,
+                        _fields: &'static [&'static str],
+                        _visitor: V) -> Result<V::Value, Self::Error>
+            where V: de::Visitor
+        {
+            Err(de::Error::invalid_type(de::Type::StructVariant))
+        }
+    }
+}

serde/src/lib.rs

@@ -30,7 +30,7 @@ extern crate alloc;
 #[cfg(feature = "std")]
 mod core {
     pub use std::{ops, hash, fmt, cmp, marker, mem, i8, i16, i32, i64, u8, u16, u32, u64, isize,
-            usize, f32, f64, char, str, num, slice, iter};
+            usize, f32, f64, char, str, num, slice, iter, cell};
     #[cfg(feature = "unstable")]
     extern crate core;
     #[cfg(feature = "unstable")]
@@ -38,7 +38,7 @@ mod core {
 }
 
 pub use ser::{Serialize, Serializer};
-pub use de::{Deserialize, Deserializer, Error};
+pub use de::{Deserialize, Deserializer};
 
 #[cfg(not(feature = "std"))]
 macro_rules! format {

serde/src/macros.rs

@@ -4,7 +4,7 @@
 macro_rules! forward_to_deserialize_method {
     ($func:ident($($arg:ty),*)) => {
         #[inline]
-        fn $func<__V>(&mut self, $(_: $arg,)* visitor: __V) -> ::std::result::Result<__V::Value, Self::Error>
+        fn $func<__V>(self, $(_: $arg,)* visitor: __V) -> ::std::result::Result<__V::Value, Self::Error>
             where __V: $crate::de::Visitor
         {
             self.deserialize(visitor)
@@ -18,7 +18,7 @@ macro_rules! forward_to_deserialize_method {
 macro_rules! forward_to_deserialize_method {
     ($func:ident($($arg:ty),*)) => {
         #[inline]
-        fn $func<__V>(&mut self, $(_: $arg,)* visitor: __V) -> ::core::result::Result<__V::Value, Self::Error>
+        fn $func<__V>(self, $(_: $arg,)* visitor: __V) -> ::core::result::Result<__V::Value, Self::Error>
             where __V: $crate::de::Visitor
         {
             self.deserialize(visitor)
@@ -26,34 +26,6 @@ macro_rules! forward_to_deserialize_method {
     };
 }
 
-#[cfg(feature = "std")]
-#[doc(hidden)]
-#[macro_export]
-macro_rules! forward_to_deserialize_enum {
-    () => {
-        #[inline]
-        fn deserialize_enum<__V>(&mut self, _: &str, _: &[&str], _: __V) -> ::std::result::Result<__V::Value, Self::Error>
-            where __V: $crate::de::EnumVisitor
-        {
-            Err($crate::de::Error::invalid_type($crate::de::Type::Enum))
-        }
-    };
-}
-
-#[cfg(not(feature = "std"))]
-#[doc(hidden)]
-#[macro_export]
-macro_rules! forward_to_deserialize_enum {
-    () => {
-        #[inline]
-        fn deserialize_enum<__V>(&mut self, _: &str, _: &[&str], _: __V) -> ::core::result::Result<__V::Value, Self::Error>
-            where __V: $crate::de::EnumVisitor
-        {
-            Err($crate::de::Error::invalid_type($crate::de::Type::Enum))
-        }
-    };
-}
-
 #[doc(hidden)]
 #[macro_export]
 macro_rules! forward_to_deserialize_helper {
@@ -141,12 +113,12 @@ macro_rules! forward_to_deserialize_helper {
     (tuple) => {
         forward_to_deserialize_method!{deserialize_tuple(usize)}
     };
+    (enum) => {
+        forward_to_deserialize_method!{deserialize_enum(&'static str, &'static [&'static str])}
+    };
     (ignored_any) => {
         forward_to_deserialize_method!{deserialize_ignored_any()}
     };
-    (enum) => {
-        forward_to_deserialize_enum!();
-    };
 }
 
 /// Helper to forward `Deserializer` methods to `Deserializer::deserialize`.
@@ -156,7 +128,7 @@ macro_rules! forward_to_deserialize_helper {
 ///
 /// ```rust,ignore
 /// impl Deserializer for MyDeserializer {
-///     fn deserialize<V>(&mut self, visitor: V) -> Result<V::Value, Self::Error>
+///     fn deserialize<V>(self, visitor: V) -> Result<V::Value, Self::Error>
 ///         where V: Visitor
 ///     {
 ///         /* ... */

serde/src/ser/impls.rs

@@ -69,16 +69,23 @@ use core::nonzero::{NonZero, Zeroable};
 use super::{
     Error,
     Serialize,
+    SerializeMap,
+    SerializeSeq,
+    SerializeStruct,
+    SerializeTuple,
     Serializer,
 };
 
+#[cfg(feature = "unstable")]
+use super::Iterator;
+
 ///////////////////////////////////////////////////////////////////////////////
 
 macro_rules! impl_visit {
     ($ty:ty, $method:ident) => {
         impl Serialize for $ty {
             #[inline]
-            fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
+            fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
                 where S: Serializer,
             {
                 serializer.$method(*self)
@@ -106,7 +113,7 @@ impl_visit!(char, serialize_char);
 
 impl Serialize for str {
     #[inline]
-    fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
         where S: Serializer,
     {
         serializer.serialize_str(self)
@@ -116,7 +123,7 @@ impl Serialize for str {
 #[cfg(any(feature = "std", feature = "collections"))]
 impl Serialize for String {
     #[inline]
-    fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
         where S: Serializer,
     {
         (&self[..]).serialize(serializer)
@@ -125,9 +132,11 @@ impl Serialize for String {
 
 ///////////////////////////////////////////////////////////////////////////////
 
-impl<T> Serialize for Option<T> where T: Serialize {
+impl<T> Serialize for Option<T>
+    where T: Serialize
+{
     #[inline]
-    fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
         where S: Serializer,
     {
         match *self {
@@ -141,7 +150,7 @@ impl<T> Serialize for Option<T> where T: Serialize {
 
 impl<T> Serialize for PhantomData<T> {
     #[inline]
-    fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
         where S: Serializer,
     {
         serializer.serialize_unit_struct("PhantomData")
@@ -155,14 +164,14 @@ impl<T> Serialize for [T]
     where T: Serialize,
 {
     #[inline]
-    fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
         where S: Serializer,
     {
-        let mut state = try!(serializer.serialize_seq(Some(self.len())));
+        let mut seq = try!(serializer.serialize_seq(Some(self.len())));
         for e in self {
-            try!(serializer.serialize_seq_elt(&mut state, e));
+            try!(seq.serialize_element(e));
         }
-        serializer.serialize_seq_end(state)
+        seq.end()
     }
 }
 
@@ -172,14 +181,14 @@ macro_rules! array_impls {
     ($len:expr) => {
         impl<T> Serialize for [T; $len] where T: Serialize {
             #[inline]
-            fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
+            fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
                 where S: Serializer,
             {
-                let mut state = try!(serializer.serialize_seq_fixed_size($len));
+                let mut seq = try!(serializer.serialize_seq_fixed_size($len));
                 for e in self {
-                    try!(serializer.serialize_seq_elt(&mut state, e));
+                    try!(seq.serialize_element(e));
                 }
-                serializer.serialize_seq_end(state)
+                seq.end()
             }
         }
     }
@@ -221,17 +230,44 @@ array_impls!(32);
 
 ///////////////////////////////////////////////////////////////////////////////
 
+#[cfg(feature = "unstable")]
+impl<'a, I> Serialize for Iterator<I>
+    where I: IntoIterator, <I as IntoIterator>::Item: Serialize
+{
+    #[inline]
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+        where S: Serializer,
+    {
+        // FIXME: use specialization to prevent invalidating the object in case of clonable iterators?
+        let iter = match self.0.borrow_mut().take() {
+            Some(iter) => iter.into_iter(),
+            None => return Err(S::Error::custom("Iterator used twice")),
+        };
+        let size = match iter.size_hint() {
+            (lo, Some(hi)) if lo == hi => Some(lo),
+            _ => None,
+        };
+        let mut seq = try!(serializer.serialize_seq(size));
+        for e in iter {
+            try!(seq.serialize_element(e));
+        }
+        seq.end()
+    }
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
 macro_rules! serialize_seq {
     () => {
         #[inline]
-        fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
+        fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
             where S: Serializer,
         {
-            let mut state = try!(serializer.serialize_seq(Some(self.len())));
+            let mut seq = try!(serializer.serialize_seq(Some(self.len())));
             for e in self {
-                try!(serializer.serialize_seq_elt(&mut state, e));
+                try!(seq.serialize_element(e));
             }
-            serializer.serialize_seq_end(state)
+            seq.end()
         }
     }
 }
@@ -273,12 +309,16 @@ impl<T> Serialize for LinkedList<T>
 }
 
 #[cfg(any(feature = "std", feature = "collections"))]
-impl<T> Serialize for Vec<T> where T: Serialize {
+impl<T> Serialize for Vec<T>
+    where T: Serialize
+{
     serialize_seq!();
 }
 
 #[cfg(any(feature = "std", feature = "collections"))]
-impl<T> Serialize for VecDeque<T> where T: Serialize {
+impl<T> Serialize for VecDeque<T>
+    where T: Serialize
+{
     serialize_seq!();
 }
 
@@ -288,15 +328,15 @@ impl<A> Serialize for ops::Range<A>
           for<'a> &'a A: ops::Add<&'a A, Output = A>,
 {
     #[inline]
-    fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
         where S: Serializer,
     {
         let len = iter::Step::steps_between(&self.start, &self.end, &A::one());
-        let mut state = try!(serializer.serialize_seq(len));
+        let mut seq = try!(serializer.serialize_seq(len));
         for e in self.clone() {
-            try!(serializer.serialize_seq_elt(&mut state, e));
+            try!(seq.serialize_element(e));
         }
-        serializer.serialize_seq_end(state)
+        seq.end()
     }
 }
 
@@ -304,7 +344,7 @@ impl<A> Serialize for ops::Range<A>
 
 impl Serialize for () {
     #[inline]
-    fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
         where S: Serializer,
     {
         serializer.serialize_unit()
@@ -324,14 +364,14 @@ macro_rules! tuple_impls {
                 where $($T: Serialize),+
             {
                 #[inline]
-                fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
+                fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
                     where S: Serializer,
                 {
-                    let mut state = try!(serializer.serialize_tuple($len));
+                    let mut tuple = try!(serializer.serialize_tuple($len));
                     $(
-                        try!(serializer.serialize_tuple_elt(&mut state, &self.$idx));
+                        try!(tuple.serialize_element(&self.$idx));
                     )+
-                    serializer.serialize_tuple_end(state)
+                    tuple.end()
                 }
             }
         )+
@@ -514,15 +554,15 @@ tuple_impls! {
 macro_rules! serialize_map {
     () => {
         #[inline]
-        fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
+        fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
             where S: Serializer,
         {
-            let mut state = try!(serializer.serialize_map(Some(self.len())));
+            let mut map = try!(serializer.serialize_map(Some(self.len())));
             for (k, v) in self {
-                try!(serializer.serialize_map_key(&mut state, k));
-                try!(serializer.serialize_map_value(&mut state, v));
+                try!(map.serialize_key(k));
+                try!(map.serialize_value(v));
             }
-            serializer.serialize_map_end(state)
+            map.end()
         }
     }
 }
@@ -548,7 +588,7 @@ impl<K, V, H> Serialize for HashMap<K, V, H>
 
 impl<'a, T: ?Sized> Serialize for &'a T where T: Serialize {
     #[inline]
-    fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
         where S: Serializer,
     {
         (**self).serialize(serializer)
@@ -557,7 +597,7 @@ impl<'a, T: ?Sized> Serialize for &'a T where T: Serialize {
 
 impl<'a, T: ?Sized> Serialize for &'a mut T where T: Serialize {
     #[inline]
-    fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
         where S: Serializer,
     {
         (**self).serialize(serializer)
@@ -565,9 +605,11 @@ impl<'a, T: ?Sized> Serialize for &'a mut T where T: Serialize {
 }
 
 #[cfg(any(feature = "std", feature = "alloc"))]
-impl<T: ?Sized> Serialize for Box<T> where T: Serialize {
+impl<T: ?Sized> Serialize for Box<T>
+    where T: Serialize
+{
     #[inline]
-    fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
         where S: Serializer,
     {
         (**self).serialize(serializer)
@@ -575,9 +617,11 @@ impl<T: ?Sized> Serialize for Box<T> where T: Serialize {
 }
 
 #[cfg(any(feature = "std", feature = "alloc"))]
-impl<T> Serialize for Rc<T> where T: Serialize, {
+impl<T> Serialize for Rc<T>
+    where T: Serialize
+{
     #[inline]
-    fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
         where S: Serializer,
     {
         (**self).serialize(serializer)
@@ -585,9 +629,11 @@ impl<T> Serialize for Rc<T> where T: Serialize, {
 }
 
 #[cfg(any(feature = "std", feature = "alloc"))]
-impl<T> Serialize for Arc<T> where T: Serialize, {
+impl<T> Serialize for Arc<T>
+    where T: Serialize
+{
     #[inline]
-    fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
         where S: Serializer,
     {
         (**self).serialize(serializer)
@@ -595,9 +641,11 @@ impl<T> Serialize for Arc<T> where T: Serialize, {
 }
 
 #[cfg(any(feature = "std", feature = "collections"))]
-impl<'a, T: ?Sized> Serialize for Cow<'a, T> where T: Serialize + ToOwned, {
+impl<'a, T: ?Sized> Serialize for Cow<'a, T>
+    where T: Serialize + ToOwned
+{
     #[inline]
-    fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
         where S: Serializer,
     {
         (**self).serialize(serializer)
@@ -606,8 +654,13 @@ impl<'a, T: ?Sized> Serialize for Cow<'a, T> where T: Serialize + ToOwned, {
 
 ///////////////////////////////////////////////////////////////////////////////
 
-impl<T, E> Serialize for Result<T, E> where T: Serialize, E: Serialize {
-    fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error> where S: Serializer {
+impl<T, E> Serialize for Result<T, E>
+    where T: Serialize,
+          E: Serialize
+{
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+        where S: Serializer
+    {
         match *self {
             Result::Ok(ref value) => {
                 serializer.serialize_newtype_variant("Result", 0, "Ok", value)
@@ -623,13 +676,13 @@ impl<T, E> Serialize for Result<T, E> where T: Serialize, E: Serialize {
 
 #[cfg(feature = "std")]
 impl Serialize for Duration {
-    fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
         where S: Serializer,
     {
         let mut state = try!(serializer.serialize_struct("Duration", 2));
-        try!(serializer.serialize_struct_elt(&mut state, "secs", self.as_secs()));
-        try!(serializer.serialize_struct_elt(&mut state, "nanos", self.subsec_nanos()));
-        serializer.serialize_struct_end(state)
+        try!(state.serialize_field("secs", self.as_secs()));
+        try!(state.serialize_field("nanos", self.subsec_nanos()));
+        state.end()
     }
 }
 
@@ -637,7 +690,7 @@ impl Serialize for Duration {
 
 #[cfg(feature = "std")]
 impl Serialize for net::IpAddr {
-    fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
         where S: Serializer,
     {
         self.to_string().serialize(serializer)
@@ -646,7 +699,7 @@ impl Serialize for net::IpAddr {
 
 #[cfg(feature = "std")]
 impl Serialize for net::Ipv4Addr {
-    fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
         where S: Serializer,
     {
         self.to_string().serialize(serializer)
@@ -655,7 +708,7 @@ impl Serialize for net::Ipv4Addr {
 
 #[cfg(feature = "std")]
 impl Serialize for net::Ipv6Addr {
-    fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
         where S: Serializer,
     {
         self.to_string().serialize(serializer)
@@ -666,7 +719,7 @@ impl Serialize for net::Ipv6Addr {
 
 #[cfg(feature = "std")]
 impl Serialize for net::SocketAddr {
-    fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
         where S: Serializer,
     {
         match *self {
@@ -678,7 +731,7 @@ impl Serialize for net::SocketAddr {
 
 #[cfg(feature = "std")]
 impl Serialize for net::SocketAddrV4 {
-    fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
         where S: Serializer,
     {
         self.to_string().serialize(serializer)
@@ -687,7 +740,7 @@ impl Serialize for net::SocketAddrV4 {
 
 #[cfg(feature = "std")]
 impl Serialize for net::SocketAddrV6 {
-    fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
         where S: Serializer,
     {
         self.to_string().serialize(serializer)
@@ -698,7 +751,7 @@ impl Serialize for net::SocketAddrV6 {
 
 #[cfg(feature = "std")]
 impl Serialize for path::Path {
-    fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
         where S: Serializer,
     {
         match self.to_str() {
@@ -710,7 +763,7 @@ impl Serialize for path::Path {
 
 #[cfg(feature = "std")]
 impl Serialize for path::PathBuf {
-    fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
         where S: Serializer,
     {
         self.as_path().serialize(serializer)
@@ -718,8 +771,12 @@ impl Serialize for path::PathBuf {
 }
 
 #[cfg(feature = "unstable")]
-impl<T> Serialize for NonZero<T> where T: Serialize + Zeroable {
-    fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error> where S: Serializer {
+impl<T> Serialize for NonZero<T>
+    where T: Serialize + Zeroable
+{
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+        where S: Serializer
+    {
         (**self).serialize(serializer)
     }
 }

serde/src/ser/mod.rs

@@ -18,6 +18,11 @@ use error;
 #[cfg(all(feature = "collections", not(feature = "std")))]
 use collections::String;
 
+#[cfg(feature = "unstable")]
+use core::marker::PhantomData;
+#[cfg(feature = "unstable")]
+use core::cell::RefCell;
+
 pub mod impls;
 
 ///////////////////////////////////////////////////////////////////////////////
@@ -44,7 +49,7 @@ pub trait Error: Sized + error::Error {
 /// A trait that describes a type that can be serialized by a `Serializer`.
 pub trait Serialize {
     /// Serializes this value into this serializer.
-    fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
         where S: Serializer;
 }
 
@@ -53,7 +58,7 @@ pub trait Serialize {
 /// A trait that describes a type that can serialize a stream of values into the underlying format.
 ///
 /// # For `Serialize` Developers
-/// Non-aggrergate types like integers and strings can be serialized directly by calling the
+/// Non-aggregate types like integers and strings can be serialized directly by calling the
 /// appropriate function. For Aggregate types there's an initial `serialize_T` method that yields
 /// a State object that you should not interact with. For each part of the aggregate there's a
 /// `serialize_T_elt` method that allows you to pass values or key/value pairs. The types of the
@@ -72,341 +77,372 @@ pub trait Serialize {
 /// state object, as it is expected that the user will not modify it. Due to the generic nature
 /// of the `Serialize` impls, modifying the object is impossible on stable Rust.
 pub trait Serializer {
-    /// The error type that can be returned if some error occurs during serialization.
+    /// Trickery to enforce correct use of the `Serialize` trait. Every
+    /// `Serializer` should set `Ok = ()`.
+    type Ok;
+
+    /// The error type when some error occurs during serialization.
     type Error: Error;
 
-    /// A state object that is initialized by `serialize_seq`, passed to
-    /// `serialize_seq_elt`, and consumed by `serialize_seq_end`. Use `()` if no
-    /// state is required.
-    type SeqState;
-    /// A state object that is initialized by `serialize_tuple`, passed to
-    /// `serialize_tuple_elt`, and consumed by `serialize_tuple_end`. Use `()`
-    /// if no state is required.
-    type TupleState;
-    /// A state object that is initialized by `serialize_tuple_struct`, passed
-    /// to `serialize_tuple_struct_elt`, and consumed by
-    /// `serialize_tuple_struct_end`. Use `()` if no state is required.
-    type TupleStructState;
-    /// A state object that is initialized by `serialize_tuple_variant`, passed
-    /// to `serialize_tuple_variant_elt`, and consumed by
-    /// `serialize_tuple_variant_end`. Use `()` if no state is required.
-    type TupleVariantState;
-    /// A state object that is initialized by `serialize_map`, passed to
-    /// `serialize_map_elt`, and consumed by `serialize_map_end`. Use `()` if no
-    /// state is required.
-    type MapState;
-    /// A state object that is initialized by `serialize_struct`, passed to
-    /// `serialize_struct_elt`, and consumed by `serialize_struct_end`. Use `()`
-    /// if no state is required.
-    type StructState;
-    /// A state object that is initialized by `serialize_struct_variant`, passed
-    /// to `serialize_struct_variant_elt`, and consumed by
-    /// `serialize_struct_variant_end`. Use `()` if no state is required.
-    type StructVariantState;
+    /// Type returned from `serialize_seq` and `serialize_seq_fixed_size` for
+    /// serializing the content of the sequence.
+    type SerializeSeq: SerializeSeq<Ok=Self::Ok, Error=Self::Error>;
+
+    /// Type returned from `serialize_tuple` for serializing the content of the
+    /// tuple.
+    type SerializeTuple: SerializeTuple<Ok=Self::Ok, Error=Self::Error>;
+
+    /// Type returned from `serialize_tuple_struct` for serializing the content
+    /// of the tuple struct.
+    type SerializeTupleStruct: SerializeTupleStruct<Ok=Self::Ok, Error=Self::Error>;
+
+    /// Type returned from `serialize_tuple_variant` for serializing the content
+    /// of the tuple variant.
+    type SerializeTupleVariant: SerializeTupleVariant<Ok=Self::Ok, Error=Self::Error>;
+
+    /// Type returned from `serialize_map` for serializing the content of the
+    /// map.
+    type SerializeMap: SerializeMap<Ok=Self::Ok, Error=Self::Error>;
+
+    /// Type returned from `serialize_struct` for serializing the content of the
+    /// struct.
+    type SerializeStruct: SerializeStruct<Ok=Self::Ok, Error=Self::Error>;
+
+    /// Type returned from `serialize_struct_variant` for serializing the
+    /// content of the struct variant.
+    type SerializeStructVariant: SerializeStructVariant<Ok=Self::Ok, Error=Self::Error>;
 
     /// Serializes a `bool` value.
-    fn serialize_bool(&mut self, v: bool) -> Result<(), Self::Error>;
+    fn serialize_bool(self, v: bool) -> Result<Self::Ok, Self::Error>;
 
     /// Serializes an `isize` value. If the format does not differentiate
     /// between `isize` and `i64`, a reasonable implementation would be to cast
     /// the value to `i64` and forward to `serialize_i64`.
-    fn serialize_isize(&mut self, v: isize) -> Result<(), Self::Error>;
+    fn serialize_isize(self, v: isize) -> Result<Self::Ok, Self::Error>;
 
     /// Serializes an `i8` value. If the format does not differentiate between
     /// `i8` and `i64`, a reasonable implementation would be to cast the value
     /// to `i64` and forward to `serialize_i64`.
-    fn serialize_i8(&mut self, v: i8) -> Result<(), Self::Error>;
+    fn serialize_i8(self, v: i8) -> Result<Self::Ok, Self::Error>;
 
     /// Serializes an `i16` value. If the format does not differentiate between
     /// `i16` and `i64`, a reasonable implementation would be to cast the value
     /// to `i64` and forward to `serialize_i64`.
-    fn serialize_i16(&mut self, v: i16) -> Result<(), Self::Error>;
+    fn serialize_i16(self, v: i16) -> Result<Self::Ok, Self::Error>;
 
     /// Serializes an `i32` value. If the format does not differentiate between
     /// `i32` and `i64`, a reasonable implementation would be to cast the value
     /// to `i64` and forward to `serialize_i64`.
-    fn serialize_i32(&mut self, v: i32) -> Result<(), Self::Error>;
+    fn serialize_i32(self, v: i32) -> Result<Self::Ok, Self::Error>;
 
     /// Serializes an `i64` value.
-    fn serialize_i64(&mut self, v: i64) -> Result<(), Self::Error>;
+    fn serialize_i64(self, v: i64) -> Result<Self::Ok, Self::Error>;
 
     /// Serializes a `usize` value. If the format does not differentiate between
     /// `usize` and `u64`, a reasonable implementation would be to cast the
     /// value to `u64` and forward to `serialize_u64`.
-    fn serialize_usize(&mut self, v: usize) -> Result<(), Self::Error>;
+    fn serialize_usize(self, v: usize) -> Result<Self::Ok, Self::Error>;
 
     /// Serializes a `u8` value. If the format does not differentiate between
     /// `u8` and `u64`, a reasonable implementation would be to cast the value
     /// to `u64` and forward to `serialize_u64`.
-    fn serialize_u8(&mut self, v: u8) -> Result<(), Self::Error>;
+    fn serialize_u8(self, v: u8) -> Result<Self::Ok, Self::Error>;
 
     /// Serializes a `u16` value. If the format does not differentiate between
     /// `u16` and `u64`, a reasonable implementation would be to cast the value
     /// to `u64` and forward to `serialize_u64`.
-    fn serialize_u16(&mut self, v: u16) -> Result<(), Self::Error>;
+    fn serialize_u16(self, v: u16) -> Result<Self::Ok, Self::Error>;
 
     /// Serializes a `u32` value. If the format does not differentiate between
     /// `u32` and `u64`, a reasonable implementation would be to cast the value
     /// to `u64` and forward to `serialize_u64`.
-    fn serialize_u32(&mut self, v: u32) -> Result<(), Self::Error>;
+    fn serialize_u32(self, v: u32) -> Result<Self::Ok, Self::Error>;
 
     /// `Serializes a `u64` value.
-    fn serialize_u64(&mut self, v: u64) -> Result<(), Self::Error>;
+    fn serialize_u64(self, v: u64) -> Result<Self::Ok, Self::Error>;
 
     /// Serializes an `f32` value. If the format does not differentiate between
     /// `f32` and `f64`, a reasonable implementation would be to cast the value
     /// to `f64` and forward to `serialize_f64`.
-    fn serialize_f32(&mut self, v: f32) -> Result<(), Self::Error>;
+    fn serialize_f32(self, v: f32) -> Result<Self::Ok, Self::Error>;
 
     /// Serializes an `f64` value.
-    fn serialize_f64(&mut self, v: f64) -> Result<(), Self::Error>;
+    fn serialize_f64(self, v: f64) -> Result<Self::Ok, Self::Error>;
 
     /// Serializes a character. If the format does not support characters,
     /// it is reasonable to serialize it as a single element `str` or a `u32`.
-    fn serialize_char(&mut self, v: char) -> Result<(), Self::Error>;
+    fn serialize_char(self, v: char) -> Result<Self::Ok, Self::Error>;
 
     /// Serializes a `&str`.
-    fn serialize_str(&mut self, value: &str) -> Result<(), Self::Error>;
+    fn serialize_str(self, value: &str) -> Result<Self::Ok, Self::Error>;
 
     /// Enables serializers to serialize byte slices more compactly or more
     /// efficiently than other types of slices. If no efficient implementation
     /// is available, a reasonable implementation would be to forward to
     /// `serialize_seq`. If forwarded, the implementation looks usually just like this:
     /// ```rust
-    /// let mut state = try!(self.serialize_seq(value));
+    /// let mut seq = self.serialize_seq(Some(value.len()))?;
     /// for b in value {
-    ///     try!(self.serialize_seq_elt(&mut state, b));
+    ///     seq.serialize_element(b)?;
     /// }
-    /// self.serialize_seq_end(state)
+    /// seq.end()
     /// ```
-    fn serialize_bytes(&mut self, value: &[u8]) -> Result<(), Self::Error>;
+    fn serialize_bytes(self, value: &[u8]) -> Result<Self::Ok, Self::Error>;
 
     /// Serializes a `()` value. It's reasonable to just not serialize anything.
-    fn serialize_unit(&mut self) -> Result<(), Self::Error>;
+    fn serialize_unit(self) -> Result<Self::Ok, Self::Error>;
 
     /// Serializes a unit struct value. A reasonable implementation would be to
     /// forward to `serialize_unit`.
     fn serialize_unit_struct(
-        &mut self,
+        self,
         name: &'static str,
-    ) -> Result<(), Self::Error>;
+    ) -> Result<Self::Ok, Self::Error>;
 
     /// Serializes a unit variant, otherwise known as a variant with no
     /// arguments. A reasonable implementation would be to forward to
     /// `serialize_unit`.
     fn serialize_unit_variant(
-        &mut self,
+        self,
         name: &'static str,
         variant_index: usize,
         variant: &'static str,
-    ) -> Result<(), Self::Error>;
+    ) -> Result<Self::Ok, Self::Error>;
 
     /// Allows a tuple struct with a single element, also known as a newtype
     /// struct, to be more efficiently serialized than a tuple struct with
     /// multiple items. A reasonable implementation would be to forward to
     /// `serialize_tuple_struct` or to just serialize the inner value without wrapping.
     fn serialize_newtype_struct<T: Serialize>(
-        &mut self,
+        self,
         name: &'static str,
         value: T,
-    ) -> Result<(), Self::Error>;
+    ) -> Result<Self::Ok, Self::Error>;
 
     /// Allows a variant with a single item to be more efficiently serialized
     /// than a variant with multiple items. A reasonable implementation would be
     /// to forward to `serialize_tuple_variant`.
     fn serialize_newtype_variant<T: Serialize>(
-        &mut self,
+        self,
         name: &'static str,
         variant_index: usize,
         variant: &'static str,
         value: T,
-    ) -> Result<(), Self::Error>;
+    ) -> Result<Self::Ok, Self::Error>;
 
     /// Serializes a `None` value.
-    fn serialize_none(&mut self) -> Result<(), Self::Error>;
+    fn serialize_none(self) -> Result<Self::Ok, Self::Error>;
 
     /// Serializes a `Some(...)` value.
     fn serialize_some<T: Serialize>(
-        &mut self,
+        self,
         value: T,
-    ) -> Result<(), Self::Error>;
+    ) -> Result<Self::Ok, Self::Error>;
 
     /// Begins to serialize a sequence. This call must be followed by zero or
     /// more calls to `serialize_seq_elt`, then a call to `serialize_seq_end`.
     fn serialize_seq(
-        &mut self,
+        self,
         len: Option<usize>,
-    ) -> Result<Self::SeqState, Self::Error>;
-
-    /// Serializes a sequence element. Must have previously called
-    /// `serialize_seq`.
-    fn serialize_seq_elt<T: Serialize>(
-        &mut self,
-        state: &mut Self::SeqState,
-        value: T,
-    ) -> Result<(), Self::Error>;
-
-    /// Finishes serializing a sequence.
-    fn serialize_seq_end(
-        &mut self,
-        state: Self::SeqState,
-    ) -> Result<(), Self::Error>;
+    ) -> Result<Self::SerializeSeq, Self::Error>;
 
     /// Begins to serialize a sequence whose length will be known at
     /// deserialization time. This call must be followed by zero or more calls
     /// to `serialize_seq_elt`, then a call to `serialize_seq_end`. A reasonable
     /// implementation would be to forward to `serialize_seq`.
     fn serialize_seq_fixed_size(
-        &mut self,
+        self,
         size: usize,
-    ) -> Result<Self::SeqState, Self::Error>;
+    ) -> Result<Self::SerializeSeq, Self::Error>;
 
     /// Begins to serialize a tuple. This call must be followed by zero or more
     /// calls to `serialize_tuple_elt`, then a call to `serialize_tuple_end`. A
     /// reasonable implementation would be to forward to `serialize_seq`.
     fn serialize_tuple(
-        &mut self,
+        self,
         len: usize,
-    ) -> Result<Self::TupleState, Self::Error>;
-
-    /// Serializes a tuple element. Must have previously called
-    /// `serialize_tuple`.
-    fn serialize_tuple_elt<T: Serialize>(
-        &mut self,
-        state: &mut Self::TupleState,
-        value: T,
-    ) -> Result<(), Self::Error>;
-
-    /// Finishes serializing a tuple.
-    fn serialize_tuple_end(
-        &mut self,
-        state: Self::TupleState,
-    ) -> Result<(), Self::Error>;
+    ) -> Result<Self::SerializeTuple, Self::Error>;
 
     /// Begins to serialize a tuple struct. This call must be followed by zero
     /// or more calls to `serialize_tuple_struct_elt`, then a call to
     /// `serialize_tuple_struct_end`. A reasonable implementation would be to
     /// forward to `serialize_tuple`.
     fn serialize_tuple_struct(
-        &mut self,
+        self,
         name: &'static str,
         len: usize,
-    ) -> Result<Self::TupleStructState, Self::Error>;
-
-    /// Serializes a tuple struct element. Must have previously called
-    /// `serialize_tuple_struct`.
-    fn serialize_tuple_struct_elt<T: Serialize>(
-        &mut self,
-        state: &mut Self::TupleStructState,
-        value: T,
-    ) -> Result<(), Self::Error>;
-
-    /// Finishes serializing a tuple struct.
-    fn serialize_tuple_struct_end(
-        &mut self,
-        state: Self::TupleStructState,
-    ) -> Result<(), Self::Error>;
+    ) -> Result<Self::SerializeTupleStruct, Self::Error>;
 
     /// Begins to serialize a tuple variant. This call must be followed by zero
     /// or more calls to `serialize_tuple_variant_elt`, then a call to
     /// `serialize_tuple_variant_end`. A reasonable implementation would be to
     /// forward to `serialize_tuple_struct`.
     fn serialize_tuple_variant(
-        &mut self,
+        self,
         name: &'static str,
         variant_index: usize,
         variant: &'static str,
         len: usize,
-    ) -> Result<Self::TupleVariantState, Self::Error>;
-
-    /// Serializes a tuple variant element. Must have previously called
-    /// `serialize_tuple_variant`.
-    fn serialize_tuple_variant_elt<T: Serialize>(
-        &mut self,
-        state: &mut Self::TupleVariantState,
-        value: T,
-    ) -> Result<(), Self::Error>;
-
-    /// Finishes serializing a tuple variant.
-    fn serialize_tuple_variant_end(
-        &mut self,
-        state: Self::TupleVariantState,
-    ) -> Result<(), Self::Error>;
+    ) -> Result<Self::SerializeTupleVariant, Self::Error>;
 
     /// Begins to serialize a map. This call must be followed by zero or more
     /// calls to `serialize_map_key` and `serialize_map_value`, then a call to
     /// `serialize_map_end`.
     fn serialize_map(
-        &mut self,
+        self,
         len: Option<usize>,
-    ) -> Result<Self::MapState, Self::Error>;
-
-    /// Serialize a map key. Must have previously called `serialize_map`.
-    fn serialize_map_key<T: Serialize>(
-        &mut self,
-        state: &mut Self::MapState,
-        key: T
-    ) -> Result<(), Self::Error>;
-
-    /// Serialize a map value. Must have previously called `serialize_map`.
-    fn serialize_map_value<T: Serialize>(
-        &mut self,
-        state: &mut Self::MapState,
-        value: T
-    ) -> Result<(), Self::Error>;
-
-    /// Finishes serializing a map.
-    fn serialize_map_end(
-        &mut self,
-        state: Self::MapState,
-    ) -> Result<(), Self::Error>;
+    ) -> Result<Self::SerializeMap, Self::Error>;
 
     /// Begins to serialize a struct. This call must be followed by zero or more
     /// calls to `serialize_struct_elt`, then a call to `serialize_struct_end`.
     fn serialize_struct(
-        &mut self,
+        self,
         name: &'static str,
         len: usize,
-    ) -> Result<Self::StructState, Self::Error>;
-
-    /// Serializes a struct field. Must have previously called
-    /// `serialize_struct`.
-    fn serialize_struct_elt<V: Serialize>(
-        &mut self,
-        state: &mut Self::StructState,
-        key: &'static str,
-        value: V,
-    ) -> Result<(), Self::Error>;
-
-    /// Finishes serializing a struct.
-    fn serialize_struct_end(
-        &mut self,
-        state: Self::StructState,
-    ) -> Result<(), Self::Error>;
+    ) -> Result<Self::SerializeStruct, Self::Error>;
 
     /// Begins to serialize a struct variant. This call must be followed by zero
     /// or more calls to `serialize_struct_variant_elt`, then a call to
     /// `serialize_struct_variant_end`.
     fn serialize_struct_variant(
-        &mut self,
+        self,
         name: &'static str,
         variant_index: usize,
         variant: &'static str,
         len: usize,
-    ) -> Result<Self::StructVariantState, Self::Error>;
+    ) -> Result<Self::SerializeStructVariant, Self::Error>;
+}
 
-    /// Serialize a struct variant element. Must have previously called
-    /// `serialize_struct_variant`.
-    fn serialize_struct_variant_elt<V: Serialize>(
-        &mut self,
-        state: &mut Self::StructVariantState,
-        key: &'static str,
-        value: V,
-    ) -> Result<(), Self::Error>;
+/// Returned from `Serializer::serialize_seq` and
+/// `Serializer::serialize_seq_fixed_size`.
+pub trait SerializeSeq {
+    /// Trickery to enforce correct use of the `Serialize` trait. Every
+    /// `SerializeSeq` should set `Ok = ()`.
+    type Ok;
+
+    /// The error type when some error occurs during serialization.
+    type Error: Error;
+
+    /// Serializes a sequence element.
+    fn serialize_element<T: Serialize>(&mut self, value: T) -> Result<(), Self::Error>;
+
+    /// Finishes serializing a sequence.
+    fn end(self) -> Result<Self::Ok, Self::Error>;
+}
+
+/// Returned from `Serializer::serialize_tuple`.
+pub trait SerializeTuple {
+    /// Trickery to enforce correct use of the `Serialize` trait. Every
+    /// `SerializeTuple` should set `Ok = ()`.
+    type Ok;
+
+    /// The error type when some error occurs during serialization.
+    type Error: Error;
+
+    /// Serializes a tuple element.
+    fn serialize_element<T: Serialize>(&mut self, value: T) -> Result<(), Self::Error>;
+
+    /// Finishes serializing a tuple.
+    fn end(self) -> Result<Self::Ok, Self::Error>;
+}
+
+/// Returned from `Serializer::serialize_tuple_struct`.
+pub trait SerializeTupleStruct {
+    /// Trickery to enforce correct use of the `Serialize` trait. Every
+    /// `SerializeTupleStruct` should set `Ok = ()`.
+    type Ok;
+
+    /// The error type when some error occurs during serialization.
+    type Error: Error;
+
+    /// Serializes a tuple struct element.
+    fn serialize_field<T: Serialize>(&mut self, value: T) -> Result<(), Self::Error>;
+
+    /// Finishes serializing a tuple struct.
+    fn end(self) -> Result<Self::Ok, Self::Error>;
+}
+
+/// Returned from `Serializer::serialize_tuple_variant`.
+pub trait SerializeTupleVariant {
+    /// Trickery to enforce correct use of the `Serialize` trait. Every
+    /// `SerializeTupleVariant` should set `Ok = ()`.
+    type Ok;
+
+    /// The error type when some error occurs during serialization.
+    type Error: Error;
+
+    /// Serializes a tuple variant element.
+    fn serialize_field<T: Serialize>(&mut self, value: T) -> Result<(), Self::Error>;
+
+    /// Finishes serializing a tuple variant.
+    fn end(self) -> Result<Self::Ok, Self::Error>;
+}
+
+/// Returned from `Serializer::serialize_map`.
+pub trait SerializeMap {
+    /// Trickery to enforce correct use of the `Serialize` trait. Every
+    /// `SerializeMap` should set `Ok = ()`.
+    type Ok;
+
+    /// The error type when some error occurs during serialization.
+    type Error: Error;
+
+    /// Serialize a map key.
+    fn serialize_key<T: Serialize>(&mut self, key: T) -> Result<(), Self::Error>;
+
+    /// Serialize a map value.
+    fn serialize_value<T: Serialize>(&mut self, value: T) -> Result<(), Self::Error>;
+
+    /// Finishes serializing a map.
+    fn end(self) -> Result<Self::Ok, Self::Error>;
+}
+
+/// Returned from `Serializer::serialize_struct`.
+pub trait SerializeStruct {
+    /// Trickery to enforce correct use of the `Serialize` trait. Every
+    /// `SerializeStruct` should set `Ok = ()`.
+    type Ok;
+
+    /// The error type when some error occurs during serialization.
+    type Error: Error;
+
+    /// Serializes a struct field.
+    fn serialize_field<V: Serialize>(&mut self, key: &'static str, value: V) -> Result<(), Self::Error>;
+
+    /// Finishes serializing a struct.
+    fn end(self) -> Result<Self::Ok, Self::Error>;
+}
+
+/// Returned from `Serializer::serialize_struct_variant`.
+pub trait SerializeStructVariant {
+    /// Trickery to enforce correct use of the `Serialize` trait. Every
+    /// `SerializeStructVariant` should set `Ok = ()`.
+    type Ok;
+
+    /// The error type when some error occurs during serialization.
+    type Error: Error;
+
+    /// Serialize a struct variant element.
+    fn serialize_field<V: Serialize>(&mut self, key: &'static str, value: V) -> Result<(), Self::Error>;
 
     /// Finishes serializing a struct variant.
-    fn serialize_struct_variant_end(
-        &mut self,
-        state: Self::StructVariantState,
-    ) -> Result<(), Self::Error>;
+    fn end(self) -> Result<Self::Ok, Self::Error>;
+}
+
+/// A wrapper type for iterators that implements `Serialize` for iterators whose items implement
+/// `Serialize`. Don't use multiple times. Create new versions of this with the `iterator` function
+/// every time you want to serialize an iterator.
+#[cfg(feature = "unstable")]
+pub struct Iterator<I>(RefCell<Option<I>>)
+    where <I as IntoIterator>::Item: Serialize,
+          I: IntoIterator;
+
+/// Creates a temporary type that can be passed to any function expecting a `Serialize` and will
+/// serialize the given iterator as a sequence
+#[cfg(feature = "unstable")]
+pub fn iterator<I>(iter: I) -> Iterator<I>
+    where <I as IntoIterator>::Item: Serialize,
+          I: IntoIterator
+{
+    Iterator(RefCell::new(Some(iter)))
 }

serde_codegen/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "serde_codegen"
-version = "0.8.17"
+version = "0.9.0-rc1"
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>"]
 license = "MIT/Apache-2.0"
 description = "Macros to auto-generate implementations for the serde framework"
@@ -22,9 +22,8 @@ with-syn = []
 
 [dependencies]
 clippy = { version = "^0.*", optional = true }
-post-expansion = "0.1.0"
-quote = "0.3"
-serde_codegen_internals = { version = "=0.10.0", default-features = false, path = "../serde_codegen_internals" }
-syn = { version = "0.9", features = ["aster", "visit"] }
-syntex = { version = "^0.48.0", optional = true }
-syntex_syntax = { version = "^0.48.0", optional = true }
+quote = "0.3.8"
+serde_codegen_internals = { version = "=0.11.3", default-features = false, path = "../serde_codegen_internals" }
+syn = { version = "0.10", features = ["aster", "visit"] }
+syntex = { version = "^0.54.0", optional = true }
+syntex_syntax = { version = "^0.54.0", optional = true }

serde_codegen/src/de.rs

@@ -1,5 +1,5 @@
-use syn::{self, aster};
-use quote::{self, Tokens};
+use syn::{self, aster, Ident};
+use quote::Tokens;
 
 use bound;
 use internals::ast::{Body, Field, Item, Style, Variant};
@@ -28,16 +28,16 @@ pub fn expand_derive_deserialize(item: &syn::MacroInput) -> Result<Tokens, Strin
 
     let where_clause = &impl_generics.where_clause;
 
-    let dummy_const = aster::id(format!("_IMPL_DESERIALIZE_FOR_{}", item.ident));
+    let dummy_const = Ident::new(format!("_IMPL_DESERIALIZE_FOR_{}", item.ident));
 
     Ok(quote! {
         #[allow(non_upper_case_globals, unused_attributes, unused_qualifications)]
         const #dummy_const: () = {
             extern crate serde as _serde;
             #[automatically_derived]
-            impl #impl_generics _serde::de::Deserialize for #ty #where_clause {
-                fn deserialize<__D>(deserializer: &mut __D) -> ::std::result::Result<#ty, __D::Error>
-                    where __D: _serde::de::Deserializer
+            impl #impl_generics _serde::Deserialize for #ty #where_clause {
+                fn deserialize<__D>(deserializer: __D) -> ::std::result::Result<#ty, __D::Error>
+                    where __D: _serde::Deserializer
                 #body
             }
         };
@@ -61,7 +61,7 @@ fn build_impl_generics(item: &Item) -> syn::Generics {
         None => {
             let generics = bound::with_bound(item, &generics,
                 needs_deserialize_bound,
-                &aster::path().ids(&["_serde", "de", "Deserialize"]).build());
+                &aster::path().ids(&["_serde", "Deserialize"]).build());
             bound::with_bound(item, &generics,
                 requires_default,
                 &aster::path().global().ids(&["std", "default", "Default"]).build())
@@ -175,16 +175,10 @@ fn deserialize_visitor(generics: &syn::Generics) -> (Tokens, Tokens, Tokens) {
                     quote!(#ident)
                 }));
 
-        let ty_param_idents: Vec<_> = generics.ty_params.iter()
-            .map(|t| {
-                let ident = &t.ident;
-                quote!(#ident)
-            })
-            .collect();
-
-        let ty_param_idents = if ty_param_idents.is_empty() {
+        let ty_param_idents = if generics.ty_params.is_empty() {
             None
         } else {
+            let ty_param_idents = generics.ty_params.iter().map(|t| &t.ident);
             Some(quote!(::<#(#ty_param_idents),*>))
         };
 
@@ -213,18 +207,17 @@ fn deserialize_unit_struct(
             type Value = #type_ident;
 
             #[inline]
-            fn visit_unit<__E>(&mut self) -> ::std::result::Result<#type_ident, __E>
+            fn visit_unit<__E>(self) -> ::std::result::Result<#type_ident, __E>
                 where __E: _serde::de::Error,
             {
                 Ok(#type_ident)
             }
 
             #[inline]
-            fn visit_seq<__V>(&mut self, mut visitor: __V) -> ::std::result::Result<#type_ident, __V::Error>
+            fn visit_seq<__V>(self, _: __V) -> ::std::result::Result<#type_ident, __V::Error>
                 where __V: _serde::de::SeqVisitor,
             {
-                try!(visitor.end());
-                self.visit_unit()
+                Ok(#type_ident)
             }
         }
 
@@ -272,7 +265,7 @@ fn deserialize_tuple(
     );
 
     let dispatch = if is_enum {
-        quote!(visitor.visit_tuple(#nfields, #visitor_expr))
+        quote!(_serde::de::VariantVisitor::visit_tuple(visitor, #nfields, #visitor_expr))
     } else if nfields == 1 {
         let type_name = item_attrs.name().deserialize_name();
         quote!(deserializer.deserialize_newtype_struct(#type_name, #visitor_expr))
@@ -281,6 +274,13 @@ fn deserialize_tuple(
         quote!(deserializer.deserialize_tuple_struct(#type_name, #nfields, #visitor_expr))
     };
 
+    let all_skipped = fields.iter().all(|field| field.attrs.skip_deserializing());
+    let visitor_var = if all_skipped {
+        quote!(_)
+    } else {
+        quote!(mut visitor)
+    };
+
     quote!({
         #visitor_item
 
@@ -290,7 +290,7 @@ fn deserialize_tuple(
             #visit_newtype_struct
 
             #[inline]
-            fn visit_seq<__V>(&mut self, mut visitor: __V) -> ::std::result::Result<#ty, __V::Error>
+            fn visit_seq<__V>(self, #visitor_var: __V) -> ::std::result::Result<#ty, __V::Error>
                 where __V: _serde::de::SeqVisitor
             {
                 #visit_seq
@@ -308,15 +308,15 @@ fn deserialize_seq(
     fields: &[Field],
     is_struct: bool,
 ) -> Tokens {
+    let vars = (0..fields.len()).map(field_i as fn(_) -> _);
+
     let mut index_in_seq = 0usize;
-    let let_values: Vec<_> = fields.iter()
-        .enumerate()
-        .map(|(i, field)| {
-            let name = aster::id(format!("__field{}", i));
+    let let_values = vars.clone().zip(fields)
+        .map(|(var, field)| {
             if field.attrs.skip_deserializing() {
                 let default = expr_is_missing(&field.attrs);
                 quote! {
-                    let #name = #default;
+                    let #var = #default;
                 }
             } else {
                 let visit = match field.attrs.deserialize_with() {
@@ -335,10 +335,9 @@ fn deserialize_seq(
                     }
                 };
                 let assign = quote! {
-                    let #name = match #visit {
+                    let #var = match #visit {
                         Some(value) => { value },
                         None => {
-                            try!(visitor.end());
                             return Err(_serde::de::Error::invalid_length(#index_in_seq));
                         }
                     };
@@ -346,32 +345,21 @@ fn deserialize_seq(
                 index_in_seq += 1;
                 assign
             }
-        })
-        .collect();
+        });
 
     let result = if is_struct {
-        let args = fields.iter()
-            .enumerate()
-            .map(|(i, field)| {
-                let ident = field.ident.clone().expect("struct contains unnamed fields");
-                let value = aster::id(format!("__field{}", i));
-                quote!(#ident: #value)
-            });
+        let names = fields.iter().map(|f| &f.ident);
         quote! {
-            #type_path { #(#args),* }
+            #type_path { #( #names: #vars ),* }
         }
     } else {
-        let args = (0..fields.len()).map(|i| aster::id(format!("__field{}", i)));
         quote! {
-            #type_path ( #(#args),* )
+            #type_path ( #(#vars),* )
         }
     };
 
     quote! {
         #(#let_values)*
-
-        try!(visitor.end());
-
         Ok(#result)
     }
 }
@@ -401,8 +389,8 @@ fn deserialize_newtype_struct(
     };
     quote! {
         #[inline]
-        fn visit_newtype_struct<__E>(&mut self, __e: &mut __E) -> ::std::result::Result<Self::Value, __E::Error>
-            where __E: _serde::de::Deserializer,
+        fn visit_newtype_struct<__E>(self, __e: __E) -> ::std::result::Result<Self::Value, __E::Error>
+            where __E: _serde::Deserializer,
         {
             Ok(#type_path(#value))
         }
@@ -445,7 +433,7 @@ fn deserialize_struct(
     let is_enum = variant_ident.is_some();
     let dispatch = if is_enum {
         quote! {
-            visitor.visit_struct(FIELDS, #visitor_expr)
+            _serde::de::VariantVisitor::visit_struct(visitor, FIELDS, #visitor_expr)
         }
     } else {
         let type_name = item_attrs.name().deserialize_name();
@@ -454,6 +442,13 @@ fn deserialize_struct(
         }
     };
 
+    let all_skipped = fields.iter().all(|field| field.attrs.skip_deserializing());
+    let visitor_var = if all_skipped {
+        quote!(_)
+    } else {
+        quote!(mut visitor)
+    };
+
     quote!({
         #field_visitor
 
@@ -463,14 +458,14 @@ fn deserialize_struct(
             type Value = #ty;
 
             #[inline]
-            fn visit_seq<__V>(&mut self, mut visitor: __V) -> ::std::result::Result<#ty, __V::Error>
+            fn visit_seq<__V>(self, #visitor_var: __V) -> ::std::result::Result<#ty, __V::Error>
                 where __V: _serde::de::SeqVisitor
             {
                 #visit_seq
             }
 
             #[inline]
-            fn visit_map<__V>(&mut self, mut visitor: __V) -> ::std::result::Result<#ty, __V::Error>
+            fn visit_map<__V>(self, mut visitor: __V) -> ::std::result::Result<#ty, __V::Error>
                 where __V: _serde::de::MapVisitor
             {
                 #visit_map
@@ -494,48 +489,61 @@ fn deserialize_item_enum(
 
     let type_name = item_attrs.name().deserialize_name();
 
+    let variant_names_idents = variants.iter()
+        .enumerate()
+        .filter(|&(_, variant)| !variant.attrs.skip_deserializing())
+        .map(|(i, variant)| (variant.attrs.name().deserialize_name(), field_i(i)))
+        .collect();
+
     let variant_visitor = deserialize_field_visitor(
-        variants.iter()
-            .map(|variant| variant.attrs.name().deserialize_name())
-            .collect(),
+        variant_names_idents,
         item_attrs,
         true,
     );
 
-    let variant_names = variants.iter().map(|variant| variant.ident.to_string());
+    let variant_names = variants.iter().map(|variant| variant.attrs.name().deserialize_name());
 
     let variants_stmt = quote! {
         const VARIANTS: &'static [&'static str] = &[ #(#variant_names),* ];
     };
 
-    let ignored_arm = if item_attrs.deny_unknown_fields() {
-        None
-    } else {
-        Some(quote! {
-            __Field::__ignore => { Err(_serde::de::Error::end_of_stream()) }
-        })
-    };
-
     // Match arms to extract a variant from a string
-    let mut variant_arms = vec![];
-    for (i, variant) in variants.iter().enumerate() {
-        let variant_name = aster::id(format!("__field{}", i));
-        let variant_name = quote!(__Field::#variant_name);
+    let variant_arms = variants.iter()
+        .enumerate()
+        .filter(|&(_, variant)| !variant.attrs.skip_deserializing())
+        .map(|(i, variant)| {
+            let variant_name = field_i(i);
 
-        let block = deserialize_variant(
-            type_ident,
-            impl_generics,
-            ty.clone(),
-            variant,
-            item_attrs,
-        );
+            let block = deserialize_variant(
+                type_ident,
+                impl_generics,
+                ty.clone(),
+                variant,
+                item_attrs,
+            );
 
-        let arm = quote! {
-            #variant_name => #block
-        };
-        variant_arms.push(arm);
-    }
-    variant_arms.extend(ignored_arm.into_iter());
+            quote! {
+                (__Field::#variant_name, visitor) => #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 we drop support for Rust 1.15:
+            // let Err(err) = visitor.visit_variant::<__Field>();
+            // Err(err)
+            visitor.visit_variant::<__Field>().map(|(impossible, _)| match impossible {})
+        }
+    } else {
+        quote! {
+            match try!(visitor.visit_variant()) {
+                #(#variant_arms)*
+            }
+        }
+    };
 
     let (visitor_item, visitor_ty, visitor_expr) = deserialize_visitor(impl_generics);
 
@@ -544,15 +552,13 @@ fn deserialize_item_enum(
 
         #visitor_item
 
-        impl #impl_generics _serde::de::EnumVisitor for #visitor_ty #where_clause {
+        impl #impl_generics _serde::de::Visitor for #visitor_ty #where_clause {
             type Value = #ty;
 
-            fn visit<__V>(&mut self, mut visitor: __V) -> ::std::result::Result<#ty, __V::Error>
-                where __V: _serde::de::VariantVisitor,
+            fn visit_enum<__V>(self, visitor: __V) -> ::std::result::Result<#ty, __V::Error>
+                where __V: _serde::de::EnumVisitor,
             {
-                match try!(visitor.visit_variant()) {
-                    #(#variant_arms)*
-                }
+                #match_variant
             }
         }
 
@@ -574,7 +580,7 @@ fn deserialize_variant(
     match variant.style {
         Style::Unit => {
             quote!({
-                try!(visitor.visit_unit());
+                try!(_serde::de::VariantVisitor::visit_unit(visitor));
                 Ok(#type_ident::#variant_ident)
             })
         }
@@ -618,7 +624,9 @@ fn deserialize_newtype_variant(
     let visit = match field.attrs.deserialize_with() {
         None => {
             let field_ty = &field.ty;
-            quote!(try!(visitor.visit_newtype::<#field_ty>()))
+            quote! {
+                try!(_serde::de::VariantVisitor::visit_newtype::<#field_ty>(visitor))
+            }
         }
         Some(path) => {
             let (wrapper, wrapper_impl, wrapper_ty) = wrap_deserialize_with(
@@ -626,7 +634,7 @@ fn deserialize_newtype_variant(
             quote!({
                 #wrapper
                 #wrapper_impl
-                try!(visitor.visit_newtype::<#wrapper_ty>()).value
+                try!(_serde::de::VariantVisitor::visit_newtype::<#wrapper_ty>(visitor)).value
             })
         }
     };
@@ -636,105 +644,31 @@ fn deserialize_newtype_variant(
 }
 
 fn deserialize_field_visitor(
-    field_names: Vec<String>,
+    fields: Vec<(String, Ident)>,
     item_attrs: &attr::Item,
     is_variant: bool,
 ) -> Tokens {
-    // Create the field names for the fields.
-    let field_idents: Vec<_> = (0 .. field_names.len())
-        .map(|i| aster::id(format!("__field{}", i)))
-        .collect();
+    let field_names = fields.iter().map(|&(ref name, _)| name);
+    let field_idents: &Vec<_> = &fields.iter().map(|&(_, ref ident)| ident).collect();
 
-    let ignore_variant = if item_attrs.deny_unknown_fields() {
+    let ignore_variant = if is_variant || item_attrs.deny_unknown_fields() {
         None
     } else {
         Some(quote!(__ignore,))
     };
 
-    let index_field_arms: Vec<_> = field_idents.iter()
-        .enumerate()
-        .map(|(field_index, field_ident)| {
-            quote! {
-                #field_index => { Ok(__Field::#field_ident) }
-            }
-        })
-        .collect();
-
-    let (index_error_msg, unknown_ident) = if is_variant {
-        ("expected a variant", aster::id("unknown_variant"))
+    let fallthrough_arm = if is_variant {
+        quote! {
+            Err(_serde::de::Error::unknown_variant(value))
+        }
+    } else if item_attrs.deny_unknown_fields() {
+        quote! {
+            Err(_serde::de::Error::unknown_field(value))
+        }
     } else {
-        ("expected a field", aster::id("unknown_field"))
-    };
-
-    let fallthrough_index_arm_expr = if !is_variant && !item_attrs.deny_unknown_fields() {
         quote! {
             Ok(__Field::__ignore)
         }
-    } else {
-        quote! {
-            Err(_serde::de::Error::invalid_value(#index_error_msg))
-        }
-    };
-
-    let index_body = quote! {
-        match value {
-            #(#index_field_arms)*
-            _ => #fallthrough_index_arm_expr
-        }
-    };
-
-    // Match arms to extract a field from a string
-    let str_field_arms: Vec<_> = field_idents.iter().zip(field_names.iter())
-        .map(|(field_ident, field_name)| {
-            quote! {
-                #field_name => { Ok(__Field::#field_ident) }
-            }
-        })
-        .collect();
-
-    let fallthrough_str_arm_expr = if !is_variant && !item_attrs.deny_unknown_fields() {
-        quote! {
-            Ok(__Field::__ignore)
-        }
-    } else {
-        quote! {
-            Err(_serde::de::Error::#unknown_ident(value))
-        }
-    };
-
-    let str_body = quote! {
-        match value {
-            #(#str_field_arms)*
-            _ => #fallthrough_str_arm_expr
-        }
-    };
-
-    // Match arms to extract a field from a string
-    let bytes_field_arms: Vec<_> = field_idents.iter().zip(field_names.iter())
-        .map(|(field_ident, field_name)| {
-            let bytes_field_name = quote::ByteStr(field_name);
-            quote! {
-                #bytes_field_name => { Ok(__Field::#field_ident) }
-            }
-        })
-        .collect();
-
-    let fallthrough_bytes_arm_expr = if !is_variant && !item_attrs.deny_unknown_fields() {
-        quote! {
-            Ok(__Field::__ignore)
-        }
-    } else {
-        quote!({
-            let value = ::std::string::String::from_utf8_lossy(value);
-            Err(_serde::de::Error::#unknown_ident(&value))
-        })
-    };
-
-    let bytes_body = quote! {
-        match value {
-            #(#bytes_field_arms)*
-            _ => #fallthrough_bytes_arm_expr
-        }
     };
 
     quote! {
@@ -744,32 +678,25 @@ fn deserialize_field_visitor(
             #ignore_variant
         }
 
-        impl _serde::de::Deserialize for __Field {
+        impl _serde::Deserialize for __Field {
             #[inline]
-            fn deserialize<__D>(deserializer: &mut __D) -> ::std::result::Result<__Field, __D::Error>
-                where __D: _serde::de::Deserializer,
+            fn deserialize<__D>(deserializer: __D) -> ::std::result::Result<__Field, __D::Error>
+                where __D: _serde::Deserializer,
             {
                 struct __FieldVisitor;
 
                 impl _serde::de::Visitor for __FieldVisitor {
                     type Value = __Field;
 
-                    fn visit_usize<__E>(&mut self, value: usize) -> ::std::result::Result<__Field, __E>
+                    fn visit_str<__E>(self, value: &str) -> ::std::result::Result<__Field, __E>
                         where __E: _serde::de::Error
                     {
-                        #index_body
-                    }
-
-                    fn visit_str<__E>(&mut self, value: &str) -> ::std::result::Result<__Field, __E>
-                        where __E: _serde::de::Error
-                    {
-                        #str_body
-                    }
-
-                    fn visit_bytes<__E>(&mut self, value: &[u8]) -> ::std::result::Result<__Field, __E>
-                        where __E: _serde::de::Error
-                    {
-                        #bytes_body
+                        match value {
+                            #(
+                                #field_names => Ok(__Field::#field_idents),
+                            )*
+                            _ => #fallthrough_arm
+                        }
                     }
                 }
 
@@ -786,12 +713,14 @@ fn deserialize_struct_visitor(
     fields: &[Field],
     item_attrs: &attr::Item,
 ) -> (Tokens, Tokens, Tokens) {
-    let field_exprs = fields.iter()
-        .map(|field| field.attrs.name().deserialize_name())
+    let field_names_idents = fields.iter()
+        .enumerate()
+        .filter(|&(_, field)| !field.attrs.skip_deserializing())
+        .map(|(i, field)| (field.attrs.name().deserialize_name(), field_i(i)))
         .collect();
 
     let field_visitor = deserialize_field_visitor(
-        field_exprs,
+        field_names_idents,
         item_attrs,
         false,
     );
@@ -804,10 +733,7 @@ fn deserialize_struct_visitor(
         item_attrs,
     );
 
-    let field_names = fields.iter().map(|field| {
-        field.ident.clone().expect("struct contains unnamed field").to_string()
-    });
-
+    let field_names = fields.iter().map(|field| field.attrs.name().deserialize_name());
     let fields_stmt = quote! {
         const FIELDS: &'static [&'static str] = &[ #(#field_names),* ];
     };
@@ -823,22 +749,20 @@ fn deserialize_map(
     item_attrs: &attr::Item,
 ) -> Tokens {
     // Create the field names for the fields.
-    let fields_names = fields.iter()
+    let fields_names: Vec<_> = fields.iter()
         .enumerate()
-        .map(|(i, field)|
-             (field, aster::id(format!("__field{}", i))))
-        .collect::<Vec<_>>();
+        .map(|(i, field)| (field, field_i(i)))
+        .collect();
 
     // Declare each field that will be deserialized.
-    let let_values: Vec<_> = fields_names.iter()
+    let let_values = fields_names.iter()
         .filter(|&&(field, _)| !field.attrs.skip_deserializing())
         .map(|&(field, ref name)| {
             let field_ty = &field.ty;
             quote! {
                 let mut #name: Option<#field_ty> = None;
             }
-        })
-        .collect();
+        });
 
     // Match arms to extract a value for a field.
     let value_arms = fields_names.iter()
@@ -871,21 +795,7 @@ fn deserialize_map(
                     #name = Some(#visit);
                 }
             }
-        })
-        .collect::<Vec<_>>();
-
-    // Match arms to ignore value for fields that have `skip_deserializing`.
-    // Ignored even if `deny_unknown_fields` is set.
-    let skipped_arms = fields_names.iter()
-        .filter(|&&(field, _)| field.attrs.skip_deserializing())
-        .map(|&(_, ref name)| {
-            quote! {
-                __Field::#name => {
-                    let _ = try!(visitor.visit_value::<_serde::de::impls::IgnoredAny>());
-                }
-            }
-        })
-        .collect::<Vec<_>>();
+        });
 
     // Visit ignored values to consume them
     let ignored_arm = if item_attrs.deny_unknown_fields() {
@@ -896,6 +806,24 @@ fn deserialize_map(
         })
     };
 
+    let all_skipped = fields.iter().all(|field| field.attrs.skip_deserializing());
+    let match_keys = if item_attrs.deny_unknown_fields() && all_skipped {
+        quote! {
+            // FIXME: Once we drop support for Rust 1.15:
+            // let None::<__Field> = try!(visitor.visit_key());
+            try!(visitor.visit_key::<__Field>()).map(|impossible| match impossible {});
+        }
+    } else {
+        quote! {
+            while let Some(key) = try!(visitor.visit_key::<__Field>()) {
+                match key {
+                    #(#value_arms)*
+                    #ignored_arm
+                }
+            }
+        }
+    };
+
     let extract_values = fields_names.iter()
         .filter(|&&(field, _)| !field.attrs.skip_deserializing())
         .map(|&(field, ref name)| {
@@ -907,8 +835,7 @@ fn deserialize_map(
                     None => #missing_expr
                 };
             }
-        })
-        .collect::<Vec<_>>();
+        });
 
     let result = fields_names.iter()
         .map(|&(field, ref name)| {
@@ -924,15 +851,7 @@ fn deserialize_map(
     quote! {
         #(#let_values)*
 
-        while let Some(key) = try!(visitor.visit_key::<__Field>()) {
-            match key {
-                #(#value_arms)*
-                #(#skipped_arms)*
-                #ignored_arm
-            }
-        }
-
-        try!(visitor.end());
+        #match_keys
 
         #(#extract_values)*
 
@@ -940,6 +859,10 @@ fn deserialize_map(
     }
 }
 
+fn field_i(i: usize) -> Ident {
+    Ident::new(format!("__field{}", i))
+}
+
 /// This function wraps the expression in `#[serde(deserialize_with="...")]` in
 /// a trait to prevent it from accessing the internal `Deserialize` state.
 fn wrap_deserialize_with(
@@ -974,9 +897,9 @@ fn wrap_deserialize_with(
             }
         },
         quote! {
-            impl #impl_generics _serde::de::Deserialize for #wrapper_ty #where_clause {
-                fn deserialize<__D>(__d: &mut __D) -> ::std::result::Result<Self, __D::Error>
-                    where __D: _serde::de::Deserializer
+            impl #impl_generics _serde::Deserialize for #wrapper_ty #where_clause {
+                fn deserialize<__D>(__d: __D) -> ::std::result::Result<Self, __D::Error>
+                    where __D: _serde::Deserializer
                 {
                     let value = try!(#deserialize_with(__d));
                     Ok(__SerdeDeserializeWithStruct {

serde_codegen/src/lib.rs

@@ -2,7 +2,6 @@
 #![cfg_attr(feature = "clippy", feature(plugin))]
 #![cfg_attr(feature = "clippy", allow(too_many_arguments))]
 #![cfg_attr(feature = "clippy", allow(used_underscore_binding))]
-#![cfg_attr(not(feature = "with-syntex"), feature(rustc_private, plugin))]
 
 // The `quote!` macro requires deep recursion.
 #![recursion_limit = "192"]
@@ -16,26 +15,13 @@ extern crate syntex;
 #[macro_use]
 extern crate syntex_syntax as syntax;
 
-#[cfg(not(feature = "with-syntex"))]
-#[macro_use]
-extern crate syntax;
-
-#[cfg(not(feature = "with-syntex"))]
-extern crate rustc_plugin;
-
 extern crate syn;
 #[macro_use]
 extern crate quote;
 
-#[cfg(feature = "with-syn")]
-extern crate post_expansion;
-
 #[cfg(feature = "with-syntex")]
 use std::path::Path;
 
-#[cfg(not(feature = "with-syntex"))]
-use syntax::feature_gate::AttributeType;
-
 mod bound;
 mod de;
 mod ser;
@@ -52,11 +38,11 @@ fn syntex_registry() -> syntex::Registry {
 
         impl fold::Folder for StripAttributeFolder {
             fn fold_attribute(&mut self, attr: ast::Attribute) -> Option<ast::Attribute> {
-                match attr.node.value.node {
-                    ast::MetaItemKind::List(ref n, _) if n == &"serde" => { return None; }
-                    _ => {}
+                if attr.value.name == "serde" {
+                    if let ast::MetaItemKind::List(..) = attr.value.node {
+                        return None;
+                    }
                 }
-
                 Some(attr)
             }
 
@@ -73,8 +59,8 @@ fn syntex_registry() -> syntex::Registry {
     reg.add_attr("feature(custom_derive)");
     reg.add_attr("feature(custom_attribute)");
 
-    reg.add_decorator("derive_Serialize", expand_derive_serialize);
-    reg.add_decorator("derive_Deserialize", expand_derive_deserialize);
+    reg.add_decorator("derive_Serialize", shim::expand_derive_serialize);
+    reg.add_decorator("derive_Deserialize", shim::expand_derive_deserialize);
 
     reg.add_post_expansion_pass(strip_attributes);
 
@@ -107,24 +93,9 @@ pub fn expand<S, D>(src: S, dst: D) -> Result<(), syntex::Error>
     syntex::with_extra_stack(expand_thread)
 }
 
-#[cfg(not(feature = "with-syntex"))]
-pub fn register(reg: &mut rustc_plugin::Registry) {
-    reg.register_syntax_extension(
-        syntax::parse::token::intern("derive_Serialize"),
-        syntax::ext::base::MultiDecorator(
-            Box::new(expand_derive_serialize)));
-
-    reg.register_syntax_extension(
-        syntax::parse::token::intern("derive_Deserialize"),
-        syntax::ext::base::MultiDecorator(
-            Box::new(expand_derive_deserialize)));
-
-    reg.register_attribute("serde".to_owned(), AttributeType::Normal);
-}
-
 macro_rules! shim {
     ($name:ident $pkg:ident :: $func:ident) => {
-        fn $func(
+        pub fn $func(
             cx: &mut ::syntax::ext::base::ExtCtxt,
             span: ::syntax::codemap::Span,
             meta_item: &::syntax::ast::MetaItem,
@@ -145,13 +116,12 @@ macro_rules! shim {
 
             use syntax::{attr, ast, visit};
             struct MarkSerdeAttributesUsed;
-            impl visit::Visitor for MarkSerdeAttributesUsed {
+            impl<'a> visit::Visitor<'a> for MarkSerdeAttributesUsed {
                 fn visit_attribute(&mut self, attr: &ast::Attribute) {
-                    match attr.node.value.node {
-                        ast::MetaItemKind::List(ref name, _) if name == "serde" => {
+                    if attr.value.name == "serde" {
+                        if let ast::MetaItemKind::List(..) = attr.value.node {
                             attr::mark_used(attr);
                         }
-                        _ => {}
                     }
                 }
             }
@@ -160,6 +130,7 @@ macro_rules! shim {
             use syntax::print::pprust;
             let s = pprust::item_to_string(item);
 
+            use {syn, $pkg};
             let syn_item = syn::parse_macro_input(&s).unwrap();
             let expanded = match $pkg::$func(&syn_item) {
                 Ok(expanded) => expanded.to_string(),
@@ -178,70 +149,24 @@ macro_rules! shim {
     };
 }
 
-shim!(Serialize ser::expand_derive_serialize);
-shim!(Deserialize de::expand_derive_deserialize);
+#[cfg(feature = "with-syntex")]
+mod shim {
+    shim!(Serialize ser::expand_derive_serialize);
+    shim!(Deserialize de::expand_derive_deserialize);
+}
 
 #[cfg(feature = "with-syn")]
-pub fn expand_single_item(item: &str) -> Result<String, String> {
+#[doc(hidden)]
+/// Not public API. Use the serde_derive crate.
+pub fn expand_derive_serialize(item: &str) -> Result<quote::Tokens, String> {
     let syn_item = syn::parse_macro_input(item).unwrap();
-    let (ser, de, syn_item) = strip_serde_derives(syn_item);
-    let expanded_ser = if ser {
-        Some(try!(ser::expand_derive_serialize(&syn_item)))
-    } else {
-        None
-    };
-    let expanded_de = if de {
-        Some(try!(de::expand_derive_deserialize(&syn_item)))
-    } else {
-        None
-    };
-    let syn_item = post_expansion::strip_attrs_later(syn_item, &["serde"], "serde");
-    return Ok(quote!(#expanded_ser #expanded_de #syn_item).to_string());
-
-    fn strip_serde_derives(item: syn::MacroInput) -> (bool, bool, syn::MacroInput) {
-        let mut ser = false;
-        let mut de = false;
-        let item = syn::MacroInput {
-            attrs: item.attrs.into_iter().flat_map(|attr| {
-                if attr.is_sugared_doc || attr.style != syn::AttrStyle::Outer {
-                    return Some(attr);
-                }
-                let (name, nested) = match attr.value {
-                    syn::MetaItem::List(name, nested) => (name, nested),
-                    _ => return Some(attr)
-                };
-                if name != "derive" {
-                    return Some(syn::Attribute {
-                        style: syn::AttrStyle::Outer,
-                        value: syn::MetaItem::List(name, nested),
-                        is_sugared_doc: false,
-                    });
-                }
-                let rest: Vec<_> = nested.into_iter().filter(|nested| {
-                    match *nested {
-                        syn::MetaItem::Word(ref word) if word == "Serialize" => {
-                            ser = true;
-                            false
-                        }
-                        syn::MetaItem::Word(ref word) if word == "Deserialize" => {
-                            de = true;
-                            false
-                        }
-                        _ => true,
-                    }
-                }).collect();
-                if rest.is_empty() {
-                    None
-                } else {
-                    Some(syn::Attribute {
-                        style: syn::AttrStyle::Outer,
-                        value: syn::MetaItem::List(name, rest),
-                        is_sugared_doc: false,
-                    })
-                }
-            }).collect(),
-            ..item
-        };
-        (ser, de, item)
-    }
+    ser::expand_derive_serialize(&syn_item)
+}
+
+#[cfg(feature = "with-syn")]
+#[doc(hidden)]
+/// Not public API. Use the serde_derive crate.
+pub fn expand_derive_deserialize(item: &str) -> Result<quote::Tokens, String> {
+    let syn_item = syn::parse_macro_input(item).unwrap();
+    de::expand_derive_deserialize(&syn_item)
 }

serde_codegen/src/ser.rs

@@ -1,4 +1,4 @@
-use syn::{self, aster};
+use syn::{self, aster, Ident};
 use quote::Tokens;
 
 use bound;
@@ -22,16 +22,16 @@ pub fn expand_derive_serialize(item: &syn::MacroInput) -> Result<Tokens, String>
 
     let where_clause = &impl_generics.where_clause;
 
-    let dummy_const = aster::id(format!("_IMPL_SERIALIZE_FOR_{}", item.ident));
+    let dummy_const = Ident::new(format!("_IMPL_SERIALIZE_FOR_{}", item.ident));
 
     Ok(quote! {
         #[allow(non_upper_case_globals, unused_attributes, unused_qualifications)]
         const #dummy_const: () = {
             extern crate serde as _serde;
             #[automatically_derived]
-            impl #impl_generics _serde::ser::Serialize for #ty #where_clause {
-                fn serialize<__S>(&self, _serializer: &mut __S) -> ::std::result::Result<(), __S::Error>
-                    where __S: _serde::ser::Serializer
+            impl #impl_generics _serde::Serialize for #ty #where_clause {
+                fn serialize<__S>(&self, _serializer: __S) -> ::std::result::Result<__S::Ok, __S::Error>
+                    where __S: _serde::Serializer
                 {
                     #body
                 }
@@ -56,7 +56,7 @@ fn build_impl_generics(item: &Item) -> syn::Generics {
         None => {
             bound::with_bound(item, &generics,
                 needs_serialize_bound,
-                &aster::path().ids(&["_serde", "ser", "Serialize"]).build())
+                &aster::path().ids(&["_serde", "Serialize"]).build())
         }
     }
 }
@@ -159,7 +159,7 @@ fn serialize_tuple_struct(
         fields,
         impl_generics,
         false,
-        aster::id("serialize_tuple_struct_elt"),
+        quote!(_serde::ser::SerializeTupleStruct::serialize_field),
     );
 
     let type_name = item_attrs.name().serialize_name();
@@ -169,7 +169,7 @@ fn serialize_tuple_struct(
     quote! {
         let #let_mut __serde_state = try!(_serializer.serialize_tuple_struct(#type_name, #len));
         #(#serialize_stmts)*
-        _serializer.serialize_tuple_struct_end(__serde_state)
+        _serde::ser::SerializeTupleStruct::end(__serde_state)
     }
 }
 
@@ -184,7 +184,7 @@ fn serialize_struct(
         fields,
         impl_generics,
         false,
-        aster::id("serialize_struct_elt"),
+        quote!(_serde::ser::SerializeStruct::serialize_field),
     );
 
     let type_name = item_attrs.name().serialize_name();
@@ -210,7 +210,7 @@ fn serialize_struct(
     quote! {
         let #let_mut __serde_state = try!(_serializer.serialize_struct(#type_name, #len));
         #(#serialize_fields)*
-        _serializer.serialize_struct_end(__serde_state)
+        _serde::ser::SerializeStruct::end(__serde_state)
     }
 }
 
@@ -256,76 +256,80 @@ fn serialize_variant(
     let variant_ident = variant.ident.clone();
     let variant_name = variant.attrs.name().serialize_name();
 
-    match variant.style {
-        Style::Unit => {
-            quote! {
-                #type_ident::#variant_ident =>
-                    _serde::ser::Serializer::serialize_unit_variant(
-                        _serializer,
-                        #type_name,
-                        #variant_index,
-                        #variant_name,
-                    ),
-            }
-        },
-        Style::Newtype => {
-            let block = serialize_newtype_variant(
-                type_name,
-                variant_index,
-                variant_name,
-                ty,
-                generics,
-                &variant.fields[0],
-            );
-
-            quote! {
-                #type_ident::#variant_ident(ref __simple_value) => #block,
-            }
-        },
-        Style::Tuple => {
-            let field_names: Vec<Tokens> = (0 .. variant.fields.len())
-                .map(|i| {
-                    let id = aster::id(format!("__field{}", i));
-                    quote!(ref #id)
-                })
-                .collect();
-
-            let pat = quote!(#type_ident::#variant_ident(#(#field_names),*));
-
-            let block = serialize_tuple_variant(
-                type_name,
-                variant_index,
-                variant_name,
-                generics,
-                ty,
-                &variant.fields,
-            );
-
-            quote! {
-                #pat => { #block }
-            }
+    if variant.attrs.skip_serializing() {
+        let skipped_msg = format!("The enum variant {}::{} cannot be serialized",
+                                type_ident, variant_ident);
+        let skipped_err = quote! {
+            Err(_serde::ser::Error::invalid_value(#skipped_msg))
+        };
+        let fields_pat = match variant.style {
+            Style::Unit => quote!(),
+            Style::Newtype | Style::Tuple => quote!( (..) ),
+            Style::Struct => quote!( {..} ),
+        };
+        quote! {
+            #type_ident::#variant_ident #fields_pat => #skipped_err,
         }
-        Style::Struct => {
-            let fields = variant.fields.iter().map(|field| {
-                let id = match field.ident {
-                    Some(ref name) => name.clone(),
-                    None => panic!("struct variant has unnamed fields"),
-                };
-                quote!(ref #id)
-            });
-            let pat = quote!(#type_ident::#variant_ident { #(#fields),* });
+    } else { // variant wasn't skipped
+        match variant.style {
+            Style::Unit => {
+                quote! {
+                    #type_ident::#variant_ident =>
+                        _serde::Serializer::serialize_unit_variant(
+                            _serializer,
+                            #type_name,
+                            #variant_index,
+                            #variant_name,
+                        ),
+                }
+            },
+            Style::Newtype => {
+                let block = serialize_newtype_variant(
+                    type_name,
+                    variant_index,
+                    variant_name,
+                    ty,
+                    generics,
+                    &variant.fields[0],
+                );
 
-            let block = serialize_struct_variant(
-                variant_index,
-                variant_name,
-                generics,
-                ty,
-                &variant.fields,
-                item_attrs,
-            );
+                quote! {
+                    #type_ident::#variant_ident(ref __simple_value) => #block,
+                }
+            },
+            Style::Tuple => {
+                let field_names = (0 .. variant.fields.len())
+                    .map(|i| Ident::new(format!("__field{}", i)));
 
-            quote! {
-                #pat => { #block }
+                let block = serialize_tuple_variant(
+                    type_name,
+                    variant_index,
+                    variant_name,
+                    generics,
+                    ty,
+                    &variant.fields,
+                );
+
+                quote! {
+                    #type_ident::#variant_ident(#(ref #field_names),*) => { #block }
+                }
+            }
+            Style::Struct => {
+                let fields = variant.fields.iter()
+                    .map(|f| f.ident.clone().expect("struct variant has unnamed fields"));
+
+                let block = serialize_struct_variant(
+                    variant_index,
+                    variant_name,
+                    generics,
+                    ty,
+                    &variant.fields,
+                    item_attrs,
+                );
+
+                quote! {
+                    #type_ident::#variant_ident { #(ref #fields),* } => { #block }
+                }
             }
         }
     }
@@ -346,7 +350,7 @@ fn serialize_newtype_variant(
     }
 
     quote! {
-        _serde::ser::Serializer::serialize_newtype_variant(
+        _serde::Serializer::serialize_newtype_variant(
             _serializer,
             #type_name,
             #variant_index,
@@ -369,7 +373,7 @@ fn serialize_tuple_variant(
         fields,
         generics,
         true,
-        aster::id("serialize_tuple_variant_elt"),
+        quote!(_serde::ser::SerializeTupleVariant::serialize_field),
     );
 
     let len = serialize_stmts.len();
@@ -382,7 +386,7 @@ fn serialize_tuple_variant(
             #variant_name,
             #len));
         #(#serialize_stmts)*
-        _serializer.serialize_tuple_variant_end(__serde_state)
+        _serde::ser::SerializeTupleVariant::end(__serde_state)
     }
 }
 
@@ -399,7 +403,7 @@ fn serialize_struct_variant(
         fields,
         generics,
         true,
-        aster::id("serialize_struct_variant_elt"),
+        quote!(_serde::ser::SerializeStructVariant::serialize_field),
     );
 
     let item_name = item_attrs.name().serialize_name();
@@ -429,7 +433,7 @@ fn serialize_struct_variant(
             #len,
         ));
         #(#serialize_fields)*
-        _serializer.serialize_struct_variant_end(__serde_state)
+        _serde::ser::SerializeStructVariant::end(__serde_state)
     }
 }
 
@@ -438,16 +442,16 @@ fn serialize_tuple_struct_visitor(
     fields: &[Field],
     generics: &syn::Generics,
     is_enum: bool,
-    func: syn::Ident,
+    func: Tokens,
 ) -> Vec<Tokens> {
     fields.iter()
         .enumerate()
         .map(|(i, field)| {
             let mut field_expr = if is_enum {
-                let id = aster::id(format!("__field{}", i));
+                let id = Ident::new(format!("__field{}", i));
                 quote!(#id)
             } else {
-                let i = aster::id(i);
+                let i = Ident::new(i);
                 quote!(&self.#i)
             };
 
@@ -460,7 +464,7 @@ fn serialize_tuple_struct_visitor(
             }
 
             let ser = quote! {
-                try!(_serializer.#func(&mut __serde_state, #field_expr));
+                try!(#func(&mut __serde_state, #field_expr));
             };
 
             match skip {
@@ -476,7 +480,7 @@ fn serialize_struct_visitor(
     fields: &[Field],
     generics: &syn::Generics,
     is_enum: bool,
-    func: syn::Ident,
+    func: Tokens,
 ) -> Vec<Tokens> {
     fields.iter()
         .filter(|&field| !field.attrs.skip_serializing())
@@ -499,7 +503,7 @@ fn serialize_struct_visitor(
             }
 
             let ser = quote! {
-                try!(_serializer.#func(&mut __serde_state, #key_expr, #field_expr));
+                try!(#func(&mut __serde_state, #key_expr, #field_expr));
             };
 
             match skip {
@@ -536,9 +540,9 @@ fn wrap_serialize_with(
             phantom: ::std::marker::PhantomData<#item_ty>,
         }
 
-        impl #wrapper_generics _serde::ser::Serialize for #wrapper_ty #where_clause {
-            fn serialize<__S>(&self, __s: &mut __S) -> ::std::result::Result<(), __S::Error>
-                where __S: _serde::ser::Serializer
+        impl #wrapper_generics _serde::Serialize for #wrapper_ty #where_clause {
+            fn serialize<__S>(&self, __s: __S) -> ::std::result::Result<__S::Ok, __S::Error>
+                where __S: _serde::Serializer
             {
                 #path(self.value, __s)
             }
@@ -554,7 +558,7 @@ fn wrap_serialize_with(
 // Serialization of an empty struct results in code like:
 //
 //     let mut __serde_state = try!(serializer.serialize_struct("S", 0));
-//     serializer.serialize_struct_end(__serde_state)
+//     _serde::ser::SerializeStruct::end(__serde_state)
 //
 // where we want to omit the `mut` to avoid a warning.
 fn mut_if(is_mut: bool) -> Option<Tokens> {

serde_codegen_internals/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "serde_codegen_internals"
-version = "0.10.0"
+version = "0.11.3"
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>"]
 license = "MIT/Apache-2.0"
 description = "AST representation used by Serde codegen. Unstable."
@@ -15,4 +15,4 @@ unstable-testing = ["clippy"]
 
 [dependencies]
 clippy = { version = "^0.*", optional = true }
-syn = "0.9"
+syn = "0.10"

serde_codegen_internals/src/attr.rs

@@ -1,5 +1,7 @@
 use Ctxt;
 use syn;
+use syn::MetaItem::{List, NameValue, Word};
+use syn::NestedMetaItem::{Literal, MetaItem};
 
 // This module handles parsing of `#[serde(...)]` attributes. The entrypoints
 // are `attr::Item::from_ast`, `attr::Variant::from_ast`, and
@@ -105,7 +107,7 @@ impl Item {
             for meta_item in meta_items {
                 match meta_item {
                     // Parse `#[serde(rename="foo")]`
-                    syn::MetaItem::NameValue(ref name, ref lit) if name == "rename" => {
+                    MetaItem(NameValue(ref name, ref lit)) if name == "rename" => {
                         if let Ok(s) = get_string_from_lit(cx, name.as_ref(), name.as_ref(), lit) {
                             ser_name.set(s.clone());
                             de_name.set(s);
@@ -113,7 +115,7 @@ impl Item {
                     }
 
                     // Parse `#[serde(rename(serialize="foo", deserialize="bar"))]`
-                    syn::MetaItem::List(ref name, ref meta_items) if name == "rename" => {
+                    MetaItem(List(ref name, ref meta_items)) if name == "rename" => {
                         if let Ok((ser, de)) = get_renames(cx, meta_items) {
                             ser_name.set_opt(ser);
                             de_name.set_opt(de);
@@ -121,12 +123,12 @@ impl Item {
                     }
 
                     // Parse `#[serde(deny_unknown_fields)]`
-                    syn::MetaItem::Word(ref name) if name == "deny_unknown_fields" => {
+                    MetaItem(Word(ref name)) if name == "deny_unknown_fields" => {
                         deny_unknown_fields.set_true();
                     }
 
                     // Parse `#[serde(bound="D: Serialize")]`
-                    syn::MetaItem::NameValue(ref name, ref lit) if name == "bound" => {
+                    MetaItem(NameValue(ref name, ref lit)) if name == "bound" => {
                         if let Ok(where_predicates) = parse_lit_into_where(cx, name.as_ref(), name.as_ref(), lit) {
                             ser_bound.set(where_predicates.clone());
                             de_bound.set(where_predicates);
@@ -134,17 +136,21 @@ impl Item {
                     }
 
                     // Parse `#[serde(bound(serialize="D: Serialize", deserialize="D: Deserialize"))]`
-                    syn::MetaItem::List(ref name, ref meta_items) if name == "bound" => {
+                    MetaItem(List(ref name, ref meta_items)) if name == "bound" => {
                         if let Ok((ser, de)) = get_where_predicates(cx, meta_items) {
                             ser_bound.set_opt(ser);
                             de_bound.set_opt(de);
                         }
                     }
 
-                    _ => {
+                    MetaItem(ref meta_item) => {
                         cx.error(format!("unknown serde container attribute `{}`",
                                          meta_item.name()));
                     }
+
+                    Literal(_) => {
+                        cx.error(format!("unexpected literal in serde container attribute"));
+                    }
                 }
             }
         }
@@ -181,18 +187,22 @@ impl Item {
 #[derive(Debug)]
 pub struct Variant {
     name: Name,
+    skip_deserializing: bool,
+    skip_serializing: bool,
 }
 
 impl Variant {
     pub fn from_ast(cx: &Ctxt, variant: &syn::Variant) -> Self {
         let mut ser_name = Attr::none(cx, "rename");
         let mut de_name = Attr::none(cx, "rename");
+        let mut skip_deserializing = BoolAttr::none(cx, "skip_deserializing");
+        let mut skip_serializing = BoolAttr::none(cx, "skip_serializing");
 
         for meta_items in variant.attrs.iter().filter_map(get_serde_meta_items) {
             for meta_item in meta_items {
                 match meta_item {
                     // Parse `#[serde(rename="foo")]`
-                    syn::MetaItem::NameValue(ref name, ref lit) if name == "rename" => {
+                    MetaItem(NameValue(ref name, ref lit)) if name == "rename" => {
                         if let Ok(s) = get_string_from_lit(cx, name.as_ref(), name.as_ref(), lit) {
                             ser_name.set(s.clone());
                             de_name.set(s);
@@ -200,17 +210,29 @@ impl Variant {
                     }
 
                     // Parse `#[serde(rename(serialize="foo", deserialize="bar"))]`
-                    syn::MetaItem::List(ref name, ref meta_items) if name == "rename" => {
+                    MetaItem(List(ref name, ref meta_items)) if name == "rename" => {
                         if let Ok((ser, de)) = get_renames(cx, meta_items) {
                             ser_name.set_opt(ser);
                             de_name.set_opt(de);
                         }
                     }
+                    // Parse `#[serde(skip_deserializing)]`
+                    MetaItem(Word(ref name)) if name == "skip_deserializing" => {
+                        skip_deserializing.set_true();
+                    }
+                    // Parse `#[serde(skip_serializing)]`
+                    MetaItem(Word(ref name)) if name == "skip_serializing" => {
+                        skip_serializing.set_true();
+                    }
 
-                    _ => {
+                    MetaItem(ref meta_item) => {
                         cx.error(format!("unknown serde variant attribute `{}`",
                                          meta_item.name()));
                     }
+
+                    Literal(_) => {
+                        cx.error(format!("unexpected literal in serde variant attribute"));
+                    }
                 }
             }
         }
@@ -220,12 +242,22 @@ impl Variant {
                 serialize: ser_name.get().unwrap_or_else(|| variant.ident.to_string()),
                 deserialize: de_name.get().unwrap_or_else(|| variant.ident.to_string()),
             },
+            skip_deserializing: skip_deserializing.get(),
+            skip_serializing: skip_serializing.get(),
         }
     }
 
     pub fn name(&self) -> &Name {
         &self.name
     }
+
+    pub fn skip_deserializing(&self) -> bool {
+        self.skip_deserializing
+    }
+
+    pub fn skip_serializing(&self) -> bool {
+        self.skip_serializing
+    }
 }
 
 /// Represents field attribute information
@@ -278,7 +310,7 @@ impl Field {
             for meta_item in meta_items {
                 match meta_item {
                     // Parse `#[serde(rename="foo")]`
-                    syn::MetaItem::NameValue(ref name, ref lit) if name == "rename" => {
+                    MetaItem(NameValue(ref name, ref lit)) if name == "rename" => {
                         if let Ok(s) = get_string_from_lit(cx, name.as_ref(), name.as_ref(), lit) {
                             ser_name.set(s.clone());
                             de_name.set(s);
@@ -286,7 +318,7 @@ impl Field {
                     }
 
                     // Parse `#[serde(rename(serialize="foo", deserialize="bar"))]`
-                    syn::MetaItem::List(ref name, ref meta_items) if name == "rename" => {
+                    MetaItem(List(ref name, ref meta_items)) if name == "rename" => {
                         if let Ok((ser, de)) = get_renames(cx, meta_items) {
                             ser_name.set_opt(ser);
                             de_name.set_opt(de);
@@ -294,50 +326,50 @@ impl Field {
                     }
 
                     // Parse `#[serde(default)]`
-                    syn::MetaItem::Word(ref name) if name == "default" => {
+                    MetaItem(Word(ref name)) if name == "default" => {
                         default.set(FieldDefault::Default);
                     }
 
                     // Parse `#[serde(default="...")]`
-                    syn::MetaItem::NameValue(ref name, ref lit) if name == "default" => {
+                    MetaItem(NameValue(ref name, ref lit)) if name == "default" => {
                         if let Ok(path) = parse_lit_into_path(cx, name.as_ref(), lit) {
                             default.set(FieldDefault::Path(path));
                         }
                     }
 
                     // Parse `#[serde(skip_serializing)]`
-                    syn::MetaItem::Word(ref name) if name == "skip_serializing" => {
+                    MetaItem(Word(ref name)) if name == "skip_serializing" => {
                         skip_serializing.set_true();
                     }
 
                     // Parse `#[serde(skip_deserializing)]`
-                    syn::MetaItem::Word(ref name) if name == "skip_deserializing" => {
+                    MetaItem(Word(ref name)) if name == "skip_deserializing" => {
                         skip_deserializing.set_true();
                     }
 
                     // Parse `#[serde(skip_serializing_if="...")]`
-                    syn::MetaItem::NameValue(ref name, ref lit) if name == "skip_serializing_if" => {
+                    MetaItem(NameValue(ref name, ref lit)) if name == "skip_serializing_if" => {
                         if let Ok(path) = parse_lit_into_path(cx, name.as_ref(), lit) {
                             skip_serializing_if.set(path);
                         }
                     }
 
                     // Parse `#[serde(serialize_with="...")]`
-                    syn::MetaItem::NameValue(ref name, ref lit) if name == "serialize_with" => {
+                    MetaItem(NameValue(ref name, ref lit)) if name == "serialize_with" => {
                         if let Ok(path) = parse_lit_into_path(cx, name.as_ref(), lit) {
                             serialize_with.set(path);
                         }
                     }
 
                     // Parse `#[serde(deserialize_with="...")]`
-                    syn::MetaItem::NameValue(ref name, ref lit) if name == "deserialize_with" => {
+                    MetaItem(NameValue(ref name, ref lit)) if name == "deserialize_with" => {
                         if let Ok(path) = parse_lit_into_path(cx, name.as_ref(), lit) {
                             deserialize_with.set(path);
                         }
                     }
 
                     // Parse `#[serde(bound="D: Serialize")]`
-                    syn::MetaItem::NameValue(ref name, ref lit) if name == "bound" => {
+                    MetaItem(NameValue(ref name, ref lit)) if name == "bound" => {
                         if let Ok(where_predicates) = parse_lit_into_where(cx, name.as_ref(), name.as_ref(), lit) {
                             ser_bound.set(where_predicates.clone());
                             de_bound.set(where_predicates);
@@ -345,17 +377,21 @@ impl Field {
                     }
 
                     // Parse `#[serde(bound(serialize="D: Serialize", deserialize="D: Deserialize"))]`
-                    syn::MetaItem::List(ref name, ref meta_items) if name == "bound" => {
+                    MetaItem(List(ref name, ref meta_items)) if name == "bound" => {
                         if let Ok((ser, de)) = get_where_predicates(cx, meta_items) {
                             ser_bound.set_opt(ser);
                             de_bound.set_opt(de);
                         }
                     }
 
-                    _ => {
+                    MetaItem(ref meta_item) => {
                         cx.error(format!("unknown serde field attribute `{}`",
                                          meta_item.name()));
                     }
+
+                    Literal(_) => {
+                        cx.error(format!("unexpected literal in serde field attribute"));
+                    }
                 }
             }
         }
@@ -424,7 +460,7 @@ type SerAndDe<T> = (Option<T>, Option<T>);
 fn get_ser_and_de<T, F>(
     cx: &Ctxt,
     attr_name: &'static str,
-    items: &[syn::MetaItem],
+    items: &[syn::NestedMetaItem],
     f: F
 ) -> Result<SerAndDe<T>, ()>
     where F: Fn(&Ctxt, &str, &str, &syn::Lit) -> Result<T, ()>,
@@ -434,13 +470,13 @@ fn get_ser_and_de<T, F>(
 
     for item in items {
         match *item {
-            syn::MetaItem::NameValue(ref name, ref lit) if name == "serialize" => {
+            MetaItem(NameValue(ref name, ref lit)) if name == "serialize" => {
                 if let Ok(v) = f(cx, attr_name, name.as_ref(), lit) {
                     ser_item.set(v);
                 }
             }
 
-            syn::MetaItem::NameValue(ref name, ref lit) if name == "deserialize" => {
+            MetaItem(NameValue(ref name, ref lit)) if name == "deserialize" => {
                 if let Ok(v) = f(cx, attr_name, name.as_ref(), lit) {
                     de_item.set(v);
                 }
@@ -459,21 +495,21 @@ fn get_ser_and_de<T, F>(
 
 fn get_renames(
     cx: &Ctxt,
-    items: &[syn::MetaItem],
+    items: &[syn::NestedMetaItem],
 ) -> Result<SerAndDe<String>, ()> {
     get_ser_and_de(cx, "rename", items, get_string_from_lit)
 }
 
 fn get_where_predicates(
     cx: &Ctxt,
-    items: &[syn::MetaItem],
+    items: &[syn::NestedMetaItem],
 ) -> Result<SerAndDe<Vec<syn::WherePredicate>>, ()> {
     get_ser_and_de(cx, "bound", items, parse_lit_into_where)
 }
 
-pub fn get_serde_meta_items(attr: &syn::Attribute) -> Option<Vec<syn::MetaItem>> {
+pub fn get_serde_meta_items(attr: &syn::Attribute) -> Option<Vec<syn::NestedMetaItem>> {
     match attr.value {
-        syn::MetaItem::List(ref name, ref items) if name == "serde" => {
+        List(ref name, ref items) if name == "serde" => {
             Some(items.iter().cloned().collect())
         }
         _ => None

serde_derive/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "serde_derive"
-version = "0.8.17"
+version = "0.9.0-rc1"
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>"]
 license = "MIT/Apache-2.0"
 description = "Macros 1.1 implementation of #[derive(Serialize, Deserialize)]"
@@ -14,11 +14,8 @@ include = ["Cargo.toml", "src/**/*.rs"]
 name = "serde_derive"
 proc-macro = true
 
-[dependencies]
-post-expansion = "0.1.0"
-
 [dependencies.serde_codegen]
-version = "=0.8.17"
+version = "=0.9.0-rc1"
 path = "../serde_codegen"
 default-features = false
 features = ["with-syn"]
@@ -26,5 +23,5 @@ features = ["with-syn"]
 [dev-dependencies]
 compiletest_rs = "^0.2.0"
 fnv = "1.0"
-serde = { version = "0.8.17", path = "../serde" }
-serde_test = { version = "0.8.17", path = "../serde_test" }
+serde = { version = "0.9.0-rc1", path = "../serde" }
+serde_test = { version = "0.9.0-rc1", path = "../serde_test" }

serde_derive/src/lib.rs

@@ -1,30 +1,20 @@
-#![feature(proc_macro, proc_macro_lib)]
-#![cfg(not(test))]
-
 extern crate proc_macro;
 extern crate serde_codegen;
 
-#[macro_use]
-extern crate post_expansion;
-
 use proc_macro::TokenStream;
 
-#[proc_macro_derive(Serialize)]
+#[proc_macro_derive(Serialize, attributes(serde))]
 pub fn derive_serialize(input: TokenStream) -> TokenStream {
-    let item = format!("#[derive(Serialize)]\n{}", input);
-    match serde_codegen::expand_single_item(&item) {
+    match serde_codegen::expand_derive_serialize(&input.to_string()) {
         Ok(expanded) => expanded.parse().unwrap(),
         Err(msg) => panic!(msg),
     }
 }
 
-#[proc_macro_derive(Deserialize)]
+#[proc_macro_derive(Deserialize, attributes(serde))]
 pub fn derive_deserialize(input: TokenStream) -> TokenStream {
-    let item = format!("#[derive(Deserialize)]\n{}", input);
-    match serde_codegen::expand_single_item(&item) {
+    match serde_codegen::expand_derive_deserialize(&input.to_string()) {
         Ok(expanded) => expanded.parse().unwrap(),
         Err(msg) => panic!(msg),
     }
 }
-
-register_post_expansion!(PostExpansion_serde);

serde_derive/tests/compile-fail/duplicate-attribute/rename-and-ser.rs

@@ -1,5 +1,3 @@
-#![feature(proc_macro)]
-
 #[macro_use]
 extern crate serde_derive;
 

serde_derive/tests/compile-fail/duplicate-attribute/rename-rename-de.rs

@@ -1,5 +1,3 @@
-#![feature(proc_macro)]
-
 #[macro_use]
 extern crate serde_derive;
 

serde_derive/tests/compile-fail/duplicate-attribute/rename-ser-rename-ser.rs

@@ -1,5 +1,3 @@
-#![feature(proc_macro)]
-
 #[macro_use]
 extern crate serde_derive;
 

serde_derive/tests/compile-fail/duplicate-attribute/rename-ser-rename.rs

@@ -1,5 +1,3 @@
-#![feature(proc_macro)]
-
 #[macro_use]
 extern crate serde_derive;
 

serde_derive/tests/compile-fail/duplicate-attribute/rename-ser-ser.rs

@@ -1,5 +1,3 @@
-#![feature(proc_macro)]
-
 #[macro_use]
 extern crate serde_derive;
 

serde_derive/tests/compile-fail/duplicate-attribute/two-rename-ser.rs

@@ -1,5 +1,3 @@
-#![feature(proc_macro)]
-
 #[macro_use]
 extern crate serde_derive;
 

serde_derive/tests/compile-fail/str_ref_deser.rs

@@ -1,5 +1,3 @@
-#![feature(proc_macro)]
-
 #[macro_use]
 extern crate serde_derive;
 

serde_derive/tests/compile-fail/unknown-attribute/container.rs

@@ -1,5 +1,3 @@
-#![feature(proc_macro)]
-
 #[macro_use]
 extern crate serde_derive;
 

serde_derive/tests/compile-fail/unknown-attribute/field.rs

@@ -1,5 +1,3 @@
-#![feature(proc_macro)]
-
 #[macro_use]
 extern crate serde_derive;
 

serde_derive/tests/compile-fail/unknown-attribute/variant.rs

@@ -1,5 +1,3 @@
-#![feature(proc_macro)]
-
 #[macro_use]
 extern crate serde_derive;
 

serde_derive/tests/run-pass/identity-op.rs

@@ -1,4 +1,3 @@
-#![feature(proc_macro)]
 #![deny(identity_op)]
 
 #[macro_use]

serde_derive/tests/test.rs

@@ -1,4 +1,4 @@
-#![feature(test, proc_macro)]
+#![feature(test)]
 
 #[macro_use]
 extern crate serde_derive;

serde_test/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "serde_test"
-version = "0.8.17"
+version = "0.9.0-rc1"
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>"]
 license = "MIT/Apache-2.0"
 description = "Token De/Serializer for testing De/Serialize implementations"
@@ -12,4 +12,4 @@ keywords = ["serde", "serialization"]
 include = ["Cargo.toml", "src/**/*.rs"]
 
 [dependencies]
-serde = { version = "0.8.17", path = "../serde" }
+serde = { version = "0.9.0-rc1", path = "../serde" }

serde_test/src/de.rs

@@ -9,6 +9,7 @@ use serde::de::{
     VariantVisitor,
     Visitor,
 };
+use serde::de::value::ValueDeserializer;
 
 use error::Error;
 use token::Token;
@@ -32,174 +33,203 @@ impl<I> Deserializer<I>
         self.tokens.next()
     }
 
-    fn visit_seq<V>(&mut self, len: Option<usize>, mut visitor: V) -> Result<V::Value, Error>
-        where V: Visitor,
-    {
-        visitor.visit_seq(DeserializerSeqVisitor {
-            de: self,
-            len: len,
-        })
+    pub fn expect_token(&mut self, expected: Token) -> Result<(), Error> {
+        match self.tokens.next() {
+            Some(token) => {
+                if expected == token {
+                    Ok(())
+                } else {
+                    Err(Error::UnexpectedToken(token))
+                }
+            }
+            None => Err(Error::EndOfStream),
+        }
     }
 
-    fn visit_array<V>(&mut self, len: usize, mut visitor: V) -> Result<V::Value, Error>
+    fn visit_seq<V>(&mut self, len: Option<usize>, visitor: V) -> Result<V::Value, Error>
         where V: Visitor,
     {
-        visitor.visit_seq(DeserializerArrayVisitor {
+        let value = try!(visitor.visit_seq(DeserializerSeqVisitor {
             de: self,
             len: len,
-        })
+        }));
+        try!(self.expect_token(Token::SeqEnd));
+        Ok(value)
     }
 
-    fn visit_tuple<V>(&mut self, len: usize, mut visitor: V) -> Result<V::Value, Error>
+    fn visit_array<V>(&mut self, len: usize, visitor: V) -> Result<V::Value, Error>
         where V: Visitor,
     {
-        visitor.visit_seq(DeserializerTupleVisitor {
+        let value = try!(visitor.visit_seq(DeserializerArrayVisitor {
             de: self,
             len: len,
-        })
+        }));
+        try!(self.expect_token(Token::SeqEnd));
+        Ok(value)
     }
 
-    fn visit_tuple_struct<V>(&mut self, len: usize, mut visitor: V) -> Result<V::Value, Error>
+    fn visit_tuple<V>(&mut self, len: usize, visitor: V) -> Result<V::Value, Error>
         where V: Visitor,
     {
-        visitor.visit_seq(DeserializerTupleStructVisitor {
+        let value = try!(visitor.visit_seq(DeserializerTupleVisitor {
             de: self,
             len: len,
-        })
+        }));
+        try!(self.expect_token(Token::TupleEnd));
+        Ok(value)
     }
 
-    fn visit_variant_seq<V>(&mut self, len: Option<usize>, mut visitor: V) -> Result<V::Value, Error>
+    fn visit_tuple_struct<V>(&mut self, len: usize, visitor: V) -> Result<V::Value, Error>
         where V: Visitor,
     {
-        visitor.visit_seq(DeserializerVariantSeqVisitor {
+        let value = try!(visitor.visit_seq(DeserializerTupleStructVisitor {
             de: self,
             len: len,
-        })
+        }));
+        try!(self.expect_token(Token::TupleStructEnd));
+        Ok(value)
     }
 
-    fn visit_map<V>(&mut self, len: Option<usize>, mut visitor: V) -> Result<V::Value, Error>
+    fn visit_variant_seq<V>(&mut self, len: Option<usize>, visitor: V) -> Result<V::Value, Error>
         where V: Visitor,
     {
-        visitor.visit_map(DeserializerMapVisitor {
+        let value = try!(visitor.visit_seq(DeserializerVariantSeqVisitor {
             de: self,
             len: len,
-        })
+        }));
+        try!(self.expect_token(Token::EnumSeqEnd));
+        Ok(value)
     }
 
-    fn visit_struct<V>(&mut self, len: Option<usize>, mut visitor: V) -> Result<V::Value, Error>
+    fn visit_map<V>(&mut self, len: Option<usize>, visitor: V) -> Result<V::Value, Error>
         where V: Visitor,
     {
-        visitor.visit_map(DeserializerStructVisitor {
+        let value = try!(visitor.visit_map(DeserializerMapVisitor {
             de: self,
             len: len,
-        })
+        }));
+        try!(self.expect_token(Token::MapEnd));
+        Ok(value)
     }
 
-    fn visit_variant_map<V>(&mut self, len: Option<usize>, mut visitor: V) -> Result<V::Value, Error>
+    fn visit_struct<V>(&mut self, fields: &'static [&'static str], visitor: V) -> Result<V::Value, Error>
         where V: Visitor,
     {
-        visitor.visit_map(DeserializerVariantMapVisitor {
+        let value = try!(visitor.visit_map(DeserializerStructVisitor {
+            de: self,
+            len: fields.len(),
+        }));
+        try!(self.expect_token(Token::StructEnd));
+        Ok(value)
+    }
+
+    fn visit_variant_map<V>(&mut self, len: Option<usize>, visitor: V) -> Result<V::Value, Error>
+        where V: Visitor,
+    {
+        let value = try!(visitor.visit_map(DeserializerVariantMapVisitor {
             de: self,
             len: len,
-        })
+        }));
+        try!(self.expect_token(Token::EnumMapEnd));
+        Ok(value)
     }
 }
 
-impl<I> de::Deserializer for Deserializer<I>
+impl<'a, I> de::Deserializer for &'a mut Deserializer<I>
     where I: Iterator<Item=Token<'static>>,
 {
     type Error = Error;
 
-    fn deserialize_seq<__V>(&mut self, visitor: __V) -> Result<__V::Value, Self::Error>
+    fn deserialize_seq<__V>(self, visitor: __V) -> Result<__V::Value, Self::Error>
         where __V: de::Visitor {
         self.deserialize(visitor)
     }
-    fn deserialize_struct_field<__V>(&mut self, visitor: __V) -> Result<__V::Value, Self::Error>
+    fn deserialize_struct_field<__V>(self, visitor: __V) -> Result<__V::Value, Self::Error>
         where __V: de::Visitor {
         self.deserialize(visitor)
     }
-    fn deserialize_map<__V>(&mut self, visitor: __V) -> Result<__V::Value, Self::Error>
+    fn deserialize_map<__V>(self, visitor: __V) -> Result<__V::Value, Self::Error>
         where __V: de::Visitor {
         self.deserialize(visitor)
     }
-    fn deserialize_unit<__V>(&mut self, visitor: __V) -> Result<__V::Value, Self::Error>
+    fn deserialize_unit<__V>(self, visitor: __V) -> Result<__V::Value, Self::Error>
         where __V: de::Visitor {
         self.deserialize(visitor)
     }
-    fn deserialize_bytes<__V>(&mut self, visitor: __V) -> Result<__V::Value, Self::Error>
+    fn deserialize_bytes<__V>(self, visitor: __V) -> Result<__V::Value, Self::Error>
         where __V: de::Visitor {
         self.deserialize(visitor)
     }
-    fn deserialize_ignored_any<__V>(&mut self, visitor: __V) -> Result<__V::Value, Self::Error>
+    fn deserialize_ignored_any<__V>(self, visitor: __V) -> Result<__V::Value, Self::Error>
         where __V: de::Visitor {
         self.deserialize(visitor)
     }
-    fn deserialize_string<__V>(&mut self, visitor: __V) -> Result<__V::Value, Self::Error>
+    fn deserialize_string<__V>(self, visitor: __V) -> Result<__V::Value, Self::Error>
         where __V: de::Visitor {
         self.deserialize(visitor)
     }
-    fn deserialize_str<__V>(&mut self, visitor: __V) -> Result<__V::Value, Self::Error>
+    fn deserialize_str<__V>(self, visitor: __V) -> Result<__V::Value, Self::Error>
         where __V: de::Visitor {
         self.deserialize(visitor)
     }
-    fn deserialize_char<__V>(&mut self, visitor: __V) -> Result<__V::Value, Self::Error>
+    fn deserialize_char<__V>(self, visitor: __V) -> Result<__V::Value, Self::Error>
         where __V: de::Visitor {
         self.deserialize(visitor)
     }
-    fn deserialize_i64<__V>(&mut self, visitor: __V) -> Result<__V::Value, Self::Error>
+    fn deserialize_i64<__V>(self, visitor: __V) -> Result<__V::Value, Self::Error>
         where __V: de::Visitor {
         self.deserialize(visitor)
     }
-    fn deserialize_i32<__V>(&mut self, visitor: __V) -> Result<__V::Value, Self::Error>
+    fn deserialize_i32<__V>(self, visitor: __V) -> Result<__V::Value, Self::Error>
         where __V: de::Visitor {
         self.deserialize(visitor)
     }
-    fn deserialize_i16<__V>(&mut self, visitor: __V) -> Result<__V::Value, Self::Error>
+    fn deserialize_i16<__V>(self, visitor: __V) -> Result<__V::Value, Self::Error>
         where __V: de::Visitor {
         self.deserialize(visitor)
     }
-    fn deserialize_i8<__V>(&mut self, visitor: __V) -> Result<__V::Value, Self::Error>
+    fn deserialize_i8<__V>(self, visitor: __V) -> Result<__V::Value, Self::Error>
         where __V: de::Visitor {
         self.deserialize(visitor)
     }
-    fn deserialize_u64<__V>(&mut self, visitor: __V) -> Result<__V::Value, Self::Error>
+    fn deserialize_u64<__V>(self, visitor: __V) -> Result<__V::Value, Self::Error>
         where __V: de::Visitor {
         self.deserialize(visitor)
     }
-    fn deserialize_u32<__V>(&mut self, visitor: __V) -> Result<__V::Value, Self::Error>
+    fn deserialize_u32<__V>(self, visitor: __V) -> Result<__V::Value, Self::Error>
         where __V: de::Visitor {
         self.deserialize(visitor)
     }
-    fn deserialize_u16<__V>(&mut self, visitor: __V) -> Result<__V::Value, Self::Error>
+    fn deserialize_u16<__V>(self, visitor: __V) -> Result<__V::Value, Self::Error>
         where __V: de::Visitor {
         self.deserialize(visitor)
     }
-    fn deserialize_u8<__V>(&mut self, visitor: __V) -> Result<__V::Value, Self::Error>
+    fn deserialize_u8<__V>(self, visitor: __V) -> Result<__V::Value, Self::Error>
         where __V: de::Visitor {
         self.deserialize(visitor)
     }
-    fn deserialize_f32<__V>(&mut self, visitor: __V) -> Result<__V::Value, Self::Error>
+    fn deserialize_f32<__V>(self, visitor: __V) -> Result<__V::Value, Self::Error>
         where __V: de::Visitor {
         self.deserialize(visitor)
     }
-    fn deserialize_f64<__V>(&mut self, visitor: __V) -> Result<__V::Value, Self::Error>
+    fn deserialize_f64<__V>(self, visitor: __V) -> Result<__V::Value, Self::Error>
         where __V: de::Visitor {
         self.deserialize(visitor)
     }
-    fn deserialize_bool<__V>(&mut self, visitor: __V) -> Result<__V::Value, Self::Error>
+    fn deserialize_bool<__V>(self, visitor: __V) -> Result<__V::Value, Self::Error>
         where __V: de::Visitor {
         self.deserialize(visitor)
     }
-    fn deserialize_usize<__V>(&mut self, visitor: __V) -> Result<__V::Value, Self::Error>
+    fn deserialize_usize<__V>(self, visitor: __V) -> Result<__V::Value, Self::Error>
         where __V: de::Visitor {
         self.deserialize(visitor)
     }
-    fn deserialize_isize<__V>(&mut self, visitor: __V) -> Result<__V::Value, Self::Error>
+    fn deserialize_isize<__V>(self, visitor: __V) -> Result<__V::Value, Self::Error>
         where __V: de::Visitor {
         self.deserialize(visitor)
     }
 
-    fn deserialize<V>(&mut self, mut visitor: V) -> Result<V::Value, Error>
+    fn deserialize<V>(self, visitor: V) -> Result<V::Value, Error>
         where V: Visitor,
     {
         match self.tokens.next() {
@@ -243,7 +273,7 @@ impl<I> de::Deserializer for Deserializer<I>
 
     /// Hook into `Option` deserializing so we can treat `Unit` as a
     /// `None`, or a regular value as `Some(value)`.
-    fn deserialize_option<V>(&mut self, mut visitor: V) -> Result<V::Value, Error>
+    fn deserialize_option<V>(self, visitor: V) -> Result<V::Value, Error>
         where V: Visitor,
     {
         match self.tokens.peek() {
@@ -264,17 +294,17 @@ impl<I> de::Deserializer for Deserializer<I>
         }
     }
 
-    fn deserialize_enum<V>(&mut self,
+    fn deserialize_enum<V>(self,
                      name: &str,
                      _variants: &'static [&'static str],
-                     mut visitor: V) -> Result<V::Value, Error>
-        where V: EnumVisitor,
+                     visitor: V) -> Result<V::Value, Error>
+        where V: Visitor,
     {
         match self.tokens.peek() {
             Some(&Token::EnumStart(n)) if name == n => {
                 self.tokens.next();
 
-                visitor.visit(DeserializerVariantVisitor {
+                visitor.visit_enum(DeserializerEnumVisitor {
                     de: self,
                 })
             }
@@ -282,7 +312,7 @@ impl<I> de::Deserializer for Deserializer<I>
             | Some(&Token::EnumNewType(n, _))
             | Some(&Token::EnumSeqStart(n, _, _))
             | Some(&Token::EnumMapStart(n, _, _)) if name == n => {
-                visitor.visit(DeserializerVariantVisitor {
+                visitor.visit_enum(DeserializerEnumVisitor {
                     de: self,
                 })
             }
@@ -294,7 +324,7 @@ impl<I> de::Deserializer for Deserializer<I>
         }
     }
 
-    fn deserialize_unit_struct<V>(&mut self, name: &str, mut visitor: V) -> Result<V::Value, Error>
+    fn deserialize_unit_struct<V>(self, name: &str, visitor: V) -> Result<V::Value, Error>
         where V: Visitor,
     {
         match self.tokens.peek() {
@@ -311,9 +341,9 @@ impl<I> de::Deserializer for Deserializer<I>
         }
     }
 
-    fn deserialize_newtype_struct<V>(&mut self,
+    fn deserialize_newtype_struct<V>(self,
                                      name: &str,
-                                     mut visitor: V) -> Result<V::Value, Error>
+                                     visitor: V) -> Result<V::Value, Error>
         where V: Visitor,
     {
         match self.tokens.peek() {
@@ -330,7 +360,7 @@ impl<I> de::Deserializer for Deserializer<I>
         }
     }
 
-    fn deserialize_seq_fixed_size<V>(&mut self,
+    fn deserialize_seq_fixed_size<V>(self,
                                        len: usize,
                                        visitor: V) -> Result<V::Value, Error>
         where V: Visitor,
@@ -345,9 +375,9 @@ impl<I> de::Deserializer for Deserializer<I>
         }
     }
 
-    fn deserialize_tuple<V>(&mut self,
+    fn deserialize_tuple<V>(self,
                             len: usize,
-                            mut visitor: V) -> Result<V::Value, Error>
+                            visitor: V) -> Result<V::Value, Error>
         where V: Visitor,
     {
         match self.tokens.peek() {
@@ -380,10 +410,10 @@ impl<I> de::Deserializer for Deserializer<I>
         }
     }
 
-    fn deserialize_tuple_struct<V>(&mut self,
+    fn deserialize_tuple_struct<V>(self,
                                    name: &str,
                                    len: usize,
-                                   mut visitor: V) -> Result<V::Value, Error>
+                                   visitor: V) -> Result<V::Value, Error>
         where V: Visitor,
     {
         match self.tokens.peek() {
@@ -424,7 +454,7 @@ impl<I> de::Deserializer for Deserializer<I>
         }
     }
 
-    fn deserialize_struct<V>(&mut self,
+    fn deserialize_struct<V>(self,
                              name: &str,
                              fields: &'static [&'static str],
                              visitor: V) -> Result<V::Value, Error>
@@ -434,7 +464,7 @@ impl<I> de::Deserializer for Deserializer<I>
             Some(&Token::StructStart(n, _)) => {
                 self.tokens.next();
                 if name == n {
-                    self.visit_struct(Some(fields.len()), visitor)
+                    self.visit_struct(fields, visitor)
                 } else {
                     Err(Error::InvalidName(n))
                 }
@@ -468,7 +498,7 @@ impl<'a, I> SeqVisitor for DeserializerSeqVisitor<'a, I>
             Some(&Token::SeqSep) => {
                 self.de.tokens.next();
                 self.len = self.len.map(|len| len - 1);
-                Ok(Some(try!(Deserialize::deserialize(self.de))))
+                Deserialize::deserialize(&mut *self.de).map(Some)
             }
             Some(&Token::SeqEnd) => Ok(None),
             Some(_) => {
@@ -479,15 +509,6 @@ impl<'a, I> SeqVisitor for DeserializerSeqVisitor<'a, I>
         }
     }
 
-    fn end(&mut self) -> Result<(), Error> {
-        //assert_eq!(self.len.unwrap_or(0), 0);
-        match self.de.tokens.next() {
-            Some(Token::SeqEnd) => Ok(()),
-            Some(token) => Err(Error::UnexpectedToken(token)),
-            None => Err(Error::EndOfStream),
-        }
-    }
-
     fn size_hint(&self) -> (usize, Option<usize>) {
         let len = self.len.unwrap_or(0);
         (len, self.len)
@@ -513,7 +534,7 @@ impl<'a, I> SeqVisitor for DeserializerArrayVisitor<'a, I>
             Some(&Token::SeqSep) => {
                 self.de.tokens.next();
                 self.len -= 1;
-                Ok(Some(try!(Deserialize::deserialize(self.de))))
+                Deserialize::deserialize(&mut *self.de).map(Some)
             }
             Some(&Token::SeqEnd) => Ok(None),
             Some(_) => {
@@ -524,15 +545,6 @@ impl<'a, I> SeqVisitor for DeserializerArrayVisitor<'a, I>
         }
     }
 
-    fn end(&mut self) -> Result<(), Error> {
-        assert_eq!(self.len, 0);
-        match self.de.tokens.next() {
-            Some(Token::SeqEnd) => Ok(()),
-            Some(token) => Err(Error::UnexpectedToken(token)),
-            None => Err(Error::EndOfStream),
-        }
-    }
-
     fn size_hint(&self) -> (usize, Option<usize>) {
         (self.len, Some(self.len))
     }
@@ -557,7 +569,7 @@ impl<'a, I> SeqVisitor for DeserializerTupleVisitor<'a, I>
             Some(&Token::TupleSep) => {
                 self.de.tokens.next();
                 self.len -= 1;
-                Ok(Some(try!(Deserialize::deserialize(self.de))))
+                Deserialize::deserialize(&mut *self.de).map(Some)
             }
             Some(&Token::TupleEnd) => Ok(None),
             Some(_) => {
@@ -568,15 +580,6 @@ impl<'a, I> SeqVisitor for DeserializerTupleVisitor<'a, I>
         }
     }
 
-    fn end(&mut self) -> Result<(), Error> {
-        assert_eq!(self.len, 0);
-        match self.de.tokens.next() {
-            Some(Token::TupleEnd) => Ok(()),
-            Some(token) => Err(Error::UnexpectedToken(token)),
-            None => Err(Error::EndOfStream),
-        }
-    }
-
     fn size_hint(&self) -> (usize, Option<usize>) {
         (self.len, Some(self.len))
     }
@@ -601,7 +604,7 @@ impl<'a, I> SeqVisitor for DeserializerTupleStructVisitor<'a, I>
             Some(&Token::TupleStructSep) => {
                 self.de.tokens.next();
                 self.len -= 1;
-                Ok(Some(try!(Deserialize::deserialize(self.de))))
+                Deserialize::deserialize(&mut *self.de).map(Some)
             }
             Some(&Token::TupleStructEnd) => Ok(None),
             Some(_) => {
@@ -612,15 +615,6 @@ impl<'a, I> SeqVisitor for DeserializerTupleStructVisitor<'a, I>
         }
     }
 
-    fn end(&mut self) -> Result<(), Error> {
-        assert_eq!(self.len, 0);
-        match self.de.tokens.next() {
-            Some(Token::TupleStructEnd) => Ok(()),
-            Some(token) => Err(Error::UnexpectedToken(token)),
-            None => Err(Error::EndOfStream),
-        }
-    }
-
     fn size_hint(&self) -> (usize, Option<usize>) {
         (self.len, Some(self.len))
     }
@@ -645,7 +639,7 @@ impl<'a, I> SeqVisitor for DeserializerVariantSeqVisitor<'a, I>
             Some(&Token::EnumSeqSep) => {
                 self.de.tokens.next();
                 self.len = self.len.map(|len| len - 1);
-                Ok(Some(try!(Deserialize::deserialize(self.de))))
+                Deserialize::deserialize(&mut *self.de).map(Some)
             }
             Some(&Token::EnumSeqEnd) => Ok(None),
             Some(_) => {
@@ -656,15 +650,6 @@ impl<'a, I> SeqVisitor for DeserializerVariantSeqVisitor<'a, I>
         }
     }
 
-    fn end(&mut self) -> Result<(), Error> {
-        //assert_eq!(self.len.unwrap_or(0), 0);
-        match self.de.tokens.next() {
-            Some(Token::EnumSeqEnd) => Ok(()),
-            Some(token) => Err(Error::UnexpectedToken(token)),
-            None => Err(Error::EndOfStream),
-        }
-    }
-
     fn size_hint(&self) -> (usize, Option<usize>) {
         let len = self.len.unwrap_or(0);
         (len, self.len)
@@ -690,7 +675,7 @@ impl<'a, I> MapVisitor for DeserializerMapVisitor<'a, I>
             Some(&Token::MapSep) => {
                 self.de.tokens.next();
                 self.len = self.len.map(|len| if len > 0 { len - 1} else { 0 });
-                Ok(Some(try!(Deserialize::deserialize(self.de))))
+                Deserialize::deserialize(&mut *self.de).map(Some)
             }
             Some(&Token::MapEnd) => Ok(None),
             Some(_) => {
@@ -704,16 +689,7 @@ impl<'a, I> MapVisitor for DeserializerMapVisitor<'a, I>
     fn visit_value<V>(&mut self) -> Result<V, Error>
         where V: Deserialize,
     {
-        Ok(try!(Deserialize::deserialize(self.de)))
-    }
-
-    fn end(&mut self) -> Result<(), Error> {
-        //assert_eq!(self.len.unwrap_or(0), 0);
-        match self.de.tokens.next() {
-            Some(Token::MapEnd) => Ok(()),
-            Some(token) => Err(Error::UnexpectedToken(token)),
-            None => Err(Error::EndOfStream),
-        }
+        Deserialize::deserialize(&mut *self.de)
     }
 
     fn size_hint(&self) -> (usize, Option<usize>) {
@@ -726,7 +702,7 @@ impl<'a, I> MapVisitor for DeserializerMapVisitor<'a, I>
 
 struct DeserializerStructVisitor<'a, I: 'a> where I: Iterator<Item=Token<'static>> {
     de: &'a mut Deserializer<I>,
-    len: Option<usize>,
+    len: usize,
 }
 
 impl<'a, I> MapVisitor for DeserializerStructVisitor<'a, I>
@@ -740,8 +716,8 @@ impl<'a, I> MapVisitor for DeserializerStructVisitor<'a, I>
         match self.de.tokens.peek() {
             Some(&Token::StructSep) => {
                 self.de.tokens.next();
-                self.len = self.len.map(|len| if len > 0 { len - 1} else { 0 });
-                Ok(Some(try!(Deserialize::deserialize(self.de))))
+                self.len = self.len.saturating_sub(1);
+                Deserialize::deserialize(&mut *self.de).map(Some)
             }
             Some(&Token::StructEnd) => Ok(None),
             Some(_) => {
@@ -755,36 +731,27 @@ impl<'a, I> MapVisitor for DeserializerStructVisitor<'a, I>
     fn visit_value<V>(&mut self) -> Result<V, Error>
         where V: Deserialize,
     {
-        Ok(try!(Deserialize::deserialize(self.de)))
-    }
-
-    fn end(&mut self) -> Result<(), Error> {
-        //assert_eq!(self.len.unwrap_or(0), 0);
-        match self.de.tokens.next() {
-            Some(Token::StructEnd) => Ok(()),
-            Some(token) => Err(Error::UnexpectedToken(token)),
-            None => Err(Error::EndOfStream),
-        }
+        Deserialize::deserialize(&mut *self.de)
     }
 
     fn size_hint(&self) -> (usize, Option<usize>) {
-        let len = self.len.unwrap_or(0);
-        (len, self.len)
+        (self.len, Some(self.len))
     }
 }
 
 //////////////////////////////////////////////////////////////////////////
 
-struct DeserializerVariantVisitor<'a, I: 'a> where I: Iterator<Item=Token<'static>> {
+struct DeserializerEnumVisitor<'a, I: 'a> where I: Iterator<Item=Token<'static>> {
     de: &'a mut Deserializer<I>,
 }
 
-impl<'a, I> VariantVisitor for DeserializerVariantVisitor<'a, I>
+impl<'a, I> EnumVisitor for DeserializerEnumVisitor<'a, I>
     where I: Iterator<Item=Token<'static>>,
 {
     type Error = Error;
+    type Variant = Self;
 
-    fn visit_variant<V>(&mut self) -> Result<V, Error>
+    fn visit_variant<V>(self) -> Result<(V, Self), Error>
         where V: Deserialize,
     {
         match self.de.tokens.peek() {
@@ -792,18 +759,25 @@ impl<'a, I> VariantVisitor for DeserializerVariantVisitor<'a, I>
             | Some(&Token::EnumNewType(_, v))
             | Some(&Token::EnumSeqStart(_, v, _))
             | Some(&Token::EnumMapStart(_, v, _)) => {
-                let mut de = de::value::ValueDeserializer::<Error>::into_deserializer(v);
-                let value = try!(Deserialize::deserialize(&mut de));
-                Ok(value)
+                let de = v.into_deserializer();
+                let value = try!(Deserialize::deserialize(de));
+                Ok((value, self))
             }
             Some(_) => {
-                Deserialize::deserialize(self.de)
+                let value = try!(Deserialize::deserialize(&mut *self.de));
+                Ok((value, self))
             }
             None => Err(Error::EndOfStream),
         }
     }
+}
 
-    fn visit_unit(&mut self) -> Result<(), Error> {
+impl<'a, I> VariantVisitor for DeserializerEnumVisitor<'a, I>
+    where I: Iterator<Item=Token<'static>>
+{
+    type Error = Error;
+
+    fn visit_unit(self) -> Result<(), Error> {
         match self.de.tokens.peek() {
             Some(&Token::EnumUnit(_, _)) => {
                 self.de.tokens.next();
@@ -816,7 +790,7 @@ impl<'a, I> VariantVisitor for DeserializerVariantVisitor<'a, I>
         }
     }
 
-    fn visit_newtype<T>(&mut self) -> Result<T, Self::Error>
+    fn visit_newtype<T>(self) -> Result<T, Self::Error>
         where T: Deserialize,
     {
         match self.de.tokens.peek() {
@@ -831,7 +805,7 @@ impl<'a, I> VariantVisitor for DeserializerVariantVisitor<'a, I>
         }
     }
 
-    fn visit_tuple<V>(&mut self,
+    fn visit_tuple<V>(self,
                       len: usize,
                       visitor: V) -> Result<V::Value, Error>
         where V: Visitor,
@@ -856,13 +830,13 @@ impl<'a, I> VariantVisitor for DeserializerVariantVisitor<'a, I>
                 }
             }
             Some(_) => {
-                Deserialize::deserialize(self.de)
+                de::Deserializer::deserialize(self.de, visitor)
             }
             None => Err(Error::EndOfStream),
         }
     }
 
-    fn visit_struct<V>(&mut self,
+    fn visit_struct<V>(self,
                        fields: &'static [&'static str],
                        visitor: V) -> Result<V::Value, Error>
         where V: Visitor,
@@ -887,7 +861,7 @@ impl<'a, I> VariantVisitor for DeserializerVariantVisitor<'a, I>
                 }
             }
             Some(_) => {
-                Deserialize::deserialize(self.de)
+                de::Deserializer::deserialize(self.de, visitor)
             }
             None => Err(Error::EndOfStream),
         }
@@ -913,7 +887,7 @@ impl<'a, I> MapVisitor for DeserializerVariantMapVisitor<'a, I>
             Some(&Token::EnumMapSep) => {
                 self.de.tokens.next();
                 self.len = self.len.map(|len| if len > 0 { len - 1} else { 0 });
-                Ok(Some(try!(Deserialize::deserialize(self.de))))
+                Deserialize::deserialize(&mut *self.de).map(Some)
             }
             Some(&Token::EnumMapEnd) => Ok(None),
             Some(_) => {
@@ -927,16 +901,7 @@ impl<'a, I> MapVisitor for DeserializerVariantMapVisitor<'a, I>
     fn visit_value<V>(&mut self) -> Result<V, Error>
         where V: Deserialize,
     {
-        Ok(try!(Deserialize::deserialize(self.de)))
-    }
-
-    fn end(&mut self) -> Result<(), Error> {
-        //assert_eq!(self.len.unwrap_or(0), 0);
-        match self.de.tokens.next() {
-            Some(Token::EnumMapEnd) => Ok(()),
-            Some(token) => Err(Error::UnexpectedToken(token)),
-            None => Err(Error::EndOfStream),
-        }
+        Deserialize::deserialize(&mut *self.de)
     }
 
     fn size_hint(&self) -> (usize, Option<usize>) {

serde_test/src/ser.rs

@@ -1,9 +1,6 @@
 use std::marker::PhantomData;
 
-use serde::ser::{
-    self,
-    Serialize,
-};
+use serde::{ser, Serialize};
 
 use error::Error;
 use token::Token;
@@ -30,178 +27,119 @@ impl<'a, I> Serializer<'a, I>
     }
 }
 
-impl<'a, I> ser::Serializer for Serializer<'a, I>
+impl<'s, 'a, I> ser::Serializer for &'s mut Serializer<'a, I>
     where I: Iterator<Item=&'a Token<'a>>,
 {
+    type Ok = ();
     type Error = Error;
-    type MapState = ();
-    type SeqState = ();
-    type TupleState = ();
-    type TupleStructState = ();
-    type TupleVariantState = ();
-    type StructState = ();
-    type StructVariantState = ();
 
-    fn serialize_unit(&mut self) -> Result<(), Error> {
-        assert_eq!(self.tokens.next(), Some(&Token::Unit));
-        Ok(())
-    }
+    type SerializeSeq = Self;
+    type SerializeTuple = Self;
+    type SerializeTupleStruct = Self;
+    type SerializeTupleVariant = Self;
+    type SerializeMap = Self;
+    type SerializeStruct = Self;
+    type SerializeStructVariant = Self;
 
-    fn serialize_newtype_variant<T>(&mut self,
-                                name: &str,
-                                _variant_index: usize,
-                                variant: &str,
-                                value: T) -> Result<(), Error>
-        where T: Serialize,
-    {
-        assert_eq!(self.tokens.next(), Some(&Token::EnumNewType(name, variant)));
-        value.serialize(self)
-    }
-
-    fn serialize_unit_struct(&mut self, name: &str) -> Result<(), Error> {
-        assert_eq!(self.tokens.next(), Some(&Token::UnitStruct(name)));
-        Ok(())
-    }
-
-    fn serialize_unit_variant(&mut self,
-                          name: &str,
-                          _variant_index: usize,
-                          variant: &str) -> Result<(), Error> {
-        assert_eq!(self.tokens.next(), Some(&Token::EnumUnit(name, variant)));
-
-        Ok(())
-    }
-
-    fn serialize_bool(&mut self, v: bool) -> Result<(), Error> {
+    fn serialize_bool(self, v: bool) -> Result<(), Error> {
         assert_eq!(self.tokens.next(), Some(&Token::Bool(v)));
         Ok(())
     }
 
-    fn serialize_isize(&mut self, v: isize) -> Result<(), Error> {
+    fn serialize_isize(self, v: isize) -> Result<(), Error> {
         assert_eq!(self.tokens.next(), Some(&Token::Isize(v)));
         Ok(())
     }
 
-    fn serialize_i8(&mut self, v: i8) -> Result<(), Error> {
+    fn serialize_i8(self, v: i8) -> Result<(), Error> {
         assert_eq!(self.tokens.next(), Some(&Token::I8(v)));
         Ok(())
     }
 
-    fn serialize_i16(&mut self, v: i16) -> Result<(), Error> {
+    fn serialize_i16(self, v: i16) -> Result<(), Error> {
         assert_eq!(self.tokens.next(), Some(&Token::I16(v)));
         Ok(())
     }
 
-    fn serialize_i32(&mut self, v: i32) -> Result<(), Error> {
+    fn serialize_i32(self, v: i32) -> Result<(), Error> {
         assert_eq!(self.tokens.next(), Some(&Token::I32(v)));
         Ok(())
     }
 
-    fn serialize_i64(&mut self, v: i64) -> Result<(), Error> {
+    fn serialize_i64(self, v: i64) -> Result<(), Error> {
         assert_eq!(self.tokens.next(), Some(&Token::I64(v)));
         Ok(())
     }
 
-    fn serialize_usize(&mut self, v: usize) -> Result<(), Error> {
+    fn serialize_usize(self, v: usize) -> Result<(), Error> {
         assert_eq!(self.tokens.next(), Some(&Token::Usize(v)));
         Ok(())
     }
 
-    fn serialize_u8(&mut self, v: u8) -> Result<(), Error> {
+    fn serialize_u8(self, v: u8) -> Result<(), Error> {
         assert_eq!(self.tokens.next(), Some(&Token::U8(v)));
         Ok(())
     }
 
-    fn serialize_u16(&mut self, v: u16) -> Result<(), Error> {
+    fn serialize_u16(self, v: u16) -> Result<(), Error> {
         assert_eq!(self.tokens.next(), Some(&Token::U16(v)));
         Ok(())
     }
 
-    fn serialize_u32(&mut self, v: u32) -> Result<(), Error> {
+    fn serialize_u32(self, v: u32) -> Result<(), Error> {
         assert_eq!(self.tokens.next(), Some(&Token::U32(v)));
         Ok(())
     }
 
-    fn serialize_u64(&mut self, v: u64) -> Result<(), Error> {
+    fn serialize_u64(self, v: u64) -> Result<(), Error> {
         assert_eq!(self.tokens.next(), Some(&Token::U64(v)));
         Ok(())
     }
 
-    fn serialize_f32(&mut self, v: f32) -> Result<(), Error> {
+    fn serialize_f32(self, v: f32) -> Result<(), Error> {
         assert_eq!(self.tokens.next(), Some(&Token::F32(v)));
         Ok(())
     }
 
-    fn serialize_f64(&mut self, v: f64) -> Result<(), Error> {
+    fn serialize_f64(self, v: f64) -> Result<(), Error> {
         assert_eq!(self.tokens.next(), Some(&Token::F64(v)));
         Ok(())
     }
 
-    fn serialize_char(&mut self, v: char) -> Result<(), Error> {
+    fn serialize_char(self, v: char) -> Result<(), Error> {
         assert_eq!(self.tokens.next(), Some(&Token::Char(v)));
         Ok(())
     }
 
-    fn serialize_str(&mut self, v: &str) -> Result<(), Error> {
+    fn serialize_str(self, v: &str) -> Result<(), Error> {
         assert_eq!(self.tokens.next(), Some(&Token::Str(v)));
         Ok(())
     }
 
-    fn serialize_none(&mut self) -> Result<(), Error> {
-        assert_eq!(self.tokens.next(), Some(&Token::Option(false)));
+    fn serialize_bytes(self, value: &[u8]) -> Result<(), Self::Error> {
+        assert_eq!(self.tokens.next(), Some(&Token::Bytes(value)));
         Ok(())
     }
 
-    fn serialize_some<V>(&mut self, value: V) -> Result<(), Error>
-        where V: Serialize,
-    {
-        assert_eq!(self.tokens.next(), Some(&Token::Option(true)));
-        value.serialize(self)
-    }
-
-    fn serialize_seq<'b>(&'b mut self, len: Option<usize>) -> Result<(), Error>
-    {
-        assert_eq!(self.tokens.next(), Some(&Token::SeqStart(len)));
+    fn serialize_unit(self) -> Result<(), Error> {
+        assert_eq!(self.tokens.next(), Some(&Token::Unit));
         Ok(())
     }
 
-    fn serialize_seq_elt<T>(&mut self, _: &mut (), value: T) -> Result<(), Error>
-        where T: Serialize
-    {
-        assert_eq!(self.tokens.next(), Some(&Token::SeqSep));
-        value.serialize(self)
-    }
-
-    fn serialize_seq_end(&mut self, _: ()) -> Result<(), Error> {
-        assert_eq!(self.tokens.next(), Some(&Token::SeqEnd));
+    fn serialize_unit_struct(self, name: &str) -> Result<(), Error> {
+        assert_eq!(self.tokens.next(), Some(&Token::UnitStruct(name)));
         Ok(())
     }
 
-    fn serialize_seq_fixed_size(&mut self, len: usize) -> Result<(), Error>
-    {
-        assert_eq!(self.tokens.next(), Some(&Token::SeqArrayStart(len)));
+    fn serialize_unit_variant(self,
+                              name: &str,
+                              _variant_index: usize,
+                              variant: &str) -> Result<(), Error> {
+        assert_eq!(self.tokens.next(), Some(&Token::EnumUnit(name, variant)));
         Ok(())
     }
 
-    fn serialize_tuple(&mut self, len: usize) -> Result<(), Error>
-    {
-        assert_eq!(self.tokens.next(), Some(&Token::TupleStart(len)));
-        Ok(())
-    }
-
-    fn serialize_tuple_elt<T>(&mut self, _: &mut (), value: T) -> Result<(), Error>
-        where T: Serialize
-    {
-        assert_eq!(self.tokens.next(), Some(&Token::TupleSep));
-        value.serialize(self)
-    }
-
-    fn serialize_tuple_end(&mut self, _: ()) -> Result<(), Error> {
-        assert_eq!(self.tokens.next(), Some(&Token::TupleEnd));
-        Ok(())
-    }
-
-    fn serialize_newtype_struct<T>(&mut self,
+    fn serialize_newtype_struct<T>(self,
                                    name: &'static str,
                                    value: T) -> Result<(), Error>
         where T: Serialize,
@@ -210,114 +148,209 @@ impl<'a, I> ser::Serializer for Serializer<'a, I>
         value.serialize(self)
     }
 
-    fn serialize_tuple_struct(&mut self, name: &'static str, len: usize) -> Result<(), Error>
+    fn serialize_newtype_variant<T>(self,
+                                    name: &str,
+                                    _variant_index: usize,
+                                    variant: &str,
+                                    value: T) -> Result<(), Error>
+        where T: Serialize,
     {
-        assert_eq!(self.tokens.next(), Some(&Token::TupleStructStart(name, len)));
-
-        Ok(())
-    }
-
-    fn serialize_tuple_struct_elt<T>(&mut self, _: &mut (), value: T) -> Result<(), Error>
-        where T: Serialize
-    {
-        assert_eq!(self.tokens.next(), Some(&Token::TupleStructSep));
+        assert_eq!(self.tokens.next(), Some(&Token::EnumNewType(name, variant)));
         value.serialize(self)
     }
 
-    fn serialize_tuple_struct_end(&mut self, _: ()) -> Result<(), Error> {
-        assert_eq!(self.tokens.next(), Some(&Token::TupleStructEnd));
+    fn serialize_none(self) -> Result<(), Error> {
+        assert_eq!(self.tokens.next(), Some(&Token::Option(false)));
         Ok(())
     }
 
-    fn serialize_tuple_variant(&mut self,
+    fn serialize_some<V>(self, value: V) -> Result<(), Error>
+        where V: Serialize,
+    {
+        assert_eq!(self.tokens.next(), Some(&Token::Option(true)));
+        value.serialize(self)
+    }
+
+    fn serialize_seq(self, len: Option<usize>) -> Result<Self, Error> {
+        assert_eq!(self.tokens.next(), Some(&Token::SeqStart(len)));
+        Ok(self)
+    }
+
+    fn serialize_seq_fixed_size(self, len: usize) -> Result<Self, Error> {
+        assert_eq!(self.tokens.next(), Some(&Token::SeqArrayStart(len)));
+        Ok(self)
+    }
+
+    fn serialize_tuple(self, len: usize) -> Result<Self, Error> {
+        assert_eq!(self.tokens.next(), Some(&Token::TupleStart(len)));
+        Ok(self)
+    }
+
+    fn serialize_tuple_struct(self, name: &'static str, len: usize) -> Result<Self, Error> {
+        assert_eq!(self.tokens.next(), Some(&Token::TupleStructStart(name, len)));
+        Ok(self)
+    }
+
+    fn serialize_tuple_variant(self,
                                name: &str,
                                _variant_index: usize,
                                variant: &str,
-                               len: usize) -> Result<(), Error>
+                               len: usize) -> Result<Self, Error>
     {
         assert_eq!(self.tokens.next(), Some(&Token::EnumSeqStart(name, variant, len)));
-
-        Ok(())
+        Ok(self)
     }
 
-    fn serialize_tuple_variant_elt<T>(&mut self, _: &mut (), value: T) -> Result<(), Error>
-        where T: Serialize
-    {
-        assert_eq!(self.tokens.next(), Some(&Token::EnumSeqSep));
-        value.serialize(self)
-    }
-
-    fn serialize_tuple_variant_end(&mut self, _: ()) -> Result<(), Error> {
-        assert_eq!(self.tokens.next(), Some(&Token::EnumSeqEnd));
-        Ok(())
-    }
-
-    fn serialize_map(&mut self, len: Option<usize>) -> Result<(), Error>
-    {
+    fn serialize_map(self, len: Option<usize>) -> Result<Self, Error> {
         assert_eq!(self.tokens.next(), Some(&Token::MapStart(len)));
-
-        Ok(())
+        Ok(self)
     }
 
-    fn serialize_map_key<T>(&mut self, _: &mut (), key: T) -> Result<(), Self::Error> where T: Serialize {
-        assert_eq!(self.tokens.next(), Some(&Token::MapSep));
-        key.serialize(self)
-    }
-
-    fn serialize_map_value<T>(&mut self, _: &mut (), value: T) -> Result<(), Self::Error> where T: Serialize {
-        value.serialize(self)
-    }
-
-    fn serialize_map_end(&mut self, _: ()) -> Result<(), Self::Error> {
-        assert_eq!(self.tokens.next(), Some(&Token::MapEnd));
-        Ok(())
-    }
-
-    fn serialize_struct(&mut self, name: &str, len: usize) -> Result<(), Error>
-    {
+    fn serialize_struct(self, name: &str, len: usize) -> Result<Self, Error> {
         assert_eq!(self.tokens.next(), Some(&Token::StructStart(name, len)));
-
-        Ok(())
+        Ok(self)
     }
 
-    fn serialize_struct_elt<V>(&mut self, _: &mut (), key: &'static str, value: V) -> Result<(), Self::Error> where V: Serialize {
-        assert_eq!(self.tokens.next(), Some(&Token::StructSep));
-        try!(key.serialize(self));
-        value.serialize(self)
-    }
-
-    fn serialize_struct_end(&mut self, _: ()) -> Result<(), Self::Error> {
-        assert_eq!(self.tokens.next(), Some(&Token::StructEnd));
-        Ok(())
-    }
-
-    fn serialize_struct_variant(&mut self,
+    fn serialize_struct_variant(self,
                                 name: &str,
                                 _variant_index: usize,
                                 variant: &str,
-                                len: usize) -> Result<(), Error>
+                                len: usize) -> Result<Self, Error>
     {
         assert_eq!(self.tokens.next(), Some(&Token::EnumMapStart(name, variant, len)));
+        Ok(self)
+    }
+}
 
+impl<'s, 'a, I> ser::SerializeSeq for &'s mut Serializer<'a, I>
+    where I: Iterator<Item=&'a Token<'a>>,
+{
+    type Ok = ();
+    type Error = Error;
+
+    fn serialize_element<T>(&mut self, value: T) -> Result<(), Error>
+        where T: Serialize
+    {
+        assert_eq!(self.tokens.next(), Some(&Token::SeqSep));
+        value.serialize(&mut **self)
+    }
+
+    fn end(self) -> Result<(), Error> {
+        assert_eq!(self.tokens.next(), Some(&Token::SeqEnd));
         Ok(())
     }
+}
 
-    fn serialize_struct_variant_elt<V>(&mut self, _: &mut (), key: &'static str, value: V) -> Result<(), Self::Error> where V: Serialize {
-        assert_eq!(self.tokens.next(), Some(&Token::EnumMapSep));
-        try!(key.serialize(self));
-        value.serialize(self)
+impl<'s, 'a, I> ser::SerializeTuple for &'s mut Serializer<'a, I>
+    where I: Iterator<Item=&'a Token<'a>>,
+{
+    type Ok = ();
+    type Error = Error;
+
+    fn serialize_element<T>(&mut self, value: T) -> Result<(), Error>
+        where T: Serialize
+    {
+        assert_eq!(self.tokens.next(), Some(&Token::TupleSep));
+        value.serialize(&mut **self)
     }
 
-    fn serialize_struct_variant_end(&mut self, _: ()) -> Result<(), Self::Error> {
+    fn end(self) -> Result<(), Error> {
+        assert_eq!(self.tokens.next(), Some(&Token::TupleEnd));
+        Ok(())
+    }
+}
+
+impl<'s, 'a, I> ser::SerializeTupleStruct for &'s mut Serializer<'a, I>
+    where I: Iterator<Item=&'a Token<'a>>,
+{
+    type Ok = ();
+    type Error = Error;
+
+    fn serialize_field<T>(&mut self, value: T) -> Result<(), Error>
+        where T: Serialize
+    {
+        assert_eq!(self.tokens.next(), Some(&Token::TupleStructSep));
+        value.serialize(&mut **self)
+    }
+
+    fn end(self) -> Result<(), Error> {
+        assert_eq!(self.tokens.next(), Some(&Token::TupleStructEnd));
+        Ok(())
+    }
+}
+
+impl<'s, 'a, I> ser::SerializeTupleVariant for &'s mut Serializer<'a, I>
+    where I: Iterator<Item=&'a Token<'a>>,
+{
+    type Ok = ();
+    type Error = Error;
+
+    fn serialize_field<T>(&mut self, value: T) -> Result<(), Error>
+        where T: Serialize
+    {
+        assert_eq!(self.tokens.next(), Some(&Token::EnumSeqSep));
+        value.serialize(&mut **self)
+    }
+
+    fn end(self) -> Result<(), Error> {
+        assert_eq!(self.tokens.next(), Some(&Token::EnumSeqEnd));
+        Ok(())
+    }
+}
+
+impl<'s, 'a, I> ser::SerializeMap for &'s mut Serializer<'a, I>
+    where I: Iterator<Item=&'a Token<'a>>,
+{
+    type Ok = ();
+    type Error = Error;
+
+    fn serialize_key<T>(&mut self, key: T) -> Result<(), Self::Error> where T: Serialize {
+        assert_eq!(self.tokens.next(), Some(&Token::MapSep));
+        key.serialize(&mut **self)
+    }
+
+    fn serialize_value<T>(&mut self, value: T) -> Result<(), Self::Error> where T: Serialize {
+        value.serialize(&mut **self)
+    }
+
+    fn end(self) -> Result<(), Self::Error> {
+        assert_eq!(self.tokens.next(), Some(&Token::MapEnd));
+        Ok(())
+    }
+}
+
+impl<'s, 'a, I> ser::SerializeStruct for &'s mut Serializer<'a, I>
+    where I: Iterator<Item=&'a Token<'a>>,
+{
+    type Ok = ();
+    type Error = Error;
+
+    fn serialize_field<V>(&mut self, key: &'static str, value: V) -> Result<(), Self::Error> where V: Serialize {
+        assert_eq!(self.tokens.next(), Some(&Token::StructSep));
+        try!(key.serialize(&mut **self));
+        value.serialize(&mut **self)
+    }
+
+    fn end(self) -> Result<(), Self::Error> {
+        assert_eq!(self.tokens.next(), Some(&Token::StructEnd));
+        Ok(())
+    }
+}
+
+impl<'s, 'a, I> ser::SerializeStructVariant for &'s mut Serializer<'a, I>
+    where I: Iterator<Item=&'a Token<'a>>,
+{
+    type Ok = ();
+    type Error = Error;
+
+    fn serialize_field<V>(&mut self, key: &'static str, value: V) -> Result<(), Self::Error> where V: Serialize {
+        assert_eq!(self.tokens.next(), Some(&Token::EnumMapSep));
+        try!(key.serialize(&mut **self));
+        value.serialize(&mut **self)
+    }
+
+    fn end(self) -> Result<(), Self::Error> {
         assert_eq!(self.tokens.next(), Some(&Token::EnumMapEnd));
         Ok(())
     }
-
-    fn serialize_bytes(&mut self, value: &[u8]) -> Result<(), Self::Error> {
-        let mut state = try!(self.serialize_seq(Some(value.len())));
-        for c in value {
-            try!(self.serialize_seq_elt(&mut state, c));
-        }
-        self.serialize_seq_end(state)
-    }
 }

testing/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "serde_testing"
-version = "0.8.17"
+version = "0.9.0-rc1"
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>"]
 license = "MIT/Apache-2.0"
 description = "A generic serialization/deserialization framework"
@@ -10,6 +10,7 @@ documentation = "https://docs.serde.rs/serde/"
 readme = "README.md"
 keywords = ["serialization"]
 build = "build.rs"
+publish = false
 
 [features]
 unstable-testing = ["clippy", "serde/unstable-testing", "serde_codegen/unstable-testing"]

testing/tests/test.rs

@@ -1,4 +1,6 @@
 #![cfg_attr(feature = "clippy", feature(plugin))]
 #![cfg_attr(feature = "clippy", plugin(clippy))]
 
+#![cfg_attr(feature = "unstable-testing", feature(non_ascii_idents))]
+
 include!(concat!(env!("OUT_DIR"), "/test.rs"));

testing/tests/test.rs.in

@@ -1,4 +1,5 @@
 extern crate serde;
+extern crate serde_test;
 
 #[macro_use]
 mod macros;

testing/tests/test_annotations.rs

@@ -20,12 +20,12 @@ trait ShouldSkip: Sized {
 }
 
 trait SerializeWith: Sized {
-    fn serialize_with<S>(&self, ser: &mut S) -> Result<(), S::Error>
+    fn serialize_with<S>(&self, ser: S) -> Result<S::Ok, S::Error>
         where S: Serializer;
 }
 
 trait DeserializeWith: Sized {
-    fn deserialize_with<D>(de: &mut D) -> Result<Self, D::Error>
+    fn deserialize_with<D>(de: D) -> Result<Self, D::Error>
         where D: Deserializer;
 }
 
@@ -38,7 +38,7 @@ impl ShouldSkip for i32 {
 }
 
 impl SerializeWith for i32 {
-    fn serialize_with<S>(&self, ser: &mut S) -> Result<(), S::Error>
+    fn serialize_with<S>(&self, ser: S) -> Result<S::Ok, S::Error>
         where S: Serializer
     {
         if *self == 123 {
@@ -50,7 +50,7 @@ impl SerializeWith for i32 {
 }
 
 impl DeserializeWith for i32 {
-    fn deserialize_with<D>(de: &mut D) -> Result<Self, D::Error>
+    fn deserialize_with<D>(de: D) -> Result<Self, D::Error>
         where D: Deserializer
     {
         if try!(Deserialize::deserialize(de)) {
@@ -239,7 +239,7 @@ impl Default for NotDeserializeStruct {
 }
 
 impl DeserializeWith for NotDeserializeStruct {
-    fn deserialize_with<D>(_: &mut D) -> Result<Self, D::Error>
+    fn deserialize_with<D>(_: D) -> Result<Self, D::Error>
         where D: Deserializer
     {
         panic!()
@@ -642,7 +642,7 @@ struct NotSerializeStruct(i8);
 enum NotSerializeEnum { Trouble }
 
 impl SerializeWith for NotSerializeEnum {
-    fn serialize_with<S>(&self, ser: &mut S) -> Result<(), S::Error>
+    fn serialize_with<S>(&self, ser: S) -> Result<S::Ok, S::Error>
         where S: Serializer
     {
         "trouble".serialize(ser)

testing/tests/test_bytes.rs

@@ -1,460 +1,53 @@
-use std::fmt;
-use std::error;
-
-use serde::{Serialize, Serializer, Deserialize, Deserializer};
 use serde::bytes::{ByteBuf, Bytes};
-use serde::ser;
-use serde::de;
-
-///////////////////////////////////////////////////////////////////////////////
-
-#[derive(Debug, PartialEq)]
-struct Error;
-
-impl ser::Error for Error {
-    fn custom<T: Into<String>>(_: T) -> Error { Error }
-}
-
-impl de::Error for Error {
-    fn custom<T: Into<String>>(_: T) -> Error { Error }
-
-    fn end_of_stream() -> Error { Error }
-}
-
-impl fmt::Display for Error {
-    fn fmt(&self, formatter: &mut fmt::Formatter) -> Result<(), fmt::Error> {
-        formatter.write_str(format!("{:?}", self).as_ref())
-    }
-}
-
-impl error::Error for Error {
-    fn description(&self) -> &str {
-        "Serde Deserialization Error"
-    }
-
-    fn cause(&self) -> Option<&error::Error> {
-        None
-    }
-}
-
-///////////////////////////////////////////////////////////////////////////////
-
-struct BytesSerializer {
-    bytes: Vec<u8>,
-}
-
-impl BytesSerializer {
-    fn new(bytes: Vec<u8>) -> Self {
-        BytesSerializer {
-            bytes: bytes,
-        }
-    }
-}
-
-impl Serializer for BytesSerializer {
-    type Error = Error;
-    type SeqState = ();
-    type MapState = ();
-    type TupleState = ();
-    type TupleStructState = ();
-    type TupleVariantState = ();
-    type StructState = ();
-    type StructVariantState = ();
-
-    fn serialize_unit(&mut self) -> Result<(), Error> {
-        Err(Error)
-    }
-
-    fn serialize_unit_struct(&mut self, _name: &'static str) -> Result<(), Error> {
-        Err(Error)
-    }
-
-    fn serialize_unit_variant(&mut self, _: &'static str, _: usize, _: &'static str) -> Result<(), Error> {
-        Err(Error)
-    }
-
-    fn serialize_bool(&mut self, _v: bool) -> Result<(), Error> {
-        Err(Error)
-    }
-
-    fn serialize_isize(&mut self, _v: isize) -> Result<(), Error> {
-        Err(Error)
-    }
-
-    fn serialize_usize(&mut self, _v: usize) -> Result<(), Error> {
-        Err(Error)
-    }
-
-    fn serialize_i8(&mut self, _v: i8) -> Result<(), Error> {
-        Err(Error)
-    }
-
-    fn serialize_u8(&mut self, _v: u8) -> Result<(), Error> {
-        Err(Error)
-    }
-
-    fn serialize_i16(&mut self, _v: i16) -> Result<(), Error> {
-        Err(Error)
-    }
-
-    fn serialize_u16(&mut self, _v: u16) -> Result<(), Error> {
-        Err(Error)
-    }
-
-    fn serialize_i32(&mut self, _v: i32) -> Result<(), Error> {
-        Err(Error)
-    }
-
-    fn serialize_u32(&mut self, _v: u32) -> Result<(), Error> {
-        Err(Error)
-    }
-
-    fn serialize_i64(&mut self, _v: i64) -> Result<(), Error> {
-        Err(Error)
-    }
-
-    fn serialize_u64(&mut self, _v: u64) -> Result<(), Error> {
-        Err(Error)
-    }
-
-    fn serialize_f32(&mut self, _v: f32) -> Result<(), Error> {
-        Err(Error)
-    }
-
-    fn serialize_f64(&mut self, _v: f64) -> Result<(), Error> {
-        Err(Error)
-    }
-
-    fn serialize_char(&mut self, _v: char) -> Result<(), Error> {
-        Err(Error)
-    }
-
-    fn serialize_str(&mut self, _v: &str) -> Result<(), Error> {
-        Err(Error)
-    }
-
-    fn serialize_none(&mut self) -> Result<(), Error> {
-        Err(Error)
-    }
-
-    fn serialize_some<V>(&mut self, _value: V) -> Result<(), Error>
-        where V: Serialize,
-    {
-        Err(Error)
-    }
-
-    fn serialize_newtype_struct<V>(&mut self, _: &'static str, _value: V) -> Result<(), Error>
-        where V: Serialize,
-    {
-        Err(Error)
-    }
-
-    fn serialize_newtype_variant<V>(&mut self, _: &'static str, _: usize, _: &'static str, _value: V) -> Result<(), Error>
-        where V: Serialize,
-    {
-        Err(Error)
-    }
-
-    fn serialize_seq(&mut self, _len: Option<usize>) -> Result<(), Error>
-    {
-        Err(Error)
-    }
-
-    fn serialize_seq_fixed_size(&mut self, _len: usize) -> Result<(), Error>
-    {
-        Err(Error)
-    }
-
-    fn serialize_seq_elt<T>(&mut self, _: &mut (), _value: T) -> Result<(), Error>
-        where T: Serialize
-    {
-        Err(Error)
-    }
-
-    fn serialize_seq_end(&mut self, _: ()) -> Result<(), Error>
-    {
-        Err(Error)
-    }
-
-    fn serialize_tuple(&mut self, _len: usize) -> Result<(), Error>
-    {
-        Err(Error)
-    }
-
-    fn serialize_tuple_elt<T>(&mut self, _: &mut (), _value: T) -> Result<(), Error>
-        where T: Serialize
-    {
-        Err(Error)
-    }
-
-    fn serialize_tuple_end(&mut self, _: ()) -> Result<(), Error>
-    {
-        Err(Error)
-    }
-
-    fn serialize_tuple_struct(&mut self, _: &'static str, _len: usize) -> Result<(), Error>
-    {
-        Err(Error)
-    }
-
-    fn serialize_tuple_struct_elt<T>(&mut self, _: &mut (), _value: T) -> Result<(), Error>
-        where T: Serialize
-    {
-        Err(Error)
-    }
-
-    fn serialize_tuple_struct_end(&mut self, _: ()) -> Result<(), Error>
-    {
-        Err(Error)
-    }
-
-    fn serialize_tuple_variant(&mut self, _: &'static str, _: usize, _: &'static str, _len: usize) -> Result<(), Error>
-    {
-        Err(Error)
-    }
-
-    fn serialize_tuple_variant_elt<T>(&mut self, _: &mut (), _value: T) -> Result<(), Error>
-        where T: Serialize
-    {
-        Err(Error)
-    }
-
-    fn serialize_tuple_variant_end(&mut self, _: ()) -> Result<(), Error>
-    {
-        Err(Error)
-    }
-
-    fn serialize_map(&mut self, _: Option<usize>) -> Result<(), Error>
-    {
-        Err(Error)
-    }
-
-    fn serialize_map_key<T>(&mut self, _: &mut (), _key: T) -> Result<(), Error>
-        where T: Serialize
-    {
-        Err(Error)
-    }
-
-    fn serialize_map_value<T>(&mut self, _: &mut (), _value: T) -> Result<(), Error>
-        where T: Serialize
-    {
-        Err(Error)
-    }
-
-    fn serialize_map_end(&mut self, _: ()) -> Result<(), Error>
-    {
-        Err(Error)
-    }
-
-    fn serialize_struct(&mut self, _: &'static str, _: usize) -> Result<(), Error>
-    {
-        Err(Error)
-    }
-
-    fn serialize_struct_elt<V>(&mut self, _: &mut (), _key: &'static str, _value: V) -> Result<(), Error>
-        where V: Serialize,
-    {
-        Err(Error)
-    }
-
-    fn serialize_struct_end(&mut self, _: ()) -> Result<(), Error>
-    {
-        Err(Error)
-    }
-
-    fn serialize_struct_variant(&mut self, _: &'static str, _: usize, _: &'static str, _: usize) -> Result<(), Error>
-    {
-        Err(Error)
-    }
-
-    fn serialize_struct_variant_elt<V>(&mut self, _: &mut (), _key: &'static str, _value: V) -> Result<(), Error>
-        where V: Serialize,
-    {
-        Err(Error)
-    }
-
-    fn serialize_struct_variant_end(&mut self, _: ()) -> Result<(), Error>
-    {
-        Err(Error)
-    }
-
-    fn serialize_bytes(&mut self, bytes: &[u8]) -> Result<(), Error> {
-        assert_eq!(self.bytes, bytes);
-        Ok(())
-    }
-}
-
-///////////////////////////////////////////////////////////////////////////////
-
-struct BytesDeserializer {
-    bytes: Option<Vec<u8>>,
-}
-
-impl BytesDeserializer {
-    fn new(bytes: Vec<u8>) -> Self {
-        BytesDeserializer {
-            bytes: Some(bytes),
-        }
-    }
-}
-
-impl Deserializer for BytesDeserializer {
-    type Error = Error;
-
-    fn deserialize<V>(&mut self, _visitor: V) -> Result<V::Value, Error>
-        where V: de::Visitor,
-    {
-        Err(Error)
-    }
-
-    fn deserialize_bytes<V>(&mut self, mut visitor: V) -> Result<V::Value, Error>
-        where V: de::Visitor,
-    {
-        visitor.visit_byte_buf(self.bytes.take().unwrap())
-    }
-
-    fn deserialize_seq<__V>(&mut self, visitor: __V) -> Result<__V::Value, Self::Error>
-        where __V: de::Visitor {
-        self.deserialize(visitor)
-    }
-    fn deserialize_struct_field<__V>(&mut self, visitor: __V) -> Result<__V::Value, Self::Error>
-        where __V: de::Visitor {
-        self.deserialize(visitor)
-    }
-    fn deserialize_map<__V>(&mut self, visitor: __V) -> Result<__V::Value, Self::Error>
-        where __V: de::Visitor {
-        self.deserialize(visitor)
-    }
-    fn deserialize_unit<__V>(&mut self, visitor: __V) -> Result<__V::Value, Self::Error>
-        where __V: de::Visitor {
-        self.deserialize(visitor)
-    }
-    fn deserialize_ignored_any<__V>(&mut self, visitor: __V) -> Result<__V::Value, Self::Error>
-        where __V: de::Visitor {
-        self.deserialize(visitor)
-    }
-    fn deserialize_string<__V>(&mut self, visitor: __V) -> Result<__V::Value, Self::Error>
-        where __V: de::Visitor {
-        self.deserialize(visitor)
-    }
-    fn deserialize_str<__V>(&mut self, visitor: __V) -> Result<__V::Value, Self::Error>
-        where __V: de::Visitor {
-        self.deserialize(visitor)
-    }
-    fn deserialize_char<__V>(&mut self, visitor: __V) -> Result<__V::Value, Self::Error>
-        where __V: de::Visitor {
-        self.deserialize(visitor)
-    }
-    fn deserialize_i64<__V>(&mut self, visitor: __V) -> Result<__V::Value, Self::Error>
-        where __V: de::Visitor {
-        self.deserialize(visitor)
-    }
-    fn deserialize_i32<__V>(&mut self, visitor: __V) -> Result<__V::Value, Self::Error>
-        where __V: de::Visitor {
-        self.deserialize(visitor)
-    }
-    fn deserialize_i16<__V>(&mut self, visitor: __V) -> Result<__V::Value, Self::Error>
-        where __V: de::Visitor {
-        self.deserialize(visitor)
-    }
-    fn deserialize_i8<__V>(&mut self, visitor: __V) -> Result<__V::Value, Self::Error>
-        where __V: de::Visitor {
-        self.deserialize(visitor)
-    }
-    fn deserialize_u64<__V>(&mut self, visitor: __V) -> Result<__V::Value, Self::Error>
-        where __V: de::Visitor {
-        self.deserialize(visitor)
-    }
-    fn deserialize_u32<__V>(&mut self, visitor: __V) -> Result<__V::Value, Self::Error>
-        where __V: de::Visitor {
-        self.deserialize(visitor)
-    }
-    fn deserialize_u16<__V>(&mut self, visitor: __V) -> Result<__V::Value, Self::Error>
-        where __V: de::Visitor {
-        self.deserialize(visitor)
-    }
-    fn deserialize_u8<__V>(&mut self, visitor: __V) -> Result<__V::Value, Self::Error>
-        where __V: de::Visitor {
-        self.deserialize(visitor)
-    }
-    fn deserialize_f32<__V>(&mut self, visitor: __V) -> Result<__V::Value, Self::Error>
-        where __V: de::Visitor {
-        self.deserialize(visitor)
-    }
-    fn deserialize_f64<__V>(&mut self, visitor: __V) -> Result<__V::Value, Self::Error>
-        where __V: de::Visitor {
-        self.deserialize(visitor)
-    }
-    fn deserialize_bool<__V>(&mut self, visitor: __V) -> Result<__V::Value, Self::Error>
-        where __V: de::Visitor {
-        self.deserialize(visitor)
-    }
-    fn deserialize_usize<__V>(&mut self, visitor: __V) -> Result<__V::Value, Self::Error>
-        where __V: de::Visitor {
-        self.deserialize(visitor)
-    }
-    fn deserialize_isize<__V>(&mut self, visitor: __V) -> Result<__V::Value, Self::Error>
-        where __V: de::Visitor {
-        self.deserialize(visitor)
-    }
-    fn deserialize_option<__V>(&mut self, visitor: __V)
-     -> Result<__V::Value, Self::Error> where __V: de::Visitor {
-        self.deserialize(visitor)
-    }
-    fn deserialize_seq_fixed_size<__V>(&mut self, _: usize, visitor: __V)
-     -> Result<__V::Value, Self::Error> where __V: de::Visitor {
-        self.deserialize(visitor)
-    }
-    fn deserialize_unit_struct<__V>(&mut self, _: &str, visitor: __V)
-     -> Result<__V::Value, Self::Error> where __V: de::Visitor {
-        self.deserialize(visitor)
-    }
-    fn deserialize_newtype_struct<__V>(&mut self, _: &str, visitor: __V)
-     -> Result<__V::Value, Self::Error> where __V: de::Visitor {
-        self.deserialize(visitor)
-    }
-    fn deserialize_tuple_struct<__V>(&mut self, _: &str, _: usize, visitor: __V)
-     -> Result<__V::Value, Self::Error> where __V: de::Visitor {
-        self.deserialize(visitor)
-    }
-    fn deserialize_struct<__V>(&mut self, _: &str, _: &[&str], visitor: __V)
-     -> Result<__V::Value, Self::Error> where __V: de::Visitor {
-        self.deserialize(visitor)
-    }
-    fn deserialize_tuple<__V>(&mut self, _: usize, visitor: __V)
-     -> Result<__V::Value, Self::Error> where __V: de::Visitor {
-        self.deserialize(visitor)
-    }
-    fn deserialize_enum<__V>(&mut self, _: &str, _: &[&str], _visitor: __V)
-     -> Result<__V::Value, Self::Error> where __V: de::EnumVisitor {
-        Err(Error)
-    }
-}
-
-///////////////////////////////////////////////////////////////////////////////
+use serde_test::{assert_tokens, assert_ser_tokens, assert_de_tokens, Token};
 
 #[test]
-fn test_bytes_ser_bytes() {
-    let buf = vec![];
-    let bytes = Bytes::from(&buf);
-    let mut ser = BytesSerializer::new(vec![]);
-    bytes.serialize(&mut ser).unwrap();
+fn test_bytes() {
+    let empty = Bytes::new(&[]);
+    assert_ser_tokens(&empty, &[Token::Bytes(b"")]);
 
-    let buf = vec![1, 2, 3];
-    let bytes = Bytes::from(&buf);
-    let mut ser = BytesSerializer::new(vec![1, 2, 3]);
-    bytes.serialize(&mut ser).unwrap();
+    let buf = vec![65, 66, 67];
+    let bytes = Bytes::new(&buf);
+    assert_ser_tokens(&bytes, &[Token::Bytes(b"ABC")]);
 }
 
-///////////////////////////////////////////////////////////////////////////////
-
 #[test]
-fn test_byte_buf_de_bytes() {
-    let mut de = BytesDeserializer::new(vec![]);
-    let bytes = Deserialize::deserialize(&mut de);
-    assert_eq!(bytes, Ok(ByteBuf::new()));
+fn test_byte_buf() {
+    let empty = ByteBuf::new();
+    assert_tokens(&empty, &[Token::Bytes(b"")]);
+    assert_de_tokens(&empty, &[Token::Str("")]);
+    assert_de_tokens(&empty, &[Token::String(String::new())]);
+    assert_de_tokens(&empty, &[
+        Token::SeqStart(None),
+        Token::SeqEnd,
+    ]);
+    assert_de_tokens(&empty, &[
+        Token::SeqStart(Some(0)),
+        Token::SeqEnd,
+    ]);
 
-    let mut de = BytesDeserializer::new(vec![1, 2, 3]);
-    let bytes = Deserialize::deserialize(&mut de);
-    assert_eq!(bytes, Ok(ByteBuf::from(vec![1, 2, 3])));
+    let buf = ByteBuf::from(vec![65, 66, 67]);
+    assert_tokens(&buf, &[Token::Bytes(b"ABC")]);
+    assert_de_tokens(&buf, &[Token::Str("ABC")]);
+    assert_de_tokens(&buf, &[Token::String("ABC".to_owned())]);
+    assert_de_tokens(&buf, &[
+        Token::SeqStart(None),
+        Token::SeqSep,
+        Token::U8(65),
+        Token::SeqSep,
+        Token::U8(66),
+        Token::SeqSep,
+        Token::U8(67),
+        Token::SeqEnd,
+    ]);
+    assert_de_tokens(&buf, &[
+        Token::SeqStart(Some(3)),
+        Token::SeqSep,
+        Token::U8(65),
+        Token::SeqSep,
+        Token::U8(66),
+        Token::SeqSep,
+        Token::U8(67),
+        Token::SeqEnd,
+    ]);
 }

testing/tests/test_de.rs

@@ -3,7 +3,7 @@ use std::net;
 use std::path::PathBuf;
 use std::time::Duration;
 
-use serde::Deserialize;
+use serde::de::{Deserialize, Type};
 
 extern crate fnv;
 use self::fnv::FnvHasher;
@@ -32,12 +32,43 @@ struct Struct {
     c: i32,
 }
 
+#[derive(PartialEq, Debug, Deserialize)]
+#[serde(deny_unknown_fields)]
+struct StructDenyUnknown {
+    a: i32,
+    #[serde(skip_deserializing)]
+    b: i32,
+}
+
+#[derive(PartialEq, Debug, Deserialize)]
+struct StructSkipAll {
+    #[serde(skip_deserializing)]
+    a: i32,
+}
+
+#[derive(PartialEq, Debug, Deserialize)]
+#[serde(deny_unknown_fields)]
+struct StructSkipAllDenyUnknown {
+    #[serde(skip_deserializing)]
+    a: i32,
+}
+
 #[derive(PartialEq, Debug, Deserialize)]
 enum Enum {
+    #[allow(dead_code)]
+    #[serde(skip_deserializing)]
+    Skipped,
     Unit,
     Simple(i32),
     Seq(i32, i32, i32),
-    Map { a: i32, b: i32, c: i32 }
+    Map { a: i32, b: i32, c: i32 },
+}
+
+#[derive(PartialEq, Debug, Deserialize)]
+enum EnumSkipAll {
+    #[allow(dead_code)]
+    #[serde(skip_deserializing)]
+    Skipped,
 }
 
 //////////////////////////////////////////////////////////////////////////
@@ -215,6 +246,9 @@ declare_tests! {
             Token::SeqEnd,
         ],
     }
+    test_unit_string {
+        String::new() => &[Token::Unit],
+    }
     test_tuple_struct {
         TupleStruct(1, 2, 3) => &[
             Token::SeqStart(Some(3)),
@@ -675,6 +709,29 @@ declare_tests! {
             Token::StructEnd,
         ],
     }
+    test_struct_skip_all {
+        StructSkipAll { a: 0 } => &[
+            Token::StructStart("StructSkipAll", 0),
+            Token::StructEnd,
+        ],
+        StructSkipAll { a: 0 } => &[
+            Token::StructStart("StructSkipAll", 1),
+                Token::StructSep,
+                Token::Str("a"),
+                Token::I32(1),
+
+                Token::StructSep,
+                Token::Str("b"),
+                Token::I32(2),
+            Token::StructEnd,
+        ],
+    }
+    test_struct_skip_all_deny_unknown {
+        StructSkipAllDenyUnknown { a: 0 } => &[
+            Token::StructStart("StructSkipAllDenyUnknown", 0),
+            Token::StructEnd,
+        ],
+    }
     test_enum_unit {
         Enum::Unit => &[
             Token::EnumUnit("Enum", "Unit"),
@@ -717,20 +774,6 @@ declare_tests! {
             Token::EnumMapEnd,
         ],
     }
-    test_enum_unit_usize {
-        Enum::Unit => &[
-            Token::EnumStart("Enum"),
-            Token::Usize(0),
-            Token::Unit,
-        ],
-    }
-    test_enum_unit_bytes {
-        Enum::Unit => &[
-            Token::EnumStart("Enum"),
-            Token::Bytes(b"Unit"),
-            Token::Unit,
-        ],
-    }
     test_box {
         Box::new(0i32) => &[Token::I32(0)],
     }
@@ -796,12 +839,52 @@ fn test_net_ipaddr() {
 }
 
 declare_error_tests! {
+    test_unknown_field<StructDenyUnknown> {
+        &[
+            Token::StructStart("StructDenyUnknown", 2),
+                Token::StructSep,
+                Token::Str("a"),
+                Token::I32(0),
+
+                Token::StructSep,
+                Token::Str("d"),
+        ],
+        Error::UnknownField("d".to_owned()),
+    }
+    test_skipped_field_is_unknown<StructDenyUnknown> {
+        &[
+            Token::StructStart("StructDenyUnknown", 2),
+                Token::StructSep,
+                Token::Str("b"),
+        ],
+        Error::UnknownField("b".to_owned()),
+    }
+    test_skip_all_deny_unknown<StructSkipAllDenyUnknown> {
+        &[
+            Token::StructStart("StructSkipAllDenyUnknown", 1),
+                Token::StructSep,
+                Token::Str("a"),
+        ],
+        Error::UnknownField("a".to_owned()),
+    }
     test_unknown_variant<Enum> {
         &[
             Token::EnumUnit("Enum", "Foo"),
         ],
         Error::UnknownVariant("Foo".to_owned()),
     }
+    test_enum_skipped_variant<Enum> {
+        &[
+            Token::EnumUnit("Enum", "Skipped"),
+        ],
+        Error::UnknownVariant("Skipped".to_owned()),
+    }
+    test_enum_skip_all<EnumSkipAll> {
+        &[
+            Token::EnumUnit("EnumSkipAll", "Skipped"),
+        ],
+        Error::UnknownVariant("Skipped".to_owned()),
+    }
     test_struct_seq_too_long<Struct> {
         &[
             Token::SeqStart(Some(4)),
@@ -835,4 +918,20 @@ declare_error_tests! {
         ],
         Error::DuplicateField("a"),
     }
+    test_enum_unit_usize<Enum> {
+        &[
+            Token::EnumStart("Enum"),
+            Token::Usize(0),
+            Token::Unit,
+        ],
+        Error::InvalidType(Type::U64),
+    }
+    test_enum_unit_bytes<Enum> {
+        &[
+            Token::EnumStart("Enum"),
+            Token::Bytes(b"Unit"),
+            Token::Unit,
+        ],
+        Error::InvalidType(Type::Bytes),
+    }
 }

testing/tests/test_gen.rs

@@ -202,6 +202,91 @@ fn test_gen() {
         EmptyStruct {},
     }
     assert::<EmptyEnumVariant>();
+
+    #[cfg(feature = "unstable-testing")]
+    #[cfg_attr(feature = "unstable-testing", derive(Serialize, Deserialize))]
+    struct NonAsciiIdents {
+        σ: f64
+    }
+
+    #[derive(Serialize, Deserialize)]
+    struct EmptyBraced {}
+
+    #[derive(Serialize, Deserialize)]
+    #[serde(deny_unknown_fields)]
+    struct EmptyBracedDenyUnknown {}
+
+    #[derive(Serialize, Deserialize)]
+    struct BracedSkipAll {
+        #[serde(skip_deserializing)]
+        f: u8,
+    }
+
+    #[derive(Serialize, Deserialize)]
+    #[serde(deny_unknown_fields)]
+    struct BracedSkipAllDenyUnknown {
+        #[serde(skip_deserializing)]
+        f: u8,
+    }
+
+    #[cfg(feature = "unstable-testing")]
+    #[cfg_attr(feature = "unstable-testing", derive(Serialize, Deserialize))]
+    struct EmptyTuple();
+
+    #[cfg(feature = "unstable-testing")]
+    #[cfg_attr(feature = "unstable-testing", derive(Serialize, Deserialize))]
+    #[serde(deny_unknown_fields)]
+    struct EmptyTupleDenyUnknown();
+
+    #[derive(Serialize, Deserialize)]
+    struct TupleSkipAll(#[serde(skip_deserializing)] u8);
+
+    #[derive(Serialize, Deserialize)]
+    #[serde(deny_unknown_fields)]
+    struct TupleSkipAllDenyUnknown(#[serde(skip_deserializing)] u8);
+
+    #[derive(Serialize, Deserialize)]
+    enum EmptyEnum {}
+
+    #[derive(Serialize, Deserialize)]
+    #[serde(deny_unknown_fields)]
+    enum EmptyEnumDenyUnknown {}
+
+    #[derive(Serialize, Deserialize)]
+    enum EnumSkipAll {
+        #[serde(skip_deserializing)]
+        #[allow(dead_code)]
+        Variant,
+    }
+
+    #[cfg(feature = "unstable-testing")]
+    #[cfg_attr(feature = "unstable-testing", derive(Serialize, Deserialize))]
+    enum EmptyVariants {
+        Braced {},
+        Tuple(),
+        BracedSkip {
+            #[serde(skip_deserializing)]
+            f: u8,
+        },
+        TupleSkip(#[serde(skip_deserializing)] u8),
+    }
+
+    #[cfg(feature = "unstable-testing")]
+    #[cfg_attr(feature = "unstable-testing", derive(Serialize, Deserialize))]
+    #[serde(deny_unknown_fields)]
+    enum EmptyVariantsDenyUnknown {
+        Braced {},
+        Tuple(),
+        BracedSkip {
+            #[serde(skip_deserializing)]
+            f: u8,
+        },
+        TupleSkip(#[serde(skip_deserializing)] u8),
+    }
+
+    #[derive(Serialize, Deserialize)]
+    #[serde(deny_unknown_fields)]
+    struct UnitDenyUnknown;
 }
 
 //////////////////////////////////////////////////////////////////////////
@@ -210,32 +295,32 @@ fn assert<T: Serialize + Deserialize>() {}
 fn assert_ser<T: Serialize>() {}
 
 trait SerializeWith {
-    fn serialize_with<S: Serializer>(_: &Self, _: &mut S) -> StdResult<(), S::Error>;
+    fn serialize_with<S: Serializer>(_: &Self, _: S) -> StdResult<S::Ok, S::Error>;
 }
 
 trait DeserializeWith: Sized {
-    fn deserialize_with<D: Deserializer>(_: &mut D) -> StdResult<Self, D::Error>;
+    fn deserialize_with<D: Deserializer>(_: D) -> StdResult<Self, D::Error>;
 }
 
 // Implements neither Serialize nor Deserialize
 struct X;
 
-fn ser_x<S: Serializer>(_: &X, _: &mut S) -> StdResult<(), S::Error> {
+fn ser_x<S: Serializer>(_: &X, _: S) -> StdResult<S::Ok, S::Error> {
     unimplemented!()
 }
 
-fn de_x<D: Deserializer>(_: &mut D) -> StdResult<X, D::Error> {
+fn de_x<D: Deserializer>(_: D) -> StdResult<X, D::Error> {
     unimplemented!()
 }
 
 impl SerializeWith for X {
-    fn serialize_with<S: Serializer>(_: &Self, _: &mut S) -> StdResult<(), S::Error> {
+    fn serialize_with<S: Serializer>(_: &Self, _: S) -> StdResult<S::Ok, S::Error> {
         unimplemented!()
     }
 }
 
 impl DeserializeWith for X {
-    fn deserialize_with<D: Deserializer>(_: &mut D) -> StdResult<Self, D::Error> {
+    fn deserialize_with<D: Deserializer>(_: D) -> StdResult<Self, D::Error> {
         unimplemented!()
     }
 }

testing/tests/test_ser.rs

@@ -15,6 +15,9 @@ use self::serde_test::{
 extern crate fnv;
 use self::fnv::FnvHasher;
 
+#[cfg(feature = "unstable")]
+use serde::ser::iterator;
+
 //////////////////////////////////////////////////////////////////////////
 
 #[derive(Serialize)]
@@ -30,12 +33,20 @@ struct Struct {
     c: i32,
 }
 
-#[derive(Serialize)]
+#[derive(Serialize, PartialEq, Debug)]
 enum Enum {
     Unit,
     One(i32),
     Seq(i32, i32),
     Map { a: i32, b: i32 },
+    #[serde(skip_serializing)]
+    SkippedUnit,
+    #[serde(skip_serializing)]
+    SkippedOne(i32),
+    #[serde(skip_serializing)]
+    SkippedSeq(i32, i32),
+    #[serde(skip_serializing)]
+    SkippedMap { _a: i32, _b: i32 },
 }
 
 //////////////////////////////////////////////////////////////////////////
@@ -361,6 +372,49 @@ declare_ser_tests! {
     }
 }
 
+
+#[cfg(feature = "unstable")]
+#[test]
+fn test_iterator() {
+    assert_ser_tokens(iterator([0; 0].iter()), &[
+        Token::SeqStart(Some(0)),
+        Token::SeqEnd,
+    ]);
+    assert_ser_tokens(iterator([1, 2, 3].iter()), &[
+        Token::SeqStart(Some(3)),
+            Token::SeqSep,
+            Token::I32(1),
+
+            Token::SeqSep,
+            Token::I32(2),
+
+            Token::SeqSep,
+            Token::I32(3),
+        Token::SeqEnd,
+    ]);
+    assert_ser_tokens(iterator([1, 2, 3].iter().map(|x| x * 2)), &[
+        Token::SeqStart(Some(3)),
+            Token::SeqSep,
+            Token::I32(2),
+
+            Token::SeqSep,
+            Token::I32(4),
+
+            Token::SeqSep,
+            Token::I32(6),
+        Token::SeqEnd,
+    ]);
+    assert_ser_tokens(iterator([1, 2, 3].iter().filter(|&x| x % 2 != 0)), &[
+        Token::SeqStart(None),
+            Token::SeqSep,
+            Token::I32(1),
+
+            Token::SeqSep,
+            Token::I32(3),
+        Token::SeqEnd,
+    ]);
+}
+
 #[cfg(feature = "unstable")]
 #[test]
 fn test_net_ipaddr() {
@@ -388,3 +442,23 @@ fn test_cannot_serialize_paths() {
         &[],
         Error::InvalidValue("Path contains invalid UTF-8 characters".to_owned()));
 }
+
+#[test]
+fn test_enum_skipped() {
+    assert_ser_tokens_error(
+        &Enum::SkippedUnit,
+        &[],
+        Error::InvalidValue("The enum variant Enum::SkippedUnit cannot be serialized".to_owned()));
+    assert_ser_tokens_error(
+        &Enum::SkippedOne(42),
+        &[],
+        Error::InvalidValue("The enum variant Enum::SkippedOne cannot be serialized".to_owned()));
+    assert_ser_tokens_error(
+        &Enum::SkippedSeq(1, 2),
+        &[],
+        Error::InvalidValue("The enum variant Enum::SkippedSeq cannot be serialized".to_owned()));
+    assert_ser_tokens_error(
+        &Enum::SkippedMap { _a: 1, _b: 2 },
+        &[],
+        Error::InvalidValue("The enum variant Enum::SkippedMap cannot be serialized".to_owned()));
+}