Release 0.8.8

Auto merge of #546 - serde-rs:qual, r=oli-obk
Result needs to be fully qualified Without this: ``` error[E0244]: wrong number of type arguments --> src/api/accounts.rs:19:10 | 19 | #[derive(Serialize, Deserialize, Debug)] | ^^^^^^^^^^ expected 1 type arguments, found 2 ```
2026-04-23 11:48:00 +00:00 · 2016-09-08 08:34:20 -07:00 · 2016-09-08 18:05:36 +09:00 · 2016-09-07 16:37:26 -07:00 · 2016-09-05 09:39:27 -07:00 · 2016-09-06 01:10:43 +09:00
49 changed files with 2821 additions and 2563 deletions
@@ -2,10 +2,10 @@ sudo: false
 language: rust
 rust:
 - stable
- beta
 - nightly
- 1.7.0
 - 1.8.0
+- 1.9.0
+- beta
 addons:
  apt:
    packages:
@@ -18,20 +18,18 @@ before_script:
 script:
 - (cd serde && travis-cargo build)
 - (cd serde && travis-cargo --skip nightly test)
- (cd serde && travis-cargo --only nightly test -- --features nightly-testing)
+- (cd serde && travis-cargo --only nightly test -- --features unstable-testing)
 - (cd serde && travis-cargo build -- --no-default-features)
 - (cd serde && travis-cargo --only nightly build -- --no-default-features --features alloc)
 - (cd serde && travis-cargo --only nightly build -- --no-default-features --features collections)
 - (cd testing && travis-cargo --skip nightly test)
- (cd testing && travis-cargo --only nightly test -- --features nightly-testing)
- (cd serde_macros && travis-cargo --only nightly test -- --features nightly-testing)
+- (cd testing && travis-cargo --only nightly test -- --features unstable-testing)
+- (cd serde_macros && travis-cargo --only nightly test -- --features unstable-testing)
 - (cd examples/serde-syntex-example && travis-cargo --skip nightly run)
- (cd examples/serde-syntex-example && travis-cargo --only nightly run -- --no-default-features --features nightly)
+- (cd examples/serde-syntex-example && travis-cargo --only nightly run -- --no-default-features --features unstable)
 - (cd serde && travis-cargo --only stable doc)
 after_success:
- (cd serde && travis-cargo --only stable doc-upload)
 - (cd testing && travis-cargo --only stable coveralls --no-sudo)
 env:
  global:
  - TRAVIS_CARGO_NIGHTLY_FEATURE=""
-  - secure: Jcd11Jy0xLyacBUB+oKOaxKBm9iZNInenRDtNBY8GKOtqF5fHUfEjgDf538hwRl5L0FP7DLr8oK0IHmzA7lPjJxlzoKVKV3IM7bRZEYzW5DMonf/lcliuGte7SH0NVFhifM87T8HI2hjGdAb+7+m34siBR7M3AY/XjLInrvUFvY=
@@ -0,0 +1,45 @@
+# Contributing to Serde
+
+Serde welcomes contribution from everyone. Here are the guidelines if you are
+thinking of helping us:
+
+## Contributions
+
+Contributions to Serde or its dependencies should be made in the form of GitHub
+pull requests. Each pull request will be reviewed by a core contributor
+(someone with permission to land patches) and either landed in the main tree or
+given feedback for changes that would be required. All contributions should
+follow this format, even those from core contributors.
+
+Should you wish to work on an issue, please claim it first by commenting on
+the GitHub issue that you want to work on it. This is to prevent duplicated
+efforts from contributors on the same issue.
+
+## Pull Request Checklist
+
+- Branch from the master branch and, if needed, rebase to the current master
+  branch before submitting your pull request. If it doesn't merge cleanly with
+  master you may be asked to rebase your changes.
+
+- Commits should be as small as possible, while ensuring that each commit is
+  correct independently (i.e., each commit should compile and pass tests). 
+
+- If your patch is not getting reviewed or you need a specific person to review
+  it, you can @-reply a reviewer asking for a review in the pull request or a
+  comment, or you can ask for a review in `#serde` on `irc.mozilla.org`.
+
+- Add tests relevant to the fixed bug or new feature.
+
+## Conduct
+
+In all Serde-related forums, we follow the [Rust Code of
+Conduct](https://www.rust-lang.org/conduct.html).  For escalation or moderation
+issues, please contact Erick (erick.tryzelaar@gmail.com) instead of the Rust
+moderation team.
+
+## Communication
+
+Beyond opening tickets on the
+[serde-rs/serde](https://github.com/serde-rs/serde) project, Serde contributors
+frequent the `#serde` channel on
+[`irc.mozilla.org`](https://wiki.mozilla.org/IRC).
@@ -1,49 +1,21 @@
-Serde Rust Serialization Framework
-==================================
+# Serde &emsp; [![Build Status](https://api.travis-ci.org/serde-rs/serde.svg?branch=master)](https://travis-ci.org/serde-rs/serde) [![Latest Version](https://img.shields.io/crates/v/serde.svg)](https://crates.io/crates/serde)

-[![Build Status](https://api.travis-ci.org/serde-rs/serde.svg?branch=master)](https://travis-ci.org/serde-rs/serde)
-[![Coverage Status](https://coveralls.io/repos/serde-rs/serde/badge.svg?branch=master&service=github)](https://coveralls.io/github/serde-rs/serde?branch=master)
-[![Latest Version](https://img.shields.io/crates/v/serde.svg)](https://crates.io/crates/serde)
-[![Clippy Linting Result](https://clippy.bashy.io/github/serde-rs/serde/master/badge.svg)](https://clippy.bashy.io/github/serde-rs/serde/master/log)
+**Serde is a framework for *ser*ializing and *de*serializing Rust data structures efficiently and generically.**

-Serde is a powerful framework that enables serialization libraries to
-generically serialize Rust data structures without the overhead of runtime type
-information. In many situations, the handshake protocol between serializers and
-serializees can be completely optimized away, leaving Serde to perform roughly
-the same speed as a hand written serializer for a specific type.
+---

-Documentation is available at:
+You may be looking for:

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

-Using Serde with Nightly Rust and serde\_macros
-===============================================
-
-Here is a simple example that demonstrates how to use Serde by serializing and
-deserializing to JSON. Serde comes with some powerful code generation libraries
-that work with Stable and Nightly Rust that eliminate much of the complexity of
-hand rolling serialization and deserialization for a given type. First lets see
-how we would use Nightly Rust, which is currently a bit simpler than Stable
-Rust:
-
-`Cargo.toml`:
-
-```toml
-[package]
-name = "serde_example_nightly"
-version = "0.1.0"
-authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>"]
-
-[dependencies]
-serde = "*"
-serde_json = "*"
-serde_macros = "*"
-```
-
-`src/main.rs`
+## Serde in action

 ```rust
-#![feature(custom_derive, plugin)]
+#![feature(plugin, custom_derive)]
 #![plugin(serde_macros)]

 extern crate serde_json;
@@ -56,691 +28,42 @@ struct Point {

 fn main() {
    let point = Point { x: 1, y: 2 };
+
+    // Convert the Point to a JSON string.
    let serialized = serde_json::to_string(&point).unwrap();

-    println!("{}", serialized);
+    // Prints serialized = {"x":1,"y":2}
+    println!("serialized = {}", serialized);

+    // Convert the JSON string back to a Point.
    let deserialized: Point = serde_json::from_str(&serialized).unwrap();

-    println!("{:?}", deserialized);
+    // Prints deserialized = Point { x: 1, y: 2 }
+    println!("deserialized = {:?}", deserialized);
 }
 ```

-When run, it produces:
+## Getting help

-```
-% cargo run
-{"x":1,"y":2}
-Point { x: 1, y: 2 }
-```
+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.

-Using Serde with Stable Rust and serde\_codegen
-===============================================
+## License

-Stable Rust is a little more complicated because it does not yet support
-compiler plugins. Instead we need to use `serde_codegen` which is based on the
-code generation library [syntex](https://github.com/serde-rs/syntex):
+Serde is licensed under either of

-```toml
-[package]
-name = "serde_example"
-version = "0.1.0"
-authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>"]
-build = "build.rs"
+ * Apache License, Version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or
+   http://www.apache.org/licenses/LICENSE-2.0)
+ * MIT license ([LICENSE-MIT](LICENSE-MIT) or
+   http://opensource.org/licenses/MIT)

-[build-dependencies]
-serde_codegen = "*"
+at your option.

-[dependencies]
-serde = "*"
-serde_json = "*"
-```
+### Contribution

-`src/main.rs`:
-
-```rust,ignore
-extern crate serde;
-extern crate serde_json;
-
-include!(concat!(env!("OUT_DIR"), "/main.rs"));
-```
-
-`src/main.rs.in`:
-
-```rust,ignore
-#[derive(Serialize, Deserialize, Debug)]
-struct Point {
-    x: i32,
-    y: i32,
-}
-
-fn main() {
-    let point = Point { x: 1, y: 2 };
-    let serialized = serde_json::to_string(&point).unwrap();
-
-    println!("{}", serialized);
-
-    let deserialized: Point = serde_json::from_str(&serialized).unwrap();
-
-    println!("{:?}", deserialized);
-}
-```
-
-`build.rs`
-
-```rust,ignore
-extern crate serde_codegen;
-
-use std::env;
-use std::path::Path;
-
-pub fn main() {
-    let out_dir = env::var_os("OUT_DIR").unwrap();
-
-    let src = Path::new("src/main.rs.in");
-    let dst = Path::new(&out_dir).join("main.rs");
-
-    serde_codegen::expand(&src, &dst).unwrap();
-}
-```
-
-This also produces:
-
-```
-% cargo run
-{"x":1,"y":2}
-Point { x: 1, y: 2 }
-```
-
-While this works well with Stable Rust, be aware that the error locations
-currently are reported in the generated file instead of in the source file. You
-may find it easier to develop with Nightly Rust and `serde\_macros`, then
-deploy with Stable Rust and `serde_codegen`. It's possible to combine both
-approaches in one setup:
-
-`Cargo.toml`:
-
-```toml
-[package]
-name = "serde_example"
-version = "0.1.0"
-authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>"]
-build = "build.rs"
-
-[features]
-default = ["serde_codegen"]
-nightly = ["serde_macros"]
-
-[build-dependencies]
-serde_codegen = { version = "*", optional = true }
-
-[dependencies]
-serde = "*"
-serde_json = "*"
-serde_macros = { version = "*", optional = true }
-```
-
-`build.rs`:
-
-```rust,ignore
-#[cfg(not(feature = "serde_macros"))]
-mod inner {
-    extern crate serde_codegen;
-
-    use std::env;
-    use std::path::Path;
-
-    pub fn main() {
-        let out_dir = env::var_os("OUT_DIR").unwrap();
-
-        let src = Path::new("src/main.rs.in");
-        let dst = Path::new(&out_dir).join("main.rs");
-
-        serde_codegen::expand(&src, &dst).unwrap();
-    }
-}
-
-#[cfg(feature = "serde_macros")]
-mod inner {
-    pub fn main() {}
-}
-
-fn main() {
-    inner::main();
-}
-```
-
-`src/main.rs`:
-
-```rust,ignore
-#![cfg_attr(feature = "serde_macros", feature(custom_derive, plugin))]
-#![cfg_attr(feature = "serde_macros", plugin(serde_macros))]
-
-extern crate serde;
-extern crate serde_json;
-
-#[cfg(feature = "serde_macros")]
-include!("main.rs.in");
-
-#[cfg(not(feature = "serde_macros"))]
-include!(concat!(env!("OUT_DIR"), "/main.rs"));
-```
-
-The `src/main.rs.in` is the same as before.
-
-Then to run with stable:
-
-```
-% cargo build
-...
-```
-
-Or with nightly:
-
-```
-% cargo build --features nightly --no-default-features
-...
-```
-
-Serialization without Macros
-============================
-
-Under the covers, Serde extensively uses the Visitor pattern to thread state
-between the
-[Serializer](http://serde-rs.github.io/serde/serde/serde/ser/trait.Serializer.html)
-and
-[Serialize](http://serde-rs.github.io/serde/serde/serde/ser/trait.Serialize.html)
-without the two having specific information about each other's concrete type.
-This has many of the same benefits as frameworks that use runtime type
-information without the overhead.  In fact, when compiling with optimizations,
-Rust is able to remove most or all the visitor state, and generate code that's
-nearly as fast as a hand written serializer format for a specific type.
-
-To see it in action, lets look at how a simple type like `i32` is serialized.
-The
-[Serializer](http://serde-rs.github.io/serde/serde/serde/ser/trait.Serializer.html)
-is threaded through the type:
-
-```rust,ignore
-impl serde::Serialize for i32 {
-    fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
-        where S: serde::Serializer,
-    {
-        serializer.serialize_i32(*self)
-    }
-}
-```
-
-As you can see it's pretty simple. More complex types like `BTreeMap` need to
-pass a
-[MapVisitor](http://serde-rs.github.io/serde/serde/serde/ser/trait.MapVisitor.html)
-to the 
-[Serializer](http://serde-rs.github.io/serde/serde/serde/ser/trait.Serializer.html)
-in order to walk through the type:
-
-```rust,ignore
-impl<K, V> Serialize for BTreeMap<K, V>
-    where K: Serialize + Ord,
-          V: Serialize,
-{
-    #[inline]
-    fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
-        where S: Serializer,
-    {
-        serializer.serialize_map(MapIteratorVisitor::new(self.iter(), Some(self.len())))
-    }
-}
-
-pub struct MapIteratorVisitor<Iter> {
-    iter: Iter,
-    len: Option<usize>,
-}
-
-impl<K, V, Iter> MapIteratorVisitor<Iter>
-    where Iter: Iterator<Item=(K, V)>
-{
-    #[inline]
-    pub fn new(iter: Iter, len: Option<usize>) -> MapIteratorVisitor<Iter> {
-        MapIteratorVisitor {
-            iter: iter,
-            len: len,
-        }
-    }
-}
-
-impl<K, V, I> MapVisitor for MapIteratorVisitor<I>
-    where K: Serialize,
-          V: Serialize,
-          I: Iterator<Item=(K, V)>,
-{
-    #[inline]
-    fn visit<S>(&mut self, serializer: &mut S) -> Result<Option<()>, S::Error>
-        where S: Serializer,
-    {
-        match self.iter.next() {
-            Some((key, value)) => {
-                let value = try!(serializer.serialize_map_elt(key, value));
-                Ok(Some(value))
-            }
-            None => Ok(None)
-        }
-    }
-
-    #[inline]
-    fn len(&self) -> Option<usize> {
-        self.len
-    }
-}
-```
-
-Serializing structs follow this same pattern. In fact, structs are represented
-as a named map. Its visitor uses a simple state machine to iterate through all
-the fields:
-
-```rust
-extern crate serde;
-extern crate serde_json;
-
-struct Point {
-    x: i32,
-    y: i32,
-}
-
-impl serde::Serialize for Point {
-    fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
-        where S: serde::Serializer
-    {
-        serializer.serialize_struct("Point", PointMapVisitor {
-            value: self,
-            state: 0,
-        })
-    }
-}
-
-struct PointMapVisitor<'a> {
-    value: &'a Point,
-    state: u8,
-}
-
-impl<'a> serde::ser::MapVisitor for PointMapVisitor<'a> {
-    fn visit<S>(&mut self, serializer: &mut S) -> Result<Option<()>, S::Error>
-        where S: serde::Serializer
-    {
-        match self.state {
-            0 => {
-                self.state += 1;
-                Ok(Some(try!(serializer.serialize_struct_elt("x", &self.value.x))))
-            }
-            1 => {
-                self.state += 1;
-                Ok(Some(try!(serializer.serialize_struct_elt("y", &self.value.y))))
-            }
-            _ => {
-                Ok(None)
-            }
-        }
-    }
-}
-
-fn main() {
-    let point = Point { x: 1, y: 2 };
-    let serialized = serde_json::to_string(&point).unwrap();
-
-    println!("{}", serialized);
-}
-```
-
-Deserialization without Macros
-==============================
-
-Deserialization is a little more complicated since there's a bit more error
-handling that needs to occur. Let's start with the simple `i32`
-[Deserialize](http://serde-rs.github.io/serde/serde/serde/de/trait.Deserialize.html)
-implementation. It passes a
-[Visitor](http://serde-rs.github.io/serde/serde/serde/de/trait.Visitor.html) to the
-[Deserializer](http://serde-rs.github.io/serde/serde/serde/de/trait.Deserializer.html).
-The [Visitor](http://serde-rs.github.io/serde/serde/serde/de/trait.Visitor.html)
-can create the `i32` from a variety of different types:
-
-```rust,ignore
-impl Deserialize for i32 {
-    fn deserialize<D>(deserializer: &mut D) -> Result<i32, D::Error>
-        where D: serde::Deserializer,
-    {
-        deserializer.deserialize(I32Visitor)
-    }
-}
-
-struct I32Visitor;
-
-impl serde::de::Visitor for I32Visitor {
-    type Value = i32;
-
-    fn visit_i16<E>(&mut self, value: i16) -> Result<i32, E>
-        where E: Error,
-    {
-        self.visit_i32(value as i32)
-    }
-
-    fn visit_i32<E>(&mut self, value: i32) -> Result<i32, E>
-        where E: Error,
-    {
-        Ok(value)
-    }
-
-    ...
-
-```
-
-Since it's possible for this type to get passed an unexpected type, we need a
-way to error out. This is done by way of the
-[Error](http://serde-rs.github.io/serde/serde/serde/de/trait.Error.html) trait,
-which allows a 
-[Deserialize](http://serde-rs.github.io/serde/serde/serde/de/trait.Deserialize.html)
-to generate an error for a few common error conditions. Here's how it could be used:
-
-```rust,ignore
-    ...
-
-    fn visit_string<E>(&mut self, _: String) -> Result<i32, E>
-        where E: Error,
-    {
-        Err(serde::de::Error::custom("expect a string"))
-    }
-
-    ...
-
-```
-
-Maps follow a similar pattern as before, and use a
-[MapVisitor](http://serde-rs.github.io/serde/serde/serde/de/trait.MapVisitor.html)
-to walk through the values generated by the 
-[Deserializer](http://serde-rs.github.io/serde/serde/serde/de/trait.Deserializer.html).
-
-```rust,ignore
-impl<K, V> serde::Deserialize for BTreeMap<K, V>
-    where K: serde::Deserialize + Eq + Ord,
-          V: serde::Deserialize,
-{
-    fn deserialize<D>(deserializer: &mut D) -> Result<BTreeMap<K, V>, D::Error>
-        where D: serde::Deserializer,
-    {
-        deserializer.deserialize(BTreeMapVisitor::new())
-    }
-}
-
-pub struct BTreeMapVisitor<K, V> {
-    marker: PhantomData<BTreeMap<K, V>>,
-}
-
-impl<K, V> BTreeMapVisitor<K, V> {
-    pub fn new() -> Self {
-        BTreeMapVisitor {
-            marker: PhantomData,
-        }
-    }
-}
-
-impl<K, V> serde::de::Visitor for BTreeMapVisitor<K, V>
-    where K: serde::de::Deserialize + Ord,
-          V: serde::de::Deserialize
-{
-    type Value = BTreeMap<K, V>;
-
-    fn visit_unit<E>(&mut self) -> Result<BTreeMap<K, V>, E>
-        where E: Error,
-    {
-        Ok(BTreeMap::new())
-    }
-
-    fn visit_map<V_>(&mut self, mut visitor: V_) -> Result<BTreeMap<K, V>, V_::Error>
-        where V_: MapVisitor,
-    {
-        let mut values = BTreeMap::new();
-
-        while let Some((key, value)) = try!(visitor.visit()) {
-            values.insert(key, value);
-        }
-
-        try!(visitor.end());
-
-        Ok(values)
-    }
-}
-```
-
-Deserializing structs goes a step further in order to support not allocating a
-`String` to hold the field names. This is done by custom field enum that
-deserializes an enum variant from a string. So for our `Point` example from
-before, we need to generate:
-
-```rust
-extern crate serde;
-extern crate serde_json;
-
-#[derive(Debug)]
-struct Point {
-    x: i32,
-    y: i32,
-}
-
-enum PointField {
-    X,
-    Y,
-}
-
-impl serde::Deserialize for PointField {
-    fn deserialize<D>(deserializer: &mut D) -> Result<PointField, D::Error>
-        where D: serde::de::Deserializer
-    {
-        struct PointFieldVisitor;
-
-        impl serde::de::Visitor for PointFieldVisitor {
-            type Value = PointField;
-
-            fn visit_str<E>(&mut self, value: &str) -> Result<PointField, E>
-                where E: serde::de::Error
-            {
-                match value {
-                    "x" => Ok(PointField::X),
-                    "y" => Ok(PointField::Y),
-                    _ => Err(serde::de::Error::custom("expected x or y")),
-                }
-            }
-        }
-
-        deserializer.deserialize(PointFieldVisitor)
-    }
-}
-
-impl serde::Deserialize for Point {
-    fn deserialize<D>(deserializer: &mut D) -> Result<Point, D::Error>
-        where D: serde::de::Deserializer
-    {
-        static FIELDS: &'static [&'static str] = &["x", "y"];
-        deserializer.deserialize_struct("Point", FIELDS, PointVisitor)
-    }
-}
-
-struct PointVisitor;
-
-impl serde::de::Visitor for PointVisitor {
-    type Value = Point;
-
-    fn visit_map<V>(&mut self, mut visitor: V) -> Result<Point, V::Error>
-        where V: serde::de::MapVisitor
-    {
-        let mut x = None;
-        let mut y = None;
-
-        loop {
-            match try!(visitor.visit_key()) {
-                Some(PointField::X) => { x = Some(try!(visitor.visit_value())); }
-                Some(PointField::Y) => { y = Some(try!(visitor.visit_value())); }
-                None => { break; }
-            }
-        }
-
-        let x = match x {
-            Some(x) => x,
-            None => try!(visitor.missing_field("x")),
-        };
-
-        let y = match y {
-            Some(y) => y,
-            None => try!(visitor.missing_field("y")),
-        };
-
-        try!(visitor.end());
-
-        Ok(Point{ x: x, y: y })
-    }
-}
-
-
-fn main() {
-    let serialized = "{\"x\":1,\"y\":2}";
-
-    let deserialized: Point = serde_json::from_str(&serialized).unwrap();
-
-    println!("{:?}", deserialized);
-}
-```
-
-Design Considerations and tradeoffs for Serializers and Deserializers
-=====================================================================
-
-Serde serialization and deserialization implementations are written in such a
-way that they err on being able to represent more values, and also provide
-better error messages when they are passed an incorrect type to deserialize
-from. For example, by default, it is a syntax error to deserialize a `String`
-into an `Option<String>`. This is implemented such that it is possible to
-distinguish between the values `None` and `Some(())`, if the serialization
-format supports option types.
-
-However, many formats do not have option types, and represents optional values
-as either a `null`, or some other value. Serde `Serializer`s and
-`Deserializer`s can opt-in support for this. For serialization, this is pretty
-easy. Simply implement these methods:
-
-```rust,ignore
-...
-
-    fn visit_none(&mut self) -> Result<(), Self::Error> {
-        self.visit_unit()
-    }
-
-    fn visit_some<T>(&mut self, value: T) -> Result<(), Self::Error> {
-        value.serialize(self)
-    }
-...
-```
-
-For deserialization, this can be implemented by way of the
-`Deserializer::visit_option` hook, which presumes that there is some ability to peek at what is the
-next value in the serialized token stream. This following example is from
-[serde_tests::TokenDeserializer](https://github.com/serde-rs/serde/blob/master/serde_tests/tests/token.rs#L435-L454),
-where it checks to see if the next value is an `Option`, a `()`, or some other
-value:
-
-```rust,ignore
-...
-
-    fn visit_option<V>(&mut self, mut visitor: V) -> Result<V::Value, Error>
-        where V: de::Visitor,
-    {
-        match self.tokens.peek() {
-            Some(&Token::Option(false)) => {
-                self.tokens.next();
-                visitor.visit_none()
-            }
-            Some(&Token::Option(true)) => {
-                self.tokens.next();
-                visitor.visit_some(self)
-            }
-            Some(&Token::Unit) => {
-                self.tokens.next();
-                visitor.visit_none()
-            }
-            Some(_) => visitor.visit_some(self),
-            None => Err(Error::EndOfStreamError),
-        }
-    }
-
-...
-```
-
-Annotations
-===========
-
-`serde_codegen` and `serde_macros` support annotations that help to customize
-how types are serialized. Here are the supported annotations:
-
-Container Annotations:
-
-| Annotation                                  | Function                                                                                                                                           |
-| ----------                                  | --------                                                                                                                                           |
-| `#[serde(rename="name")]`                   | Serialize and deserialize this container with the given name                                                                                       |
-| `#[serde(rename(serialize="name1"))]`       | Serialize this container with the given name                                                                                                       |
-| `#[serde(rename(deserialize="name1"))]`     | Deserialize this container with the given name                                                                                                     |
-| `#[serde(deny_unknown_fields)]`             | Always error during serialization when encountering unknown fields. When absent, unknown fields are ignored for self-describing formats like JSON. |
-| `#[serde(bound="T: MyTrait")]`              | Where-clause for the Serialize and Deserialize impls. This replaces any bounds inferred by Serde.                                                  |
-| `#[serde(bound(serialize="T: MyTrait"))]`   | Where-clause for the Serialize impl.                                                                                                               |
-| `#[serde(bound(deserialize="T: MyTrait"))]` | Where-clause for the Deserialize impl.                                                                                                             |
-
-Variant Annotations:
-
-| Annotation                              | Function                                                   |
-| ----------                              | --------                                                   |
-| `#[serde(rename="name")]`               | Serialize and deserialize this variant with the given name |
-| `#[serde(rename(serialize="name1"))]`   | Serialize this variant with the given name                 |
-| `#[serde(rename(deserialize="name1"))]` | Deserialize this variant with the given name               |
-
-Field Annotations:
-
-| Annotation                                  | Function                                                                                                                |
-| ----------                                  | --------                                                                                                                |
-| `#[serde(rename="name")]`                   | Serialize and deserialize this field with the given name                                                                |
-| `#[serde(rename(serialize="name1"))]`       | Serialize this field with the given name                                                                                |
-| `#[serde(rename(deserialize="name1"))]`     | Deserialize this field with the given name                                                                              |
-| `#[serde(default)]`                         | If the value is not specified, use the `Default::default()`                                                             |
-| `#[serde(default="$path")]`                 | Call the path to a function `fn() -> T` to build the value                                                              |
-| `#[serde(skip_serializing)]`                | Do not serialize this value                                                                                             |
-| `#[serde(skip_deserializing)]`              | Always use `Default::default()` or `#[serde(default="$path")]` instead of deserializing this value                      |
-| `#[serde(skip_serializing_if="$path")]`     | Do not serialize this value if this function `fn(&T) -> bool` returns `true`                                            |
-| `#[serde(serialize_with="$path")]`          | Call a function `fn<S>(&T, &mut S) -> Result<(), S::Error> where S: Serializer` to serialize this value of type `T`     |
-| `#[serde(deserialize_with="$path")]`        | Call a function `fn<D>(&mut D) -> Result<T, D::Error> where D: Deserializer` to deserialize this value of type `T`      |
-| `#[serde(bound="T: MyTrait")]`              | Where-clause for the Serialize and Deserialize impls. This replaces any bounds inferred by Serde for the current field. |
-| `#[serde(bound(serialize="T: MyTrait"))]`   | Where-clause for the Serialize impl.                                                                                    |
-| `#[serde(bound(deserialize="T: MyTrait"))]` | Where-clause for the Deserialize impl.                                                                                  |
-
-Using in `no_std` crates
-========================
-
-The core `serde` package defines a number of features to enable usage in a
-variety of freestanding environments. Enable any or none of the following
-features, and use `default-features = false` in your `Cargo.toml`:
-
- `alloc` (implies `nightly`)
- `collections` (implies `alloc` and `nightly`)
- `std` (default)
-
-If you only use `default-features = false`, you will receive a stock `no_std`
-serde with no support for any of the collection types.
-
-Upgrading from Serde 0.6
-========================
-
-* `#[serde(skip_serializing_if_none)]` was replaced with `#[serde(skip_serializing_if="Option::is_none")]`.
-* `#[serde(skip_serializing_if_empty)]` was replaced with `#[serde(skip_serializing_if="Vec::is_empty")]`.
-
-Serialization Formats Using Serde
-=================================
-
-| Format      | Name                                                 |
-| ------      | ----                                                 |
-| Bincode     | [bincode](https://crates.io/crates/bincode)          |
-| JSON        | [serde\_json](https://crates.io/crates/serde_json)   |
-| MessagePack | [rmp](https://crates.io/crates/rmp)                  |
-| XML         | [serde\_xml](https://github.com/serde-rs/xml)        |
-| YAML        | [serde\_yaml](https://github.com/dtolnay/serde-yaml) |
+Unless you explicitly state otherwise, any contribution intentionally submitted
+for inclusion in Serde by you, as defined in the Apache-2.0 license, shall be
+dual licensed as above, without any additional terms or conditions.
@@ -1,5 +0,0 @@
-paths = [
-    "../serde",
-    "../serde_codegen",
-    "../serde_macros",
-]
@@ -6,12 +6,12 @@ build = "build.rs"

 [features]
 default = ["serde_codegen"]
-nightly = ["serde_macros"]
+unstable = ["serde_macros"]

 [build-dependencies]
-serde_codegen = { version = "^0.7.12", optional = true }
+serde_codegen = { version = "^0.8", optional = true, path = "../../serde_codegen" }

 [dependencies]
-serde = "^0.7.12"
-serde_json = "^0.7.0"
-serde_macros = { version = "^0.7.12", optional = true }
+serde = "^0.8"
+serde_json = "^0.8"
+serde_macros = { version = "^0.8", optional = true, path = "../../serde_macros" }
@@ -16,5 +16,5 @@ Point { x: 1, y: 2 }
 On nightly, it can use a plugin with:

 ```
-% rustup run nightly cargo run --features nightly --no-default-features
+% rustup run nightly cargo run --features unstable --no-default-features
 ```
@@ -1,11 +1,12 @@
 [package]
 name = "serde"
-version = "0.7.12"
+version = "0.8.8"
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>"]
 license = "MIT/Apache-2.0"
 description = "A generic serialization/deserialization framework"
+homepage = "https://serde.rs"
 repository = "https://github.com/serde-rs/serde"
-documentation = "https://serde-rs.github.io/serde/serde/"
+documentation = "https://docs.serde.rs/serde/"
 readme = "../README.md"
 keywords = ["serde", "serialization"]
 include = ["Cargo.toml", "src/**/*.rs"]
@@ -14,10 +15,10 @@ include = ["Cargo.toml", "src/**/*.rs"]
 default = ["std"]

 std = []
-nightly = []
-alloc = ["nightly"]
+unstable = []
+alloc = ["unstable"]
 collections = ["alloc"]
-nightly-testing = ["clippy", "nightly", "std"]
+unstable-testing = ["clippy", "unstable", "std"]

 [dependencies]
 clippy = { version = "^0.*", optional = true }
@@ -19,6 +19,15 @@ pub struct Bytes<'a> {
    bytes: &'a [u8],
 }

+impl<'a> Bytes<'a> {
+    /// Wrap an existing `&[u8]`.
+    pub fn new(bytes: &'a [u8]) -> Self {
+        Bytes {
+            bytes: bytes,
+        }
+    }
+}
+
 impl<'a> fmt::Debug for Bytes<'a> {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        try!(f.write_str("b\""));
@@ -31,18 +40,14 @@ impl<'a> fmt::Debug for Bytes<'a> {

 impl<'a> From<&'a [u8]> for Bytes<'a> {
    fn from(bytes: &'a [u8]) -> Self {
-        Bytes {
-            bytes: bytes,
-        }
+        Bytes::new(bytes)
    }
 }

 #[cfg(any(feature = "std", feature = "collections"))]
 impl<'a> From<&'a Vec<u8>> for Bytes<'a> {
    fn from(bytes: &'a Vec<u8>) -> Self {
-        Bytes {
-            bytes: bytes,
-        }
+        Bytes::new(bytes)
    }
 }

@@ -90,15 +95,18 @@ mod bytebuf {
    impl ByteBuf {
        /// Construct a new, empty `ByteBuf`.
        pub fn new() -> Self {
-            ByteBuf {
-                bytes: Vec::new(),
-            }
+            ByteBuf::from(Vec::new())
        }

        /// Construct a new, empty `ByteBuf` with the specified capacity.
        pub fn with_capacity(cap: usize) -> Self {
+            ByteBuf::from(Vec::with_capacity(cap))
+        }
+
+        /// Wrap existing bytes in a `ByteBuf`.
+        pub fn from<T: Into<Vec<u8>>>(bytes: T) -> Self {
            ByteBuf {
-                bytes: Vec::with_capacity(cap)
+                bytes: bytes.into(),
            }
        }
    }
@@ -121,9 +129,7 @@ mod bytebuf {

    impl From<Vec<u8>> for ByteBuf {
        fn from(bytes: Vec<u8>) -> Self {
-            ByteBuf {
-                bytes: bytes,
-            }
+            ByteBuf::from(bytes)
        }
    }

@@ -179,9 +185,7 @@ mod bytebuf {
        fn visit_unit<E>(&mut self) -> Result<ByteBuf, E>
            where E: de::Error,
        {
-            Ok(ByteBuf {
-                bytes: Vec::new(),
-            })
+            Ok(ByteBuf::new())
        }

        #[inline]
@@ -197,9 +201,7 @@ mod bytebuf {

            try!(visitor.end());

-            Ok(ByteBuf {
-                bytes: values,
-            })
+            Ok(ByteBuf::from(values))
        }

        #[inline]
@@ -213,9 +215,7 @@ mod bytebuf {
        fn visit_byte_buf<E>(&mut self, v: Vec<u8>) -> Result<ByteBuf, E>
            where E: de::Error,
        {
-            Ok(ByteBuf {
-                bytes: v,
-            })
+            Ok(ByteBuf::from(v))
        }
    }

@@ -2,7 +2,7 @@

 #[cfg(feature = "std")]
 use std::borrow::Cow;
-#[cfg(all(feature = "nightly", feature = "collections", not(feature = "std")))]
+#[cfg(all(feature = "unstable", feature = "collections", not(feature = "std")))]
 use collections::borrow::Cow;

 #[cfg(all(feature = "collections", not(feature = "std")))]
@@ -27,9 +27,9 @@ use std::collections::{
    VecDeque,
 };

-#[cfg(all(feature = "nightly", feature = "collections"))]
+#[cfg(all(feature = "unstable", feature = "collections"))]
 use collections::enum_set::{CLike, EnumSet};
-#[cfg(all(feature = "nightly", feature = "collections"))]
+#[cfg(all(feature = "unstable", feature = "collections"))]
 use collections::borrow::ToOwned;

 use core::hash::{Hash, BuildHasher};
@@ -42,21 +42,24 @@ use core::str;

 #[cfg(feature = "std")]
 use std::rc::Rc;
-#[cfg(all(feature = "nightly", feature = "alloc", not(feature = "std")))]
+#[cfg(all(feature = "unstable", feature = "alloc", not(feature = "std")))]
 use alloc::rc::Rc;

 #[cfg(feature = "std")]
 use std::sync::Arc;
-#[cfg(all(feature = "nightly", feature = "alloc", not(feature = "std")))]
+#[cfg(all(feature = "unstable", feature = "alloc", not(feature = "std")))]
 use alloc::arc::Arc;

-#[cfg(all(feature = "nightly", feature = "alloc", not(feature = "std")))]
+#[cfg(all(feature = "unstable", feature = "alloc", not(feature = "std")))]
 use alloc::boxed::Box;

-#[cfg(feature = "nightly")]
+#[cfg(feature = "std")]
+use std::time::Duration;
+
+#[cfg(feature = "unstable")]
 use core::nonzero::{NonZero, Zeroable};

-#[cfg(feature = "nightly")]
+#[cfg(feature = "unstable")]
 use core::num::Zero;

 use de::{
@@ -356,7 +359,7 @@ pub struct PhantomDataVisitor<T> {
    marker: PhantomData<T>,
 }

-impl<T> Visitor for PhantomDataVisitor<T> where T: Deserialize {
+impl<T> Visitor for PhantomDataVisitor<T> {
    type Value = PhantomData<T>;

    #[inline]
@@ -367,7 +370,7 @@ impl<T> Visitor for PhantomDataVisitor<T> where T: Deserialize {
    }
 }

-impl<T> Deserialize for PhantomData<T> where T: Deserialize {
+impl<T> Deserialize for PhantomData<T> {
    fn deserialize<D>(deserializer: &mut D) -> Result<PhantomData<T>, D::Error>
        where D: Deserializer,
    {
@@ -461,7 +464,7 @@ seq_impl!(
    BTreeSet::new(),
    BTreeSet::insert);

-#[cfg(all(feature = "nightly", feature = "collections"))]
+#[cfg(all(feature = "unstable", feature = "collections"))]
 seq_impl!(
    EnumSet<T>,
    EnumSetVisitor<T: Deserialize + CLike>,
@@ -593,7 +596,7 @@ macro_rules! array_impls {
                fn deserialize<D>(deserializer: &mut D) -> Result<[T; $len], D::Error>
                    where D: Deserializer,
                {
-                    deserializer.deserialize_fixed_size_array($len, $visitor::new())
+                    deserializer.deserialize_seq_fixed_size($len, $visitor::new())
                }
            }
        )+
@@ -788,7 +791,7 @@ macro_rules! map_impl {
 #[cfg(any(feature = "std", feature = "collections"))]
 map_impl!(
    BTreeMap<K, V>,
-    BTreeMapVisitor<K: Deserialize + Eq + Ord,
+    BTreeMapVisitor<K: Deserialize + Ord,
                    V: Deserialize>,
    visitor,
    BTreeMap::new(),
@@ -806,7 +809,7 @@ map_impl!(

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

-#[cfg(all(feature = "nightly", feature = "std"))]
+#[cfg(all(feature = "unstable", feature = "std"))]
 impl Deserialize for net::IpAddr {
    fn deserialize<D>(deserializer: &mut D) -> Result<Self, D::Error>
        where D: Deserializer,
@@ -939,6 +942,16 @@ 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>
+        where D: Deserializer
+    {
+        let s = try!(String::deserialize(deserializer));
+        Ok(s.into_boxed_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>
@@ -972,7 +985,136 @@ impl<'a, T: ?Sized> Deserialize for Cow<'a, T> where T: ToOwned, T::Owned: Deser

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

-#[cfg(feature = "nightly")]
+// This is a cleaned-up version of the impl generated by:
+//
+//     #[derive(Deserialize)]
+//     #[serde(deny_unknown_fields)]
+//     struct Duration {
+//         secs: u64,
+//         nanos: u32,
+//     }
+#[cfg(feature = "std")]
+impl Deserialize for Duration {
+    fn deserialize<D>(deserializer: &mut 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>
+                where D: Deserializer,
+            {
+                struct FieldVisitor;
+
+                impl Visitor for FieldVisitor {
+                    type Value = Field;
+
+                    fn visit_usize<E>(&mut self, value: usize) -> Result<Field, E>
+                        where E: Error,
+                    {
+                        match value {
+                            0usize => Ok(Field::Secs),
+                            1usize => Ok(Field::Nanos),
+                            _ => Err(Error::invalid_value("expected a field")),
+                        }
+                    }
+
+                    fn visit_str<E>(&mut self, value: &str) -> Result<Field, E>
+                        where E: Error,
+                    {
+                        match value {
+                            "secs" => Ok(Field::Secs),
+                            "nanos" => Ok(Field::Nanos),
+                            _ => Err(Error::unknown_field(value)),
+                        }
+                    }
+
+                    fn visit_bytes<E>(&mut self, value: &[u8]) -> Result<Field, E>
+                        where E: Error,
+                    {
+                        match value {
+                            b"secs" => Ok(Field::Secs),
+                            b"nanos" => Ok(Field::Nanos),
+                            _ => {
+                                let value = String::from_utf8_lossy(value);
+                                Err(Error::unknown_field(&value))
+                            }
+                        }
+                    }
+                }
+
+                deserializer.deserialize_struct_field(FieldVisitor)
+            }
+        }
+
+        struct DurationVisitor;
+
+        impl Visitor for DurationVisitor {
+            type Value = Duration;
+
+            fn visit_seq<V>(&mut 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>
+                where V: MapVisitor,
+            {
+                let mut secs: Option<u64> = None;
+                let mut nanos: Option<u32> = None;
+                while let Some(key) = try!(visitor.visit_key::<Field>()) {
+                    match key {
+                        Field::Secs => {
+                            if secs.is_some() {
+                                return Err(<V::Error as Error>::duplicate_field("secs"));
+                            }
+                            secs = Some(try!(visitor.visit_value()));
+                        }
+                        Field::Nanos => {
+                            if nanos.is_some() {
+                                return Err(<V::Error as Error>::duplicate_field("nanos"));
+                            }
+                            nanos = Some(try!(visitor.visit_value()));
+                        }
+                    }
+                }
+                try!(visitor.end());
+                let secs = match secs {
+                    Some(secs) => secs,
+                    None => try!(visitor.missing_field("secs")),
+                };
+                let nanos = match nanos {
+                    Some(nanos) => nanos,
+                    None => try!(visitor.missing_field("nanos")),
+                };
+                Ok(Duration::new(secs, nanos))
+            }
+        }
+
+        const FIELDS: &'static [&'static str] = &["secs", "nanos"];
+        deserializer.deserialize_struct("Duration", FIELDS, DurationVisitor)
+    }
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+#[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 {
        let value = try!(Deserialize::deserialize(deserializer));
@@ -8,6 +8,10 @@ use error;
 #[cfg(all(not(feature = "std"), feature = "collections"))]
 use collections::{String, Vec};

+use core::fmt;
+
+///////////////////////////////////////////////////////////////////////////////
+
 pub mod impls;
 pub mod value;
 mod from_primitive;
@@ -169,6 +173,46 @@ pub enum Type {
    Bytes,
 }

+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",
+        };
+        display.fmt(formatter)
+    }
+}
+
 ///////////////////////////////////////////////////////////////////////////////

 /// `Deserialize` represents a type that can be deserialized.
@@ -201,278 +245,166 @@ pub trait Deserializer {
        where V: Visitor;

    /// This method hints that the `Deserialize` type is expecting a `bool` value.
-    #[inline]
    fn deserialize_bool<V>(&mut self, visitor: V) -> Result<V::Value, Self::Error>
-        where V: Visitor,
-    {
-        self.deserialize(visitor)
-    }
+        where V: Visitor;

    /// This method hints that the `Deserialize` type is expecting an `usize` value.
-    #[inline]
+    /// A reasonable default is to forward to `deserialize_u64`.
    fn deserialize_usize<V>(&mut self, visitor: V) -> Result<V::Value, Self::Error>
-        where V: Visitor,
-    {
-        self.deserialize_u64(visitor)
-    }
+        where V: Visitor;

    /// This method hints that the `Deserialize` type is expecting an `u8` value.
-    #[inline]
+    /// A reasonable default is to forward to `deserialize_u64`.
    fn deserialize_u8<V>(&mut self, visitor: V) -> Result<V::Value, Self::Error>
-        where V: Visitor,
-    {
-        self.deserialize_u64(visitor)
-    }
+        where V: Visitor;

    /// This method hints that the `Deserialize` type is expecting an `u16` value.
-    #[inline]
+    /// A reasonable default is to forward to `deserialize_u64`.
    fn deserialize_u16<V>(&mut self, visitor: V) -> Result<V::Value, Self::Error>
-        where V: Visitor,
-    {
-        self.deserialize_u64(visitor)
-    }
+        where V: Visitor;

    /// This method hints that the `Deserialize` type is expecting an `u32` value.
-    #[inline]
+    /// A reasonable default is to forward to `deserialize_u64`.
    fn deserialize_u32<V>(&mut self, visitor: V) -> Result<V::Value, Self::Error>
-        where V: Visitor,
-    {
-        self.deserialize_u64(visitor)
-    }
+        where V: Visitor;

    /// This method hints that the `Deserialize` type is expecting an `u64` value.
-    #[inline]
    fn deserialize_u64<V>(&mut self, visitor: V) -> Result<V::Value, Self::Error>
-        where V: Visitor,
-    {
-        self.deserialize(visitor)
-    }
+        where V: Visitor;

    /// This method hints that the `Deserialize` type is expecting an `isize` value.
-    #[inline]
+    /// A reasonable default is to forward to `deserialize_i64`.
    fn deserialize_isize<V>(&mut self, visitor: V) -> Result<V::Value, Self::Error>
-        where V: Visitor,
-    {
-        self.deserialize_i64(visitor)
-    }
+        where V: Visitor;

    /// This method hints that the `Deserialize` type is expecting an `i8` value.
-    #[inline]
+    /// A reasonable default is to forward to `deserialize_i64`.
    fn deserialize_i8<V>(&mut self, visitor: V) -> Result<V::Value, Self::Error>
-        where V: Visitor,
-    {
-        self.deserialize_i64(visitor)
-    }
+        where V: Visitor;

    /// This method hints that the `Deserialize` type is expecting an `i16` value.
-    #[inline]
+    /// A reasonable default is to forward to `deserialize_i64`.
    fn deserialize_i16<V>(&mut self, visitor: V) -> Result<V::Value, Self::Error>
-        where V: Visitor,
-    {
-        self.deserialize_i64(visitor)
-    }
+        where V: Visitor;

    /// This method hints that the `Deserialize` type is expecting an `i32` value.
-    #[inline]
+    /// A reasonable default is to forward to `deserialize_i64`.
    fn deserialize_i32<V>(&mut self, visitor: V) -> Result<V::Value, Self::Error>
-        where V: Visitor,
-    {
-        self.deserialize_i64(visitor)
-    }
+        where V: Visitor;

    /// This method hints that the `Deserialize` type is expecting an `i64` value.
-    #[inline]
    fn deserialize_i64<V>(&mut self, visitor: V) -> Result<V::Value, Self::Error>
-        where V: Visitor,
-    {
-        self.deserialize(visitor)
-    }
+        where V: Visitor;

    /// This method hints that the `Deserialize` type is expecting a `f32` value.
-    #[inline]
+    /// A reasonable default is to forward to `deserialize_f64`.
    fn deserialize_f32<V>(&mut self, visitor: V) -> Result<V::Value, Self::Error>
-        where V: Visitor,
-    {
-        self.deserialize_f64(visitor)
-    }
+        where V: Visitor;

    /// This method hints that the `Deserialize` type is expecting a `f64` value.
-    #[inline]
    fn deserialize_f64<V>(&mut self, visitor: V) -> Result<V::Value, Self::Error>
-        where V: Visitor,
-    {
-        self.deserialize(visitor)
-    }
+        where V: Visitor;

    /// This method hints that the `Deserialize` type is expecting a `char` value.
-    #[inline]
    fn deserialize_char<V>(&mut self, visitor: V) -> Result<V::Value, Self::Error>
-        where V: Visitor,
-    {
-        self.deserialize(visitor)
-    }
+        where V: Visitor;

    /// This method hints that the `Deserialize` type is expecting a `&str` value.
-    #[inline]
    fn deserialize_str<V>(&mut self, visitor: V) -> Result<V::Value, Self::Error>
-        where V: Visitor,
-    {
-        self.deserialize(visitor)
-    }
+        where V: Visitor;

    /// This method hints that the `Deserialize` type is expecting a `String` value.
-    #[inline]
    fn deserialize_string<V>(&mut self, visitor: V) -> Result<V::Value, Self::Error>
-        where V: Visitor,
-    {
-        self.deserialize_str(visitor)
-    }
+        where V: Visitor;

    /// This method hints that the `Deserialize` type is expecting an `unit` value.
-    #[inline]
    fn deserialize_unit<V>(&mut self, visitor: V) -> Result<V::Value, Self::Error>
-        where V: Visitor,
-    {
-        self.deserialize(visitor)
-    }
+        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)`.
-    #[inline]
    fn deserialize_option<V>(&mut self, visitor: V) -> Result<V::Value, Self::Error>
-        where V: Visitor,
-    {
-        self.deserialize(visitor)
-    }
+        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.
-    #[inline]
    fn deserialize_seq<V>(&mut self, visitor: V) -> Result<V::Value, Self::Error>
-        where V: Visitor,
-    {
-        self.deserialize(visitor)
-    }
+        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.
-    ///
-    /// By default, this deserializes arrays from a sequence.
-    #[inline]
-    fn deserialize_fixed_size_array<V>(&mut self,
-                                       _len: usize,
-                                       visitor: V) -> Result<V::Value, Self::Error>
-        where V: Visitor,
-    {
-        self.deserialize(visitor)
-    }
+    fn deserialize_seq_fixed_size<V>(&mut self,
+                                     len: usize,
+                                     visitor: V) -> Result<V::Value, Self::Error>
+        where V: Visitor;

    /// 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.
-    #[inline]
    fn deserialize_bytes<V>(&mut self, visitor: V) -> Result<V::Value, Self::Error>
-        where V: Visitor,
-    {
-        self.deserialize_seq(visitor)
-    }
+        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.
-    #[inline]
    fn deserialize_map<V>(&mut self, visitor: V) -> Result<V::Value, Self::Error>
-        where V: Visitor,
-    {
-        self.deserialize(visitor)
-    }
+        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.
-    #[inline]
    fn deserialize_unit_struct<V>(&mut self,
-                                  _name: &'static str,
+                                  name: &'static str,
                                  visitor: V) -> Result<V::Value, Self::Error>
-        where V: Visitor,
-    {
-        self.deserialize_unit(visitor)
-    }
+        where V: Visitor;

    /// 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.
-    #[inline]
+    /// A reasonable default is to simply deserialize the expected value directly.
    fn deserialize_newtype_struct<V>(&mut self,
                                     name: &'static str,
                                     visitor: V) -> Result<V::Value, Self::Error>
-        where V: Visitor,
-    {
-        self.deserialize_tuple_struct(name, 1, visitor)
-    }
+        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.
-    #[inline]
    fn deserialize_tuple_struct<V>(&mut self,
-                                   _name: &'static str,
+                                   name: &'static str,
                                   len: usize,
                                   visitor: V) -> Result<V::Value, Self::Error>
-        where V: Visitor,
-    {
-        self.deserialize_tuple(len, visitor)
-    }
+        where V: Visitor;

    /// This method hints that the `Deserialize` type is expecting a struct. This allows
    /// deserializers to parse sequences that aren't tagged as maps.
-    #[inline]
    fn deserialize_struct<V>(&mut self,
-                             _name: &'static str,
-                             _fields: &'static [&'static str],
+                             name: &'static str,
+                             fields: &'static [&'static str],
                             visitor: V) -> Result<V::Value, Self::Error>
-        where V: Visitor,
-    {
-        self.deserialize_map(visitor)
-    }
+        where V: Visitor;

    /// 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.
-    #[inline]
    fn deserialize_struct_field<V>(&mut self, visitor: V) -> Result<V::Value, Self::Error>
-        where V: Visitor,
-    {
-        self.deserialize(visitor)
-    }
+        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.
-    #[inline]
-    fn deserialize_tuple<V>(&mut self, _len: usize, visitor: V) -> Result<V::Value, Self::Error>
-        where V: Visitor,
-    {
-        self.deserialize_seq(visitor)
-    }
+    fn deserialize_tuple<V>(&mut 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.
-    #[inline]
    fn deserialize_enum<V>(&mut self,
-                           _enum: &'static str,
-                           _variants: &'static [&'static str],
-                           _visitor: V) -> Result<V::Value, Self::Error>
-        where V: EnumVisitor,
-    {
-        Err(Error::invalid_type(Type::Enum))
-    }
+                           name: &'static str,
+                           variants: &'static [&'static str],
+                           visitor: V) -> Result<V::Value, Self::Error>
+        where V: EnumVisitor;

    /// This method hints that the `Deserialize` type needs to deserialize a value whose type
    /// doesn't matter because it is ignored.
-    #[inline]
    fn deserialize_ignored_any<V>(&mut self, visitor: V) -> Result<V::Value, Self::Error>
-        where V: Visitor
-    {
-        self.deserialize(visitor)
-    }
+        where V: Visitor;
 }

 ///////////////////////////////////////////////////////////////////////////////
@@ -483,9 +415,10 @@ pub trait Visitor {
    type Value: Deserialize;

    /// `visit_bool` deserializes a `bool` into a `Value`.
-    fn visit_bool<E>(&mut self, _v: bool) -> Result<Self::Value, E>
+    fn visit_bool<E>(&mut self, v: bool) -> Result<Self::Value, E>
        where E: Error,
    {
+        let _ = v;
        Err(Error::invalid_type(Type::Bool))
    }

@@ -518,9 +451,10 @@ pub trait Visitor {
    }

    /// `visit_i64` deserializes a `i64` into a `Value`.
-    fn visit_i64<E>(&mut self, _v: i64) -> Result<Self::Value, E>
+    fn visit_i64<E>(&mut self, v: i64) -> Result<Self::Value, E>
        where E: Error,
    {
+        let _ = v;
        Err(Error::invalid_type(Type::I64))
    }

@@ -553,9 +487,10 @@ pub trait Visitor {
    }

    /// `visit_u64` deserializes a `u64` into a `Value`.
-    fn visit_u64<E>(&mut self, _v: u64) -> Result<Self::Value, E>
+    fn visit_u64<E>(&mut self, v: u64) -> Result<Self::Value, E>
        where E: Error,
    {
+        let _ = v;
        Err(Error::invalid_type(Type::U64))
    }

@@ -567,9 +502,10 @@ pub trait Visitor {
    }

    /// `visit_f64` deserializes a `f64` into a `Value`.
-    fn visit_f64<E>(&mut self, _v: f64) -> Result<Self::Value, E>
+    fn visit_f64<E>(&mut self, v: f64) -> Result<Self::Value, E>
        where E: Error,
    {
+        let _ = v;
        Err(Error::invalid_type(Type::F64))
    }

@@ -582,9 +518,10 @@ pub trait Visitor {
    }

    /// `visit_str` deserializes a `&str` into a `Value`.
-    fn visit_str<E>(&mut self, _v: &str) -> Result<Self::Value, E>
+    fn visit_str<E>(&mut self, v: &str) -> Result<Self::Value, E>
        where E: Error,
    {
+        let _ = v;
        Err(Error::invalid_type(Type::Str))
    }

@@ -608,9 +545,10 @@ 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>(&mut self, name: &'static str) -> Result<Self::Value, E>
        where E: Error,
    {
+        let _ = name;
        self.visit_unit()
    }

@@ -622,37 +560,42 @@ pub trait Visitor {
    }

    /// `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>(&mut self, deserializer: &mut D) -> Result<Self::Value, D::Error>
        where D: Deserializer,
    {
+        let _ = deserializer;
        Err(Error::invalid_type(Type::Option))
    }

    /// `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>(&mut self, deserializer: &mut D) -> Result<Self::Value, D::Error>
        where D: Deserializer,
    {
+        let _ = deserializer;
        Err(Error::invalid_type(Type::NewtypeStruct))
    }

    /// `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>(&mut self, visitor: V) -> Result<Self::Value, V::Error>
        where V: SeqVisitor,
    {
+        let _ = visitor;
        Err(Error::invalid_type(Type::Seq))
    }

    /// `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>(&mut self, visitor: V) -> Result<Self::Value, V::Error>
        where V: MapVisitor,
    {
+        let _ = visitor;
        Err(Error::invalid_type(Type::Map))
    }

    /// `visit_bytes` deserializes a `&[u8]` into a `Value`.
-    fn visit_bytes<E>(&mut self, _v: &[u8]) -> Result<Self::Value, E>
+    fn visit_bytes<E>(&mut self, v: &[u8]) -> Result<Self::Value, E>
        where E: Error,
    {
+        let _ = v;
        Err(Error::invalid_type(Type::Bytes))
    }

@@ -828,33 +771,26 @@ pub trait VariantVisitor {
        Err(Error::invalid_type(Type::UnitVariant))
    }

-    /// `visit_newtype` is called when deserializing a variant with a single value. By default this
-    /// uses the `visit_tuple` method to deserialize the value.
-    #[inline]
+    /// `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>
-        where T: Deserialize,
-    {
-        let (value,) = try!(self.visit_tuple(1, impls::TupleVisitor1::new()));
-        Ok(value)
-    }
+        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,
-                      _len: usize,
-                      _visitor: V) -> Result<V::Value, Self::Error>
-        where V: Visitor
-    {
-        Err(Error::invalid_type(Type::TupleVariant))
-    }
+                      len: usize,
+                      visitor: V) -> Result<V::Value, Self::Error>
+        where V: Visitor;

    /// `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,
-                       _fields: &'static [&'static str],
-                       _visitor: V) -> Result<V::Value, Self::Error>
-        where V: Visitor
-    {
-        Err(Error::invalid_type(Type::StructVariant))
-    }
+                       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 {
@@ -12,6 +12,8 @@ use std::collections::{
    hash_set,
 };
 #[cfg(feature = "std")]
+use std::borrow::Cow;
+#[cfg(feature = "std")]
 use std::vec;

 #[cfg(all(feature = "collections", not(feature = "std")))]
@@ -24,8 +26,10 @@ use collections::{
    btree_set,
    vec,
 };
+#[cfg(all(feature = "collections", not(feature = "std")))]
+use collections::borrow::Cow;

-#[cfg(all(feature = "nightly", feature = "collections"))]
+#[cfg(all(feature = "unstable", feature = "collections"))]
 use collections::borrow::ToOwned;

 use core::hash::Hash;
@@ -128,7 +132,7 @@ impl fmt::Display for Error {
                write!(formatter, "Unknown variant: {}", variant)
            }
            Error::UnknownField(ref field) => write!(formatter, "Unknown field: {}", field),
-            Error::MissingField(ref field) => write!(formatter, "Missing field: {}", field),
+            Error::MissingField(field) => write!(formatter, "Missing field: {}", field),
        }
    }
 }
@@ -174,6 +178,12 @@ impl<E> de::Deserializer for UnitDeserializer<E>
 {
    type Error = E;

+    forward_to_deserialize! {
+        bool usize u8 u16 u32 u64 isize i8 i16 i32 i64 f32 f64 char str string
+        unit seq seq_fixed_size bytes map unit_struct newtype_struct
+        tuple_struct struct struct_field tuple enum ignored_any
+    }
+
    fn deserialize<V>(&mut self, mut visitor: V) -> Result<V::Value, Self::Error>
        where V: de::Visitor,
    {
@@ -209,6 +219,13 @@ macro_rules! primitive_deserializer {
        {
            type Error = E;

+            forward_to_deserialize! {
+                bool usize u8 u16 u32 u64 isize i8 i16 i32 i64 f32 f64 char str
+                string unit option seq seq_fixed_size bytes map unit_struct
+                newtype_struct tuple_struct struct struct_field tuple enum
+                ignored_any
+            }
+
            fn deserialize<V>(&mut self, mut visitor: V) -> Result<V::Value, Self::Error>
                where V: de::Visitor,
            {
@@ -273,6 +290,12 @@ impl<'a, E> de::Deserializer for StrDeserializer<'a, E>
    {
        visitor.visit(self)
    }
+
+    forward_to_deserialize! {
+        bool usize u8 u16 u32 u64 isize i8 i16 i32 i64 f32 f64 char str string
+        unit option seq seq_fixed_size bytes map unit_struct newtype_struct
+        tuple_struct struct struct_field tuple ignored_any
+    }
 }

 impl<'a, E> de::VariantVisitor for StrDeserializer<'a, E>
@@ -289,6 +312,29 @@ impl<'a, E> de::VariantVisitor for StrDeserializer<'a, E>
    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))
+    }
 }

 ///////////////////////////////////////////////////////////////////////////////
@@ -331,6 +377,12 @@ impl<E> de::Deserializer for StringDeserializer<E>
    {
        visitor.visit(self)
    }
+
+    forward_to_deserialize! {
+        bool usize u8 u16 u32 u64 isize i8 i16 i32 i64 f32 f64 char str string
+        unit option seq seq_fixed_size bytes map unit_struct newtype_struct
+        tuple_struct struct struct_field tuple ignored_any
+    }
 }

 #[cfg(any(feature = "std", feature = "collections"))]
@@ -348,6 +400,118 @@ impl<'a, E> de::VariantVisitor for StringDeserializer<E>
    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))
+    }
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+/// A helper deserializer that deserializes a `String`.
+#[cfg(any(feature = "std", feature = "collections"))]
+pub struct CowStrDeserializer<'a, E>(Option<Cow<'a, str>>, PhantomData<E>);
+
+#[cfg(any(feature = "std", feature = "collections"))]
+impl<'a, E> ValueDeserializer<E> for Cow<'a, str>
+    where E: de::Error,
+{
+    type Deserializer = CowStrDeserializer<'a, E>;
+
+    fn into_deserializer(self) -> CowStrDeserializer<'a, E> {
+        CowStrDeserializer(Some(self), PhantomData)
+    }
+}
+
+#[cfg(any(feature = "std", feature = "collections"))]
+impl<'a, E> de::Deserializer for CowStrDeserializer<'a, E>
+    where E: de::Error,
+{
+    type Error = E;
+
+    fn deserialize<V>(&mut self, mut 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()),
+        }
+    }
+
+    fn deserialize_enum<V>(&mut self,
+                     _name: &str,
+                     _variants: &'static [&'static str],
+                     mut visitor: V) -> Result<V::Value, Self::Error>
+        where V: de::EnumVisitor,
+    {
+        visitor.visit(self)
+    }
+
+    forward_to_deserialize! {
+        bool usize u8 u16 u32 u64 isize i8 i16 i32 i64 f32 f64 char str string
+        unit option seq seq_fixed_size bytes map unit_struct newtype_struct
+        tuple_struct struct struct_field tuple ignored_any
+    }
+}
+
+#[cfg(any(feature = "std", feature = "collections"))]
+impl<'a, E> de::VariantVisitor for CowStrDeserializer<'a, E>
+    where E: de::Error,
+{
+    type Error = E;
+
+    fn visit_variant<T>(&mut self) -> Result<T, 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))
+    }
 }

 ///////////////////////////////////////////////////////////////////////////////
@@ -384,6 +548,12 @@ impl<I, T, E> de::Deserializer for SeqDeserializer<I, E>
    {
        visitor.visit_seq(self)
    }
+
+    forward_to_deserialize! {
+        bool usize u8 u16 u32 u64 isize i8 i16 i32 i64 f32 f64 char str string
+        unit option seq seq_fixed_size bytes map unit_struct newtype_struct
+        tuple_struct struct struct_field tuple enum ignored_any
+    }
 }

 impl<I, T, E> de::SeqVisitor for SeqDeserializer<I, E>
@@ -490,6 +660,12 @@ impl<V_, E> de::Deserializer for SeqVisitorDeserializer<V_, E>
    fn deserialize<V: de::Visitor>(&mut self, mut visitor: V) -> Result<V::Value, Self::Error> {
        visitor.visit_seq(&mut self.visitor)
    }
+
+    forward_to_deserialize! {
+        bool usize u8 u16 u32 u64 isize i8 i16 i32 i64 f32 f64 char str string
+        unit option seq seq_fixed_size bytes map unit_struct newtype_struct
+        tuple_struct struct struct_field tuple enum ignored_any
+    }
 }

 ///////////////////////////////////////////////////////////////////////////////
@@ -503,7 +679,7 @@ pub struct MapDeserializer<I, K, V, E>
 {
    iter: I,
    value: Option<V>,
-    len: usize,
+    len: Option<usize>,
    marker: PhantomData<E>,
 }

@@ -513,15 +689,35 @@ impl<I, K, V, E> MapDeserializer<I, K, V, E>
          V: ValueDeserializer<E>,
          E: de::Error,
 {
-    /// Construct a new `MapDeserializer<I, K, V>`.
+    /// Construct a new `MapDeserializer<I, K, V, E>` with a specific length.
    pub fn new(iter: I, len: usize) -> Self {
        MapDeserializer {
            iter: iter,
            value: None,
-            len: len,
+            len: Some(len),
            marker: PhantomData,
        }
    }
+
+    /// Construct a new `MapDeserializer<I, K, V, E>` that is not bounded
+    /// by a specific length and that delegates to `iter` for its size hint.
+    pub fn unbounded(iter: I) -> Self {
+        MapDeserializer {
+            iter: iter,
+            value: None,
+            len: None,
+            marker: PhantomData,
+        }
+    }
+
+    fn next(&mut self) -> Option<(K, V)> {
+        self.iter.next().map(|(k, v)| {
+            if let Some(len) = self.len.as_mut() {
+                *len -= 1;
+            }
+            (k, v)
+        })
+    }
 }

 impl<I, K, V, E> de::Deserializer for MapDeserializer<I, K, V, E>
@@ -537,6 +733,28 @@ impl<I, K, V, E> de::Deserializer for MapDeserializer<I, K, V, E>
    {
        visitor.visit_map(self)
    }
+
+    fn deserialize_seq<V_>(&mut self, mut visitor: V_) -> Result<V_::Value, Self::Error>
+        where V_: de::Visitor,
+    {
+        visitor.visit_seq(self)
+    }
+
+    fn deserialize_seq_fixed_size<V_>(&mut self, len: usize, mut 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),
+        }
+    }
+
+    forward_to_deserialize! {
+        bool usize u8 u16 u32 u64 isize i8 i16 i32 i64 f32 f64 char str string
+        unit option bytes map unit_struct newtype_struct tuple_struct struct
+        struct_field tuple enum ignored_any
+    }
 }

 impl<I, K, V, E> de::MapVisitor for MapDeserializer<I, K, V, E>
@@ -550,12 +768,11 @@ impl<I, K, V, E> de::MapVisitor for MapDeserializer<I, K, V, E>
    fn visit_key<T>(&mut self) -> Result<Option<T>, Self::Error>
        where T: de::Deserialize,
    {
-        match self.iter.next() {
+        match self.next() {
            Some((key, value)) => {
-                self.len -= 1;
                self.value = Some(value);
                let mut de = key.into_deserializer();
-                Ok(Some(try!(de::Deserialize::deserialize(&mut de))))
+                de::Deserialize::deserialize(&mut de).map(Some)
            }
            None => Ok(None),
        }
@@ -576,15 +793,133 @@ impl<I, K, V, E> de::MapVisitor for MapDeserializer<I, K, V, E>
    }

    fn end(&mut self) -> Result<(), Self::Error> {
-        if self.len == 0 {
-            Ok(())
-        } else {
-            Err(de::Error::invalid_length(self.len))
+        match self.len {
+            Some(len) if len > 0 => Err(de::Error::invalid_length(len)),
+            _ => Ok(())
        }
    }

    fn size_hint(&self) -> (usize, Option<usize>) {
-        (self.len, Some(self.len))
+        self.len.map_or_else(
+            || self.iter.size_hint(),
+            |len| (len, Some(len)))
+    }
+}
+
+impl<I, K, V, E> de::SeqVisitor for MapDeserializer<I, K, V, E>
+    where I: Iterator<Item=(K, V)>,
+          K: ValueDeserializer<E>,
+          V: ValueDeserializer<E>,
+          E: de::Error,
+{
+    type Error = E;
+
+    fn visit<T>(&mut self) -> Result<Option<T>, Self::Error>
+        where T: de::Deserialize,
+    {
+        match self.next() {
+            Some(kv) => {
+                let mut de = PairDeserializer(Some(kv), PhantomData);
+                de::Deserialize::deserialize(&mut 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)
+    }
+}
+
+// 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>);
+
+impl<A, B, E> de::Deserializer for PairDeserializer<A, B, E>
+    where A: ValueDeserializer<E>,
+          B: ValueDeserializer<E>,
+          E: de::Error
+{
+    type Error = E;
+
+    forward_to_deserialize! {
+        bool usize u8 u16 u32 u64 isize i8 i16 i32 i64 f32 f64 char str string
+        unit option bytes map unit_struct newtype_struct tuple_struct struct
+        struct_field tuple enum ignored_any
+    }
+
+    fn deserialize<V>(&mut 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>
+        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()),
+        }
+    }
+
+    fn deserialize_seq_fixed_size<V>(&mut self, len: usize, visitor: V) -> Result<V::Value, Self::Error>
+        where V: de::Visitor,
+    {
+        if len == 2 {
+            self.deserialize_seq(visitor)
+        } else {
+            Err(de::Error::invalid_length(len))
+        }
+    }
+}
+
+struct PairVisitor<A, B, E>(Option<A>, Option<B>, PhantomData<E>);
+
+impl<A, B, E> de::SeqVisitor for PairVisitor<A, B, E>
+    where A: ValueDeserializer<E>,
+          B: ValueDeserializer<E>,
+          E: de::Error,
+{
+    type Error = E;
+
+    fn visit<T>(&mut self) -> Result<Option<T>, Self::Error>
+        where T: de::Deserialize,
+    {
+        if let Some(k) = self.0.take() {
+            let mut de = k.into_deserializer();
+            de::Deserialize::deserialize(&mut de).map(Some)
+        } else if let Some(v) = self.1.take() {
+            let mut de = v.into_deserializer();
+            de::Deserialize::deserialize(&mut de).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
+        } else if self.1.is_some() {
+            1
+        } else {
+            0
+        };
+        (len, Some(len))
    }
 }

@@ -648,6 +983,12 @@ impl<V_, E> de::Deserializer for MapVisitorDeserializer<V_, E>
    fn deserialize<V: de::Visitor>(&mut self, mut visitor: V) -> Result<V::Value, Self::Error> {
        visitor.visit_map(&mut self.visitor)
    }
+
+    forward_to_deserialize! {
+        bool usize u8 u16 u32 u64 isize i8 i16 i32 i64 f32 f64 char str string
+        unit option seq seq_fixed_size bytes map unit_struct newtype_struct
+        tuple_struct struct struct_field tuple enum ignored_any
+    }
 }

 ///////////////////////////////////////////////////////////////////////////////
@@ -678,8 +1019,13 @@ impl<'a, E> de::Deserializer for BytesDeserializer<'a, E>
            None => Err(de::Error::end_of_stream()),
        }
    }
-}

+    forward_to_deserialize! {
+        bool usize u8 u16 u32 u64 isize i8 i16 i32 i64 f32 f64 char str string
+        unit option seq seq_fixed_size bytes map unit_struct newtype_struct
+        tuple_struct struct struct_field tuple enum ignored_any
+    }
+}

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

@@ -712,4 +1058,10 @@ impl<E> de::Deserializer for ByteBufDeserializer<E>
            None => Err(de::Error::end_of_stream()),
        }
    }
+
+    forward_to_deserialize! {
+        bool usize u8 u16 u32 u64 isize i8 i16 i32 i64 f32 f64 char str string
+        unit option seq seq_fixed_size bytes map unit_struct newtype_struct
+        tuple_struct struct struct_field tuple enum ignored_any
+    }
 }
@@ -4,7 +4,7 @@ use core::fmt::{Debug, Display};


 /// A stand-in for `std::error::Error`, which requires no allocation.
-#[cfg(feature = "nightly")]
+#[cfg(feature = "unstable")]
 pub trait Error: Debug + Display + ::core::marker::Reflect {
    /// A short description of the error.
    ///
@@ -24,7 +24,7 @@ pub trait Error: Debug + Display + ::core::marker::Reflect {
 }

 /// A stand-in for `std::error::Error`, which requires no allocation.
-#[cfg(not(feature = "nightly"))]
+#[cfg(not(feature = "unstable"))]
 pub trait Error: Debug + Display {
    /// A short description of the error.
    ///
@@ -5,35 +5,35 @@
 //! handshake protocol between serializers and serializees can be completely optimized away,
 //! leaving serde to perform roughly the same speed as a hand written serializer for a specific
 //! type.
-//! 
+//!
 //! For a detailed tutorial on the different ways to use serde please check out the
 //! [github repository](https://github.com/serde-rs/serde)

-#![doc(html_root_url="https://serde-rs.github.io/serde/serde")]
+#![doc(html_root_url="https://docs.serde.rs")]
 #![cfg_attr(not(feature = "std"), no_std)]
-#![cfg_attr(feature = "nightly", feature(reflect_marker, unicode, nonzero, plugin, step_trait, zero_one))]
+#![cfg_attr(feature = "unstable", feature(reflect_marker, unicode, nonzero, plugin, step_trait, zero_one))]
 #![cfg_attr(feature = "alloc", feature(alloc))]
 #![cfg_attr(feature = "collections", feature(collections, enumset))]
-#![cfg_attr(feature = "nightly-testing", plugin(clippy))]
-#![cfg_attr(feature = "nightly-testing", allow(linkedlist))]
+#![cfg_attr(feature = "clippy", plugin(clippy))]
+#![cfg_attr(feature = "clippy", allow(linkedlist))]

-#![cfg_attr(any(not(feature = "std"), feature = "nightly"), allow(unused_variables, unused_imports, unused_features, dead_code))]
+#![cfg_attr(any(not(feature = "std"), feature = "unstable"), allow(unused_variables, unused_imports, unused_features, dead_code))]

 #![deny(missing_docs)]

-#[cfg(all(feature = "nightly", feature = "collections"))]
+#[cfg(all(feature = "unstable", feature = "collections"))]
 extern crate collections;

-#[cfg(all(feature = "nightly", feature = "alloc"))]
+#[cfg(all(feature = "unstable", feature = "alloc"))]
 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};
-    #[cfg(feature = "nightly")]
+    #[cfg(feature = "unstable")]
    extern crate core;
-    #[cfg(feature = "nightly")]
+    #[cfg(feature = "unstable")]
    pub use self::core::nonzero;
 }

@@ -45,6 +45,9 @@ macro_rules! format {
    ($s:expr, $($rest:tt)*) => ($s)
 }

+#[macro_use]
+mod macros;
+
 pub mod bytes;
 pub mod de;
 #[cfg(feature = "std")]
@@ -0,0 +1,179 @@
+#[cfg(feature = "std")]
+#[doc(hidden)]
+#[macro_export]
+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>
+            where __V: $crate::de::Visitor
+        {
+            self.deserialize(visitor)
+        }
+    };
+}
+
+#[cfg(not(feature = "std"))]
+#[doc(hidden)]
+#[macro_export]
+macro_rules! forward_to_deserialize_method {
+    ($func:ident($($arg:ty),*)) => {
+        #[inline]
+        fn $func<__V>(&mut self, $(_: $arg,)* visitor: __V) -> ::core::result::Result<__V::Value, Self::Error>
+            where __V: $crate::de::Visitor
+        {
+            self.deserialize(visitor)
+        }
+    };
+}
+
+#[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 {
+    (bool) => {
+        forward_to_deserialize_method!{deserialize_bool()}
+    };
+    (usize) => {
+        forward_to_deserialize_method!{deserialize_usize()}
+    };
+    (u8) => {
+        forward_to_deserialize_method!{deserialize_u8()}
+    };
+    (u16) => {
+        forward_to_deserialize_method!{deserialize_u16()}
+    };
+    (u32) => {
+        forward_to_deserialize_method!{deserialize_u32()}
+    };
+    (u64) => {
+        forward_to_deserialize_method!{deserialize_u64()}
+    };
+    (isize) => {
+        forward_to_deserialize_method!{deserialize_isize()}
+    };
+    (i8) => {
+        forward_to_deserialize_method!{deserialize_i8()}
+    };
+    (i16) => {
+        forward_to_deserialize_method!{deserialize_i16()}
+    };
+    (i32) => {
+        forward_to_deserialize_method!{deserialize_i32()}
+    };
+    (i64) => {
+        forward_to_deserialize_method!{deserialize_i64()}
+    };
+    (f32) => {
+        forward_to_deserialize_method!{deserialize_f32()}
+    };
+    (f64) => {
+        forward_to_deserialize_method!{deserialize_f64()}
+    };
+    (char) => {
+        forward_to_deserialize_method!{deserialize_char()}
+    };
+    (str) => {
+        forward_to_deserialize_method!{deserialize_str()}
+    };
+    (string) => {
+        forward_to_deserialize_method!{deserialize_string()}
+    };
+    (unit) => {
+        forward_to_deserialize_method!{deserialize_unit()}
+    };
+    (option) => {
+        forward_to_deserialize_method!{deserialize_option()}
+    };
+    (seq) => {
+        forward_to_deserialize_method!{deserialize_seq()}
+    };
+    (seq_fixed_size) => {
+        forward_to_deserialize_method!{deserialize_seq_fixed_size(usize)}
+    };
+    (bytes) => {
+        forward_to_deserialize_method!{deserialize_bytes()}
+    };
+    (map) => {
+        forward_to_deserialize_method!{deserialize_map()}
+    };
+    (unit_struct) => {
+        forward_to_deserialize_method!{deserialize_unit_struct(&'static str)}
+    };
+    (newtype_struct) => {
+        forward_to_deserialize_method!{deserialize_newtype_struct(&'static str)}
+    };
+    (tuple_struct) => {
+        forward_to_deserialize_method!{deserialize_tuple_struct(&'static str, usize)}
+    };
+    (struct) => {
+        forward_to_deserialize_method!{deserialize_struct(&'static str, &'static [&'static str])}
+    };
+    (struct_field) => {
+        forward_to_deserialize_method!{deserialize_struct_field()}
+    };
+    (tuple) => {
+        forward_to_deserialize_method!{deserialize_tuple(usize)}
+    };
+    (ignored_any) => {
+        forward_to_deserialize_method!{deserialize_ignored_any()}
+    };
+    (enum) => {
+        forward_to_deserialize_enum!();
+    };
+}
+
+/// Helper to forward `Deserializer` methods to `Deserializer::deserialize`.
+/// Every given method ignores all arguments and forwards to `deserialize`.
+/// Note that `deserialize_enum` simply returns an `Error::invalid_type`; a
+/// better approach is tracked in [serde-rs/serde#521][1].
+///
+/// ```rust,ignore
+/// impl Deserializer for MyDeserializer {
+///     fn deserialize<V>(&mut self, visitor: V) -> Result<V::Value, Self::Error>
+///         where V: Visitor
+///     {
+///         /* ... */
+///     }
+///
+///     forward_to_deserialize! {
+///         bool usize u8 u16 u32 u64 isize i8 i16 i32 i64 f32 f64 char str string
+///         unit option seq seq_fixed_size bytes map unit_struct newtype_struct
+///         tuple_struct struct struct_field tuple enum ignored_any
+///     }
+/// }
+/// ```
+///
+/// [1]: https://github.com/serde-rs/serde/issues/521
+#[macro_export]
+macro_rules! forward_to_deserialize {
+    ($($func:ident)*) => {
+        $(forward_to_deserialize_helper!{$func})*
+    };
+}
@@ -1,4 +1,8 @@
-//! Implementations for all of Rust's builtin types.
+//! Implementations for all of Rust's builtin types. Tuples implement the `Serialize` trait if they
+//! have at most 16 fields. Arrays implement the `Serialize` trait if their length is 32 or less.
+//! You can always forward array serialization to slice serialization, which works for any length.
+//! Long tuples are best replaced by tuple structs, for which you can use `derive(Serialize)`. In
+//! that case the number of fields is irrelevant.

 #[cfg(feature = "std")]
 use std::borrow::Cow;
@@ -26,19 +30,19 @@ use collections::{
    Vec,
 };

-#[cfg(all(feature = "nightly", feature = "collections"))]
+#[cfg(all(feature = "unstable", feature = "collections"))]
 use collections::enum_set::{CLike, EnumSet};
-#[cfg(all(feature = "nightly", feature = "collections"))]
+#[cfg(all(feature = "unstable", feature = "collections"))]
 use collections::borrow::ToOwned;

 use core::hash::{Hash, BuildHasher};
-#[cfg(feature = "nightly")]
+#[cfg(feature = "unstable")]
 use core::iter;
 #[cfg(feature = "std")]
 use std::net;
-#[cfg(feature = "nightly")]
+#[cfg(feature = "unstable")]
 use core::num;
-#[cfg(feature = "nightly")]
+#[cfg(feature = "unstable")]
 use core::ops;
 #[cfg(feature = "std")]
 use std::path;
@@ -46,6 +50,8 @@ use std::path;
 use std::rc::Rc;
 #[cfg(all(feature = "alloc", not(feature = "std")))]
 use alloc::rc::Rc;
+#[cfg(feature = "std")]
+use std::time::Duration;

 #[cfg(feature = "std")]
 use std::sync::Arc;
@@ -57,15 +63,13 @@ use alloc::boxed::Box;

 use core::marker::PhantomData;

-#[cfg(feature = "nightly")]
+#[cfg(feature = "unstable")]
 use core::nonzero::{NonZero, Zeroable};

 use super::{
    Error,
    Serialize,
    Serializer,
-    SeqVisitor,
-    MapVisitor,
 };

 ///////////////////////////////////////////////////////////////////////////////
@@ -133,26 +137,6 @@ impl<T> Serialize for Option<T> where T: Serialize {
    }
 }

-impl<T> SeqVisitor for Option<T> where T: Serialize {
-    #[inline]
-    fn visit<S>(&mut self, serializer: &mut S) -> Result<Option<()>, S::Error>
-        where S: Serializer,
-    {
-        match self.take() {
-            Some(value) => {
-                try!(serializer.serialize_seq_elt(value));
-                Ok(Some(()))
-            }
-            None => Ok(None),
-        }
-    }
-
-    #[inline]
-    fn len(&self) -> Option<usize> {
-        Some(if self.is_some() { 1 } else { 0 })
-    }
-}
-
 ///////////////////////////////////////////////////////////////////////////////

 impl<T> Serialize for PhantomData<T> {
@@ -164,69 +148,6 @@ impl<T> Serialize for PhantomData<T> {
    }
 }

-///////////////////////////////////////////////////////////////////////////////
-
-/// A `serde::Visitor` for sequence iterators.
-///
-/// # Examples
-///
-/// ```
-/// use serde::{Serialize, Serializer};
-/// use serde::ser::impls::SeqIteratorVisitor;
-///
-/// struct Seq(Vec<u32>);
-///
-/// impl Serialize for Seq {
-///     fn serialize<S>(&self, ser: &mut S) -> Result<(), S::Error>
-///         where S: Serializer,
-///     {
-///         ser.serialize_seq(SeqIteratorVisitor::new(
-///             self.0.iter(),
-///             Some(self.0.len()),
-///         ))
-///     }
-/// }
-/// ```
-pub struct SeqIteratorVisitor<Iter> {
-    iter: Iter,
-    len: Option<usize>,
-}
-
-impl<T, Iter> SeqIteratorVisitor<Iter>
-    where Iter: Iterator<Item=T>
-{
-    /// Construct a new `SeqIteratorVisitor<Iter>`.
-    #[inline]
-    pub fn new(iter: Iter, len: Option<usize>) -> SeqIteratorVisitor<Iter> {
-        SeqIteratorVisitor {
-            iter: iter,
-            len: len,
-        }
-    }
-}
-
-impl<T, Iter> SeqVisitor for SeqIteratorVisitor<Iter>
-    where T: Serialize,
-          Iter: Iterator<Item=T>,
-{
-    #[inline]
-    fn visit<S>(&mut self, serializer: &mut S) -> Result<Option<()>, S::Error>
-        where S: Serializer,
-    {
-        match self.iter.next() {
-            Some(value) => {
-                try!(serializer.serialize_seq_elt(value));
-                Ok(Some(()))
-            }
-            None => Ok(None),
-        }
-    }
-
-    #[inline]
-    fn len(&self) -> Option<usize> {
-        self.len
-    }
-}

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

@@ -237,7 +158,11 @@ impl<T> Serialize for [T]
    fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
        where S: Serializer,
    {
-        serializer.serialize_seq(SeqIteratorVisitor::new(self.iter(), Some(self.len())))
+        let mut state = try!(serializer.serialize_seq(Some(self.len())));
+        for e in self {
+            try!(serializer.serialize_seq_elt(&mut state, e));
+        }
+        serializer.serialize_seq_end(state)
    }
 }

@@ -250,8 +175,11 @@ macro_rules! array_impls {
            fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
                where S: Serializer,
            {
-                let visitor = SeqIteratorVisitor::new(self.iter(), Some($len));
-                serializer.serialize_fixed_size_array(visitor)
+                let mut state = try!(serializer.serialize_seq_fixed_size($len));
+                for e in self {
+                    try!(serializer.serialize_seq_elt(&mut state, e));
+                }
+                serializer.serialize_seq_end(state)
            }
        }
    }
@@ -293,40 +221,40 @@ array_impls!(32);

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

+macro_rules! serialize_seq {
+    () => {
+        #[inline]
+        fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
+            where S: Serializer,
+        {
+            let mut state = try!(serializer.serialize_seq(Some(self.len())));
+            for e in self {
+                try!(serializer.serialize_seq_elt(&mut state, e));
+            }
+            serializer.serialize_seq_end(state)
+        }
+    }
+}
+
 #[cfg(any(feature = "std", feature = "collections"))]
 impl<T> Serialize for BinaryHeap<T>
    where T: Serialize + Ord
 {
-    #[inline]
-    fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
-        where S: Serializer,
-    {
-        serializer.serialize_seq(SeqIteratorVisitor::new(self.iter(), Some(self.len())))
-    }
+    serialize_seq!();
 }

 #[cfg(any(feature = "std", feature = "collections"))]
 impl<T> Serialize for BTreeSet<T>
    where T: Serialize + Ord,
 {
-    #[inline]
-    fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
-        where S: Serializer,
-    {
-        serializer.serialize_seq(SeqIteratorVisitor::new(self.iter(), Some(self.len())))
-    }
+    serialize_seq!();
 }

-#[cfg(all(feature = "nightly", feature = "collections"))]
+#[cfg(all(feature = "unstable", feature = "collections"))]
 impl<T> Serialize for EnumSet<T>
    where T: Serialize + CLike
 {
-    #[inline]
-    fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
-        where S: Serializer,
-    {
-        serializer.serialize_seq(SeqIteratorVisitor::new(self.iter(), Some(self.len())))
-    }
+    serialize_seq!();
 }

 #[cfg(feature = "std")]
@@ -334,27 +262,27 @@ impl<T, H> Serialize for HashSet<T, H>
    where T: Serialize + Eq + Hash,
          H: BuildHasher,
 {
-    #[inline]
-    fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
-        where S: Serializer,
-    {
-        serializer.serialize_seq(SeqIteratorVisitor::new(self.iter(), Some(self.len())))
-    }
+    serialize_seq!();
 }

 #[cfg(any(feature = "std", feature = "collections"))]
 impl<T> Serialize for LinkedList<T>
    where T: Serialize,
 {
-    #[inline]
-    fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
-        where S: Serializer,
-    {
-        serializer.serialize_seq(SeqIteratorVisitor::new(self.iter(), Some(self.len())))
-    }
+    serialize_seq!();
 }

-#[cfg(feature = "nightly")]
+#[cfg(any(feature = "std", feature = "collections"))]
+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 {
+    serialize_seq!();
+}
+
+#[cfg(feature = "unstable")]
 impl<A> Serialize for ops::Range<A>
    where A: Serialize + Clone + iter::Step + num::One,
          for<'a> &'a A: ops::Add<&'a A, Output = A>,
@@ -364,27 +292,11 @@ impl<A> Serialize for ops::Range<A>
        where S: Serializer,
    {
        let len = iter::Step::steps_between(&self.start, &self.end, &A::one());
-        serializer.serialize_seq(SeqIteratorVisitor::new(self.clone(), len))
-    }
-}
-
-#[cfg(any(feature = "std", feature = "collections"))]
-impl<T> Serialize for Vec<T> where T: Serialize {
-    #[inline]
-    fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
-        where S: Serializer,
-    {
-        (&self[..]).serialize(serializer)
-    }
-}
-
-#[cfg(any(feature = "std", feature = "collections"))]
-impl<T> Serialize for VecDeque<T> where T: Serialize {
-    #[inline]
-    fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
-        where S: Serializer,
-    {
-        serializer.serialize_seq(SeqIteratorVisitor::new(self.iter(), Some(self.len())))
+        let mut state = try!(serializer.serialize_seq(len));
+        for e in self.clone() {
+            try!(serializer.serialize_seq_elt(&mut state, e));
+        }
+        serializer.serialize_seq_end(state)
    }
 }

@@ -413,52 +325,18 @@ macro_rules! tuple_impls {
        }
    )+) => {
        $(
-            /// A tuple visitor.
-            pub struct $TupleVisitor<'a, $($T: 'a),+> {
-                tuple: &'a ($($T,)+),
-                state: u8,
-            }
-
-            impl<'a, $($T: 'a),+> $TupleVisitor<'a, $($T),+> {
-                /// Construct a new, empty `TupleVisitor`.
-                pub fn new(tuple: &'a ($($T,)+)) -> $TupleVisitor<'a, $($T),+> {
-                    $TupleVisitor {
-                        tuple: tuple,
-                        state: 0,
-                    }
-                }
-            }
-
-            impl<'a, $($T),+> SeqVisitor for $TupleVisitor<'a, $($T),+>
-                where $($T: Serialize),+
-            {
-                fn visit<S>(&mut self, serializer: &mut S) -> Result<Option<()>, S::Error>
-                    where S: Serializer,
-                {
-                    match self.state {
-                        $(
-                            $state => {
-                                self.state += 1;
-                                Ok(Some(try!(serializer.serialize_tuple_elt(&e!(self.tuple.$idx)))))
-                            }
-                        )+
-                        _ => {
-                            Ok(None)
-                        }
-                    }
-                }
-
-                fn len(&self) -> Option<usize> {
-                    Some($len)
-                }
-            }
-
            impl<$($T),+> Serialize for ($($T,)+)
                where $($T: Serialize),+
            {
                #[inline]
-                fn serialize<S: Serializer>(&self, serializer: &mut S) -> Result<(), S::Error> {
-                    serializer.serialize_tuple($TupleVisitor::new(self))
+                fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
+                    where S: Serializer,
+                {
+                    let mut state = try!(serializer.serialize_tuple($len));
+                    $(
+                        try!(serializer.serialize_tuple_elt(&mut state, &e!(self.$idx)));
+                    )+
+                    serializer.serialize_tuple_end(state)
                }
            }
        )+
@@ -638,83 +516,28 @@ tuple_impls! {

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

-/// A `serde::Visitor` for (key, value) map iterators.
-///
-/// # Examples
-///
-/// ```
-/// use std::collections::HashMap;
-/// use serde::{Serialize, Serializer};
-/// use serde::ser::impls::MapIteratorVisitor;
-///
-/// struct Map(HashMap<u32, u32>);
-///
-/// impl Serialize for Map {
-///     fn serialize<S>(&self, ser: &mut S) -> Result<(), S::Error>
-///         where S: Serializer,
-///     {
-///         ser.serialize_map(MapIteratorVisitor::new(
-///             self.0.iter(),
-///             Some(self.0.len()),
-///         ))
-///     }
-/// }
-/// ```
-pub struct MapIteratorVisitor<Iter> {
-    iter: Iter,
-    len: Option<usize>,
-}
-
-impl<K, V, Iter> MapIteratorVisitor<Iter>
-    where Iter: Iterator<Item=(K, V)>
-{
-    /// Construct a new `MapIteratorVisitor<Iter>`.
-    #[inline]
-    pub fn new(iter: Iter, len: Option<usize>) -> MapIteratorVisitor<Iter> {
-        MapIteratorVisitor {
-            iter: iter,
-            len: len,
-        }
-    }
-}
-
-impl<K, V, I> MapVisitor for MapIteratorVisitor<I>
-    where K: Serialize,
-          V: Serialize,
-          I: Iterator<Item=(K, V)>,
-{
-    #[inline]
-    fn visit<S>(&mut self, serializer: &mut S) -> Result<Option<()>, S::Error>
-        where S: Serializer,
-    {
-        match self.iter.next() {
-            Some((key, value)) => {
-                try!(serializer.serialize_map_elt(key, value));
-                Ok(Some(()))
+macro_rules! serialize_map {
+    () => {
+        #[inline]
+        fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
+            where S: Serializer,
+        {
+            let mut state = 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));
            }
-            None => Ok(None)
+            serializer.serialize_map_end(state)
        }
    }
-
-    #[inline]
-    fn len(&self) -> Option<usize> {
-        self.len
-    }
 }

-///////////////////////////////////////////////////////////////////////////////
-
 #[cfg(any(feature = "std", feature = "collections"))]
 impl<K, V> Serialize for BTreeMap<K, V>
    where K: Serialize + Ord,
          V: Serialize,
 {
-    #[inline]
-    fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
-        where S: Serializer,
-    {
-        serializer.serialize_map(MapIteratorVisitor::new(self.iter(), Some(self.len())))
-    }
+    serialize_map!();
 }

 #[cfg(feature = "std")]
@@ -723,12 +546,7 @@ impl<K, V, H> Serialize for HashMap<K, V, H>
          V: Serialize,
          H: BuildHasher,
 {
-    #[inline]
-    fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
-        where S: Serializer,
-    {
-        serializer.serialize_map(MapIteratorVisitor::new(self.iter(), Some(self.len())))
-    }
+    serialize_map!();
 }

 ///////////////////////////////////////////////////////////////////////////////
@@ -808,7 +626,21 @@ impl<T, E> Serialize for Result<T, E> where T: Serialize, E: Serialize {

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

-#[cfg(all(feature = "std", feature = "nightly"))]
+#[cfg(feature = "std")]
+impl Serialize for Duration {
+    fn serialize<S>(&self, serializer: &mut S) -> Result<(), 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)
+    }
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+#[cfg(all(feature = "std", feature = "unstable"))]
 impl Serialize for net::IpAddr {
    fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
        where S: Serializer,
@@ -893,7 +725,7 @@ impl Serialize for path::PathBuf {
    }
 }

-#[cfg(feature = "nightly")]
+#[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 {
        (**self).serialize(serializer)
@@ -1,4 +1,14 @@
 //! Generic serialization framework.
+//! # For Developers who want to serialize objects
+//! Implement the `Serialize` trait for the type of objects you want to serialize. Call methods of
+//! the `serializer` object. For which methods to call and how to do so, look at the documentation
+//! of the `Serializer` trait.
+//!
+//! # For Serialization Format Developers
+//! Implement the `Serializer` trait for a structure that contains fields that enable it to write
+//! the serialization result to your target. When a method's argument is an object of type
+//! `Serialize`, you can either forward the serializer object (`self`) or create a new one,
+//! depending on the quirks of your format.

 #[cfg(feature = "std")]
 use std::error;
@@ -15,11 +25,11 @@ pub mod impls;
 /// `Error` is a trait that allows a `Serialize` to generically create a
 /// `Serializer` error.
 pub trait Error: Sized + error::Error {
-    /// Raised when there is general error when deserializing a type.
+    /// Raised when there is a general error when serializing a type.
    #[cfg(any(feature = "std", feature = "collections"))]
    fn custom<T: Into<String>>(msg: T) -> Self;

-    /// Raised when there is general error when deserializing a type.
+    /// Raised when there is a general error when serializing a type.
    #[cfg(all(not(feature = "std"), not(feature = "collections")))]
    fn custom<T: Into<&'static str>>(msg: T) -> Self;

@@ -41,343 +51,362 @@ 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
+/// 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
+/// values or the keys may change between calls, but the serialization format may not necessarily
+/// accept it. The `serialize_T_elt` method also takes a mutable reference to the state object.
+/// Make sure that you always use the same state object and only the state object that was returned
+/// by the `serialize_T` method. Finally, when your object is done, call the `serialize_T_end`
+/// method and pass the state object by value
+///
+/// # For Serialization Format Developers
+/// If your format has different situations where it accepts different types, create a
+/// `Serializer` for each situation. You can create the sub-`Serializer` in one of the aggregate
+/// `serialize_T` methods and return it as a state object. Remember to also set the corresponding
+/// associated type `TState`. In the `serialize_T_elt` methods you will be given a mutable
+/// reference to that state. You do not need to do any additional checks for the correctness of the
+/// 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.
    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;
+
    /// Serializes a `bool` value.
    fn serialize_bool(&mut self, v: bool) -> Result<(), Self::Error>;

-    /// Serializes a `isize` value. By default it casts the value to a `i64` and
-    /// passes it to the `serialize_i64` method.
-    #[inline]
-    fn serialize_isize(&mut self, v: isize) -> Result<(), Self::Error> {
-        self.serialize_i64(v as i64)
-    }
+    /// 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>;

-    /// Serializes a `i8` value. By default it casts the value to a `i64` and
-    /// passes it to the `serialize_i64` method.
-    #[inline]
-    fn serialize_i8(&mut self, v: i8) -> Result<(), Self::Error> {
-        self.serialize_i64(v as i64)
-    }
+    /// 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>;

-    /// Serializes a `i16` value. By default it casts the value to a `i64` and
-    /// passes it to the `serialize_i64` method.
-    #[inline]
-    fn serialize_i16(&mut self, v: i16) -> Result<(), Self::Error> {
-        self.serialize_i64(v as i64)
-    }
+    /// 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>;

-    /// Serializes a `i32` value. By default it casts the value to a `i64` and
-    /// passes it to the `serialize_i64` method.
-    #[inline]
-    fn serialize_i32(&mut self, v: i32) -> Result<(), Self::Error> {
-        self.serialize_i64(v as i64)
-    }
+    /// 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>;

-    /// Serializes a `i64` value.
-    #[inline]
+    /// Serializes an `i64` value.
    fn serialize_i64(&mut self, v: i64) -> Result<(), Self::Error>;

-    /// Serializes a `usize` value. By default it casts the value to a `u64` and
-    /// passes it to the `serialize_u64` method.
-    #[inline]
-    fn serialize_usize(&mut self, v: usize) -> Result<(), Self::Error> {
-        self.serialize_u64(v as u64)
-    }
+    /// 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>;

-    /// Serializes a `u8` value. By default it casts the value to a `u64` and passes
-    /// it to the `serialize_u64` method.
-    #[inline]
-    fn serialize_u8(&mut self, v: u8) -> Result<(), Self::Error> {
-        self.serialize_u64(v as u64)
-    }
+    /// 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>;

-    /// Serializes a `u32` value. By default it casts the value to a `u64` and passes
-    /// it to the `serialize_u64` method.
-    #[inline]
-    fn serialize_u16(&mut self, v: u16) -> Result<(), Self::Error> {
-        self.serialize_u64(v as u64)
-    }
+    /// 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>;

-    /// Serializes a `u32` value. By default it casts the value to a `u64` and passes
-    /// it to the `serialize_u64` method.
-    #[inline]
-    fn serialize_u32(&mut self, v: u32) -> Result<(), Self::Error> {
-        self.serialize_u64(v as u64)
-    }
+    /// 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>;

    /// `Serializes a `u64` value.
-    #[inline]
    fn serialize_u64(&mut self, v: u64) -> Result<(), Self::Error>;

-    /// Serializes a `f32` value. By default it casts the value to a `f64` and passes
-    /// it to the `serialize_f64` method.
-    #[inline]
-    fn serialize_f32(&mut self, v: f32) -> Result<(), Self::Error> {
-        self.serialize_f64(v as f64)
-    }
+    /// 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>;

-    /// Serializes a `f64` value.
+    /// Serializes an `f64` value.
    fn serialize_f64(&mut self, v: f64) -> Result<(), Self::Error>;

-    /// Serializes a character. By default it serializes it as a `&str` containing a
-    /// single character.
-    #[inline]
-    fn serialize_char(&mut self, v: char) -> Result<(), Self::Error> {
-        self.serialize_str(::utils::encode_utf8(v).as_str())
-    }
+    /// 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>;

    /// Serializes a `&str`.
    fn serialize_str(&mut self, value: &str) -> Result<(), Self::Error>;

-    /// Enables those serialization formats that support serializing
-    /// byte slices separately from generic arrays. By default it serializes as a regular array.
-    #[inline]
-    fn serialize_bytes(&mut self, value: &[u8]) -> Result<(), Self::Error> {
-        self.serialize_seq(impls::SeqIteratorVisitor::new(value.iter(), Some(value.len())))
-    }
+    /// 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));
+    /// for b in value {
+    ///     try!(self.serialize_seq_elt(&mut state, b));
+    /// }
+    /// self.serialize_seq_end(state)
+    /// ```
+    fn serialize_bytes(&mut self, value: &[u8]) -> Result<(), Self::Error>;

-    /// Serializes a `()` value.
+    /// Serializes a `()` value. It's reasonable to just not serialize anything.
    fn serialize_unit(&mut self) -> Result<(), Self::Error>;

-    /// Serializes a unit struct value.
-    ///
-    /// By default, unit structs are serialized as a `()`.
-    #[inline]
-    fn serialize_unit_struct(&mut self, _name: &'static str) -> Result<(), Self::Error> {
-        self.serialize_unit()
-    }
+    /// Serializes a unit struct value. A reasonable implementation would be to
+    /// forward to `serialize_unit`.
+    fn serialize_unit_struct(
+        &mut self,
+        name: &'static str,
+    ) -> Result<(), Self::Error>;

-    /// Serializes a unit variant, otherwise known as a variant with no arguments.
-    ///
-    /// By default, unit variants are serialized as a `()`.
-    #[inline]
-    fn serialize_unit_variant(&mut self,
-                              _name: &'static str,
-                              _variant_index: usize,
-                              _variant: &'static str) -> Result<(), Self::Error> {
-        self.serialize_unit()
-    }
+    /// 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,
+        name: &'static str,
+        variant_index: usize,
+        variant: &'static str,
+    ) -> Result<(), Self::Error>;

-    /// Allows a tuple struct with a single element, also known as a
-    /// newtyped value, to be more efficiently serialized than a tuple struct with multiple items.
-    /// By default it just serializes the value as a tuple struct sequence.
-    #[inline]
-    fn serialize_newtype_struct<T>(&mut self,
-                                   name: &'static str,
-                                   value: T) -> Result<(), Self::Error>
-        where T: Serialize,
-    {
-        self.serialize_tuple_struct(name, Some(value))
-    }
+    /// 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,
+        name: &'static str,
+        value: T,
+    ) -> Result<(), Self::Error>;

-    /// Allows a variant with a single item to be more efficiently
-    /// serialized than a variant with multiple items. By default it just serializes the value as a
-    /// tuple variant sequence.
-    #[inline]
-    fn serialize_newtype_variant<T>(&mut self,
-                                    name: &'static str,
-                                    variant_index: usize,
-                                    variant: &'static str,
-                                    value: T) -> Result<(), Self::Error>
-        where T: Serialize,
-    {
-        self.serialize_tuple_variant(
-            name,
-            variant_index,
-            variant,
-            Some(value))
-    }
+    /// 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,
+        name: &'static str,
+        variant_index: usize,
+        variant: &'static str,
+        value: T,
+    ) -> Result<(), Self::Error>;

-    /// Serializes a `None` value..serialize
+    /// Serializes a `None` value.
    fn serialize_none(&mut self) -> Result<(), Self::Error>;

    /// Serializes a `Some(...)` value.
-    fn serialize_some<V>(&mut self, value: V) -> Result<(), Self::Error>
-        where V: Serialize;
+    fn serialize_some<T: Serialize>(
+        &mut self,
+        value: T,
+    ) -> Result<(), Self::Error>;

-    /// Serializes a sequence.
-    ///
-    /// Callees of this method need to construct a `SeqVisitor`, which iterates through each item
-    /// in the sequence.
-    fn serialize_seq<V>(&mut self, visitor: V) -> Result<(), Self::Error>
-        where V: SeqVisitor;
+    /// 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,
+        len: Option<usize>,
+    ) -> Result<Self::SeqState, Self::Error>;

-    /// Serializes a sequence element.
-    fn serialize_seq_elt<T>(&mut self, value: T) -> Result<(), Self::Error>
-        where T: Serialize;
+    /// 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>;

-    /// Serializes a tuple.
-    ///
-    /// By default this serializes a tuple as a sequence.
-    #[inline]
-    fn serialize_tuple<V>(&mut self, visitor: V) -> Result<(), Self::Error>
-        where V: SeqVisitor,
-    {
-        self.serialize_seq(visitor)
-    }
+    /// Finishes serializing a sequence.
+    fn serialize_seq_end(
+        &mut self,
+        state: Self::SeqState,
+    ) -> Result<(), Self::Error>;

-    /// Serializes a tuple element.
-    ///
-    /// By default, tuples are serialized as a sequence.
-    #[inline]
-    fn serialize_tuple_elt<T>(&mut self, value: T) -> Result<(), Self::Error>
-        where T: Serialize
-    {
-        self.serialize_seq_elt(value)
-    }
+    /// 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,
+        size: usize,
+    ) -> Result<Self::SeqState, Self::Error>;

-    /// Serializes a fixed-size array.
-    ///
-    /// By default this serializes an array as a sequence.
-    #[inline]
-    fn serialize_fixed_size_array<V>(&mut self, visitor: V) -> Result<(), Self::Error>
-        where V: SeqVisitor,
-    {
-        self.serialize_seq(visitor)
-    }
+    /// 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,
+        len: usize,
+    ) -> Result<Self::TupleState, Self::Error>;

-    /// Serializes a tuple struct.
-    ///
-    /// By default, tuple structs are serialized as a tuple.
-    #[inline]
-    fn serialize_tuple_struct<V>(&mut self,
-                                 _name: &'static str,
-                                 visitor: V) -> Result<(), Self::Error>
-        where V: SeqVisitor,
-    {
-        self.serialize_tuple(visitor)
-    }
+    /// 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>;

-    /// Serializes a tuple struct element.
-    ///
-    /// By default, tuple struct elements are serialized as a tuple element.
-    #[inline]
-    fn serialize_tuple_struct_elt<T>(&mut self, value: T) -> Result<(), Self::Error>
-        where T: Serialize
-    {
-        self.serialize_tuple_elt(value)
-    }
+    /// Finishes serializing a tuple.
+    fn serialize_tuple_end(
+        &mut self,
+        state: Self::TupleState,
+    ) -> Result<(), Self::Error>;

-    /// Serializes a tuple variant.
-    ///
-    /// By default, tuple variants are serialized as a tuple struct.
-    #[inline]
-    fn serialize_tuple_variant<V>(&mut self,
-                                  _name: &'static str,
-                                  _variant_index: usize,
-                                  variant: &'static str,
-                                  visitor: V) -> Result<(), Self::Error>
-        where V: SeqVisitor,
-    {
-        self.serialize_tuple_struct(variant, visitor)
-    }
+    /// 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,
+        name: &'static str,
+        len: usize,
+    ) -> Result<Self::TupleStructState, Self::Error>;

-    /// Serializes a tuple element.
-    ///
-    /// By default, tuples are serialized as a sequence.
-    #[inline]
-    fn serialize_tuple_variant_elt<T>(&mut self, value: T) -> Result<(), Self::Error>
-        where T: Serialize
-    {
-        self.serialize_tuple_struct_elt(value)
-    }
+    /// 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>;

-    /// Serializes a map.
-    ///
-    /// Callees of this method need to construct a `MapVisitor`, which iterates through each item
-    /// in the map.
-    fn serialize_map<V>(&mut self, visitor: V) -> Result<(), Self::Error>
-        where V: MapVisitor;
+    /// Finishes serializing a tuple struct.
+    fn serialize_tuple_struct_end(
+        &mut self,
+        state: Self::TupleStructState,
+    ) -> Result<(), Self::Error>;

-    /// Serializes a map element (key-value pair).
-    fn serialize_map_elt<K, V>(&mut self, key: K, value: V) -> Result<(), Self::Error>
-        where K: Serialize,
-              V: Serialize;
+    /// 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,
+        name: &'static str,
+        variant_index: usize,
+        variant: &'static str,
+        len: usize,
+    ) -> Result<Self::TupleVariantState, Self::Error>;

-    /// Serializes a struct.
-    ///
-    /// By default, structs are serialized as a map with the field name as the key.
-    #[inline]
-    fn serialize_struct<V>(&mut self,
-                           _name: &'static str,
-                           visitor: V) -> Result<(), Self::Error>
-        where V: MapVisitor,
-    {
-        self.serialize_map(visitor)
-    }
+    /// 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>;

-    /// Serializes an element of a struct.
-    ///
-    /// By default, struct elements are serialized as a map element with the field name as the key.
-    #[inline]
-    fn serialize_struct_elt<V>(&mut self,
-                               key: &'static str,
-                               value: V) -> Result<(), Self::Error>
-        where V: Serialize,
-    {
-        self.serialize_map_elt(key, value)
-    }
+    /// Finishes serializing a tuple variant.
+    fn serialize_tuple_variant_end(
+        &mut self,
+        state: Self::TupleVariantState,
+    ) -> Result<(), Self::Error>;

-    /// Serializes a struct variant.
-    ///
-    /// By default, struct variants are serialized as a struct.
-    #[inline]
-    fn serialize_struct_variant<V>(&mut self,
-                                   _name: &'static str,
-                                   _variant_index: usize,
-                                   variant: &'static str,
-                                   visitor: V) -> Result<(), Self::Error>
-        where V: MapVisitor,
-    {
-        self.serialize_struct(variant, visitor)
-    }
+    /// 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,
+        len: Option<usize>,
+    ) -> Result<Self::MapState, Self::Error>;

-    /// Serializes an element of a struct variant.
-    ///
-    /// By default, struct variant elements are serialized as a struct element.
-    #[inline]
-    fn serialize_struct_variant_elt<V>(&mut self,
-                                       key: &'static str,
-                                       value: V) -> Result<(), Self::Error>
-        where V: Serialize,
-    {
-        self.serialize_struct_elt(key, value)
-    }
-}
-
-/// A trait that is used by a `Serialize` to iterate through a sequence.
-#[cfg_attr(feature = "nightly-testing", allow(len_without_is_empty))]
-pub trait SeqVisitor {
-    /// Serializes a sequence item in the serializer.
-    ///
-    /// This returns `Ok(Some(()))` when there are more items to serialize, or `Ok(None)` when
-    /// complete.
-    fn visit<S>(&mut self, serializer: &mut S) -> Result<Option<()>, S::Error>
-        where S: Serializer;
-
-    /// Return the length of the sequence if known.
-    #[inline]
-    fn len(&self) -> Option<usize> {
-        None
-    }
-}
-
-/// A trait that is used by a `Serialize` to iterate through a map.
-#[cfg_attr(feature = "nightly-testing", allow(len_without_is_empty))]
-pub trait MapVisitor {
-    /// Serializes a map item in the serializer.
-    ///
-    /// This returns `Ok(Some(()))` when there are more items to serialize, or `Ok(None)` when
-    /// complete.
-    fn visit<S>(&mut self, serializer: &mut S) -> Result<Option<()>, S::Error>
-        where S: Serializer;
-
-    /// Return the length of the map if known.
-    #[inline]
-    fn len(&self) -> Option<usize> {
-        None
-    }
+    /// 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>;
+
+    /// 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,
+        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>;
+
+    /// 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,
+        name: &'static str,
+        variant_index: usize,
+        variant: &'static str,
+        len: usize,
+    ) -> Result<Self::StructVariantState, 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>;
+
+    /// Finishes serializing a struct variant.
+    fn serialize_struct_variant_end(
+        &mut self,
+        state: Self::StructVariantState,
+    ) -> Result<(), Self::Error>;
 }
@@ -1,19 +1,20 @@
 [package]
 name = "serde_codegen"
-version = "0.7.12"
+version = "0.8.8"
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>"]
 license = "MIT/Apache-2.0"
 description = "Macros to auto-generate implementations for the serde framework"
+homepage = "https://serde.rs"
 repository = "https://github.com/serde-rs/serde"
-documentation = "https://github.com/serde-rs/serde"
+documentation = "https://serde.rs/codegen.html"
 keywords = ["serde", "serialization"]
 build = "build.rs"
 include = ["Cargo.toml", "build.rs", "src/**/*.rs", "src/lib.rs.in"]

 [features]
 default = ["with-syntex"]
-nightly = ["quasi_macros"]
-nightly-testing = ["clippy"]
+unstable = ["quasi_macros"]
+unstable-testing = ["clippy"]
 with-syntex = [
    "quasi/with-syntex",
    "quasi_codegen",
@@ -24,14 +25,14 @@ with-syntex = [
 ]

 [build-dependencies]
-quasi_codegen = { version = "^0.14.0", optional = true }
-syntex = { version = "^0.37.0", optional = true }
+quasi_codegen = { version = "^0.19.0", optional = true }
+syntex = { version = "^0.43.0", optional = true }

 [dependencies]
-aster = { version = "^0.20.0", default-features = false }
+aster = { version = "^0.26.0", default-features = false }
 clippy = { version = "^0.*", optional = true }
-quasi = { version = "^0.14.0", default-features = false }
-quasi_macros = { version = "^0.14.0", optional = true }
-serde_codegen_internals = { version = "^0.2.0", path = "../serde_codegen_internals", default-features = false }
-syntex = { version = "^0.37.0", optional = true }
-syntex_syntax = { version = "^0.37.0", optional = true }
+quasi = { version = "^0.19.0", default-features = false }
+quasi_macros = { version = "^0.19.0", optional = true }
+serde_codegen_internals = { version = "=0.8.0", default-features = false, path = "../serde_codegen_internals" }
+syntex = { version = "^0.43.0", optional = true }
+syntex_syntax = { version = "^0.43.0", optional = true }
@@ -4,14 +4,17 @@ mod inner {

    use std::env;
    use std::path::Path;
+    use std::thread::spawn;

    pub fn main() {
-        let out_dir = env::var_os("OUT_DIR").unwrap();
+        // put everything into a thread, so users can use `RUST_MIN_STACK` to increase the amount of stack
+        spawn(|| {
+            let out_dir = env::var_os("OUT_DIR").unwrap();

-        let src = Path::new("src/lib.rs.in");
-        let dst = Path::new(&out_dir).join("lib.rs");
-
-        quasi_codegen::expand(&src, &dst).unwrap();
+            let src = Path::new("src/lib.rs.in");
+            let dst = Path::new(&out_dir).join("lib.rs");
+            quasi_codegen::expand(&src, &dst).unwrap();
+        }).join().unwrap()
    }
 }

@@ -1,7 +1,8 @@
+use std::collections::HashSet;
+
 use aster::AstBuilder;

 use syntax::ast;
-use syntax::ptr::P;
 use syntax::visit;

 use internals::ast::Item;
@@ -47,6 +48,17 @@ pub fn with_where_predicates_from_fields<F>(
        .build()
 }

+// Puts the given bound on any generic type parameters that are used in fields
+// for which filter returns true.
+//
+// For example, the following struct needs the bound `A: Serialize, B: Serialize`.
+//
+//     struct S<'b, A, B: 'b, C> {
+//         a: A,
+//         b: Option<&'b B>
+//         #[serde(skip_serializing)]
+//         c: C,
+//     }
 pub fn with_bound<F>(
    builder: &AstBuilder,
    item: &Item,
@@ -56,95 +68,60 @@ pub fn with_bound<F>(
 ) -> ast::Generics
    where F: Fn(&attr::Field) -> bool,
 {
+    struct FindTyParams {
+        // Set of all generic type parameters on the current struct (A, B, C in
+        // the example). Initialized up front.
+        all_ty_params: HashSet<ast::Name>,
+        // Set of generic type parameters used in fields for which filter
+        // returns true (A and B in the example). Filled in as the visitor sees
+        // them.
+        relevant_ty_params: HashSet<ast::Name>,
+    }
+    impl visit::Visitor for FindTyParams {
+        fn visit_path(&mut self, path: &ast::Path, _id: ast::NodeId) {
+            if let Some(seg) = path.segments.last() {
+                if seg.identifier.name.as_str() == "PhantomData" {
+                    // Hardcoded exception, because PhantomData<T> implements
+                    // Serialize and Deserialize whether or not T implements it.
+                    return;
+                }
+            }
+            if !path.global && path.segments.len() == 1 {
+                let id = path.segments[0].identifier.name;
+                if self.all_ty_params.contains(&id) {
+                    self.relevant_ty_params.insert(id);
+                }
+            }
+            visit::walk_path(self, path);
+        }
+    }
+
+    let all_ty_params: HashSet<_> = generics.ty_params.iter()
+        .map(|ty_param| ty_param.ident.name)
+        .collect();
+
+    let relevant_tys = item.body.all_fields()
+        .filter(|&field| filter(&field.attrs))
+        .map(|field| &field.ty);
+
+    let mut visitor = FindTyParams {
+        all_ty_params: all_ty_params,
+        relevant_ty_params: HashSet::new(),
+    };
+    for ty in relevant_tys {
+        visit::walk_ty(&mut visitor, ty);
+    }
+
    builder.from_generics(generics.clone())
        .with_predicates(
-            item.body.all_fields()
-                .filter(|&field| filter(&field.attrs))
-                .map(|field| &field.ty)
-                .filter(|ty| !contains_recursion(ty, item.ident))
-                .map(|ty| strip_reference(ty))
-                .map(|ty| builder.where_predicate()
-                    // the type that is being bounded e.g. T
-                    .bound().build(ty.clone())
+            generics.ty_params.iter()
+                .map(|ty_param| ty_param.ident.name)
+                .filter(|id| visitor.relevant_ty_params.contains(id))
+                .map(|id| builder.where_predicate()
+                    // the type parameter that is being bounded e.g. T
+                    .bound().build(builder.ty().id(id))
                    // the bound e.g. Serialize
                    .bound().trait_(bound.clone()).build()
                    .build()))
        .build()
 }
-
-// We do not attempt to generate any bounds based on field types that are
-// directly recursive, as in:
-//
-//    struct Test<D> {
-//        next: Box<Test<D>>,
-//    }
-//
-// This does not catch field types that are mutually recursive with some other
-// type. For those, we require bounds to be specified by a `bound` attribute if
-// the inferred ones are not correct.
-//
-//    struct Test<D> {
-//        #[serde(bound="D: Serialize + Deserialize")]
-//        next: Box<Other<D>>,
-//    }
-//    struct Other<D> {
-//        #[serde(bound="D: Serialize + Deserialize")]
-//        next: Box<Test<D>>,
-//    }
-fn contains_recursion(ty: &ast::Ty, ident: ast::Ident) -> bool {
-    struct FindRecursion {
-        ident: ast::Ident,
-        found_recursion: bool,
-    }
-    impl visit::Visitor for FindRecursion {
-        fn visit_path(&mut self, path: &ast::Path, _id: ast::NodeId) {
-            if !path.global
-                    && path.segments.len() == 1
-                    && path.segments[0].identifier == self.ident {
-                self.found_recursion = true;
-            } else {
-                visit::walk_path(self, path);
-            }
-        }
-    }
-
-    let mut visitor = FindRecursion {
-        ident: ident,
-        found_recursion: false,
-    };
-    visit::walk_ty(&mut visitor, ty);
-    visitor.found_recursion
-}
-
-// This is required to handle types that use both a reference and a value of
-// the same type, as in:
-//
-//    enum Test<'a, T> where T: 'a {
-//        Lifetime(&'a T),
-//        NoLifetime(T),
-//    }
-//
-// Preserving references, we would generate an impl like:
-//
-//    impl<'a, T> Serialize for Test<'a, T>
-//        where &'a T: Serialize,
-//              T: Serialize { ... }
-//
-// And taking a reference to one of the elements would fail with:
-//
-//    error: cannot infer an appropriate lifetime for pattern due
-//    to conflicting requirements [E0495]
-//        Test::NoLifetime(ref v) => { ... }
-//                         ^~~~~
-//
-// Instead, we strip references before adding `T: Serialize` bounds in order to
-// generate:
-//
-//    impl<'a, T> Serialize for Test<'a, T>
-//        where T: Serialize { ... }
-fn strip_reference(mut ty: &P<ast::Ty>) -> &P<ast::Ty> {
-    while let ast::TyKind::Rptr(_, ref mut_ty) = ty.node {
-        ty = &mut_ty.ty;
-    }
-    ty
-}
@@ -8,6 +8,7 @@ use syntax::ptr::P;
 use syntax::tokenstream::TokenTree;

 use bound;
+use span;
 use internals::ast::{Body, Field, Item, Style, Variant};
 use internals::{attr, Error};

@@ -44,7 +45,7 @@ pub fn expand_derive_deserialize(
    let builder = aster::AstBuilder::new().span(span);

    let impl_item = deserialize_item(cx, &builder, &item);
-    push(Annotatable::Item(impl_item))
+    push(span::record_expansion(cx, impl_item, "Deserialize"))
 }

 fn deserialize_item(
@@ -75,10 +76,8 @@ fn deserialize_item(
            #[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,
-                {
-                    $body
-                }
+                    where __D: _serde::de::Deserializer
+                $body
            }
        };
    ).unwrap()
@@ -135,7 +134,7 @@ fn deserialize_body(
    item: &Item,
    impl_generics: &ast::Generics,
    ty: P<ast::Ty>,
-) -> P<ast::Expr> {
+) -> P<ast::Block> {
    match item.body {
        Body::Enum(ref variants) => {
            deserialize_item_enum(
@@ -191,31 +190,24 @@ fn deserialize_body(
 // Build `__Visitor<A, B, ...>(PhantomData<A>, PhantomData<B>, ...)`
 fn deserialize_visitor(
    builder: &aster::AstBuilder,
-    trait_generics: &ast::Generics,
-    forward_ty_params: Vec<ast::TyParam>,
-    forward_tys: Vec<P<ast::Ty>>
-) -> (P<ast::Item>, P<ast::Ty>, P<ast::Expr>, ast::Generics) {
-    if trait_generics.ty_params.is_empty() && forward_tys.is_empty() {
+    generics: &ast::Generics,
+) -> (P<ast::Item>, P<ast::Ty>, P<ast::Expr>) {
+    if generics.lifetimes.is_empty() && generics.ty_params.is_empty() {
        (
-            builder.item().tuple_struct("__Visitor").build(),
+            builder.item().unit_struct("__Visitor"),
            builder.ty().id("__Visitor"),
            builder.expr().id("__Visitor"),
-            trait_generics.clone(),
        )
    } else {
-        let placeholders : Vec<_> = trait_generics.ty_params.iter()
+        let placeholders : Vec<_> = generics.ty_params.iter()
            .map(|t| builder.ty().id(t.ident))
            .collect();
-        let mut trait_generics = trait_generics.clone();
-        let mut ty_params = forward_ty_params.clone();
-        ty_params.extend(trait_generics.ty_params.into_vec());
-        trait_generics.ty_params = P::from_vec(ty_params);

        (
            builder.item().tuple_struct("__Visitor")
-                .generics().with(trait_generics.clone()).build()
+                .generics().with(generics.clone()).build()
                .with_tys({
-                    let lifetimes = trait_generics.lifetimes.iter()
+                    let lifetimes = generics.lifetimes.iter()
                        .map(|lifetime_def| {
                            builder.ty()
                                .phantom_data()
@@ -224,7 +216,7 @@ fn deserialize_visitor(
                                .unit()
                        });

-                    let ty_params = trait_generics.ty_params.iter()
+                    let ty_params = generics.ty_params.iter()
                        .map(|ty_param| {
                            builder.ty()
                                .phantom_data()
@@ -235,48 +227,31 @@ fn deserialize_visitor(
                })
                .build(),
            builder.ty().path()
-                .segment("__Visitor").with_generics(trait_generics.clone()).build()
+                .segment("__Visitor").with_generics(generics.clone()).build()
                .build(),
            builder.expr().call()
                .path().segment("__Visitor")
-                .with_tys(forward_tys)
                .with_tys(placeholders)
                .build().build()
                .with_args({
-                    let len = trait_generics.lifetimes.len() + trait_generics.ty_params.len();
+                    let len = generics.lifetimes.len() + generics.ty_params.len();

                    (0 .. len).map(|_| builder.expr().phantom_data())
                })
                .build(),
-            trait_generics,
        )
    }
 }

-fn deserializer_ty_param(builder: &aster::AstBuilder) -> ast::TyParam {
-    builder.ty_param("__D")
-        .trait_bound(builder.path()
-                     .segment("_serde").build()
-                     .segment("de").build()
-                     .id("Deserializer")
-                     .build())
-        .build()
-        .build()
-}
-
-fn deserializer_ty_arg(builder: &aster::AstBuilder) -> P<ast::Ty>{
-    builder.ty().id("__D")
-}
-
 fn deserialize_unit_struct(
    cx: &ExtCtxt,
    builder: &aster::AstBuilder,
    type_ident: Ident,
    item_attrs: &attr::Item,
-) -> P<ast::Expr> {
+) -> P<ast::Block> {
    let type_name = name_expr(builder, item_attrs.name());

-    quote_expr!(cx, {
+    quote_block!(cx, {
        struct __Visitor;

        impl _serde::de::Visitor for __Visitor {
@@ -299,7 +274,7 @@ fn deserialize_unit_struct(
        }

        deserializer.deserialize_unit_struct($type_name, __Visitor)
-    })
+    }).unwrap()
 }

 fn deserialize_tuple(
@@ -311,14 +286,12 @@ fn deserialize_tuple(
    ty: P<ast::Ty>,
    fields: &[Field],
    item_attrs: &attr::Item,
-) -> P<ast::Expr> {
+) -> P<ast::Block> {
    let where_clause = &impl_generics.where_clause;

-    let (visitor_item, visitor_ty, visitor_expr, visitor_generics) = deserialize_visitor(
+    let (visitor_item, visitor_ty, visitor_expr) = deserialize_visitor(
        builder,
        impl_generics,
-        vec![deserializer_ty_param(builder)],
-        vec![deserializer_ty_arg(builder)],
    );

    let is_enum = variant_ident.is_some();
@@ -342,7 +315,7 @@ fn deserialize_tuple(
        None
    };

-    let visit_seq_expr = deserialize_seq(
+    let visit_seq = deserialize_seq(
        cx,
        builder,
        type_ident,
@@ -365,24 +338,22 @@ fn deserialize_tuple(
            deserializer.deserialize_tuple_struct($type_name, $nfields, $visitor_expr))
    };

-    quote_expr!(cx, {
+    quote_block!(cx, {
        $visitor_item

-        impl $visitor_generics _serde::de::Visitor for $visitor_ty $where_clause {
+        impl $impl_generics _serde::de::Visitor for $visitor_ty $where_clause {
            type Value = $ty;

            $visit_newtype_struct

            #[inline]
            fn visit_seq<__V>(&mut self, mut visitor: __V) -> ::std::result::Result<$ty, __V::Error>
-                where __V: _serde::de::SeqVisitor,
-            {
-                $visit_seq_expr
-            }
+                where __V: _serde::de::SeqVisitor
+            $visit_seq
        }

        $dispatch
-    })
+    }).unwrap()
 }

 fn deserialize_seq(
@@ -393,7 +364,8 @@ fn deserialize_seq(
    impl_generics: &ast::Generics,
    fields: &[Field],
    is_struct: bool,
-) -> P<ast::Expr> {
+) -> P<ast::Block> {
+    let mut index_in_seq = 0usize;
    let let_values: Vec<_> = fields.iter()
        .enumerate()
        .map(|(i, field)| {
@@ -419,14 +391,17 @@ fn deserialize_seq(
                        })
                    }
                };
-                quote_stmt!(cx,
+                let assign = quote_stmt!(cx,
                    let $name = match $visit {
                        Some(value) => { value },
                        None => {
-                            return Err(_serde::de::Error::end_of_stream());
+                            try!(visitor.end());
+                            return Err(_serde::de::Error::invalid_length($index_in_seq));
                        }
                    };
-                ).unwrap()
+                ).unwrap();
+                index_in_seq += 1;
+                assign
            }
        })
        .collect();
@@ -456,13 +431,13 @@ fn deserialize_seq(
            .build()
    };

-    quote_expr!(cx, {
+    quote_block!(cx, {
        $let_values

        try!(visitor.end());

        Ok($result)
-    })
+    }).unwrap()
 }

 fn deserialize_newtype_struct(
@@ -508,14 +483,12 @@ fn deserialize_struct(
    ty: P<ast::Ty>,
    fields: &[Field],
    item_attrs: &attr::Item,
-) -> P<ast::Expr> {
+) -> P<ast::Block> {
    let where_clause = &impl_generics.where_clause;

-    let (visitor_item, visitor_ty, visitor_expr, visitor_generics) = deserialize_visitor(
+    let (visitor_item, visitor_ty, visitor_expr) = deserialize_visitor(
        builder,
-        &impl_generics,
-        vec![deserializer_ty_param(builder)],
-        vec![deserializer_ty_arg(builder)],
+        impl_generics,
    );

    let type_path = match variant_ident {
@@ -523,7 +496,7 @@ fn deserialize_struct(
        None => builder.path().id(type_ident).build(),
    };

-    let visit_seq_expr = deserialize_seq(
+    let visit_seq = deserialize_seq(
        cx,
        builder,
        type_ident,
@@ -533,7 +506,7 @@ fn deserialize_struct(
        true,
    );

-    let (field_visitor, fields_stmt, visit_map_expr) = deserialize_struct_visitor(
+    let (field_visitor, fields_stmt, visit_map) = deserialize_struct_visitor(
        cx,
        builder,
        type_ident,
@@ -553,33 +526,29 @@ fn deserialize_struct(
            deserializer.deserialize_struct($type_name, FIELDS, $visitor_expr))
    };

-    quote_expr!(cx, {
+    quote_block!(cx, {
        $field_visitor

        $visitor_item

-        impl $visitor_generics _serde::de::Visitor for $visitor_ty $where_clause {
+        impl $impl_generics _serde::de::Visitor for $visitor_ty $where_clause {
            type Value = $ty;

            #[inline]
            fn visit_seq<__V>(&mut self, mut visitor: __V) -> ::std::result::Result<$ty, __V::Error>
-                where __V: _serde::de::SeqVisitor,
-            {
-                $visit_seq_expr
-            }
+                where __V: _serde::de::SeqVisitor
+            $visit_seq

            #[inline]
            fn visit_map<__V>(&mut self, mut visitor: __V) -> ::std::result::Result<$ty, __V::Error>
-                where __V: _serde::de::MapVisitor,
-            {
-                $visit_map_expr
-            }
+                where __V: _serde::de::MapVisitor
+            $visit_map
        }

        $fields_stmt

        $dispatch
-    })
+    }).unwrap()
 }

 fn deserialize_item_enum(
@@ -590,7 +559,7 @@ fn deserialize_item_enum(
    ty: P<ast::Ty>,
    variants: &[Variant],
    item_attrs: &attr::Item
-) -> P<ast::Expr> {
+) -> P<ast::Block> {
    let where_clause = &impl_generics.where_clause;

    let type_name = name_expr(builder, item_attrs.name());
@@ -628,7 +597,7 @@ fn deserialize_item_enum(
            .id("__Field").id(format!("__field{}", i))
            .build();

-        let expr = deserialize_variant(
+        let block = deserialize_variant(
            cx,
            builder,
            type_ident,
@@ -638,24 +607,22 @@ fn deserialize_item_enum(
            item_attrs,
        );

-        let arm = quote_arm!(cx, $variant_name => { $expr });
+        let arm = quote_arm!(cx, $variant_name => $block);
        variant_arms.push(arm);
    }
    variant_arms.extend(ignored_arm.into_iter());

-    let (visitor_item, visitor_ty, visitor_expr, visitor_generics) = deserialize_visitor(
+    let (visitor_item, visitor_ty, visitor_expr) = deserialize_visitor(
        builder,
        impl_generics,
-        vec![deserializer_ty_param(builder)],
-        vec![deserializer_ty_arg(builder)],
    );

-    quote_expr!(cx, {
+    quote_block!(cx, {
        $variant_visitor

        $visitor_item

-        impl $visitor_generics _serde::de::EnumVisitor for $visitor_ty $where_clause {
+        impl $impl_generics _serde::de::EnumVisitor for $visitor_ty $where_clause {
            type Value = $ty;

            fn visit<__V>(&mut self, mut visitor: __V) -> ::std::result::Result<$ty, __V::Error>
@@ -670,7 +637,7 @@ fn deserialize_item_enum(
        $variants_stmt

        deserializer.deserialize_enum($type_name, VARIANTS, $visitor_expr)
-    })
+    }).unwrap()
 }

 fn deserialize_variant(
@@ -681,15 +648,15 @@ fn deserialize_variant(
    ty: P<ast::Ty>,
    variant: &Variant,
    item_attrs: &attr::Item,
-) -> P<ast::Expr> {
+) -> P<ast::Block> {
    let variant_ident = variant.ident;

    match variant.style {
        Style::Unit => {
-            quote_expr!(cx, {
+            quote_block!(cx, {
                try!(visitor.visit_unit());
                Ok($type_ident::$variant_ident)
-            })
+            }).unwrap()
        }
        Style::Newtype => {
            deserialize_newtype_variant(
@@ -735,7 +702,7 @@ fn deserialize_newtype_variant(
    variant_ident: Ident,
    impl_generics: &ast::Generics,
    field: &Field,
-) -> P<ast::Expr> {
+) -> P<ast::Block> {
    let visit = match field.attrs.deserialize_with() {
        None => {
            let field_ty = &field.ty;
@@ -751,7 +718,9 @@ fn deserialize_newtype_variant(
            })
        }
    };
-    quote_expr!(cx, Ok($type_ident::$variant_ident($visit)))
+    quote_block!(cx, {
+        Ok($type_ident::$variant_ident($visit))
+    }).unwrap()
 }

 fn deserialize_field_visitor(
@@ -800,17 +769,15 @@ fn deserialize_field_visitor(
    let fallthrough_index_arm_expr = if !is_variant && !item_attrs.deny_unknown_fields() {
        quote_expr!(cx, Ok(__Field::__ignore))
    } else {
-        quote_expr!(cx, {
-            Err(_serde::de::Error::invalid_value($index_error_msg))
-        })
+        quote_expr!(cx, Err(_serde::de::Error::invalid_value($index_error_msg)))
    };

-    let index_body = quote_expr!(cx,
+    let index_body = quote_block!(cx, {
        match value {
            $index_field_arms
            _ => $fallthrough_index_arm_expr
        }
-    );
+    }).unwrap();

    // Convert the field names into byte strings.
    let str_field_names: Vec<_> = field_names.iter()
@@ -830,12 +797,12 @@ fn deserialize_field_visitor(
        quote_expr!(cx, Err(_serde::de::Error::$unknown_ident(value)))
    };

-    let str_body = quote_expr!(cx,
+    let str_body = quote_block!(cx, {
        match value {
            $str_field_arms
            _ => $fallthrough_str_arm_expr
        }
-    );
+    }).unwrap();

    // Convert the field names into byte strings.
    let bytes_field_names: Vec<_> = field_names.iter()
@@ -861,12 +828,12 @@ fn deserialize_field_visitor(
        })
    };

-    let bytes_body = quote_expr!(cx,
+    let bytes_body = quote_block!(cx, {
        match value {
            $bytes_field_arms
            _ => $fallthrough_bytes_arm_expr
        }
-    );
+    }).unwrap();

    let impl_item = quote_item!(cx,
        impl _serde::de::Deserialize for __Field {
@@ -874,39 +841,25 @@ fn deserialize_field_visitor(
            fn deserialize<__D>(deserializer: &mut __D) -> ::std::result::Result<__Field, __D::Error>
                where __D: _serde::de::Deserializer,
            {
-                struct __FieldVisitor<__D> {
-                    phantom: ::std::marker::PhantomData<__D>
-                }
+                struct __FieldVisitor;

-                impl<__D> _serde::de::Visitor for __FieldVisitor<__D>
-                    where __D: _serde::de::Deserializer
-                {
+                impl _serde::de::Visitor for __FieldVisitor {
                    type Value = __Field;

                    fn visit_usize<__E>(&mut self, value: usize) -> ::std::result::Result<__Field, __E>
-                        where __E: _serde::de::Error,
-                    {
-                        $index_body
-                    }
+                        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
-                    }
+                        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
-                    }
+                        where __E: _serde::de::Error
+                    $bytes_body
                }

-                deserializer.deserialize_struct_field(
-                    __FieldVisitor::<__D>{
-                        phantom: ::std::marker::PhantomData
-                    }
-                )
+                deserializer.deserialize_struct_field(__FieldVisitor)
            }
        }
    ).unwrap();
@@ -922,7 +875,7 @@ fn deserialize_struct_visitor(
    impl_generics: &ast::Generics,
    fields: &[Field],
    item_attrs: &attr::Item,
-) -> (Vec<P<ast::Item>>, ast::Stmt, P<ast::Expr>) {
+) -> (Vec<P<ast::Item>>, ast::Stmt, P<ast::Block>) {
    let field_exprs = fields.iter()
        .map(|field| field.attrs.name().deserialize_name())
        .collect();
@@ -935,7 +888,7 @@ fn deserialize_struct_visitor(
        false,
    );

-    let visit_map_expr = deserialize_map(
+    let visit_map = deserialize_map(
        cx,
        builder,
        type_ident,
@@ -963,7 +916,7 @@ fn deserialize_struct_visitor(
        const FIELDS: &'static [&'static str] = $fields_expr;
    ).unwrap();

-    (field_visitor, fields_stmt, visit_map_expr)
+    (field_visitor, fields_stmt, visit_map)
 }

 fn deserialize_map(
@@ -974,7 +927,7 @@ fn deserialize_map(
    impl_generics: &ast::Generics,
    fields: &[Field],
    item_attrs: &attr::Item,
-) -> P<ast::Expr> {
+) -> P<ast::Block> {
    // Create the field names for the fields.
    let fields_names = fields.iter()
        .enumerate()
@@ -1081,7 +1034,7 @@ fn deserialize_map(
        )
        .build();

-    quote_expr!(cx, {
+    quote_block!(cx, {
        $let_values

        while let Some(key) = try!(visitor.visit_key::<__Field>()) {
@@ -1092,12 +1045,12 @@ fn deserialize_map(
            }
        }

-        $extract_values
-
        try!(visitor.end());

+        $extract_values
+
        Ok($result)
-    })
+    }).unwrap()
 }

 /// This function wraps the expression in `#[serde(deserialize_with="...")]` in
@@ -1,7 +1,7 @@
-#![cfg_attr(feature = "nightly-testing", plugin(clippy))]
-#![cfg_attr(feature = "nightly-testing", feature(plugin))]
-#![cfg_attr(feature = "nightly-testing", allow(too_many_arguments))]
-#![cfg_attr(feature = "nightly-testing", allow(used_underscore_binding))]
+#![cfg_attr(feature = "clippy", plugin(clippy))]
+#![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))]
 #![cfg_attr(not(feature = "with-syntex"), plugin(quasi_macros))]

@@ -36,17 +36,7 @@ include!(concat!(env!("OUT_DIR"), "/lib.rs"));
 include!("lib.rs.in");

 #[cfg(feature = "with-syntex")]
-pub fn expand<S, D>(src: S, dst: D) -> Result<(), syntex::Error>
-    where S: AsRef<Path>,
-          D: AsRef<Path>,
-{
-    let mut registry = syntex::Registry::new();
-    register(&mut registry);
-    registry.expand("", src.as_ref(), dst.as_ref())
-}
-
-#[cfg(feature = "with-syntex")]
-pub fn register(reg: &mut syntex::Registry) {
+fn syntex_registry() -> syntex::Registry {
    use syntax::{ast, fold};

    /// Strip the serde attributes from the crate.
@@ -73,6 +63,8 @@ pub fn register(reg: &mut syntex::Registry) {
        fold::Folder::fold_crate(&mut StripAttributeFolder, krate)
    }

+    let mut reg = syntex::Registry::new();
+
    reg.add_attr("feature(custom_derive)");
    reg.add_attr("feature(custom_attribute)");

@@ -80,6 +72,34 @@ pub fn register(reg: &mut syntex::Registry) {
    reg.add_decorator("derive_Deserialize", de::expand_derive_deserialize);

    reg.add_post_expansion_pass(strip_attributes);
+
+    reg
+}
+
+#[cfg(feature = "with-syntex")]
+pub fn expand_str(src: &str) -> Result<String, syntex::Error> {
+    let src = src.to_owned();
+
+    let expand_thread = move || {
+        syntex_registry().expand_str("", "", &src)
+    };
+
+    syntex::with_extra_stack(expand_thread)
+}
+
+#[cfg(feature = "with-syntex")]
+pub fn expand<S, D>(src: S, dst: D) -> Result<(), syntex::Error>
+    where S: AsRef<Path>,
+          D: AsRef<Path>,
+{
+    let src = src.as_ref().to_owned();
+    let dst = dst.as_ref().to_owned();
+
+    let expand_thread = move || {
+        syntex_registry().expand("", src, dst)
+    };
+
+    syntex::with_extra_stack(expand_thread)
 }

 #[cfg(not(feature = "with-syntex"))]
@@ -1,3 +1,4 @@
 mod bound;
 mod de;
 mod ser;
+mod span;
@@ -4,8 +4,10 @@ use syntax::ast::{self, Ident, MetaItem};
 use syntax::codemap::Span;
 use syntax::ext::base::{Annotatable, ExtCtxt};
 use syntax::ptr::P;
+use syntax::tokenstream::TokenTree;

 use bound;
+use span;
 use internals::ast::{Body, Field, Item, Style, Variant};
 use internals::{attr, Error};

@@ -38,7 +40,7 @@ pub fn expand_derive_serialize(
    let builder = aster::AstBuilder::new().span(span);

    let impl_item = serialize_item(cx, &builder, &item);
-    push(Annotatable::Item(impl_item))
+    push(span::record_expansion(cx, impl_item, "Serialize"))
 }

 fn serialize_item(
@@ -69,10 +71,8 @@ fn serialize_item(
            #[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,
-                {
-                    $body
-                }
+                    where __S: _serde::ser::Serializer
+                $body
            }
        };
    ).unwrap()
@@ -118,7 +118,7 @@ fn serialize_body(
    item: &Item,
    impl_generics: &ast::Generics,
    ty: P<ast::Ty>,
-) -> P<ast::Expr> {
+) -> P<ast::Block> {
    match item.body {
        Body::Enum(ref variants) => {
            serialize_item_enum(
@@ -178,12 +178,12 @@ fn serialize_unit_struct(
    cx: &ExtCtxt,
    builder: &aster::AstBuilder,
    item_attrs: &attr::Item,
-) -> P<ast::Expr> {
+) -> P<ast::Block> {
    let type_name = name_expr(builder, item_attrs.name());

-    quote_expr!(cx,
+    quote_block!(cx, {
        _serializer.serialize_unit_struct($type_name)
-    )
+    }).unwrap()
 }

 fn serialize_newtype_struct(
@@ -193,7 +193,7 @@ fn serialize_newtype_struct(
    item_ty: P<ast::Ty>,
    field: &Field,
    item_attrs: &attr::Item,
-) -> P<ast::Expr> {
+) -> P<ast::Block> {
    let type_name = name_expr(builder, item_attrs.name());

    let mut field_expr = quote_expr!(cx, &self.0);
@@ -202,9 +202,9 @@ fn serialize_newtype_struct(
            &item_ty, impl_generics, &field.ty, path, field_expr);
    }

-    quote_expr!(cx,
+    quote_block!(cx, {
        _serializer.serialize_newtype_struct($type_name, $field_expr)
-    )
+    }).unwrap()
 }

 fn serialize_tuple_struct(
@@ -214,32 +214,26 @@ fn serialize_tuple_struct(
    ty: P<ast::Ty>,
    fields: &[Field],
    item_attrs: &attr::Item,
-) -> P<ast::Expr> {
-    let (visitor_struct, visitor_impl) = serialize_tuple_struct_visitor(
+) -> P<ast::Block> {
+    let serialize_stmts = serialize_tuple_struct_visitor(
        cx,
        builder,
        ty.clone(),
-        builder.ty()
-            .ref_()
-            .lifetime("'__a")
-            .build_ty(ty.clone()),
-        builder.id("serialize_tuple_struct_elt"),
        fields,
        impl_generics,
        false,
+        cx.ident_of("serialize_tuple_struct_elt"),
    );

    let type_name = name_expr(builder, item_attrs.name());
+    let len = serialize_stmts.len();
+    let let_mut = mut_if(cx, len > 0);

-    quote_expr!(cx, {
-        $visitor_struct
-        $visitor_impl
-        _serializer.serialize_tuple_struct($type_name, Visitor {
-            value: self,
-            state: 0,
-            _structure_ty: ::std::marker::PhantomData::<&$ty>,
-        })
-    })
+    quote_block!(cx, {
+        let $let_mut state = try!(_serializer.serialize_tuple_struct($type_name, $len));
+        $serialize_stmts
+        _serializer.serialize_tuple_struct_end(state)
+    }).unwrap()
 }

 fn serialize_struct(
@@ -249,32 +243,42 @@ fn serialize_struct(
    ty: P<ast::Ty>,
    fields: &[Field],
    item_attrs: &attr::Item,
-) -> P<ast::Expr> {
-    let (visitor_struct, visitor_impl) = serialize_struct_visitor(
+) -> P<ast::Block> {
+    let serialize_fields = serialize_struct_visitor(
        cx,
        builder,
        ty.clone(),
-        builder.ty()
-            .ref_()
-            .lifetime("'__a")
-            .build_ty(ty.clone()),
-        builder.id("serialize_struct_elt"),
        fields,
        impl_generics,
        false,
+        cx.ident_of("serialize_struct_elt"),
    );

    let type_name = name_expr(builder, item_attrs.name());

-    quote_expr!(cx, {
-        $visitor_struct
-        $visitor_impl
-        _serializer.serialize_struct($type_name, Visitor {
-            value: self,
-            state: 0,
-            _structure_ty: ::std::marker::PhantomData::<&$ty>,
-        })
-    })
+    let mut serialized_fields = fields.iter()
+        .filter(|&field| !field.attrs.skip_serializing())
+        .peekable();
+
+    let let_mut = mut_if(cx, serialized_fields.peek().is_some());
+
+    let len = serialized_fields
+        .map(|field| {
+            let ident = field.ident.expect("struct has unnamed fields");
+            let field_expr = quote_expr!(cx, &self.$ident);
+
+            match field.attrs.skip_serializing_if() {
+                Some(path) => quote_expr!(cx, if $path($field_expr) { 0 } else { 1 }),
+                None => quote_expr!(cx, 1),
+            }
+         })
+        .fold(quote_expr!(cx, 0), |sum, expr| quote_expr!(cx, $sum + $expr));
+
+    quote_block!(cx, {
+        let $let_mut state = try!(_serializer.serialize_struct($type_name, $len));
+        $serialize_fields
+        _serializer.serialize_struct_end(state)
+    }).unwrap()
 }

 fn serialize_item_enum(
@@ -285,7 +289,7 @@ fn serialize_item_enum(
    ty: P<ast::Ty>,
    variants: &[Variant],
    item_attrs: &attr::Item,
-) -> P<ast::Expr> {
+) -> P<ast::Block> {
    let arms: Vec<_> =
        variants.iter()
            .enumerate()
@@ -303,11 +307,11 @@ fn serialize_item_enum(
            })
            .collect();

-    quote_expr!(cx,
+    quote_block!(cx, {
        match *self {
            $arms
        }
-    )
+    }).unwrap()
 }

 fn serialize_variant(
@@ -328,18 +332,17 @@ fn serialize_variant(
    match variant.style {
        Style::Unit => {
            quote_arm!(cx,
-                $type_ident::$variant_ident => {
+                $type_ident::$variant_ident =>
                    _serde::ser::Serializer::serialize_unit_variant(
                        _serializer,
                        $type_name,
                        $variant_index,
                        $variant_name,
-                    )
-                }
+                    ),
            )
        },
        Style::Newtype => {
-            let expr = serialize_newtype_variant(
+            let block = serialize_newtype_variant(
                cx,
                builder,
                type_name,
@@ -351,7 +354,7 @@ fn serialize_variant(
            );

            quote_arm!(cx,
-                $type_ident::$variant_ident(ref __simple_value) => { $expr }
+                $type_ident::$variant_ident(ref __simple_value) => $block
            )
        },
        Style::Tuple => {
@@ -367,7 +370,7 @@ fn serialize_variant(
                )
                .build();

-            let expr = serialize_tuple_variant(
+            let block = serialize_tuple_variant(
                cx,
                builder,
                type_name,
@@ -376,37 +379,28 @@ fn serialize_variant(
                generics,
                ty,
                &variant.fields,
-                field_names,
            );

            quote_arm!(cx,
-                $pat => { $expr }
+                $pat => $block
            )
        }
        Style::Struct => {
-            let field_names: Vec<_> = (0 .. variant.fields.len())
-                .map(|i| builder.id(format!("__field{}", i)))
-                .collect();
+            let mut pat = builder.pat().struct_().id(type_ident).id(variant_ident).build();
+            for field in &variant.fields {
+                let name = match field.ident {
+                    Some(name) => name,
+                    None => cx.span_bug(field.span, "struct variant has unnamed fields"),
+                };
+                pat = pat.with_field_pat(ast::FieldPat {
+                    ident: name,
+                    pat: builder.pat().ref_id(name),
+                    is_shorthand: true,
+                });
+            }
+            let pat = pat.build();

-            let pat = builder.pat().struct_()
-                .id(type_ident).id(variant_ident).build()
-                .with_pats(
-                    field_names.iter()
-                        .zip(variant.fields.iter())
-                        .map(|(id, field)| {
-                            let name = match field.ident {
-                                Some(name) => name,
-                                None => {
-                                    cx.span_bug(field.span, "struct variant has unnamed fields")
-                                }
-                            };
-
-                            (name, builder.pat().ref_id(id))
-                        })
-                )
-                .build();
-
-            let expr = serialize_struct_variant(
+            let block = serialize_struct_variant(
                cx,
                builder,
                variant_index,
@@ -414,12 +408,11 @@ fn serialize_variant(
                generics,
                ty,
                &variant.fields,
-                field_names,
                item_attrs,
            );

            quote_arm!(cx,
-                $pat => { $expr }
+                $pat => $block
            )
        }
    }
@@ -434,14 +427,14 @@ fn serialize_newtype_variant(
    item_ty: P<ast::Ty>,
    generics: &ast::Generics,
    field: &Field,
-) -> P<ast::Expr> {
+) -> P<ast::Block> {
    let mut field_expr = quote_expr!(cx, __simple_value);
    if let Some(path) = field.attrs.serialize_with() {
        field_expr = wrap_serialize_with(cx, builder,
            &item_ty, generics, &field.ty, path, field_expr);
    }

-    quote_expr!(cx,
+    quote_block!(cx, {
        _serde::ser::Serializer::serialize_newtype_variant(
            _serializer,
            $type_name,
@@ -449,7 +442,7 @@ fn serialize_newtype_variant(
            $variant_name,
            $field_expr,
        )
-    )
+    }).unwrap()
 }

 fn serialize_tuple_variant(
@@ -461,47 +454,25 @@ fn serialize_tuple_variant(
    generics: &ast::Generics,
    structure_ty: P<ast::Ty>,
    fields: &[Field],
-    field_names: Vec<Ident>,
-) -> P<ast::Expr> {
-    let variant_ty = builder.ty().tuple()
-        .with_tys(
-            fields.iter().map(|field| {
-                builder.ty()
-                    .ref_()
-                    .lifetime("'__a")
-                    .build_ty(field.ty.clone())
-            })
-        )
-        .build();
-
-    let (visitor_struct, visitor_impl) = serialize_tuple_struct_visitor(
+) -> P<ast::Block> {
+    let serialize_stmts = serialize_tuple_struct_visitor(
        cx,
        builder,
-        structure_ty.clone(),
-        variant_ty,
-        builder.id("serialize_tuple_variant_elt"),
+        structure_ty,
        fields,
        generics,
        true,
+        cx.ident_of("serialize_tuple_variant_elt"),
    );

-    let value_expr = builder.expr().tuple()
-        .with_exprs(
-            field_names.iter().map(|field| {
-                builder.expr().id(field)
-            })
-        )
-        .build();
+    let len = serialize_stmts.len();
+    let let_mut = mut_if(cx, len > 0);

-    quote_expr!(cx, {
-        $visitor_struct
-        $visitor_impl
-        _serializer.serialize_tuple_variant($type_name, $variant_index, $variant_name, Visitor {
-            value: $value_expr,
-            state: 0,
-            _structure_ty: ::std::marker::PhantomData::<&$structure_ty>,
-        })
-    })
+    quote_block!(cx, {
+        let $let_mut state = try!(_serializer.serialize_tuple_variant($type_name, $variant_index, $variant_name, $len));
+        $serialize_stmts
+        _serializer.serialize_tuple_variant_end(state)
+    }).unwrap()
 }

 fn serialize_struct_variant(
@@ -512,271 +483,128 @@ fn serialize_struct_variant(
    generics: &ast::Generics,
    ty: P<ast::Ty>,
    fields: &[Field],
-    field_names: Vec<Ident>,
    item_attrs: &attr::Item,
-) -> P<ast::Expr> {
-    let variant_generics = builder.generics()
-        .with(generics.clone())
-        .add_lifetime_bound("'__serde_variant")
-        .lifetime_name("'__serde_variant")
-        .build();
+) -> P<ast::Block> {

-    let variant_struct = builder.item().struct_("__VariantStruct")
-        .with_generics(variant_generics.clone())
-        .with_fields(
-            fields.iter().map(|field| {
-                builder.struct_field(field.ident.expect("struct has unnamed fields"))
-                    .ty()
-                    .ref_()
-                    .lifetime("'__serde_variant")
-                    .build_ty(field.ty.clone())
-            })
-        )
-        .field("__serde_container_ty")
-            .ty().phantom_data().build(ty.clone())
-        .build();
-
-    let variant_expr = builder.expr().struct_id("__VariantStruct")
-        .with_id_exprs(
-            fields.iter()
-                .zip(field_names.iter())
-                .map(|(field, field_name)| {
-                    (
-                        field.ident.expect("struct has unnamed fields"),
-                        builder.expr().id(field_name),
-                    )
-                })
-        )
-        .field("__serde_container_ty").path()
-            .global()
-            .id("std").id("marker")
-            .segment("PhantomData")
-                .with_ty(ty.clone())
-                .build()
-            .build()
-        .build();
-
-    let variant_ty = builder.ty().path()
-        .segment("__VariantStruct")
-            .with_generics(variant_generics.clone())
-            .build()
-        .build();
-
-    let (visitor_struct, visitor_impl) = serialize_struct_visitor(
+    let serialize_fields = serialize_struct_visitor(
        cx,
        builder,
-        variant_ty.clone(),
-        variant_ty.clone(),
-        builder.id("serialize_struct_variant_elt"),
+        ty.clone(),
        fields,
-        &variant_generics,
+        &generics,
        true,
+        cx.ident_of("serialize_struct_variant_elt"),
    );

    let item_name = name_expr(builder, item_attrs.name());

-    quote_expr!(cx, {
-        $variant_struct
-        $visitor_struct
-        $visitor_impl
-        _serializer.serialize_struct_variant(
+    let mut serialized_fields = fields.iter()
+        .filter(|&field| !field.attrs.skip_serializing())
+        .peekable();
+
+    let let_mut = mut_if(cx, serialized_fields.peek().is_some());
+
+    let len = serialized_fields
+        .map(|field| {
+            let ident = field.ident.expect("struct has unnamed fields");
+            let field_expr = quote_expr!(cx, $ident);
+
+            match field.attrs.skip_serializing_if() {
+                Some(path) => quote_expr!(cx, if $path($field_expr) { 0 } else { 1 }),
+                None => quote_expr!(cx, 1),
+            }
+         })
+        .fold(quote_expr!(cx, 0), |sum, expr| quote_expr!(cx, $sum + $expr));
+
+    quote_block!(cx, {
+        let $let_mut state = try!(_serializer.serialize_struct_variant(
            $item_name,
            $variant_index,
            $variant_name,
-            Visitor {
-                value: $variant_expr,
-                state: 0,
-                _structure_ty: ::std::marker::PhantomData,
-            },
-        )
-    })
+            $len,
+        ));
+        $serialize_fields
+        _serializer.serialize_struct_variant_end(state)
+    }).unwrap()
 }

 fn serialize_tuple_struct_visitor(
    cx: &ExtCtxt,
    builder: &aster::AstBuilder,
    structure_ty: P<ast::Ty>,
-    variant_ty: P<ast::Ty>,
-    serializer_method: ast::Ident,
    fields: &[Field],
    generics: &ast::Generics,
    is_enum: bool,
-) -> (P<ast::Item>, P<ast::Item>) {
-    let arms: Vec<_> = fields.iter()
+    func: ast::Ident,
+) -> Vec<ast::Stmt> {
+    fields.iter()
        .enumerate()
        .map(|(i, field)| {
-            let mut field_expr = builder.expr().tup_field(i).field("value").self_();
-            if !is_enum {
-                field_expr = quote_expr!(cx, &$field_expr);
-            }
+            let mut field_expr = if is_enum {
+                builder.expr().path().id(format!("__field{}", i)).build()
+            } else {
+                builder.expr().ref_().tup_field(i).self_()
+            };

-            let continue_if_skip = field.attrs.skip_serializing_if()
-                .map(|path| quote_stmt!(cx, if $path($field_expr) { continue }));
+            let skip = field.attrs.skip_serializing_if()
+                .map(|path| quote_expr!(cx, $path($field_expr)));

            if let Some(path) = field.attrs.serialize_with() {
                field_expr = wrap_serialize_with(cx, builder,
                    &structure_ty, generics, &field.ty, path, field_expr);
            }

-            quote_arm!(cx,
-                $i => {
-                    self.state += 1;
-                    $continue_if_skip
-                    Ok(Some(try!(_serializer.$serializer_method($field_expr))))
-                }
-            )
+            let ser = quote_expr!(cx,
+                try!(_serializer.$func(&mut state, $field_expr));
+            );
+
+            match skip {
+                None => quote_stmt!(cx, $ser).unwrap(),
+                Some(skip) => quote_stmt!(cx, if !$skip { $ser }).unwrap(),
+            }
        })
-        .collect();
-
-    let visitor_impl_generics = builder.from_generics(generics.clone())
-        .add_lifetime_bound("'__a")
-        .lifetime_name("'__a")
-        .build();
-
-    let where_clause = &visitor_impl_generics.where_clause;
-
-    let visitor_generics = builder.from_generics(visitor_impl_generics.clone())
-        .strip_bounds()
-        .build();
-
-    let nfields = fields.len();
-
-    (
-        quote_item!(cx,
-            struct Visitor $visitor_impl_generics $where_clause {
-                state: usize,
-                value: $variant_ty,
-                _structure_ty: ::std::marker::PhantomData<&'__a $structure_ty>,
-            }
-        ).unwrap(),
-
-        quote_item!(cx,
-            impl $visitor_impl_generics _serde::ser::SeqVisitor
-            for Visitor $visitor_generics
-            $where_clause {
-                #[inline]
-                fn visit<__S>(&mut self, _serializer: &mut __S) -> ::std::result::Result<Option<()>, __S::Error>
-                    where __S: _serde::ser::Serializer
-                {
-                    match self.state {
-                        $arms
-                        _ => Ok(None)
-                    }
-                }
-
-                #[inline]
-                fn len(&self) -> Option<usize> {
-                    Some($nfields)
-                }
-            }
-        ).unwrap(),
-    )
+        .collect()
 }

 fn serialize_struct_visitor(
    cx: &ExtCtxt,
    builder: &aster::AstBuilder,
    structure_ty: P<ast::Ty>,
-    variant_ty: P<ast::Ty>,
-    serializer_method: ast::Ident,
    fields: &[Field],
    generics: &ast::Generics,
    is_enum: bool,
-) -> (P<ast::Item>, P<ast::Item>) {
-    let arms: Vec<ast::Arm> = fields.iter()
+    func: ast::Ident,
+) -> Vec<ast::Stmt> {
+    fields.iter()
        .filter(|&field| !field.attrs.skip_serializing())
-        .enumerate()
-        .map(|(i, field)| {
+        .map(|field| {
            let ident = field.ident.expect("struct has unnamed field");
-            let mut field_expr = quote_expr!(cx, self.value.$ident);
-            if !is_enum {
-                field_expr = quote_expr!(cx, &$field_expr);
-            }
+            let mut field_expr = if is_enum {
+                quote_expr!(cx, $ident)
+            } else {
+                quote_expr!(cx, &self.$ident)
+            };

            let key_expr = name_expr(builder, field.attrs.name());

-            let continue_if_skip = field.attrs.skip_serializing_if()
-                .map(|path| quote_stmt!(cx, if $path($field_expr) { continue }));
+            let skip = field.attrs.skip_serializing_if()
+                .map(|path| quote_expr!(cx, $path($field_expr)));

            if let Some(path) = field.attrs.serialize_with() {
                field_expr = wrap_serialize_with(cx, builder,
                    &structure_ty, generics, &field.ty, path, field_expr)
            }

-            let expr = quote_expr!(cx,
-                _serializer.$serializer_method($key_expr, $field_expr)
+            let ser = quote_expr!(cx,
+                try!(_serializer.$func(&mut state, $key_expr, $field_expr));
            );

-            quote_arm!(cx,
-                $i => {
-                    self.state += 1;
-                    $continue_if_skip
-                    return Ok(Some(try!($expr)));
-                }
-            )
-        })
-        .collect();
-
-    let visitor_impl_generics = builder.from_generics(generics.clone())
-        .add_lifetime_bound("'__a")
-        .lifetime_name("'__a")
-        .build();
-
-    let where_clause = &visitor_impl_generics.where_clause;
-
-    let visitor_generics = builder.from_generics(visitor_impl_generics.clone())
-        .strip_bounds()
-        .build();
-
-    let len = fields.iter()
-        .filter(|&field| !field.attrs.skip_serializing())
-        .map(|field| {
-            let ident = field.ident.expect("struct has unnamed fields");
-            let mut field_expr = quote_expr!(cx, self.value.$ident);
-            if !is_enum {
-                field_expr = quote_expr!(cx, &$field_expr);
-            }
-
-            match field.attrs.skip_serializing_if() {
-                Some(path) => quote_expr!(cx, if $path($field_expr) { 0 } else { 1 }),
-                None => quote_expr!(cx, 1),
+            match skip {
+                None => quote_stmt!(cx, $ser).unwrap(),
+                Some(skip) => quote_stmt!(cx, if !$skip { $ser }).unwrap(),
            }
        })
-        .fold(quote_expr!(cx, 0), |sum, expr| quote_expr!(cx, $sum + $expr));
-
-    (
-        quote_item!(cx,
-            struct Visitor $visitor_impl_generics $where_clause {
-                state: usize,
-                value: $variant_ty,
-                _structure_ty: ::std::marker::PhantomData<&'__a $structure_ty>,
-            }
-        ).unwrap(),
-
-        quote_item!(cx,
-            impl $visitor_impl_generics
-            _serde::ser::MapVisitor
-            for Visitor $visitor_generics
-            $where_clause {
-                #[inline]
-                fn visit<__S>(&mut self, _serializer: &mut __S) -> ::std::result::Result<Option<()>, __S::Error>
-                    where __S: _serde::ser::Serializer,
-                {
-                    loop {
-                        match self.state {
-                            $arms
-                            _ => { return Ok(None); }
-                        }
-                    }
-                }
-
-                #[inline]
-                fn len(&self) -> Option<usize> {
-                    Some($len)
-                }
-            }
-        ).unwrap(),
-    )
+        .collect()
 }

 fn wrap_serialize_with(
@@ -808,7 +636,7 @@ fn wrap_serialize_with(
        }

        impl $wrapper_generics _serde::ser::Serialize for $wrapper_ty $where_clause {
-            fn serialize<__S>(&self, __s: &mut __S) -> Result<(), __S::Error>
+            fn serialize<__S>(&self, __s: &mut __S) -> ::std::result::Result<(), __S::Error>
                where __S: _serde::ser::Serializer
            {
                $path(self.value, __s)
@@ -828,3 +656,17 @@ fn name_expr(
 ) -> P<ast::Expr> {
    builder.expr().str(name.serialize_name())
 }
+
+// Serialization of an empty struct results in code like:
+//
+//     let mut state = try!(serializer.serialize_struct("S", 0));
+//     serializer.serialize_struct_end(state)
+//
+// where we want to omit the `mut` to avoid a warning.
+fn mut_if(cx: &ExtCtxt, is_mut: bool) -> Vec<TokenTree> {
+    if is_mut {
+        quote_tokens!(cx, mut)
+    } else {
+        Vec::new()
+    }
+}
@@ -0,0 +1,43 @@
+use syntax::ast;
+use syntax::codemap::{self, ExpnId, Span};
+use syntax::ext::base::{Annotatable, ExtCtxt};
+use syntax::fold::{self, Folder};
+use syntax::parse::token::intern;
+use syntax::ptr::P;
+
+pub fn record_expansion(
+    cx: &ExtCtxt,
+    item: P<ast::Item>,
+    derive: &str,
+) -> Annotatable {
+    let info = codemap::ExpnInfo {
+        call_site: codemap::DUMMY_SP,
+        callee: codemap::NameAndSpan {
+            format: codemap::MacroAttribute(intern(&format!("derive({})", derive))),
+            span: None,
+            allow_internal_unstable: false,
+        },
+    };
+    let expn_id = cx.codemap().record_expansion(info);
+
+    let mut respanner = Respanner { expn_id: expn_id };
+    let item = item.map(|item| respanner.fold_item_simple(item));
+    Annotatable::Item(item)
+}
+
+struct Respanner {
+    expn_id: ExpnId,
+}
+
+impl Folder for Respanner {
+    fn new_span(&mut self, span: Span) -> Span {
+        Span {
+            expn_id: self.expn_id,
+            .. span
+        }
+    }
+
+    fn fold_mac(&mut self, mac: ast::Mac) -> ast::Mac {
+        fold::noop_fold_mac(mac, self)
+    }
+}
@@ -1,20 +1,21 @@
 [package]
 name = "serde_codegen_internals"
-version = "0.2.0"
+version = "0.8.0"
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>"]
 license = "MIT/Apache-2.0"
 description = "AST representation used by Serde codegen. Unstable."
+homepage = "https://serde.rs"
 repository = "https://github.com/serde-rs/serde"
-documentation = "https://github.com/serde-rs/serde"
+documentation = "https://docs.serde.rs/serde_codegen_internals/"
 keywords = ["serde", "serialization"]
 include = ["Cargo.toml", "src/**/*.rs"]

 [features]
 default = ["with-syntex"]
-nightly-testing = ["clippy"]
+unstable-testing = ["clippy"]
 with-syntex = ["syntex_syntax", "syntex_errors"]

 [dependencies]
 clippy = { version = "^0.*", optional = true }
-syntex_syntax = { version = "^0.37.0", optional = true }
-syntex_errors = { version = "^0.37.0", optional = true }
+syntex_syntax = { version = "^0.43.0", optional = true }
+syntex_errors = { version = "^0.43.0", optional = true }
@@ -1,3 +1,5 @@
+use std::rc::Rc;
+
 use syntax::ast;
 use syntax::attr::{self, HasAttrs};
 use syntax::codemap::{Span, Spanned, respan};
@@ -6,8 +8,7 @@ use syntax::fold::Folder;
 use syntax::parse::parser::{Parser, PathStyle};
 use syntax::parse::token::{self, InternedString};
 use syntax::parse;
-use syntax::print::pprust::{lit_to_string, meta_item_to_string};
-use syntax::ptr::P;
+use syntax::print::pprust::{lit_to_string, meta_item_to_string, meta_list_item_to_string};
 use syntax::tokenstream::{self, TokenTree};

 // This module handles parsing of `#[serde(...)]` attributes. The entrypoints
@@ -163,7 +164,7 @@ impl Item {
                        cx.span_err(
                            meta_item.span,
                            &format!("unknown serde container attribute `{}`",
-                                     meta_item_to_string(meta_item)));
+                                     meta_item_to_string(&meta_item)));
                    }
                }
            }
@@ -234,7 +235,7 @@ impl Variant {
                        cx.span_err(
                            meta_item.span,
                            &format!("unknown serde variant attribute `{}`",
-                                     meta_item_to_string(meta_item)));
+                                     meta_item_to_string(&meta_item)));
                    }
                }
            }
@@ -382,7 +383,7 @@ impl Field {
                        cx.span_err(
                            meta_item.span,
                            &format!("unknown serde field attribute `{}`",
-                                     meta_item_to_string(meta_item)));
+                                     meta_item_to_string(&meta_item)));
                    }
                }
            }
@@ -447,12 +448,14 @@ impl Field {
    }
 }

+type SerAndDe<T> = (Option<Spanned<T>>, Option<Spanned<T>>);
+
 fn get_ser_and_de<T, F>(
    cx: &ExtCtxt,
    attribute: &'static str,
-    items: &[P<ast::MetaItem>],
+    items: &[ast::NestedMetaItem],
    f: F
-) -> Result<(Option<Spanned<T>>, Option<Spanned<T>>), ()>
+) -> Result<SerAndDe<T>, ()>
    where F: Fn(&ExtCtxt, &str, &ast::Lit) -> Result<T, ()>,
 {
    let mut ser_item = Attr::none(cx, attribute);
@@ -460,15 +463,29 @@ fn get_ser_and_de<T, F>(

    for item in items {
        match item.node {
-            ast::MetaItemKind::NameValue(ref name, ref lit) if name == &"serialize" => {
-                if let Ok(v) = f(cx, name, lit) {
-                    ser_item.set(item.span, v);
-                }
-            }
+            ast::NestedMetaItemKind::MetaItem(ref meta_item) => {
+                match meta_item.node {
+                    ast::MetaItemKind::NameValue(ref name, ref lit) if name == &"serialize" => {
+                        if let Ok(v) = f(cx, name, lit) {
+                            ser_item.set(item.span, v);
+                        }
+                    }

-            ast::MetaItemKind::NameValue(ref name, ref lit) if name == &"deserialize" => {
-                if let Ok(v) = f(cx, name, lit) {
-                    de_item.set(item.span, v);
+                    ast::MetaItemKind::NameValue(ref name, ref lit) if name == &"deserialize" => {
+                        if let Ok(v) = f(cx, name, lit) {
+                            de_item.set(item.span, v);
+                        }
+                    }
+
+                    _ => {
+                        cx.span_err(
+                            item.span,
+                            &format!("unknown {} attribute `{}`",
+                                    attribute,
+                                    meta_item_to_string(meta_item)));
+
+                        return Err(());
+                    }
                }
            }

@@ -477,7 +494,7 @@ fn get_ser_and_de<T, F>(
                    item.span,
                    &format!("unknown {} attribute `{}`",
                             attribute,
-                             meta_item_to_string(item)));
+                             meta_list_item_to_string(item)));

                return Err(());
            }
@@ -489,23 +506,30 @@ fn get_ser_and_de<T, F>(

 fn get_renames(
    cx: &ExtCtxt,
-    items: &[P<ast::MetaItem>],
-) -> Result<(Option<Spanned<InternedString>>, Option<Spanned<InternedString>>), ()> {
+    items: &[ast::NestedMetaItem],
+) -> Result<SerAndDe<InternedString>, ()> {
    get_ser_and_de(cx, "rename", items, get_str_from_lit)
 }

 fn get_where_predicates(
    cx: &ExtCtxt,
-    items: &[P<ast::MetaItem>],
-) -> Result<(Option<Spanned<Vec<ast::WherePredicate>>>, Option<Spanned<Vec<ast::WherePredicate>>>), ()> {
+    items: &[ast::NestedMetaItem],
+) -> Result<SerAndDe<Vec<ast::WherePredicate>>, ()> {
    get_ser_and_de(cx, "bound", items, parse_lit_into_where)
 }

-pub fn get_serde_meta_items(attr: &ast::Attribute) -> Option<&[P<ast::MetaItem>]> {
+pub fn get_serde_meta_items(attr: &ast::Attribute) -> Option<Vec<ast::MetaItem>> {
    match attr.node.value.node {
        ast::MetaItemKind::List(ref name, ref items) if name == &"serde" => {
-            attr::mark_used(&attr);
-            Some(items)
+            attr::mark_used(attr);
+            Some(items.iter().filter_map(|item| {
+                match item.node {
+                    ast::NestedMetaItemKind::MetaItem(ref meta_item) => {
+                        Some((*meta_item.clone()).clone())
+                    }
+                    _ => None,
+                }
+            }).collect())
        }
        _ => None
    }
@@ -517,33 +541,33 @@ struct Respanner<'a, 'b: 'a> {
 }

 impl<'a, 'b> Folder for Respanner<'a, 'b> {
-    fn fold_tt(&mut self, tt: TokenTree) -> TokenTree {
-        match tt {
+    fn fold_tt(&mut self, tt: &TokenTree) -> TokenTree {
+        match *tt {
            TokenTree::Token(span, ref tok) => {
                TokenTree::Token(
                    self.new_span(span),
                    self.fold_token(tok.clone())
                )
            }
-            TokenTree::Delimited(span, delimed) => {
+            TokenTree::Delimited(span, ref delimed) => {
                TokenTree::Delimited(
                    self.new_span(span),
-                    tokenstream::Delimited {
+                    Rc::new(tokenstream::Delimited {
                        delim: delimed.delim,
                        open_span: delimed.open_span,
-                        tts: self.fold_tts(delimed.tts),
+                        tts: self.fold_tts(&delimed.tts),
                        close_span: delimed.close_span,
-                    }
+                    })
                )
            }
-            TokenTree::Sequence(span, seq) => {
+            TokenTree::Sequence(span, ref seq) => {
                TokenTree::Sequence(
                    self.new_span(span),
-                    tokenstream::SequenceRepetition {
-                        tts: self.fold_tts(seq.tts),
+                    Rc::new(tokenstream::SequenceRepetition {
+                        tts: self.fold_tts(&seq.tts),
                        separator: seq.separator.clone().map(|tok| self.fold_token(tok)),
-                        ..seq
-                    }
+                        ..**seq
+                    })
                )
            }
        }
@@ -568,7 +592,7 @@ fn get_str_from_lit(cx: &ExtCtxt, name: &str, lit: &ast::Lit) -> Result<Interned
                         name,
                         lit_to_string(lit)));

-            return Err(());
+            Err(())
        }
    }
 }
@@ -589,7 +613,7 @@ fn parse_string_via_tts<T, F>(cx: &ExtCtxt, name: &str, string: String, action:
        cx.parse_sess()));

    // Respan the spans to say they are all coming from this macro.
-    let tts = Respanner { cx: cx }.fold_tts(tts);
+    let tts = Respanner { cx: cx }.fold_tts(&tts);

    let mut parser = parse::new_parser_from_tts(cx.parse_sess(), cx.cfg(), tts);

@@ -1,5 +1,5 @@
-#![cfg_attr(feature = "nightly-testing", plugin(clippy))]
-#![cfg_attr(feature = "nightly-testing", feature(plugin))]
+#![cfg_attr(feature = "clippy", plugin(clippy))]
+#![cfg_attr(feature = "clippy", feature(plugin))]
 #![cfg_attr(not(feature = "with-syntex"), feature(rustc_private, plugin))]

 #[cfg(feature = "with-syntex")]
@@ -0,0 +1,23 @@
+[package]
+name = "serde_derive"
+version = "0.8.8"
+authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>"]
+license = "MIT/Apache-2.0"
+description = "Macros 1.1 implementation of #[derive(Serialize, Deserialize)]"
+homepage = "https://serde.rs"
+repository = "https://github.com/serde-rs/serde"
+documentation = "https://serde.rs/codegen.html"
+keywords = ["serde", "serialization"]
+include = ["Cargo.toml", "src/**/*.rs"]
+
+[lib]
+name = "serde_derive"
+rustc-macro = true
+
+[dependencies]
+serde_codegen = { version = "=0.8.8", path = "../serde_codegen" }
+
+[dev-dependencies]
+fnv = "1.0"
+serde = { version = "0.8.8", path = "../serde" }
+serde_test = { version = "0.8.8", path = "../serde_test" }
@@ -0,0 +1,21 @@
+#![feature(rustc_macro, rustc_macro_lib)]
+#![cfg(not(test))]
+
+extern crate rustc_macro;
+extern crate serde_codegen;
+
+use rustc_macro::TokenStream;
+
+#[rustc_macro_derive(Serialize)]
+pub fn derive_serialize(input: TokenStream) -> TokenStream {
+    let item = format!("#[derive(Serialize)]\n{}", input);
+    let expanded = serde_codegen::expand_str(&item).unwrap();
+    expanded.parse().unwrap()
+}
+
+#[rustc_macro_derive(Deserialize)]
+pub fn derive_deserialize(input: TokenStream) -> TokenStream {
+    let item = format!("#[derive(Deserialize)]\n{}", input);
+    let expanded = serde_codegen::expand_str(&item).unwrap();
+    expanded.parse().unwrap()
+}
@@ -0,0 +1,8 @@
+#![feature(test, rustc_macro, rustc_attrs)]
+
+#[macro_use]
+extern crate serde_derive;
+
+extern crate test;
+
+include!("../../testing/tests/test.rs.in");
@@ -0,0 +1,2 @@
+# To prevent compiletest from seeing two versions of serde
+paths = ["../serde"]
@@ -1,11 +1,12 @@
 [package]
 name = "serde_macros"
-version = "0.7.12"
+version = "0.8.8"
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>"]
 license = "MIT/Apache-2.0"
 description = "Macros to auto-generate implementations for the serde framework"
+homepage = "https://serde.rs"
 repository = "https://github.com/serde-rs/serde"
-documentation = "https://github.com/serde-rs/serde"
+documentation = "https://serde.rs/codegen.html"
 keywords = ["serde", "serialization"]
 include = ["Cargo.toml", "src/**/*.rs"]

@@ -14,18 +15,22 @@ name = "serde_macros"
 plugin = true

 [features]
-nightly-testing = ["clippy", "serde/nightly-testing", "serde_codegen/nightly-testing"]
+unstable-testing = [
+    "clippy",
+    "serde/unstable-testing",
+    "serde_codegen/unstable-testing"
+]

 [dependencies]
 clippy = { version = "^0.*", optional = true }
-serde_codegen = { version = "^0.7.12", path = "../serde_codegen", default-features = false, features = ["nightly"] }
+serde_codegen = { version = "=0.8.8", default-features = false, features = ["unstable"], path = "../serde_codegen" }

 [dev-dependencies]
 compiletest_rs = "^0.2.0"
 fnv = "1.0"
 rustc-serialize = "^0.3.16"
-serde = { version = "^0.7.12", path = "../serde" }
-serde_test = { version = "^0.7.12", path = "../serde_test" }
+serde = { version = "0.8.8", path = "../serde" }
+serde_test = { version = "0.8.8", path = "../serde_test" }

 [[test]]
 name = "test"
@@ -20,6 +20,11 @@ fn run_mode(mode: &'static str) {
 }

 #[test]
-fn compile_test() {
+fn compile_fail() {
    run_mode("compile-fail");
 }
+
+#[test]
+fn run_pass() {
+    run_mode("run-pass");
+}
@@ -0,0 +1,12 @@
+#![feature(custom_derive, plugin)]
+#![plugin(serde_macros, clippy)]
+
+#![deny(identity_op)]
+
+// The derived implementation uses 0+1 to add up the number of fields
+// serialized, which Clippy warns about. If the expansion info is registered
+// correctly, the Clippy lint is not triggered.
+#[derive(Serialize)]
+struct A { b: u8 }
+
+fn main() {}
@@ -1,7 +1,6 @@
 #![feature(test, custom_attribute, custom_derive, plugin)]
 #![plugin(serde_macros)]

-extern crate serde;
 extern crate test;

 include!("../../testing/tests/test.rs.in");
@@ -1,14 +1,15 @@
 [package]
 name = "serde_test"
-version = "0.7.12"
+version = "0.8.8"
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>"]
 license = "MIT/Apache-2.0"
 description = "Token De/Serializer for testing De/Serialize implementations"
+homepage = "https://serde.rs"
 repository = "https://github.com/serde-rs/serde"
-documentation = "https://serde-rs.github.io/serde/serde/"
+documentation = "https://docs.serde.rs/serde_test/"
 readme = "../README.md"
 keywords = ["serde", "serialization"]
 include = ["Cargo.toml", "src/**/*.rs"]

 [dependencies]
-serde = { version = "0.7.12", path = "../serde" }
+serde = { version = "0.8.8", path = "../serde" }
@@ -110,6 +110,95 @@ impl<I> de::Deserializer for Deserializer<I>
 {
    type Error = Error;

+    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_bytes<__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<V>(&mut self, mut visitor: V) -> Result<V::Value, Error>
        where V: Visitor,
    {
@@ -135,15 +224,18 @@ impl<I> de::Deserializer for Deserializer<I>
            Some(Token::Option(true)) => visitor.visit_some(self),
            Some(Token::Unit) => visitor.visit_unit(),
            Some(Token::UnitStruct(name)) => visitor.visit_unit_struct(name),
-            Some(Token::SeqStart(len)) | Some(Token::TupleStructStart(_, len)) => {
+            Some(Token::SeqStart(len)) => {
                self.visit_seq(len, visitor)
            }
-            Some(Token::SeqArrayStart(len)) => {
+            Some(Token::SeqArrayStart(len))| Some(Token::TupleStructStart(_, len)) => {
                self.visit_seq(Some(len), visitor)
            }
-            Some(Token::MapStart(len)) | Some(Token::StructStart(_, len)) => {
+            Some(Token::MapStart(len)) => {
                self.visit_map(len, visitor)
            }
+            Some(Token::StructStart(_, len)) => {
+                self.visit_map(Some(len), visitor)
+            }
            Some(token) => Err(Error::UnexpectedToken(token)),
            None => Err(Error::EndOfStream),
        }
@@ -238,7 +330,7 @@ impl<I> de::Deserializer for Deserializer<I>
        }
    }

-    fn deserialize_fixed_size_array<V>(&mut self,
+    fn deserialize_seq_fixed_size<V>(&mut self,
                                       len: usize,
                                       visitor: V) -> Result<V::Value, Error>
        where V: Visitor,
@@ -745,7 +837,7 @@ impl<'a, I> VariantVisitor for DeserializerVariantVisitor<'a, I>
        where V: Visitor,
    {
        match self.de.tokens.peek() {
-            Some(&Token::EnumSeqStart(_, _, Some(enum_len))) => {
+            Some(&Token::EnumSeqStart(_, _, enum_len)) => {
                let token = self.de.tokens.next().unwrap();

                if len == enum_len {
@@ -776,7 +868,7 @@ impl<'a, I> VariantVisitor for DeserializerVariantVisitor<'a, I>
        where V: Visitor,
    {
        match self.de.tokens.peek() {
-            Some(&Token::EnumMapStart(_, _, Some(enum_len))) => {
+            Some(&Token::EnumMapStart(_, _, enum_len)) => {
                let token = self.de.tokens.next().unwrap();

                if fields.len() == enum_len {
@@ -2,8 +2,6 @@ use std::marker::PhantomData;

 use serde::ser::{
    self,
-    MapVisitor,
-    SeqVisitor,
    Serialize,
 };

@@ -30,32 +28,19 @@ impl<'a, I> Serializer<'a, I>
    pub fn next_token(&mut self) -> Option<&'a Token<'a>> {
        self.tokens.next()
    }
-
-    fn visit_seq<V>(&mut self, mut visitor: V) -> Result<(), Error>
-        where V: SeqVisitor
-    {
-        while let Some(()) = try!(visitor.visit(self)) { }
-
-        assert_eq!(self.tokens.next(), Some(&Token::SeqEnd));
-
-        Ok(())
-    }
-
-    fn visit_map<V>(&mut self, mut visitor: V) -> Result<(), Error>
-        where V: MapVisitor
-    {
-        while let Some(()) = try!(visitor.visit(self)) { }
-
-        assert_eq!(self.tokens.next(), Some(&Token::MapEnd));
-
-        Ok(())
-    }
 }

 impl<'a, I> ser::Serializer for Serializer<'a, I>
    where I: Iterator<Item=&'a Token<'a>>,
 {
    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));
@@ -174,177 +159,165 @@ impl<'a, I> ser::Serializer for Serializer<'a, I>
        value.serialize(self)
    }

-
-    fn serialize_seq<V>(&mut self, visitor: V) -> Result<(), Error>
-        where V: SeqVisitor
+    fn serialize_seq<'b>(&'b mut self, len: Option<usize>) -> Result<(), Error>
    {
-        let len = visitor.len();
-
        assert_eq!(self.tokens.next(), Some(&Token::SeqStart(len)));
-
-        self.visit_seq(visitor)
+        Ok(())
    }

-    fn serialize_fixed_size_array<V>(&mut self, visitor: V) -> Result<(), Error>
-        where V: SeqVisitor
-    {
-        let len = visitor.len().expect("arrays must have a length");
-
-        assert_eq!(self.tokens.next(), Some(&Token::SeqArrayStart(len)));
-
-        self.visit_seq(visitor)
-    }
-
-    fn serialize_seq_elt<T>(&mut self, value: T) -> Result<(), Error>
+    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_tuple<V>(&mut self, mut visitor: V) -> Result<(), Error>
-        where V: SeqVisitor
-    {
-        let len = visitor.len().expect("arrays must have a length");
-
-        assert_eq!(self.tokens.next(), Some(&Token::TupleStart(len)));
-
-        while let Some(()) = try!(visitor.visit(self)) { }
-
-        assert_eq!(self.tokens.next(), Some(&Token::TupleEnd));
-
+    fn serialize_seq_end(&mut self, _: ()) -> Result<(), Error> {
+        assert_eq!(self.tokens.next(), Some(&Token::SeqEnd));
        Ok(())
    }

-    fn serialize_tuple_elt<T>(&mut self, value: T) -> Result<(), Error>
+    fn serialize_seq_fixed_size(&mut self, len: usize) -> Result<(), Error>
+    {
+        assert_eq!(self.tokens.next(), Some(&Token::SeqArrayStart(len)));
+        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,
-                               name: &'static str,
-                               value: T) -> Result<(), Error>
+                                   name: &'static str,
+                                   value: T) -> Result<(), Error>
        where T: Serialize,
    {
        assert_eq!(self.tokens.next(), Some(&Token::StructNewType(name)));
        value.serialize(self)
    }

-    fn serialize_tuple_struct<V>(&mut self, name: &str, mut visitor: V) -> Result<(), Error>
-        where V: SeqVisitor
+    fn serialize_tuple_struct(&mut self, name: &'static str, len: usize) -> Result<(), Error>
    {
-        let len = visitor.len();
-
        assert_eq!(self.tokens.next(), Some(&Token::TupleStructStart(name, len)));

-        while let Some(()) = try!(visitor.visit(self)) { }
-
-        assert_eq!(self.tokens.next(), Some(&Token::TupleStructEnd));
-
        Ok(())
    }

-    fn serialize_tuple_struct_elt<T>(&mut self, value: T) -> Result<(), Error>
-        where T: Serialize,
+    fn serialize_tuple_struct_elt<T>(&mut self, _: &mut (), value: T) -> Result<(), Error>
+        where T: Serialize
    {
        assert_eq!(self.tokens.next(), Some(&Token::TupleStructSep));
        value.serialize(self)
    }

-    fn serialize_tuple_variant<V>(&mut self,
-                                  name: &str,
-                                  _variant_index: usize,
-                                  variant: &str,
-                                  mut visitor: V) -> Result<(), Error>
-        where V: SeqVisitor
+    fn serialize_tuple_struct_end(&mut self, _: ()) -> Result<(), Error> {
+        assert_eq!(self.tokens.next(), Some(&Token::TupleStructEnd));
+        Ok(())
+    }
+
+    fn serialize_tuple_variant(&mut self,
+                               name: &str,
+                               _variant_index: usize,
+                               variant: &str,
+                               len: usize) -> Result<(), Error>
    {
-        let len = visitor.len();
-
        assert_eq!(self.tokens.next(), Some(&Token::EnumSeqStart(name, variant, len)));

-        while let Some(()) = try!(visitor.visit(self)) { }
-
-        assert_eq!(self.tokens.next(), Some(&Token::EnumSeqEnd));
-
        Ok(())
    }

-    fn serialize_tuple_variant_elt<T>(&mut self, value: T) -> Result<(), Error>
-        where T: Serialize,
+    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_map<V>(&mut self, visitor: V) -> Result<(), Error>
-        where V: MapVisitor
-    {
-        let len = visitor.len();
+    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>
+    {
        assert_eq!(self.tokens.next(), Some(&Token::MapStart(len)));

-        self.visit_map(visitor)
+        Ok(())
    }

-    fn serialize_map_elt<K, V>(&mut self, key: K, value: V) -> Result<(), Error>
-        where K: Serialize,
-              V: Serialize,
-    {
+    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)
+    }

-        try!(key.serialize(self));
+    fn serialize_map_value<T>(&mut self, _: &mut (), value: T) -> Result<(), Self::Error> where T: Serialize {
        value.serialize(self)
    }

-    fn serialize_struct<V>(&mut self, name: &str, mut visitor: V) -> Result<(), Error>
-        where V: MapVisitor
-    {
-        let len = visitor.len();
+    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>
+    {
        assert_eq!(self.tokens.next(), Some(&Token::StructStart(name, len)));

-        while let Some(()) = try!(visitor.visit(self)) { }
-
-        assert_eq!(self.tokens.next(), Some(&Token::StructEnd));
-
        Ok(())
    }

-    fn serialize_struct_elt<T>(&mut self, key: &'static str, value: T) -> Result<(), Error>
-        where T: Serialize,
-    {
+    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_variant<V>(&mut self,
-                                   name: &str,
-                                   _variant_index: usize,
-                                   variant: &str,
-                                   mut visitor: V) -> Result<(), Error>
-        where V: MapVisitor
-    {
-        let len = visitor.len();
+    fn serialize_struct_end(&mut self, _: ()) -> Result<(), Self::Error> {
+        assert_eq!(self.tokens.next(), Some(&Token::StructEnd));
+        Ok(())
+    }

+    fn serialize_struct_variant(&mut self,
+                                name: &str,
+                                _variant_index: usize,
+                                variant: &str,
+                                len: usize) -> Result<(), Error>
+    {
        assert_eq!(self.tokens.next(), Some(&Token::EnumMapStart(name, variant, len)));

-        while let Some(()) = try!(visitor.visit(self)) { }
-
-        assert_eq!(self.tokens.next(), Some(&Token::EnumMapEnd));
-
        Ok(())
    }

-    fn serialize_struct_variant_elt<T>(&mut self, key: &'static str, value: T) -> Result<(), Error>
-        where T: Serialize,
-    {
+    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)
    }
+
+    fn serialize_struct_variant_end(&mut 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)
+    }
 }
@@ -38,7 +38,7 @@ pub enum Token<'a> {
    TupleSep,
    TupleEnd,

-    TupleStructStart(&'a str, Option<usize>),
+    TupleStructStart(&'a str, usize),
    TupleStructSep,
    TupleStructEnd,

@@ -46,15 +46,15 @@ pub enum Token<'a> {
    MapSep,
    MapEnd,

-    StructStart(&'a str, Option<usize>),
+    StructStart(&'a str, usize),
    StructSep,
    StructEnd,

-    EnumSeqStart(&'a str, &'a str, Option<usize>),
+    EnumSeqStart(&'a str, &'a str, usize),
    EnumSeqSep,
    EnumSeqEnd,

-    EnumMapStart(&'a str, &'a str, Option<usize>),
+    EnumMapStart(&'a str, &'a str, usize),
    EnumMapSep,
    EnumMapEnd,
 }
@@ -1,26 +1,27 @@
 [package]
 name = "serde_testing"
-version = "0.7.12"
+version = "0.8.8"
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>"]
 license = "MIT/Apache-2.0"
 description = "A generic serialization/deserialization framework"
+homepage = "https://serde.rs"
 repository = "https://github.com/serde-rs/serde"
-documentation = "http://serde-rs.github.io/serde/serde"
+documentation = "https://docs.serde.rs/serde/"
 readme = "README.md"
 keywords = ["serialization"]
 build = "build.rs"

 [features]
-nightly-testing = ["clippy", "serde/nightly-testing", "serde_codegen/nightly-testing"]
+unstable-testing = ["clippy", "serde/unstable-testing", "serde_codegen/unstable-testing"]

 [build-dependencies]
-serde_codegen = { version = "*", path = "../serde_codegen", features = ["with-syntex"] }
+serde_codegen = { path = "../serde_codegen", features = ["with-syntex"] }

 [dev-dependencies]
 fnv = "1.0"
 rustc-serialize = "^0.3.16"
-serde = { version = "*", path = "../serde" }
-serde_test = { version = "*", path = "../serde_test" }
+serde = { path = "../serde" }
+serde_test = { path = "../serde_test" }

 [dependencies]
 clippy = { version = "^0.*", optional = true }
@@ -1,6 +1,6 @@
 #![feature(test)]
-#![cfg_attr(feature = "nightly", feature(plugin))]
-#![cfg_attr(feature = "nightly", plugin(clippy))]
+#![cfg_attr(feature = "clippy", feature(plugin))]
+#![cfg_attr(feature = "clippy", plugin(clippy))]

 extern crate rustc_serialize;
 extern crate serde;
@@ -1,4 +1,4 @@
-#![cfg_attr(feature = "nightly", feature(plugin))]
-#![cfg_attr(feature = "nightly", plugin(clippy))]
+#![cfg_attr(feature = "clippy", feature(plugin))]
+#![cfg_attr(feature = "clippy", plugin(clippy))]

 include!(concat!(env!("OUT_DIR"), "/test.rs"));
@@ -1,3 +1,5 @@
+extern crate serde;
+
 #[macro_use]
 mod macros;

@@ -82,7 +82,7 @@ fn test_default_struct() {
    assert_de_tokens(
        &DefaultStruct { a1: 1, a2: 2, a3: 3, a4: 0, a5: 123 },
        &[
-            Token::StructStart("DefaultStruct", Some(3)),
+            Token::StructStart("DefaultStruct", 3),

            Token::StructSep,
            Token::Str("a1"),
@@ -111,7 +111,7 @@ fn test_default_struct() {
    assert_de_tokens(
        &DefaultStruct { a1: 1, a2: 0, a3: 123, a4: 0, a5: 123 },
        &[
-            Token::StructStart("DefaultStruct", Some(1)),
+            Token::StructStart("DefaultStruct", 1),

            Token::StructSep,
            Token::Str("a1"),
@@ -145,7 +145,7 @@ fn test_default_enum() {
    assert_de_tokens(
        &DefaultEnum::Struct { a1: 1, a2: 2, a3: 3, a4: 0, a5: 123 },
        &[
-            Token::EnumMapStart("DefaultEnum", "Struct", Some(5)),
+            Token::EnumMapStart("DefaultEnum", "Struct", 5),

            Token::EnumMapSep,
            Token::Str("a1"),
@@ -174,7 +174,7 @@ fn test_default_enum() {
    assert_de_tokens(
        &DefaultEnum::Struct { a1: 1, a2: 0, a3: 123, a4: 0, a5: 123 },
        &[
-            Token::EnumMapStart("DefaultEnum", "Struct", Some(5)),
+            Token::EnumMapStart("DefaultEnum", "Struct", 5),

            Token::EnumMapSep,
            Token::Str("a1"),
@@ -208,7 +208,7 @@ fn test_no_std_default() {
    assert_de_tokens(
        &ContainsNoStdDefault { a: NoStdDefault(123) },
        &[
-            Token::StructStart("ContainsNoStdDefault", Some(1)),
+            Token::StructStart("ContainsNoStdDefault", 1),
            Token::StructEnd,
        ]
    );
@@ -216,7 +216,7 @@ fn test_no_std_default() {
    assert_de_tokens(
        &ContainsNoStdDefault { a: NoStdDefault(8) },
        &[
-            Token::StructStart("ContainsNoStdDefault", Some(1)),
+            Token::StructStart("ContainsNoStdDefault", 1),

            Token::StructSep,
            Token::Str("a"),
@@ -281,7 +281,7 @@ fn test_elt_not_deserialize() {
            e: NotDeserializeEnum::Trouble,
        },
        &[
-            Token::StructStart("ContainsNotDeserialize", Some(3)),
+            Token::StructStart("ContainsNotDeserialize", 3),
            Token::StructEnd,
        ]
    );
@@ -299,7 +299,7 @@ fn test_ignore_unknown() {
    assert_de_tokens(
        &DefaultStruct { a1: 1, a2: 2, a3: 3, a4: 0, a5: 123 },
        &[
-            Token::StructStart("DefaultStruct", Some(5)),
+            Token::StructStart("DefaultStruct", 5),

            Token::StructSep,
            Token::Str("whoops1"),
@@ -334,7 +334,7 @@ fn test_ignore_unknown() {

    assert_de_tokens_error::<DenyUnknown>(
        &[
-            Token::StructStart("DenyUnknown", Some(2)),
+            Token::StructStart("DenyUnknown", 2),

            Token::StructSep,
            Token::Str("a1"),
@@ -368,7 +368,7 @@ fn test_rename_struct() {
    assert_tokens(
        &RenameStruct { a1: 1, a2: 2 },
        &[
-            Token::StructStart("Superhero", Some(2)),
+            Token::StructStart("Superhero", 2),

            Token::StructSep,
            Token::Str("a1"),
@@ -385,7 +385,7 @@ fn test_rename_struct() {
    assert_ser_tokens(
        &RenameStructSerializeDeserialize { a1: 1, a2: 2 },
        &[
-            Token::StructStart("SuperheroSer", Some(2)),
+            Token::StructStart("SuperheroSer", 2),

            Token::StructSep,
            Token::Str("a1"),
@@ -402,7 +402,7 @@ fn test_rename_struct() {
    assert_de_tokens(
        &RenameStructSerializeDeserialize { a1: 1, a2: 2 },
        &[
-            Token::StructStart("SuperheroDe", Some(2)),
+            Token::StructStart("SuperheroDe", 2),

            Token::StructSep,
            Token::Str("a1"),
@@ -465,7 +465,7 @@ fn test_rename_enum() {
    assert_tokens(
        &RenameEnum::WonderWoman(0, 1),
        &[
-            Token::EnumSeqStart("Superhero", "diana_prince", Some(2)),
+            Token::EnumSeqStart("Superhero", "diana_prince", 2),

            Token::EnumSeqSep,
            Token::I8(0),
@@ -480,7 +480,7 @@ fn test_rename_enum() {
    assert_tokens(
        &RenameEnum::Flash { a: 1 },
        &[
-            Token::EnumMapStart("Superhero", "barry_allan", Some(1)),
+            Token::EnumMapStart("Superhero", "barry_allan", 1),

            Token::EnumMapSep,
            Token::Str("b"),
@@ -496,7 +496,7 @@ fn test_rename_enum() {
            b: String::new(),
        },
        &[
-            Token::EnumMapStart("SuperheroSer", "dick_grayson", Some(2)),
+            Token::EnumMapStart("SuperheroSer", "dick_grayson", 2),

            Token::EnumMapSep,
            Token::Str("a"),
@@ -516,7 +516,7 @@ fn test_rename_enum() {
            b: String::new(),
        },
        &[
-            Token::EnumMapStart("SuperheroDe", "jason_todd", Some(2)),
+            Token::EnumMapStart("SuperheroDe", "jason_todd", 2),

            Token::EnumMapSep,
            Token::Str("a"),
@@ -550,7 +550,7 @@ fn test_skip_serializing_struct() {
            c: 3,
        },
        &[
-            Token::StructStart("SkipSerializingStruct", Some(2)),
+            Token::StructStart("SkipSerializingStruct", 2),

            Token::StructSep,
            Token::Str("a"),
@@ -571,7 +571,7 @@ fn test_skip_serializing_struct() {
            c: 123,
        },
        &[
-            Token::StructStart("SkipSerializingStruct", Some(1)),
+            Token::StructStart("SkipSerializingStruct", 1),

            Token::StructSep,
            Token::Str("a"),
@@ -603,7 +603,7 @@ fn test_skip_serializing_enum() {
            c: 3,
        },
        &[
-            Token::EnumMapStart("SkipSerializingEnum", "Struct", Some(2)),
+            Token::EnumMapStart("SkipSerializingEnum", "Struct", 2),

            Token::EnumMapSep,
            Token::Str("a"),
@@ -624,7 +624,7 @@ fn test_skip_serializing_enum() {
            c: 123,
        },
        &[
-            Token::EnumMapStart("SkipSerializingEnum", "Struct", Some(1)),
+            Token::EnumMapStart("SkipSerializingEnum", "Struct", 1),

            Token::EnumMapSep,
            Token::Str("a"),
@@ -671,7 +671,7 @@ fn test_elt_not_serialize() {
            d: NotSerializeEnum::Trouble,
        },
        &[
-            Token::StructStart("ContainsNotSerialize", Some(2)),
+            Token::StructStart("ContainsNotSerialize", 2),

            Token::StructSep,
            Token::Str("a"),
@@ -703,7 +703,7 @@ fn test_serialize_with_struct() {
            b: 2,
        },
        &[
-            Token::StructStart("SerializeWithStruct", Some(2)),
+            Token::StructStart("SerializeWithStruct", 2),

            Token::StructSep,
            Token::Str("a"),
@@ -723,7 +723,7 @@ fn test_serialize_with_struct() {
            b: 123,
        },
        &[
-            Token::StructStart("SerializeWithStruct", Some(2)),
+            Token::StructStart("SerializeWithStruct", 2),

            Token::StructSep,
            Token::Str("a"),
@@ -756,7 +756,7 @@ fn test_serialize_with_enum() {
            b: 2,
        },
        &[
-            Token::EnumMapStart("SerializeWithEnum", "Struct", Some(2)),
+            Token::EnumMapStart("SerializeWithEnum", "Struct", 2),

            Token::EnumMapSep,
            Token::Str("a"),
@@ -776,7 +776,7 @@ fn test_serialize_with_enum() {
            b: 123,
        },
        &[
-            Token::EnumMapStart("SerializeWithEnum", "Struct", Some(2)),
+            Token::EnumMapStart("SerializeWithEnum", "Struct", 2),

            Token::EnumMapSep,
            Token::Str("a"),
@@ -806,7 +806,7 @@ fn test_deserialize_with_struct() {
            b: 2,
        },
        &[
-            Token::StructStart("DeserializeWithStruct", Some(2)),
+            Token::StructStart("DeserializeWithStruct", 2),

            Token::StructSep,
            Token::Str("a"),
@@ -826,7 +826,7 @@ fn test_deserialize_with_struct() {
            b: 123,
        },
        &[
-            Token::StructStart("DeserializeWithStruct", Some(2)),
+            Token::StructStart("DeserializeWithStruct", 2),

            Token::StructSep,
            Token::Str("a"),
@@ -858,7 +858,7 @@ fn test_deserialize_with_enum() {
            b: 2,
        },
        &[
-            Token::EnumMapStart("DeserializeWithEnum", "Struct", Some(2)),
+            Token::EnumMapStart("DeserializeWithEnum", "Struct", 2),

            Token::EnumMapSep,
            Token::Str("a"),
@@ -878,7 +878,7 @@ fn test_deserialize_with_enum() {
            b: 123,
        },
        &[
-            Token::EnumMapStart("DeserializeWithEnum", "Struct", Some(2)),
+            Token::EnumMapStart("DeserializeWithEnum", "Struct", 2),

            Token::EnumMapSep,
            Token::Str("a"),
@@ -897,7 +897,7 @@ fn test_deserialize_with_enum() {
 fn test_missing_renamed_field_struct() {
    assert_de_tokens_error::<RenameStruct>(
        &[
-            Token::StructStart("Superhero", Some(2)),
+            Token::StructStart("Superhero", 2),

            Token::StructSep,
            Token::Str("a1"),
@@ -910,7 +910,7 @@ fn test_missing_renamed_field_struct() {

    assert_de_tokens_error::<RenameStructSerializeDeserialize>(
        &[
-            Token::StructStart("SuperheroDe", Some(2)),
+            Token::StructStart("SuperheroDe", 2),

            Token::StructSep,
            Token::Str("a1"),
@@ -926,7 +926,7 @@ fn test_missing_renamed_field_struct() {
 fn test_missing_renamed_field_enum() {
    assert_de_tokens_error::<RenameEnum>(
        &[
-            Token::EnumMapStart("Superhero", "barry_allan", Some(1)),
+            Token::EnumMapStart("Superhero", "barry_allan", 1),

            Token::EnumMapEnd,
        ],
@@ -935,7 +935,7 @@ fn test_missing_renamed_field_enum() {

    assert_de_tokens_error::<RenameEnumSerializeDeserialize<i8>>(
        &[
-            Token::EnumMapStart("SuperheroDe", "jason_todd", Some(2)),
+            Token::EnumMapStart("SuperheroDe", "jason_todd", 2),

            Token::EnumMapSep,
            Token::Str("a"),
@@ -946,3 +946,31 @@ fn test_missing_renamed_field_enum() {
        Error::MissingField("d"),
    );
 }
+
+#[derive(Debug, PartialEq, Deserialize)]
+enum InvalidLengthEnum {
+    A(i32, i32, i32),
+    B(#[serde(skip_deserializing)] i32, i32, i32),
+}
+
+#[test]
+fn test_invalid_length_enum() {
+    assert_de_tokens_error::<InvalidLengthEnum>(
+        &[
+            Token::EnumSeqStart("InvalidLengthEnum", "A", 3),
+                Token::EnumSeqSep,
+                Token::I32(1),
+            Token::EnumSeqEnd,
+        ],
+        Error::InvalidLength(1),
+    );
+    assert_de_tokens_error::<InvalidLengthEnum>(
+        &[
+            Token::EnumSeqStart("InvalidLengthEnum", "B", 3),
+                Token::EnumSeqSep,
+                Token::I32(1),
+            Token::EnumSeqEnd,
+        ],
+        Error::InvalidLength(1),
+    );
+}
@@ -1,20 +1,21 @@
 use std::fmt;
 use std::error;

-extern crate serde;
-use self::serde::Serialize;
-use self::serde::bytes::{ByteBuf, Bytes};
+use serde::{Serialize, Serializer, Deserialize, Deserializer};
+use serde::bytes::{ByteBuf, Bytes};
+use serde::ser;
+use serde::de;

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

 #[derive(Debug, PartialEq)]
 struct Error;

-impl serde::ser::Error for Error {
+impl ser::Error for Error {
    fn custom<T: Into<String>>(_: T) -> Error { Error }
 }

-impl serde::de::Error for Error {
+impl de::Error for Error {
    fn custom<T: Into<String>>(_: T) -> Error { Error }

    fn end_of_stream() -> Error { Error }
@@ -50,17 +51,64 @@ impl BytesSerializer {
    }
 }

-impl serde::Serializer for BytesSerializer {
+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)
    }
@@ -90,32 +138,142 @@ impl serde::Serializer for BytesSerializer {
    }

    fn serialize_some<V>(&mut self, _value: V) -> Result<(), Error>
-        where V: serde::Serialize,
+        where V: Serialize,
    {
        Err(Error)
    }

-    fn serialize_seq<V>(&mut self, _visitor: V) -> Result<(), Error>
-        where V: serde::ser::SeqVisitor,
+    fn serialize_newtype_struct<V>(&mut self, _: &'static str, _value: V) -> Result<(), Error>
+        where V: Serialize,
    {
        Err(Error)
    }

-    fn serialize_seq_elt<T>(&mut self, _value: T) -> Result<(), Error>
-        where T: serde::Serialize
+    fn serialize_newtype_variant<V>(&mut self, _: &'static str, _: usize, _: &'static str, _value: V) -> Result<(), Error>
+        where V: Serialize,
    {
        Err(Error)
    }

-    fn serialize_map<V>(&mut self, _visitor: V) -> Result<(), Error>
-        where V: serde::ser::MapVisitor,
+    fn serialize_seq(&mut self, _len: Option<usize>) -> Result<(), Error>
    {
        Err(Error)
    }

-    fn serialize_map_elt<K, V>(&mut self, _key: K, _value: V) -> Result<(), Error>
-        where K: serde::Serialize,
-              V: serde::Serialize,
+    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)
    }
@@ -140,20 +298,137 @@ impl BytesDeserializer {
    }
 }

-impl serde::Deserializer for BytesDeserializer {
+impl Deserializer for BytesDeserializer {
    type Error = Error;

    fn deserialize<V>(&mut self, _visitor: V) -> Result<V::Value, Error>
-        where V: serde::de::Visitor,
+        where V: de::Visitor,
    {
        Err(Error)
    }

    fn deserialize_bytes<V>(&mut self, mut visitor: V) -> Result<V::Value, Error>
-        where V: serde::de::Visitor,
+        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)
+    }
 }

 ///////////////////////////////////////////////////////////////////////////////
@@ -176,10 +451,10 @@ fn test_bytes_ser_bytes() {
 #[test]
 fn test_byte_buf_de_bytes() {
    let mut de = BytesDeserializer::new(vec![]);
-    let bytes = serde::Deserialize::deserialize(&mut de);
+    let bytes = Deserialize::deserialize(&mut de);
    assert_eq!(bytes, Ok(ByteBuf::new()));

    let mut de = BytesDeserializer::new(vec![1, 2, 3]);
-    let bytes = serde::Deserialize::deserialize(&mut de);
+    let bytes = Deserialize::deserialize(&mut de);
    assert_eq!(bytes, Ok(ByteBuf::from(vec![1, 2, 3])));
 }
@@ -1,9 +1,9 @@
 use std::collections::{BTreeMap, BTreeSet, HashMap, HashSet};
 use std::net;
 use std::path::PathBuf;
+use std::time::Duration;

-extern crate serde;
-use self::serde::Deserialize;
+use serde::Deserialize;

 extern crate fnv;
 use self::fnv::FnvHasher;
@@ -81,9 +81,9 @@ fn assert_de_tokens_ignore(ignorable_tokens: &[Token<'static>]) {
    struct IgnoreBase {
        a: i32,
    }
- 
+
    let expected = IgnoreBase{a: 1};
- 
+
    // Embed the tokens to be ignored in the normal token
    // stream for an IgnoreBase type
    let concated_tokens : Vec<Token<'static>> = vec![
@@ -91,7 +91,7 @@ fn assert_de_tokens_ignore(ignorable_tokens: &[Token<'static>]) {
                Token::MapSep,
                Token::Str("a"),
                Token::I32(1),
- 
+
                Token::MapSep,
                Token::Str("ignored")
        ]
@@ -101,17 +101,17 @@ fn assert_de_tokens_ignore(ignorable_tokens: &[Token<'static>]) {
            Token::MapEnd,
        ].into_iter())
        .collect();
- 
+
    let mut de = serde_test::Deserializer::new(concated_tokens.into_iter());
    let v: Result<IgnoreBase, Error> = Deserialize::deserialize(&mut de);
- 
+
    // We run this test on every token stream for convenience, but
    // some token streams don't make sense embedded as a map value,
    // so we ignore those. SyntaxError is the real sign of trouble.
    if let Err(Error::UnexpectedToken(_)) = v {
        return;
    }
- 
+
    assert_eq!(v.as_ref(), Ok(&expected));
    assert_eq!(de.next_token(), None);
 }
@@ -197,7 +197,7 @@ declare_tests! {
            Token::SeqEnd,
        ],
        () => &[
-            Token::TupleStructStart("Anything", Some(0)),
+            Token::TupleStructStart("Anything", 0),
            Token::SeqEnd,
        ],
    }
@@ -241,7 +241,7 @@ declare_tests! {
            Token::SeqEnd,
        ],
        TupleStruct(1, 2, 3) => &[
-            Token::TupleStructStart("TupleStruct", Some(3)),
+            Token::TupleStructStart("TupleStruct", 3),
                Token::TupleStructSep,
                Token::I32(1),

@@ -253,7 +253,7 @@ declare_tests! {
            Token::TupleStructEnd,
        ],
        TupleStruct(1, 2, 3) => &[
-            Token::TupleStructStart("TupleStruct", None),
+            Token::TupleStructStart("TupleStruct", 3),
                Token::TupleStructSep,
                Token::I32(1),

@@ -299,7 +299,7 @@ declare_tests! {
            Token::UnitStruct("Anything"),
        ],
        BTreeSet::<isize>::new() => &[
-            Token::TupleStructStart("Anything", Some(0)),
+            Token::TupleStructStart("Anything", 0),
            Token::SeqEnd,
        ],
    }
@@ -327,7 +327,7 @@ declare_tests! {
            Token::UnitStruct("Anything"),
        ],
        HashSet::<isize>::new() => &[
-            Token::TupleStructStart("Anything", Some(0)),
+            Token::TupleStructStart("Anything", 0),
            Token::SeqEnd,
        ],
        hashset![FnvHasher @ 1, 2, 3] => &[
@@ -377,7 +377,7 @@ declare_tests! {
            Token::UnitStruct("Anything"),
        ],
        Vec::<isize>::new() => &[
-            Token::TupleStructStart("Anything", Some(0)),
+            Token::TupleStructStart("Anything", 0),
            Token::SeqEnd,
        ],
    }
@@ -441,7 +441,7 @@ declare_tests! {
            Token::UnitStruct("Anything"),
        ],
        [0; 0] => &[
-            Token::TupleStructStart("Anything", Some(0)),
+            Token::TupleStructStart("Anything", 0),
            Token::SeqEnd,
        ],
    }
@@ -533,7 +533,7 @@ declare_tests! {
            Token::UnitStruct("Anything"),
        ],
        BTreeMap::<isize, isize>::new() => &[
-            Token::StructStart("Anything", Some(0)),
+            Token::StructStart("Anything", 0),
            Token::MapEnd,
        ],
    }
@@ -587,7 +587,7 @@ declare_tests! {
            Token::UnitStruct("Anything"),
        ],
        HashMap::<isize, isize>::new() => &[
-            Token::StructStart("Anything", Some(0)),
+            Token::StructStart("Anything", 0),
            Token::MapEnd,
        ],
        hashmap![FnvHasher @ 1 => 2, 3 => 4] => &[
@@ -615,7 +615,7 @@ declare_tests! {
            Token::MapEnd,
        ],
        Struct { a: 1, b: 2, c: 0 } => &[
-            Token::StructStart("Struct", Some(3)),
+            Token::StructStart("Struct", 3),
                Token::StructSep,
                Token::Str("a"),
                Token::I32(1),
@@ -656,7 +656,7 @@ declare_tests! {
            Token::MapEnd,
        ],
        Struct { a: 1, b: 2, c: 0 } => &[
-            Token::StructStart("Struct", Some(3)),
+            Token::StructStart("Struct", 3),
                Token::StructSep,
                Token::Str("a"),
                Token::I32(1),
@@ -688,7 +688,7 @@ declare_tests! {
    }
    test_enum_seq {
        Enum::Seq(1, 2, 3) => &[
-            Token::EnumSeqStart("Enum", "Seq", Some(3)),
+            Token::EnumSeqStart("Enum", "Seq", 3),
                Token::EnumSeqSep,
                Token::I32(1),

@@ -702,7 +702,7 @@ declare_tests! {
    }
    test_enum_map {
        Enum::Map { a: 1, b: 2, c: 3 } => &[
-            Token::EnumMapStart("Enum", "Map", Some(3)),
+            Token::EnumMapStart("Enum", "Map", 3),
                Token::EnumMapSep,
                Token::Str("a"),
                Token::I32(1),
@@ -746,6 +746,28 @@ declare_tests! {
            Token::SeqEnd,
        ],
    }
+    test_duration {
+        Duration::new(1, 2) => &[
+            Token::StructStart("Duration", 2),
+                Token::StructSep,
+                Token::Str("secs"),
+                Token::U64(1),
+
+                Token::StructSep,
+                Token::Str("nanos"),
+                Token::U32(2),
+            Token::StructEnd,
+        ],
+        Duration::new(1, 2) => &[
+            Token::SeqStart(Some(2)),
+                Token::SeqSep,
+                Token::I64(1),
+
+                Token::SeqSep,
+                Token::I64(2),
+            Token::SeqEnd,
+        ],
+    }
    test_net_ipv4addr {
        "1.2.3.4".parse::<net::Ipv4Addr>().unwrap() => &[Token::Str("1.2.3.4")],
    }
@@ -764,7 +786,7 @@ declare_tests! {
    }
 }

-#[cfg(feature = "nightly")]
+#[cfg(feature = "unstable")]
 #[test]
 fn test_net_ipaddr() {
    assert_de_tokens(
@@ -803,7 +825,7 @@ declare_error_tests! {
    }
    test_duplicate_field_enum<Enum> {
        &[
-            Token::EnumMapStart("Enum", "Map", Some(3)),
+            Token::EnumMapStart("Enum", "Map", 3),
                Token::EnumMapSep,
                Token::Str("a"),
                Token::I32(1),
@@ -6,129 +6,236 @@ extern crate serde;
 use self::serde::ser::{Serialize, Serializer};
 use self::serde::de::{Deserialize, Deserializer};

+use std::borrow::Cow;
+use std::marker::PhantomData;
+
+// Try to trip up the generated code if it fails to use fully qualified paths.
+#[allow(dead_code)]
+struct Result;
+use std::result::Result as StdResult;
+
 //////////////////////////////////////////////////////////////////////////

-#[derive(Serialize, Deserialize)]
-struct With<T> {
-    t: T,
-    #[serde(serialize_with="ser_x", deserialize_with="de_x")]
-    x: X,
-}
-
-#[derive(Serialize, Deserialize)]
-struct WithRef<'a, T: 'a> {
-    #[serde(skip_deserializing)]
-    t: Option<&'a T>,
-    #[serde(serialize_with="ser_x", deserialize_with="de_x")]
-    x: X,
-}
-
-#[derive(Serialize, Deserialize)]
-struct Bounds<T: Serialize + Deserialize> {
-    t: T,
-    option: Option<T>,
-    boxed: Box<T>,
-    option_boxed: Option<Box<T>>,
-}
-
-#[derive(Serialize, Deserialize)]
-struct NoBounds<T> {
-    t: T,
-    option: Option<T>,
-    boxed: Box<T>,
-    option_boxed: Option<Box<T>>,
-}
-
-#[derive(Serialize, Deserialize)]
-enum EnumWith<T> {
-    Unit,
-    Newtype(
-        #[serde(serialize_with="ser_x", deserialize_with="de_x")]
-        X),
-    Tuple(
-        T,
-        #[serde(serialize_with="ser_x", deserialize_with="de_x")]
-        X),
-    Struct {
+#[test]
+fn test_gen() {
+    #[derive(Serialize, Deserialize)]
+    struct With<T> {
        t: T,
        #[serde(serialize_with="ser_x", deserialize_with="de_x")]
-        x: X },
-}
+        x: X,
+    }
+    assert::<With<i32>>();

-#[derive(Serialize)]
-struct MultipleRef<'a, 'b, 'c, T> where T: 'c, 'c: 'b, 'b: 'a {
-    t: T,
-    rrrt: &'a &'b &'c T,
-}
+    #[derive(Serialize, Deserialize)]
+    struct WithRef<'a, T: 'a> {
+        #[serde(skip_deserializing)]
+        t: Option<&'a T>,
+        #[serde(serialize_with="ser_x", deserialize_with="de_x")]
+        x: X,
+    }
+    assert::<WithRef<i32>>();

-#[derive(Serialize, Deserialize)]
-struct Newtype(
-    #[serde(serialize_with="ser_x", deserialize_with="de_x")]
-    X
-);
+    #[derive(Serialize, Deserialize)]
+    struct PhantomX {
+        x: PhantomData<X>,
+    }
+    assert::<PhantomX>();

-#[derive(Serialize, Deserialize)]
-struct Tuple<T>(
-    T,
-    #[serde(serialize_with="ser_x", deserialize_with="de_x")]
-    X,
-);
+    #[derive(Serialize, Deserialize)]
+    struct PhantomT<T> {
+        t: PhantomData<T>,
+    }
+    assert::<PhantomT<X>>();

-#[derive(Serialize, Deserialize)]
-enum TreeNode<D> {
-    Split {
-        left: Box<TreeNode<D>>,
-        right: Box<TreeNode<D>>,
-    },
-    Leaf {
+    #[derive(Serialize, Deserialize)]
+    struct Bounds<T: Serialize + Deserialize> {
+        t: T,
+        option: Option<T>,
+        boxed: Box<T>,
+        option_boxed: Option<Box<T>>,
+    }
+    assert::<Bounds<i32>>();
+
+    #[derive(Serialize, Deserialize)]
+    struct NoBounds<T> {
+        t: T,
+        option: Option<T>,
+        boxed: Box<T>,
+        option_boxed: Option<Box<T>>,
+    }
+    assert::<NoBounds<i32>>();
+
+    #[derive(Serialize, Deserialize)]
+    enum EnumWith<T> {
+        Unit,
+        Newtype(
+            #[serde(serialize_with="ser_x", deserialize_with="de_x")]
+            X),
+        Tuple(
+            T,
+            #[serde(serialize_with="ser_x", deserialize_with="de_x")]
+            X),
+        Struct {
+            t: T,
+            #[serde(serialize_with="ser_x", deserialize_with="de_x")]
+            x: X },
+    }
+    assert::<EnumWith<i32>>();
+
+    #[derive(Serialize)]
+    struct MultipleRef<'a, 'b, 'c, T> where T: 'c, 'c: 'b, 'b: 'a {
+        t: T,
+        rrrt: &'a &'b &'c T,
+    }
+    assert_ser::<MultipleRef<i32>>();
+
+    #[derive(Serialize, Deserialize)]
+    struct Newtype(
+        #[serde(serialize_with="ser_x", deserialize_with="de_x")]
+        X
+    );
+    assert::<Newtype>();
+
+    #[derive(Serialize, Deserialize)]
+    struct Tuple<T>(
+        T,
+        #[serde(serialize_with="ser_x", deserialize_with="de_x")]
+        X,
+    );
+    assert::<Tuple<i32>>();
+
+    #[derive(Serialize, Deserialize)]
+    enum TreeNode<D> {
+        Split {
+            left: Box<TreeNode<D>>,
+            right: Box<TreeNode<D>>,
+        },
+        Leaf {
+            data: D,
+        },
+    }
+    assert::<TreeNode<i32>>();
+
+    #[derive(Serialize, Deserialize)]
+    struct ListNode<D> {
        data: D,
-    },
-}
+        next: Box<ListNode<D>>,
+    }
+    assert::<ListNode<i32>>();

-#[derive(Serialize, Deserialize)]
-struct ListNode<D> {
-    data: D,
-    next: Box<ListNode<D>>,
-}
+    #[derive(Serialize, Deserialize)]
+    struct RecursiveA {
+        b: Box<RecursiveB>,
+    }
+    assert::<RecursiveA>();

-#[derive(Serialize, Deserialize)]
-#[serde(bound="D: SerializeWith + DeserializeWith")]
-struct WithTraits1<D, E> {
-    #[serde(serialize_with="SerializeWith::serialize_with",
-            deserialize_with="DeserializeWith::deserialize_with")]
-    d: D,
-    #[serde(serialize_with="SerializeWith::serialize_with",
-            deserialize_with="DeserializeWith::deserialize_with",
-            bound="E: SerializeWith + DeserializeWith")]
-    e: E,
-}
+    #[derive(Serialize, Deserialize)]
+    enum RecursiveB {
+        A(RecursiveA),
+    }
+    assert::<RecursiveB>();

-#[derive(Serialize, Deserialize)]
-#[serde(bound(serialize="D: SerializeWith",
-              deserialize="D: DeserializeWith"))]
-struct WithTraits2<D, E> {
-    #[serde(serialize_with="SerializeWith::serialize_with",
-            deserialize_with="DeserializeWith::deserialize_with")]
-    d: D,
-    #[serde(serialize_with="SerializeWith::serialize_with",
-            bound(serialize="E: SerializeWith"))]
-    #[serde(deserialize_with="DeserializeWith::deserialize_with",
-            bound(deserialize="E: DeserializeWith"))]
-    e: E,
+    #[derive(Serialize, Deserialize)]
+    struct RecursiveGenericA<T> {
+        t: T,
+        b: Box<RecursiveGenericB<T>>,
+    }
+    assert::<RecursiveGenericA<i32>>();
+
+    #[derive(Serialize, Deserialize)]
+    enum RecursiveGenericB<T> {
+        T(T),
+        A(RecursiveGenericA<T>),
+    }
+    assert::<RecursiveGenericB<i32>>();
+
+    #[derive(Serialize)]
+    struct OptionStatic<'a> {
+        a: Option<&'a str>,
+        b: Option<&'static str>,
+    }
+    assert_ser::<OptionStatic>();
+
+    #[derive(Serialize, Deserialize)]
+    #[serde(bound="D: SerializeWith + DeserializeWith")]
+    struct WithTraits1<D, E> {
+        #[serde(serialize_with="SerializeWith::serialize_with",
+                deserialize_with="DeserializeWith::deserialize_with")]
+        d: D,
+        #[serde(serialize_with="SerializeWith::serialize_with",
+                deserialize_with="DeserializeWith::deserialize_with",
+                bound="E: SerializeWith + DeserializeWith")]
+        e: E,
+    }
+    assert::<WithTraits1<X, X>>();
+
+    #[derive(Serialize, Deserialize)]
+    #[serde(bound(serialize="D: SerializeWith",
+                deserialize="D: DeserializeWith"))]
+    struct WithTraits2<D, E> {
+        #[serde(serialize_with="SerializeWith::serialize_with",
+                deserialize_with="DeserializeWith::deserialize_with")]
+        d: D,
+        #[serde(serialize_with="SerializeWith::serialize_with",
+                bound(serialize="E: SerializeWith"))]
+        #[serde(deserialize_with="DeserializeWith::deserialize_with",
+                bound(deserialize="E: DeserializeWith"))]
+        e: E,
+    }
+    assert::<WithTraits2<X, X>>();
+
+    #[derive(Serialize, Deserialize)]
+    struct CowStr<'a>(Cow<'a, str>);
+    assert::<CowStr>();
+
+    #[derive(Serialize, Deserialize)]
+    #[serde(bound(deserialize = "T::Owned: Deserialize"))]
+    struct CowT<'a, T: ?Sized + 'a + ToOwned>(Cow<'a, T>);
+    assert::<CowT<str>>();
+
+    #[derive(Serialize, Deserialize)]
+    struct EmptyStruct {}
+    assert::<EmptyStruct>();
+
+    #[derive(Serialize, Deserialize)]
+    enum EmptyEnumVariant {
+        EmptyStruct {},
+    }
+    assert::<EmptyEnumVariant>();
 }

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

+fn assert<T: Serialize + Deserialize>() {}
+fn assert_ser<T: Serialize>() {}
+
 trait SerializeWith {
-    fn serialize_with<S: Serializer>(_: &Self, _: &mut S) -> Result<(), S::Error>;
+    fn serialize_with<S: Serializer>(_: &Self, _: &mut S) -> StdResult<(), S::Error>;
 }

 trait DeserializeWith: Sized {
-    fn deserialize_with<D: Deserializer>(_: &mut D) -> Result<Self, D::Error>;
+    fn deserialize_with<D: Deserializer>(_: &mut D) -> StdResult<Self, D::Error>;
 }

 // Implements neither Serialize nor Deserialize
 struct X;
-fn ser_x<S: Serializer>(_: &X, _: &mut S) -> Result<(), S::Error> { panic!() }
-fn de_x<D: Deserializer>(_: &mut D) -> Result<X, D::Error> { panic!() }

+fn ser_x<S: Serializer>(_: &X, _: &mut S) -> StdResult<(), S::Error> {
+    unimplemented!()
+}
+
+fn de_x<D: Deserializer>(_: &mut D) -> StdResult<X, D::Error> {
+    unimplemented!()
+}
+
+impl SerializeWith for X {
+    fn serialize_with<S: Serializer>(_: &Self, _: &mut S) -> StdResult<(), S::Error> {
+        unimplemented!()
+    }
+}
+
+impl DeserializeWith for X {
+    fn deserialize_with<D: Deserializer>(_: &mut D) -> StdResult<Self, D::Error> {
+        unimplemented!()
+    }
+}
@@ -39,23 +39,19 @@ struct DeNamedMap<A, B, C> {
 }

 #[derive(Debug, PartialEq, Serialize)]
-enum SerEnum<'a, B: 'a, C: /* Trait + */ 'a, D> where D: /* Trait + */ 'a {
+enum SerEnum<'a, B: 'a, C: 'a, D> where D: 'a {
    Unit,
    Seq(
        i8,
        B,
        &'a C,
-        //C::Type,
        &'a mut D,
-        //<D as Trait>::Type,
    ),
    Map {
        a: i8,
        b: B,
        c: &'a C,
-        //d: C::Type,
-        e: &'a mut D,
-        //f: <D as Trait>::Type,
+        d: &'a mut D,
    },

    // Make sure we can support more than one variant.
@@ -64,38 +60,30 @@ enum SerEnum<'a, B: 'a, C: /* Trait + */ 'a, D> where D: /* Trait + */ 'a {
        i8,
        B,
        &'a C,
-        //C::Type,
        &'a mut D,
-        //<D as Trait>::Type,
    ),
    _Map2 {
        a: i8,
        b: B,
        c: &'a C,
-        //d: C::Type,
-        e: &'a mut D,
-        //f: <D as Trait>::Type,
+        d: &'a mut D,
    },
 }

 #[derive(Debug, PartialEq, Serialize, Deserialize)]
-enum DeEnum<B, C: /* Trait */, D> /* where D: Trait */ {
+enum DeEnum<B, C, D> {
    Unit,
    Seq(
        i8,
        B,
        C,
-        //C::Type,
        D,
-        //<D as Trait>::Type,
    ),
    Map {
        a: i8,
        b: B,
        c: C,
-        //d: C::Type,
-        e: D,
-        //f: <D as Trait>::Type,
+        d: D,
    },

    // Make sure we can support more than one variant.
@@ -104,17 +92,13 @@ enum DeEnum<B, C: /* Trait */, D> /* where D: Trait */ {
        i8,
        B,
        C,
-        //C::Type,
        D,
-        //<D as Trait>::Type,
    ),
    _Map2 {
        a: i8,
        b: B,
        c: C,
-        //d: C::Type,
-        e: D,
-        //f: <D as Trait>::Type,
+        d: D,
    },
 }

@@ -174,7 +158,7 @@ fn test_ser_named_tuple() {
    assert_ser_tokens(
        &SerNamedTuple(&a, &mut b, c),
        &[
-            Token::TupleStructStart("SerNamedTuple", Some(3)),
+            Token::TupleStructStart("SerNamedTuple", 3),
            Token::TupleStructSep,
            Token::I32(5),

@@ -211,7 +195,7 @@ fn test_de_named_tuple() {
    assert_de_tokens(
        &DeNamedTuple(5, 6, 7),
        &[
-            Token::TupleStructStart("DeNamedTuple", Some(3)),
+            Token::TupleStructStart("DeNamedTuple", 3),
            Token::TupleStructSep,
            Token::I32(5),

@@ -239,7 +223,7 @@ fn test_ser_named_map() {
            c: c,
        },
        &[
-            Token::StructStart("SerNamedMap", Some(3)),
+            Token::StructStart("SerNamedMap", 3),

            Token::StructSep,
            Token::Str("a"),
@@ -267,7 +251,7 @@ fn test_de_named_map() {
            c: 7,
        },
        &[
-            Token::StructStart("DeNamedMap", Some(3)),
+            Token::StructStart("DeNamedMap", 3),

            Token::StructSep,
            Token::Str("a"),
@@ -301,21 +285,17 @@ fn test_ser_enum_seq() {
    let a = 1;
    let b = 2;
    let c = 3;
-    //let d = 4;
-    let mut e = 5;
-    //let f = 6;
+    let mut d = 4;

    assert_ser_tokens(
        &SerEnum::Seq(
            a,
            b,
            &c,
-            //d,
-            &mut e,
-            //f,
+            &mut d,
        ),
        &[
-            Token::EnumSeqStart("SerEnum", "Seq", Some(4)),
+            Token::EnumSeqStart("SerEnum", "Seq", 4),

            Token::EnumSeqSep,
            Token::I8(1),
@@ -327,7 +307,7 @@ fn test_ser_enum_seq() {
            Token::I32(3),

            Token::EnumSeqSep,
-            Token::I32(5),
+            Token::I32(4),

            Token::EnumSeqEnd,
        ],
@@ -339,21 +319,17 @@ fn test_ser_enum_map() {
    let a = 1;
    let b = 2;
    let c = 3;
-    //let d = 4;
-    let mut e = 5;
-    //let f = 6;
+    let mut d = 4;

    assert_ser_tokens(
        &SerEnum::Map {
            a: a,
            b: b,
            c: &c,
-            //d: d,
-            e: &mut e,
-            //f: f,
+            d: &mut d,
        },
        &[
-            Token::EnumMapStart("SerEnum", "Map", Some(4)),
+            Token::EnumMapStart("SerEnum", "Map", 4),

            Token::EnumMapSep,
            Token::Str("a"),
@@ -368,8 +344,8 @@ fn test_ser_enum_map() {
            Token::I32(3),

            Token::EnumMapSep,
-            Token::Str("e"),
-            Token::I32(5),
+            Token::Str("d"),
+            Token::I32(4),

            Token::EnumMapEnd,
        ],
@@ -391,21 +367,17 @@ fn test_de_enum_seq() {
    let a = 1;
    let b = 2;
    let c = 3;
-    //let d = 4;
-    let e = 5;
-    //let f = 6;
+    let d = 4;

    assert_tokens(
        &DeEnum::Seq(
            a,
            b,
            c,
-            //d,
-            e,
-            //f,
+            d,
        ),
        &[
-            Token::EnumSeqStart("DeEnum", "Seq", Some(4)),
+            Token::EnumSeqStart("DeEnum", "Seq", 4),

            Token::EnumSeqSep,
            Token::I8(1),
@@ -417,7 +389,7 @@ fn test_de_enum_seq() {
            Token::I32(3),

            Token::EnumSeqSep,
-            Token::I32(5),
+            Token::I32(4),

            Token::EnumSeqEnd,
        ],
@@ -429,21 +401,17 @@ fn test_de_enum_map() {
    let a = 1;
    let b = 2;
    let c = 3;
-    //let d = 4;
-    let e = 5;
-    //let f = 6;
+    let d = 4;

    assert_tokens(
        &DeEnum::Map {
            a: a,
            b: b,
            c: c,
-            //d: d,
-            e: e,
-            //f: f,
+            d: d,
        },
        &[
-            Token::EnumMapStart("DeEnum", "Map", Some(4)),
+            Token::EnumMapStart("DeEnum", "Map", 4),

            Token::EnumMapSep,
            Token::Str("a"),
@@ -458,8 +426,8 @@ fn test_de_enum_map() {
            Token::I32(3),

            Token::EnumMapSep,
-            Token::Str("e"),
-            Token::I32(5),
+            Token::Str("d"),
+            Token::I32(4),

            Token::EnumMapEnd,
        ],
@@ -489,7 +457,7 @@ fn test_lifetimes() {
    assert_ser_tokens(
        &Lifetimes::LifetimeMap { a: &value },
        &[
-            Token::EnumMapStart("Lifetimes", "LifetimeMap", Some(1)),
+            Token::EnumMapStart("Lifetimes", "LifetimeMap", 1),

            Token::EnumMapSep,
            Token::Str("a"),
@@ -502,7 +470,7 @@ fn test_lifetimes() {
    assert_ser_tokens(
        &Lifetimes::NoLifetimeMap { a: 5 },
        &[
-            Token::EnumMapStart("Lifetimes", "NoLifetimeMap", Some(1)),
+            Token::EnumMapStart("Lifetimes", "NoLifetimeMap", 1),

            Token::EnumMapSep,
            Token::Str("a"),
@@ -518,7 +486,7 @@ fn test_generic_struct() {
    assert_tokens(
        &GenericStruct { x: 5u32 },
        &[
-            Token::StructStart("GenericStruct", Some(1)),
+            Token::StructStart("GenericStruct", 1),

            Token::StructSep,
            Token::Str("x"),
@@ -545,7 +513,7 @@ fn test_generic_tuple_struct() {
    assert_tokens(
        &GenericTupleStruct(5u32, 6u32),
        &[
-            Token::TupleStructStart("GenericTupleStruct", Some(2)),
+            Token::TupleStructStart("GenericTupleStruct", 2),

            Token::TupleStructSep,
            Token::U32(5),
@@ -584,7 +552,7 @@ fn test_generic_enum_seq() {
    assert_tokens(
        &GenericEnum::Seq::<u32, u32>(5, 6),
        &[
-            Token::EnumSeqStart("GenericEnum", "Seq", Some(2)),
+            Token::EnumSeqStart("GenericEnum", "Seq", 2),

            Token::EnumSeqSep,
            Token::U32(5),
@@ -602,7 +570,7 @@ fn test_generic_enum_map() {
    assert_tokens(
        &GenericEnum::Map::<u32, u32> { x: 5, y: 6 },
        &[
-            Token::EnumMapStart("GenericEnum", "Map", Some(2)),
+            Token::EnumMapStart("GenericEnum", "Map", 2),

            Token::EnumMapSep,
            Token::Str("x"),
@@ -622,7 +590,7 @@ fn test_default_ty_param() {
    assert_tokens(
        &DefaultTyParam::<i32> { phantom: PhantomData },
        &[
-            Token::StructStart("DefaultTyParam", Some(1)),
+            Token::StructStart("DefaultTyParam", 1),

            Token::StructSep,
            Token::Str("phantom"),
@@ -2,6 +2,7 @@ use std::collections::{BTreeMap, HashMap, HashSet};
 use std::net;
 use std::path::{Path, PathBuf};
 use std::str;
+use std::time::Duration;

 extern crate serde_test;
 use self::serde_test::{
@@ -256,7 +257,7 @@ declare_ser_tests! {
    }
    test_tuple_struct {
        TupleStruct(1, 2, 3) => &[
-            Token::TupleStructStart("TupleStruct", Some(3)),
+            Token::TupleStructStart("TupleStruct", 3),
                Token::TupleStructSep,
                Token::I32(1),

@@ -270,7 +271,7 @@ declare_ser_tests! {
    }
    test_struct {
        Struct { a: 1, b: 2, c: 3 } => &[
-            Token::StructStart("Struct", Some(3)),
+            Token::StructStart("Struct", 3),
                Token::StructSep,
                Token::Str("a"),
                Token::I32(1),
@@ -289,7 +290,7 @@ declare_ser_tests! {
        Enum::Unit => &[Token::EnumUnit("Enum", "Unit")],
        Enum::One(42) => &[Token::EnumNewType("Enum", "One"), Token::I32(42)],
        Enum::Seq(1, 2) => &[
-            Token::EnumSeqStart("Enum", "Seq", Some(2)),
+            Token::EnumSeqStart("Enum", "Seq", 2),
                Token::EnumSeqSep,
                Token::I32(1),

@@ -298,7 +299,7 @@ declare_ser_tests! {
            Token::EnumSeqEnd,
        ],
        Enum::Map { a: 1, b: 2 } => &[
-            Token::EnumMapStart("Enum", "Map", Some(2)),
+            Token::EnumMapStart("Enum", "Map", 2),
                Token::EnumMapSep,
                Token::Str("a"),
                Token::I32(1),
@@ -324,6 +325,19 @@ declare_ser_tests! {
            Token::SeqEnd,
        ],
    }
+    test_duration {
+        Duration::new(1, 2) => &[
+            Token::StructStart("Duration", 2),
+                Token::StructSep,
+                Token::Str("secs"),
+                Token::U64(1),
+
+                Token::StructSep,
+                Token::Str("nanos"),
+                Token::U32(2),
+            Token::StructEnd,
+        ],
+    }
    test_net_ipv4addr {
        "1.2.3.4".parse::<net::Ipv4Addr>().unwrap() => &[Token::Str("1.2.3.4")],
    }
@@ -347,7 +361,7 @@ declare_ser_tests! {
    }
 }

-#[cfg(feature = "nightly")]
+#[cfg(feature = "unstable")]
 #[test]
 fn test_net_ipaddr() {
    assert_ser_tokens(