Auto merge of #349 - oli-obk:undo, r=oli-obk

undo the breaking change introduced in 0.7.6

I should probably yank 0.7.6, too

cc @alexcrichton this should unbreak your setup, sorry about that.

.travis.yml

@@ -18,6 +18,10 @@ script:
 - (cd serde && travis-cargo build)
 - (cd serde && travis-cargo test)
 - (cd serde && travis-cargo --only nightly test -- --features nightly-testing)
+- (cd serde && travis-cargo --skip 1.5.0 build -- --no-default-features)
+- (cd serde && travis-cargo --only nightly 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 serde_tests && travis-cargo test)
 - (cd serde_tests && travis-cargo --only nightly test -- --features nightly-testing)
 - (cd serde_macros && travis-cargo --only nightly test -- --features nightly-testing)

CHANGELOG.md

@@ -0,0 +1,10 @@
+## 0.7.6
+
+NOTES:
+
+* Syncs `serde_codegen` and `serde_macros` with rustc 1.10.0-nightly (7bddce693 2016-05-27).
+
+FEATURES:
+
+* `#[serde(serialize_with=..., deserialize_with=...)]` now supports tuples. #335
+* Serde now can be used in `#[no_std]` environments. #316

README.md

@@ -705,18 +705,32 @@ Variant Annotations:
 
 Field Annotations:
 
-| Annotation                              | Function                                                                                                   |
+| Annotation                              | Function                                                                                                            |
-| ----------                              | --------                                                                                                   |
+| ----------                              | --------                                                                                                            |
-| `#[serde(rename="name")]`               | Serialize and deserialize this field with the given name                                                   |
+| `#[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(serialize="name1"))]`   | Serialize this field with the given name                                                                            |
-| `#[serde(rename(deserialize="name1"))]` | Deserialize 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)]`                     | If the value is not specified, use the `Default::default()`                                                         |
-| `#[serde(default="$path")]`             | Call the path to a function `fn() -> T` to build the value                                                 |
+| `#[serde(default="$path")]`             | Call the path to a function `fn() -> T` to build the value                                                          |
-| `#[serde(skip_serializing)]`            | Do not serialize this value                                                                                |
+| `#[serde(skip_serializing)]`            | Do not serialize this value                                                                                         |
-| `#[serde(skip_deserializing)]`          | Always use `Default::default()` or `#[serde(default="$path")]` instead of deserializing this value         |
+| `#[serde(skip_deserializing)]`          | Always use `Default::default()` or `#[serde(default="$path")]` instead of deserializing this value                  |
-| `#[serde(skip_serializing_if="$path")]` | Do not serialize this value if this function `fn(&T) -> bool` returns `true`                               |
+| `#[serde(skip_serializing_if="$path")]` | Do not serialize this value if this function `fn(&T) -> bool` returns `true`                                        |
-| `#[serde(serialize_with="$path")]`      | Call a function `fn<T, S>(&T, &mut S) -> Result<(), S::Error> where S: Serializer` to serialize this value |
+| `#[serde(serialize_with="$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="$path")]`    | Call a function `fn<T, D>(&mut D) -> Result<T, D::Error> where D: Deserializer` to deserialize this value  |
+| `#[serde(deserialize_with="$path")]`    | Call a function `fn<D>(&mut D) -> Result<T, D::Error> where D: Deserializer` to deserialize this value of type `T`  |
+
+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
 ========================

examples/serde-syntex-example/Cargo.toml

@@ -9,10 +9,10 @@ default = ["serde_codegen"]
 nightly = ["serde_macros"]
 
 [build-dependencies]
-serde_codegen = { version = "^0.6.4", optional = true }
+serde_codegen = { version = "^0.7.5", optional = true }
-syntex = "^0.22.0"
+syntex = "^0.32.0"
 
 [dependencies]
-serde = "^0.6.1"
+serde = "^0.7.5"
-serde_json = "^0.6.0"
+serde_json = "^0.7.0"
-serde_macros = { version = "^0.6.1", optional = true }
+serde_macros = { version = "^0.7.5", optional = true }

serde/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "serde"
-version = "0.7.4"
+version = "0.7.7"
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>"]
 license = "MIT/Apache-2.0"
 description = "A generic serialization/deserialization framework"
@@ -8,10 +8,16 @@ repository = "https://github.com/serde-rs/serde"
 documentation = "https://serde-rs.github.io/serde/serde/"
 readme = "../README.md"
 keywords = ["serde", "serialization"]
+include = ["Cargo.toml", "src/**/*.rs"]
 
 [features]
+default = ["std"]
+
+std = []
 nightly = []
-nightly-testing = ["clippy", "nightly"]
+alloc = ["nightly"]
+collections = ["alloc"]
+nightly-testing = ["clippy", "nightly", "std"]
 
 [dependencies]
 clippy = { version = "^0.*", optional = true }

serde/src/bytes.rs

@@ -1,11 +1,15 @@
 //! Helper module to enable serializing bytes more efficiently
 
-use std::ops;
+use core::{ops, fmt, char, iter, slice};
-use std::fmt;
+use core::fmt::Write;
-use std::ascii;
 
 use ser;
-use de;
+
+#[cfg(any(feature = "std", feature = "collections"))]
+pub use self::bytebuf::{ByteBuf, ByteBufVisitor};
+
+#[cfg(feature = "collections")]
+use collections::Vec;
 
 ///////////////////////////////////////////////////////////////////////////////
 
@@ -17,7 +21,11 @@ pub struct Bytes<'a> {
 
 impl<'a> fmt::Debug for Bytes<'a> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        write!(f, "b\"{}\"", escape_bytestring(self.bytes))
+        try!(f.write_str("b\""));
+        for c in escape_bytestring(self.bytes) {
+            try!(f.write_char(c));
+        }
+        f.write_char('"')
     }
 }
 
@@ -29,10 +37,11 @@ impl<'a> From<&'a [u8]> for Bytes<'a> {
     }
 }
 
+#[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: bytes,
         }
     }
 }
@@ -60,157 +69,172 @@ impl<'a> ser::Serialize for Bytes<'a> {
 
 ///////////////////////////////////////////////////////////////////////////////
 
-/// `ByteBuf` wraps a `Vec<u8>` and serializes as a byte array.
+#[cfg(any(feature = "std", feature = "collections"))]
-#[derive(Clone, Default, Eq, Hash, PartialEq, PartialOrd, Ord)]
+mod bytebuf {
-pub struct ByteBuf {
+    use core::ops;
-    bytes: Vec<u8>,
+    use core::fmt;
-}
+    use core::fmt::Write;
 
-impl ByteBuf {
+    use ser;
-    /// Construct a new, empty `ByteBuf`.
+    use de;
-    pub fn new() -> Self {
+
-        ByteBuf {
+    #[cfg(feature = "collections")]
-            bytes: Vec::new(),
+    use collections::Vec;
+
+    /// `ByteBuf` wraps a `Vec<u8>` and serializes as a byte array.
+    #[derive(Clone, Default, Eq, Hash, PartialEq, PartialOrd, Ord)]
+    pub struct ByteBuf {
+        bytes: Vec<u8>,
+    }
+
+    impl ByteBuf {
+        /// Construct a new, empty `ByteBuf`.
+        pub fn new() -> Self {
+            ByteBuf {
+                bytes: Vec::new(),
+            }
+        }
+
+        /// Construct a new, empty `ByteBuf` with the specified capacity.
+        pub fn with_capacity(cap: usize) -> Self {
+            ByteBuf {
+                bytes: Vec::with_capacity(cap)
+            }
         }
     }
 
-    /// Construct a new, empty `ByteBuf` with the specified capacity.
+    impl fmt::Debug for ByteBuf {
-    pub fn with_capacity(cap: usize) -> Self {
+        fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        ByteBuf {
+            try!(f.write_str("b\""));
-            bytes: Vec::with_capacity(cap)
+            for c in super::escape_bytestring(self.bytes.as_ref()) {
+                try!(f.write_char(c));
+            }
+            f.write_char('"')
         }
     }
-}
 
-impl fmt::Debug for ByteBuf {
+    impl Into<Vec<u8>> for ByteBuf {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        fn into(self) -> Vec<u8> {
-        write!(f, "b\"{}\"", escape_bytestring(self.bytes.as_ref()))
+            self.bytes
-    }
-}
-
-impl Into<Vec<u8>> for ByteBuf {
-    fn into(self) -> Vec<u8> {
-        self.bytes
-    }
-}
-
-impl From<Vec<u8>> for ByteBuf {
-    fn from(bytes: Vec<u8>) -> Self {
-        ByteBuf {
-            bytes: bytes,
         }
     }
-}
 
-impl AsRef<Vec<u8>> for ByteBuf {
+    impl From<Vec<u8>> for ByteBuf {
-    fn as_ref(&self) -> &Vec<u8> {
+        fn from(bytes: Vec<u8>) -> Self {
-        &self.bytes
+            ByteBuf {
-    }
+                bytes: bytes,
-}
+            }
-
+        }
-impl AsRef<[u8]> for ByteBuf {
-    fn as_ref(&self) -> &[u8] {
-        &self.bytes
-    }
-}
-
-impl AsMut<Vec<u8>> for ByteBuf {
-    fn as_mut(&mut self) -> &mut Vec<u8> {
-        &mut self.bytes
-    }
-}
-
-impl AsMut<[u8]> for ByteBuf {
-    fn as_mut(&mut self) -> &mut [u8] {
-        &mut self.bytes
-    }
-}
-
-impl ops::Deref for ByteBuf {
-    type Target = [u8];
-
-    fn deref(&self) -> &[u8] { &self.bytes[..] }
-}
-
-impl ops::DerefMut for ByteBuf {
-    fn deref_mut(&mut self) -> &mut [u8] { &mut self.bytes[..] }
-}
-
-impl ser::Serialize for ByteBuf {
-    fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
-        where S: ser::Serializer
-    {
-        serializer.serialize_bytes(&self)
-    }
-}
-
-/// This type implements the `serde::de::Visitor` trait for a `ByteBuf`.
-pub struct ByteBufVisitor;
-
-impl de::Visitor for ByteBufVisitor {
-    type Value = ByteBuf;
-
-    #[inline]
-    fn visit_unit<E>(&mut self) -> Result<ByteBuf, E>
-        where E: de::Error,
-    {
-        Ok(ByteBuf {
-            bytes: Vec::new(),
-        })
     }
 
-    #[inline]
+    impl AsRef<Vec<u8>> for ByteBuf {
-    fn visit_seq<V>(&mut self, mut visitor: V) -> Result<ByteBuf, V::Error>
+        fn as_ref(&self) -> &Vec<u8> {
-        where V: de::SeqVisitor,
+            &self.bytes
-    {
+        }
-        let (len, _) = visitor.size_hint();
+    }
-        let mut values = Vec::with_capacity(len);
 
-        while let Some(value) = try!(visitor.visit()) {
+    impl AsRef<[u8]> for ByteBuf {
-            values.push(value);
+        fn as_ref(&self) -> &[u8] {
+            &self.bytes
+        }
+    }
+
+    impl AsMut<Vec<u8>> for ByteBuf {
+        fn as_mut(&mut self) -> &mut Vec<u8> {
+            &mut self.bytes
+        }
+    }
+
+    impl AsMut<[u8]> for ByteBuf {
+        fn as_mut(&mut self) -> &mut [u8] {
+            &mut self.bytes
+        }
+    }
+
+    impl ops::Deref for ByteBuf {
+        type Target = [u8];
+
+        fn deref(&self) -> &[u8] { &self.bytes[..] }
+    }
+
+    impl ops::DerefMut for ByteBuf {
+        fn deref_mut(&mut self) -> &mut [u8] { &mut self.bytes[..] }
+    }
+
+    impl ser::Serialize for ByteBuf {
+        fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
+            where S: ser::Serializer
+        {
+            serializer.serialize_bytes(self)
+        }
+    }
+
+    /// This type implements the `serde::de::Visitor` trait for a `ByteBuf`.
+    pub struct ByteBufVisitor;
+
+    impl de::Visitor for ByteBufVisitor {
+        type Value = ByteBuf;
+
+        #[inline]
+        fn visit_unit<E>(&mut self) -> Result<ByteBuf, E>
+            where E: de::Error,
+        {
+            Ok(ByteBuf {
+                bytes: Vec::new(),
+            })
         }
 
-        try!(visitor.end());
+        #[inline]
+        fn visit_seq<V>(&mut self, mut visitor: V) -> Result<ByteBuf, V::Error>
+            where V: de::SeqVisitor,
+        {
+            let (len, _) = visitor.size_hint();
+            let mut values = Vec::with_capacity(len);
 
-        Ok(ByteBuf {
+            while let Some(value) = try!(visitor.visit()) {
-            bytes: values,
+                values.push(value);
-        })
+            }
+
+            try!(visitor.end());
+
+            Ok(ByteBuf {
+                bytes: values,
+            })
+        }
+
+        #[inline]
+        fn visit_bytes<E>(&mut self, v: &[u8]) -> Result<ByteBuf, E>
+            where E: de::Error,
+        {
+            self.visit_byte_buf(v.to_vec())
+        }
+
+        #[inline]
+        fn visit_byte_buf<E>(&mut self, v: Vec<u8>) -> Result<ByteBuf, E>
+            where E: de::Error,
+        {
+            Ok(ByteBuf {
+                bytes: v,
+            })
+        }
     }
 
-    #[inline]
+    impl de::Deserialize for ByteBuf {
-    fn visit_bytes<E>(&mut self, v: &[u8]) -> Result<ByteBuf, E>
+        #[inline]
-        where E: de::Error,
+        fn deserialize<D>(deserializer: &mut D) -> Result<ByteBuf, D::Error>
-    {
+            where D: de::Deserializer
-        self.visit_byte_buf(v.to_vec())
+        {
-    }
+            deserializer.deserialize_bytes(ByteBufVisitor)
-
+        }
-    #[inline]
-    fn visit_byte_buf<E>(&mut self, v: Vec<u8>) -> Result<ByteBuf, E>
-        where E: de::Error,
-    {
-        Ok(ByteBuf {
-            bytes: v,
-        })
-    }
-}
-
-impl de::Deserialize for ByteBuf {
-    #[inline]
-    fn deserialize<D>(deserializer: &mut D) -> Result<ByteBuf, D::Error>
-        where D: de::Deserializer
-    {
-        deserializer.deserialize_bytes(ByteBufVisitor)
     }
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 
-fn escape_bytestring(bytes: &[u8]) -> String {
+#[inline]
-    let mut result = String::new();
+fn escape_bytestring<'a>(bytes: &'a [u8]) -> iter::FlatMap<slice::Iter<'a, u8>, char::EscapeDefault, fn(&u8) -> char::EscapeDefault> {
-    for &b in bytes {
+    fn f(b: &u8) -> char::EscapeDefault {
-        for esc in ascii::escape_default(b) {
+        char::from_u32(*b as u32).unwrap().escape_default()
-            result.push(esc as char);
-        }
     }
-    result
+    bytes.iter().flat_map(f as fn(&u8) -> char::EscapeDefault)
 }

serde/src/de/from_primitive.rs

@@ -13,10 +13,10 @@
 // Rust 1.5 is unhappy that this private module is undocumented.
 #![allow(missing_docs)]
 
-use std::{usize, u8, u16, u32, u64};
+use core::{usize, u8, u16, u32, u64};
-use std::{isize, i8, i16, i32, i64};
+use core::{isize, i8, i16, i32, i64};
-use std::{f32, f64};
+use core::{f32, f64};
-use std::mem::size_of;
+use core::mem::size_of;
 
 /// Numbers which have upper and lower bounds
 pub trait Bounded {
@@ -274,7 +274,7 @@ macro_rules! impl_to_primitive_float_to_float {
             Some($slf as $DstT)
         } else {
             let n = $slf as f64;
-            let max_value: $SrcT = ::std::$SrcT::MAX;
+            let max_value: $SrcT = ::core::$SrcT::MAX;
             if -max_value as f64 <= n && n <= max_value as f64 {
                 Some($slf as $DstT)
             } else {

serde/src/de/impls.rs

@@ -1,30 +1,63 @@
 //! This module contains `Deserialize` and `Visitor` implementations.
 
+#[cfg(feature = "std")]
 use std::borrow::Cow;
-use std::collections::{
+#[cfg(all(feature = "nightly", feature = "collections", not(feature = "std")))]
+use collections::borrow::Cow;
+
+#[cfg(all(feature = "collections", not(feature = "std")))]
+use collections::{
     BinaryHeap,
     BTreeMap,
     BTreeSet,
     LinkedList,
+    VecDeque,
+    Vec,
+    String,
+};
+
+#[cfg(feature = "std")]
+use std::collections::{
     HashMap,
     HashSet,
+    BinaryHeap,
+    BTreeMap,
+    BTreeSet,
+    LinkedList,
     VecDeque,
 };
-#[cfg(feature = "nightly")]
+
+#[cfg(all(feature = "nightly", feature = "collections"))]
 use collections::enum_set::{CLike, EnumSet};
-use std::hash::Hash;
+#[cfg(all(feature = "nightly", feature = "collections"))]
-use std::marker::PhantomData;
+use collections::borrow::ToOwned;
+
+use core::hash::Hash;
+use core::marker::PhantomData;
+#[cfg(feature = "std")]
 use std::net;
+#[cfg(feature = "std")]
 use std::path;
+use core::str;
+
+#[cfg(feature = "std")]
 use std::rc::Rc;
-use std::str;
+#[cfg(all(feature = "nightly", 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")))]
+use alloc::arc::Arc;
+
+#[cfg(all(feature = "nightly", feature = "alloc", not(feature = "std")))]
+use alloc::boxed::Box;
 
 #[cfg(feature = "nightly")]
 use core::nonzero::{NonZero, Zeroable};
 
 #[cfg(feature = "nightly")]
-use std::num::Zero;
+use core::num::Zero;
 
 use de::{
     Deserialize,
@@ -85,7 +118,7 @@ impl Visitor for BoolVisitor {
     fn visit_str<E>(&mut self, s: &str) -> Result<bool, E>
         where E: Error,
     {
-        match s.trim() {
+        match s.trim_matches(::utils::Pattern_White_Space) {
             "true" => Ok(true),
             "false" => Ok(false),
             _ => Err(Error::invalid_type(Type::Bool)),
@@ -151,10 +184,10 @@ impl<T> Visitor for PrimitiveVisitor<T>
     impl_deserialize_num_method!(f64, visit_f64, from_f64, Type::F64);
 
     #[inline]
-    fn visit_str<E>(&mut self, v: &str) -> Result<T, E>
+    fn visit_str<E>(&mut self, s: &str) -> Result<T, E>
         where E: Error,
     {
-        str::FromStr::from_str(v.trim()).or_else(|_| {
+        str::FromStr::from_str(s.trim_matches(::utils::Pattern_White_Space)).or_else(|_| {
             Err(Error::invalid_type(Type::Str))
         })
     }
@@ -228,8 +261,10 @@ impl Deserialize for char {
 
 ///////////////////////////////////////////////////////////////////////////////
 
+#[cfg(any(feature = "std", feature = "collections"))]
 struct StringVisitor;
 
+#[cfg(any(feature = "std", feature = "collections"))]
 impl Visitor for StringVisitor {
     type Value = String;
 
@@ -264,6 +299,7 @@ impl Visitor for StringVisitor {
     }
 }
 
+#[cfg(any(feature = "std", feature = "collections"))]
 impl Deserialize for String {
     fn deserialize<D>(deserializer: &mut D) -> Result<String, D::Error>
         where D: Deserializer,
@@ -406,6 +442,7 @@ macro_rules! seq_impl {
     }
 }
 
+#[cfg(any(feature = "std", feature = "collections"))]
 seq_impl!(
     BinaryHeap<T>,
     <Deserialize, Ord>,
@@ -415,6 +452,7 @@ seq_impl!(
     BinaryHeap::with_capacity(visitor.size_hint().0),
     BinaryHeap::push);
 
+#[cfg(any(feature = "std", feature = "collections"))]
 seq_impl!(
     BTreeSet<T>,
     <Deserialize, Eq, Ord>,
@@ -424,7 +462,7 @@ seq_impl!(
     BTreeSet::new(),
     BTreeSet::insert);
 
-#[cfg(feature = "nightly")]
+#[cfg(all(feature = "nightly", feature = "collections"))]
 seq_impl!(
     EnumSet<T>,
     <Deserialize, CLike>,
@@ -434,6 +472,7 @@ seq_impl!(
     EnumSet::new(),
     EnumSet::insert);
 
+#[cfg(any(feature = "std", feature = "collections"))]
 seq_impl!(
     LinkedList<T>,
     <Deserialize>,
@@ -443,6 +482,7 @@ seq_impl!(
     LinkedList::new(),
     LinkedList::push_back);
 
+#[cfg(feature = "std")]
 seq_impl!(
     HashSet<T>,
     <Deserialize, Eq, Hash>,
@@ -452,6 +492,7 @@ seq_impl!(
     HashSet::with_capacity(visitor.size_hint().0),
     HashSet::insert);
 
+#[cfg(any(feature = "std", feature = "collections"))]
 seq_impl!(
     Vec<T>,
     <Deserialize>,
@@ -461,6 +502,7 @@ seq_impl!(
     Vec::with_capacity(visitor.size_hint().0),
     Vec::push);
 
+#[cfg(any(feature = "std", feature = "collections"))]
 seq_impl!(
     VecDeque<T>,
     <Deserialize>,
@@ -747,6 +789,7 @@ macro_rules! map_impl {
     }
 }
 
+#[cfg(any(feature = "std", feature = "collections"))]
 map_impl!(
     BTreeMap<K, V>,
     <Deserialize, Eq, Ord>,
@@ -756,6 +799,7 @@ map_impl!(
     BTreeMap::new(),
     BTreeMap::insert);
 
+#[cfg(feature = "std")]
 map_impl!(
     HashMap<K, V>,
     <Deserialize, Eq, Hash>,
@@ -767,7 +811,7 @@ map_impl!(
 
 ///////////////////////////////////////////////////////////////////////////////
 
-#[cfg(feature = "nightly")]
+#[cfg(all(feature = "nightly", feature = "std"))]
 impl Deserialize for net::IpAddr {
     fn deserialize<D>(deserializer: &mut D) -> Result<Self, D::Error>
         where D: Deserializer,
@@ -780,6 +824,7 @@ impl Deserialize for net::IpAddr {
     }
 }
 
+#[cfg(feature = "std")]
 impl Deserialize for net::Ipv4Addr {
     fn deserialize<D>(deserializer: &mut D) -> Result<Self, D::Error>
         where D: Deserializer,
@@ -792,6 +837,7 @@ impl Deserialize for net::Ipv4Addr {
     }
 }
 
+#[cfg(feature = "std")]
 impl Deserialize for net::Ipv6Addr {
     fn deserialize<D>(deserializer: &mut D) -> Result<Self, D::Error>
         where D: Deserializer,
@@ -806,6 +852,7 @@ impl Deserialize for net::Ipv6Addr {
 
 ///////////////////////////////////////////////////////////////////////////////
 
+#[cfg(feature = "std")]
 impl Deserialize for net::SocketAddr {
     fn deserialize<D>(deserializer: &mut D) -> Result<Self, D::Error>
         where D: Deserializer,
@@ -818,6 +865,7 @@ impl Deserialize for net::SocketAddr {
     }
 }
 
+#[cfg(feature = "std")]
 impl Deserialize for net::SocketAddrV4 {
     fn deserialize<D>(deserializer: &mut D) -> Result<Self, D::Error>
         where D: Deserializer,
@@ -830,6 +878,7 @@ impl Deserialize for net::SocketAddrV4 {
     }
 }
 
+#[cfg(feature = "std")]
 impl Deserialize for net::SocketAddrV6 {
     fn deserialize<D>(deserializer: &mut D) -> Result<Self, D::Error>
         where D: Deserializer,
@@ -844,8 +893,10 @@ impl Deserialize for net::SocketAddrV6 {
 
 ///////////////////////////////////////////////////////////////////////////////
 
+#[cfg(feature = "std")]
 struct PathBufVisitor;
 
+#[cfg(feature = "std")]
 impl Visitor for PathBufVisitor {
     type Value = path::PathBuf;
 
@@ -862,6 +913,7 @@ impl Visitor for PathBufVisitor {
     }
 }
 
+#[cfg(feature = "std")]
 impl Deserialize for path::PathBuf {
     fn deserialize<D>(deserializer: &mut D) -> Result<path::PathBuf, D::Error>
         where D: Deserializer,
@@ -872,6 +924,7 @@ impl Deserialize for path::PathBuf {
 
 ///////////////////////////////////////////////////////////////////////////////
 
+#[cfg(any(feature = "std", feature = "alloc"))]
 impl<T: Deserialize> Deserialize for Box<T> {
     fn deserialize<D>(deserializer: &mut D) -> Result<Box<T>, D::Error>
         where D: Deserializer,
@@ -881,6 +934,7 @@ impl<T: Deserialize> Deserialize for Box<T> {
     }
 }
 
+#[cfg(any(feature = "std", feature = "collections"))]
 impl<T: Deserialize> Deserialize for Box<[T]> {
     fn deserialize<D>(deserializer: &mut D) -> Result<Box<[T]>, D::Error>
         where D: Deserializer,
@@ -890,6 +944,7 @@ impl<T: Deserialize> Deserialize for Box<[T]> {
     }
 }
 
+#[cfg(any(feature = "std", feature = "alloc"))]
 impl<T: Deserialize> Deserialize for Arc<T> {
     fn deserialize<D>(deserializer: &mut D) -> Result<Arc<T>, D::Error>
         where D: Deserializer,
@@ -899,6 +954,7 @@ impl<T: Deserialize> Deserialize for Arc<T> {
     }
 }
 
+#[cfg(any(feature = "std", feature = "alloc"))]
 impl<T: Deserialize> Deserialize for Rc<T> {
     fn deserialize<D>(deserializer: &mut D) -> Result<Rc<T>, D::Error>
         where D: Deserializer,
@@ -908,6 +964,7 @@ impl<T: Deserialize> Deserialize for Rc<T> {
     }
 }
 
+#[cfg(any(feature = "std", feature = "collections"))]
 impl<'a, T: ?Sized> Deserialize for Cow<'a, T> where T: ToOwned, T::Owned: Deserialize, {
     #[inline]
     fn deserialize<D>(deserializer: &mut D) -> Result<Cow<'a, T>, D::Error>
@@ -954,7 +1011,10 @@ impl<T, E> Deserialize for Result<T, E> where T: Deserialize, E: Deserialize {
                 impl ::de::Visitor for FieldVisitor {
                     type Value = Field;
 
+                    #[cfg(any(feature = "std", feature = "collections"))]
                     fn visit_usize<E>(&mut self, value: usize) -> Result<Field, E> where E: Error {
+                        #[cfg(feature = "collections")]
+                        use collections::string::ToString;
                         match value {
                             0 => Ok(Field::Ok),
                             1 => Ok(Field::Err),
@@ -962,6 +1022,15 @@ impl<T, E> Deserialize for Result<T, E> where T: Deserialize, E: Deserialize {
                         }
                     }
 
+                    #[cfg(all(not(feature = "std"), not(feature = "collections")))]
+                    fn visit_usize<E>(&mut self, value: usize) -> Result<Field, E> where E: Error {
+                        match value {
+                            0 => Ok(Field::Ok),
+                            1 => Ok(Field::Err),
+                            _ => Err(Error::unknown_field("some number")),
+                        }
+                    }
+
                     fn visit_str<E>(&mut self, value: &str) -> Result<Field, E> where E: Error {
                         match value {
                             "Ok" => Ok(Field::Ok),

serde/src/de/mod.rs

@@ -1,6 +1,12 @@
 //! Generic deserialization framework.
 
+#[cfg(feature = "std")]
 use std::error;
+#[cfg(not(feature = "std"))]
+use error;
+
+#[cfg(all(not(feature = "std"), feature = "collections"))]
+use collections::{String, Vec};
 
 pub mod impls;
 pub mod value;
@@ -12,8 +18,13 @@ mod from_primitive;
 /// `Deserializer` error.
 pub trait Error: Sized + error::Error {
     /// Raised when there is general error when deserializing 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.
+    #[cfg(all(not(feature = "std"), not(feature = "collections")))]
+    fn custom<T: Into<&'static str>>(msg: T) -> Self;
+
     /// Raised when a `Deserialize` type unexpectedly hit the end of the stream.
     fn end_of_stream() -> Self;
 
@@ -28,6 +39,9 @@ pub trait Error: Sized + error::Error {
     }
 
     /// Raised when a fixed sized sequence or map was passed in the wrong amount of arguments.
+    ///
+    /// The parameter `len` is the number of arguments found in the serialization. The sequence
+    /// may either expect more arguments or less arguments.
     fn invalid_length(len: usize) -> Self {
         Error::custom(format!("Invalid length: {}", len))
     }
@@ -46,6 +60,12 @@ pub trait Error: Sized + error::Error {
     fn missing_field(field: &'static str) -> Self {
         Error::custom(format!("Missing field `{}`", field))
     }
+
+    /// Raised when a `Deserialize` struct type received more than one of the
+    /// same struct field.
+    fn duplicate_field(field: &'static str) -> Self {
+        Error::custom(format!("Duplicate field `{}`", field))
+    }
 }
 
 /// `Type` represents all the primitive types that can be deserialized. This is used by
@@ -558,9 +578,7 @@ pub trait Visitor {
     fn visit_char<E>(&mut self, v: char) -> Result<Self::Value, E>
         where E: Error,
     {
-        // FIXME: this allocation is required in order to be compatible with stable rust, which
+        self.visit_str(::utils::encode_utf8(v).as_str())
-        // doesn't support encoding a `char` into a stack buffer.
-        self.visit_string(v.to_string())
     }
 
     /// `visit_str` deserializes a `&str` into a `Value`.
@@ -574,6 +592,7 @@ pub trait Visitor {
     /// a copy if it is deserializing a string from a `String` type.  By default it passes a `&str`
     /// to the `visit_str` method.
     #[inline]
+    #[cfg(any(feature = "std", feature = "collections"))]
     fn visit_string<E>(&mut self, v: String) -> Result<Self::Value, E>
         where E: Error,
     {
@@ -638,6 +657,7 @@ pub trait Visitor {
     }
 
     /// `visit_byte_buf` deserializes a `Vec<u8>` into a `Value`.
+    #[cfg(any(feature = "std", feature = "collections"))]
     fn visit_byte_buf<E>(&mut self, v: Vec<u8>) -> Result<Self::Value, E>
         where E: Error,
     {

serde/src/de/value.rs

@@ -1,5 +1,6 @@
 //! This module supports deserializing from primitives with the `ValueDeserializer` trait.
 
+#[cfg(feature = "std")]
 use std::collections::{
     BTreeMap,
     BTreeSet,
@@ -10,11 +11,31 @@ use std::collections::{
     hash_map,
     hash_set,
 };
-use std::hash::Hash;
+#[cfg(feature = "std")]
-use std::error;
-use std::fmt;
 use std::vec;
-use std::marker::PhantomData;
+
+#[cfg(all(feature = "collections", not(feature = "std")))]
+use collections::{
+    BTreeMap,
+    BTreeSet,
+    Vec,
+    String,
+    btree_map,
+    btree_set,
+    vec,
+};
+
+#[cfg(all(feature = "nightly", feature = "collections"))]
+use collections::borrow::ToOwned;
+
+use core::hash::Hash;
+#[cfg(feature = "std")]
+use std::error;
+#[cfg(not(feature = "std"))]
+use error;
+
+use core::fmt;
+use core::marker::PhantomData;
 
 use de;
 use bytes;
@@ -25,7 +46,11 @@ use bytes;
 #[derive(Clone, Debug, PartialEq)]
 pub enum Error {
     /// The value had some custom error.
+    #[cfg(any(feature = "std", feature = "collections"))]
     Custom(String),
+    /// The value had some custom error.
+    #[cfg(all(not(feature = "std"), not(feature = "collections")))]
+    Custom(&'static str),
 
     /// The value had an incorrect type.
     InvalidType(de::Type),
@@ -34,29 +59,60 @@ pub enum Error {
     InvalidLength(usize),
 
     /// The value is invalid and cannot be deserialized.
+    #[cfg(any(feature = "std", feature = "collections"))]
     InvalidValue(String),
+    /// The value is invalid and cannot be deserialized.
+    #[cfg(all(not(feature = "std"), not(feature = "collections")))]
+    InvalidValue(&'static str),
 
     /// EOF while deserializing a value.
     EndOfStream,
 
     /// Unknown variant in enum.
+    #[cfg(any(feature = "std", feature = "collections"))]
     UnknownVariant(String),
+    /// Unknown variant in enum.
+    #[cfg(all(not(feature = "std"), not(feature = "collections")))]
+    UnknownVariant(&'static str),
 
     /// Unknown field in struct.
+    #[cfg(any(feature = "std", feature = "collections"))]
     UnknownField(String),
+    /// Unknown field in struct.
+    #[cfg(all(not(feature = "std"), not(feature = "collections")))]
+    UnknownField(&'static str),
 
     /// Struct is missing a field.
     MissingField(&'static str),
 }
 
 impl de::Error for Error {
+    #[cfg(any(feature = "std", feature = "collections"))]
     fn custom<T: Into<String>>(msg: T) -> Self { Error::Custom(msg.into()) }
+
+    #[cfg(all(not(feature = "std"), not(feature = "collections")))]
+    fn custom<T: Into<&'static str>>(msg: T) -> Self { Error::Custom(msg.into()) }
+
     fn end_of_stream() -> Self { Error::EndOfStream }
     fn invalid_type(ty: de::Type) -> Self { Error::InvalidType(ty) }
+
+    #[cfg(any(feature = "std", feature = "collections"))]
     fn invalid_value(msg: &str) -> Self { Error::InvalidValue(msg.to_owned()) }
+
+    #[cfg(all(not(feature = "std"), not(feature = "collections")))]
+    fn invalid_value(msg: &str) -> Self { Error::InvalidValue("invalid value") }
+
     fn invalid_length(len: usize) -> Self { Error::InvalidLength(len) }
+
+    #[cfg(any(feature = "std", feature = "collections"))]
     fn unknown_variant(variant: &str) -> Self { Error::UnknownVariant(String::from(variant)) }
+    #[cfg(any(feature = "std", feature = "collections"))]
     fn unknown_field(field: &str) -> Self { Error::UnknownField(String::from(field)) }
+
+    #[cfg(all(not(feature = "std"), not(feature = "collections")))]
+    fn unknown_variant(variant: &str) -> Self { Error::UnknownVariant("unknown variant") }
+    #[cfg(all(not(feature = "std"), not(feature = "collections")))]
+    fn unknown_field(field: &str) -> Self { Error::UnknownField("unknown field") }
     fn missing_field(field: &'static str) -> Self { Error::MissingField(field) }
 }
 
@@ -238,8 +294,10 @@ impl<'a, E> de::VariantVisitor for StrDeserializer<'a, E>
 ///////////////////////////////////////////////////////////////////////////////
 
 /// A helper deserializer that deserializes a `String`.
+#[cfg(any(feature = "std", feature = "collections"))]
 pub struct StringDeserializer<E>(Option<String>, PhantomData<E>);
 
+#[cfg(any(feature = "std", feature = "collections"))]
 impl<E> ValueDeserializer<E> for String
     where E: de::Error,
 {
@@ -250,6 +308,7 @@ impl<E> ValueDeserializer<E> for String
     }
 }
 
+#[cfg(any(feature = "std", feature = "collections"))]
 impl<E> de::Deserializer for StringDeserializer<E>
     where E: de::Error,
 {
@@ -274,6 +333,7 @@ impl<E> de::Deserializer for StringDeserializer<E>
     }
 }
 
+#[cfg(any(feature = "std", feature = "collections"))]
 impl<'a, E> de::VariantVisitor for StringDeserializer<E>
     where E: de::Error,
 {
@@ -361,6 +421,7 @@ impl<I, T, E> de::SeqVisitor for SeqDeserializer<I, E>
 
 ///////////////////////////////////////////////////////////////////////////////
 
+#[cfg(any(feature = "std", feature = "collections"))]
 impl<T, E> ValueDeserializer<E> for Vec<T>
     where T: ValueDeserializer<E>,
           E: de::Error,
@@ -373,6 +434,7 @@ impl<T, E> ValueDeserializer<E> for Vec<T>
     }
 }
 
+#[cfg(any(feature = "std", feature = "collections"))]
 impl<T, E> ValueDeserializer<E> for BTreeSet<T>
     where T: ValueDeserializer<E> + Eq + Ord,
           E: de::Error,
@@ -385,6 +447,7 @@ impl<T, E> ValueDeserializer<E> for BTreeSet<T>
     }
 }
 
+#[cfg(feature = "std")]
 impl<T, E> ValueDeserializer<E> for HashSet<T>
     where T: ValueDeserializer<E> + Eq + Hash,
           E: de::Error,
@@ -527,6 +590,7 @@ impl<I, K, V, E> de::MapVisitor for MapDeserializer<I, K, V, E>
 
 ///////////////////////////////////////////////////////////////////////////////
 
+#[cfg(any(feature = "std", feature = "collections"))]
 impl<K, V, E> ValueDeserializer<E> for BTreeMap<K, V>
     where K: ValueDeserializer<E> + Eq + Ord,
           V: ValueDeserializer<E>,
@@ -540,6 +604,7 @@ impl<K, V, E> ValueDeserializer<E> for BTreeMap<K, V>
     }
 }
 
+#[cfg(feature = "std")]
 impl<K, V, E> ValueDeserializer<E> for HashMap<K, V>
     where K: ValueDeserializer<E> + Eq + Hash,
           V: ValueDeserializer<E>,
@@ -618,6 +683,7 @@ impl<'a, E> de::Deserializer for BytesDeserializer<'a, E>
 
 ///////////////////////////////////////////////////////////////////////////////
 
+#[cfg(any(feature = "std", feature = "collections"))]
 impl<E> ValueDeserializer<E> for bytes::ByteBuf
     where E: de::Error,
 {
@@ -629,8 +695,10 @@ impl<E> ValueDeserializer<E> for bytes::ByteBuf
 }
 
 /// A helper deserializer that deserializes a `Vec<u8>`.
+#[cfg(any(feature = "std", feature = "collections"))]
 pub struct ByteBufDeserializer<E>(Option<Vec<u8>>, PhantomData<E>);
 
+#[cfg(any(feature = "std", feature = "collections"))]
 impl<E> de::Deserializer for ByteBufDeserializer<E>
     where E: de::Error,
 {

serde/src/error.rs

@@ -0,0 +1,44 @@
+//! A stand-in for `std::error`
+use core::any::TypeId;
+use core::fmt::{Debug, Display};
+
+
+/// A stand-in for `std::error::Error`, which requires no allocation.
+#[cfg(feature = "nightly")]
+pub trait Error: Debug + Display + ::core::marker::Reflect {
+    /// A short description of the error.
+    ///
+    /// The description should not contain newlines or sentence-ending
+    /// punctuation, to facilitate embedding in larger user-facing
+    /// strings.
+    fn description(&self) -> &str;
+
+    /// The lower-level cause of this error, if any.
+    fn cause(&self) -> Option<&Error> { None }
+
+    /// Get the `TypeId` of `self`
+    #[doc(hidden)]
+    fn type_id(&self) -> TypeId where Self: 'static {
+        TypeId::of::<Self>()
+    }
+}
+
+/// A stand-in for `std::error::Error`, which requires no allocation.
+#[cfg(not(feature = "nightly"))]
+pub trait Error: Debug + Display {
+    /// A short description of the error.
+    ///
+    /// The description should not contain newlines or sentence-ending
+    /// punctuation, to facilitate embedding in larger user-facing
+    /// strings.
+    fn description(&self) -> &str;
+
+    /// The lower-level cause of this error, if any.
+    fn cause(&self) -> Option<&Error> { None }
+
+    /// Stubbed! Returns type_id of `()`
+    #[doc(hidden)]
+    fn type_id(&self) -> TypeId where Self: 'static {
+        TypeId::of::<()>()
+    }
+}

serde/src/lib.rs

@@ -10,23 +10,46 @@
 //! [github repository](https://github.com/serde-rs/serde)
 
 #![doc(html_root_url="https://serde-rs.github.io/serde/serde")]
-#![cfg_attr(feature = "nightly", feature(collections, enumset, nonzero, plugin, step_trait,
+#![cfg_attr(not(feature = "std"), no_std)]
-                                         zero_one))]
+#![cfg_attr(feature = "nightly", 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(any(not(feature = "std"), feature = "nightly"), allow(unused_variables, unused_imports, unused_features, dead_code))]
+
 #![deny(missing_docs)]
 
-#[cfg(feature = "nightly")]
+#[cfg(all(feature = "nightly", feature = "collections"))]
 extern crate collections;
 
-#[cfg(feature = "nightly")]
+#[cfg(all(feature = "nightly", feature = "alloc"))]
-extern crate core;
+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")]
+    extern crate core;
+    #[cfg(feature = "nightly")]
+    pub use self::core::nonzero;
+}
 
 pub use ser::{Serialize, Serializer};
 pub use de::{Deserialize, Deserializer, Error};
 
+#[cfg(not(feature = "std"))]
+macro_rules! format {
+    ($s:expr, $($rest:tt)*) => ($s)
+}
+
 pub mod bytes;
 pub mod de;
+#[cfg(feature = "std")]
 pub mod iter;
 pub mod ser;
+#[cfg(not(feature = "std"))]
+pub mod error;
+mod utils;

serde/src/ser/impls.rs

@@ -1,6 +1,11 @@
 //! Implementations for all of Rust's builtin types.
 
+#[cfg(feature = "std")]
 use std::borrow::Cow;
+#[cfg(all(feature = "collections", not(feature = "std")))]
+use collections::borrow::Cow;
+
+#[cfg(feature = "std")]
 use std::collections::{
     BinaryHeap,
     BTreeMap,
@@ -10,20 +15,47 @@ use std::collections::{
     HashSet,
     VecDeque,
 };
-#[cfg(feature = "nightly")]
+#[cfg(all(feature = "collections", not(feature = "std")))]
+use collections::{
+    BinaryHeap,
+    BTreeMap,
+    BTreeSet,
+    LinkedList,
+    VecDeque,
+    String,
+    Vec,
+};
+
+#[cfg(all(feature = "nightly", feature = "collections"))]
 use collections::enum_set::{CLike, EnumSet};
-use std::hash::Hash;
+#[cfg(all(feature = "nightly", feature = "collections"))]
+use collections::borrow::ToOwned;
+
+use core::hash::Hash;
 #[cfg(feature = "nightly")]
-use std::iter;
+use core::iter;
+#[cfg(feature = "std")]
 use std::net;
 #[cfg(feature = "nightly")]
-use std::num;
+use core::num;
 #[cfg(feature = "nightly")]
-use std::ops;
+use core::ops;
+#[cfg(feature = "std")]
 use std::path;
+#[cfg(feature = "std")]
 use std::rc::Rc;
+#[cfg(all(feature = "alloc", not(feature = "std")))]
+use alloc::rc::Rc;
+
+#[cfg(feature = "std")]
 use std::sync::Arc;
-use std::marker::PhantomData;
+#[cfg(all(feature = "alloc", not(feature = "std")))]
+use alloc::arc::Arc;
+
+#[cfg(all(feature = "alloc", not(feature = "std")))]
+use alloc::boxed::Box;
+
+use core::marker::PhantomData;
 
 #[cfg(feature = "nightly")]
 use core::nonzero::{NonZero, Zeroable};
@@ -77,6 +109,7 @@ impl Serialize for str {
     }
 }
 
+#[cfg(any(feature = "std", feature = "collections"))]
 impl Serialize for String {
     #[inline]
     fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
@@ -260,6 +293,7 @@ array_impls!(32);
 
 ///////////////////////////////////////////////////////////////////////////////
 
+#[cfg(any(feature = "std", feature = "collections"))]
 impl<T> Serialize for BinaryHeap<T>
     where T: Serialize + Ord
 {
@@ -271,6 +305,7 @@ impl<T> Serialize for BinaryHeap<T>
     }
 }
 
+#[cfg(any(feature = "std", feature = "collections"))]
 impl<T> Serialize for BTreeSet<T>
     where T: Serialize + Ord,
 {
@@ -282,7 +317,7 @@ impl<T> Serialize for BTreeSet<T>
     }
 }
 
-#[cfg(feature = "nightly")]
+#[cfg(all(feature = "nightly", feature = "collections"))]
 impl<T> Serialize for EnumSet<T>
     where T: Serialize + CLike
 {
@@ -294,6 +329,7 @@ impl<T> Serialize for EnumSet<T>
     }
 }
 
+#[cfg(feature = "std")]
 impl<T> Serialize for HashSet<T>
     where T: Serialize + Eq + Hash,
 {
@@ -305,6 +341,7 @@ impl<T> Serialize for HashSet<T>
     }
 }
 
+#[cfg(any(feature = "std", feature = "collections"))]
 impl<T> Serialize for LinkedList<T>
     where T: Serialize,
 {
@@ -330,6 +367,7 @@ impl<A> Serialize for ops::Range<A>
     }
 }
 
+#[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>
@@ -339,6 +377,7 @@ impl<T> Serialize for Vec<T> where T: Serialize {
     }
 }
 
+#[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>
@@ -598,6 +637,7 @@ impl<K, V, I> MapVisitor for MapIteratorVisitor<I>
 
 ///////////////////////////////////////////////////////////////////////////////
 
+#[cfg(any(feature = "std", feature = "collections"))]
 impl<K, V> Serialize for BTreeMap<K, V>
     where K: Serialize + Ord,
           V: Serialize,
@@ -610,6 +650,7 @@ impl<K, V> Serialize for BTreeMap<K, V>
     }
 }
 
+#[cfg(feature = "std")]
 impl<K, V> Serialize for HashMap<K, V>
     where K: Serialize + Eq + Hash,
           V: Serialize,
@@ -642,6 +683,7 @@ impl<'a, T: ?Sized> Serialize for &'a mut T where T: Serialize {
     }
 }
 
+#[cfg(any(feature = "std", feature = "alloc"))]
 impl<T: ?Sized> Serialize for Box<T> where T: Serialize {
     #[inline]
     fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
@@ -651,6 +693,7 @@ impl<T: ?Sized> Serialize for Box<T> where T: Serialize {
     }
 }
 
+#[cfg(any(feature = "std", feature = "alloc"))]
 impl<T> Serialize for Rc<T> where T: Serialize, {
     #[inline]
     fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
@@ -660,6 +703,7 @@ impl<T> Serialize for Rc<T> where T: Serialize, {
     }
 }
 
+#[cfg(any(feature = "std", feature = "alloc"))]
 impl<T> Serialize for Arc<T> where T: Serialize, {
     #[inline]
     fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
@@ -669,6 +713,7 @@ impl<T> Serialize for Arc<T> where T: Serialize, {
     }
 }
 
+#[cfg(any(feature = "std", feature = "collections"))]
 impl<'a, T: ?Sized> Serialize for Cow<'a, T> where T: Serialize + ToOwned, {
     #[inline]
     fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
@@ -695,7 +740,7 @@ impl<T, E> Serialize for Result<T, E> where T: Serialize, E: Serialize {
 
 ///////////////////////////////////////////////////////////////////////////////
 
-#[cfg(feature = "nightly")]
+#[cfg(all(feature = "std", feature = "nightly"))]
 impl Serialize for net::IpAddr {
     fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
         where S: Serializer,
@@ -707,6 +752,7 @@ impl Serialize for net::IpAddr {
     }
 }
 
+#[cfg(feature = "std")]
 impl Serialize for net::Ipv4Addr {
     fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
         where S: Serializer,
@@ -715,6 +761,7 @@ impl Serialize for net::Ipv4Addr {
     }
 }
 
+#[cfg(feature = "std")]
 impl Serialize for net::Ipv6Addr {
     fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
         where S: Serializer,
@@ -725,6 +772,7 @@ impl Serialize for net::Ipv6Addr {
 
 ///////////////////////////////////////////////////////////////////////////////
 
+#[cfg(feature = "std")]
 impl Serialize for net::SocketAddr {
     fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
         where S: Serializer,
@@ -736,6 +784,7 @@ impl Serialize for net::SocketAddr {
     }
 }
 
+#[cfg(feature = "std")]
 impl Serialize for net::SocketAddrV4 {
     fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
         where S: Serializer,
@@ -744,6 +793,7 @@ impl Serialize for net::SocketAddrV4 {
     }
 }
 
+#[cfg(feature = "std")]
 impl Serialize for net::SocketAddrV6 {
     fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
         where S: Serializer,
@@ -754,6 +804,7 @@ impl Serialize for net::SocketAddrV6 {
 
 ///////////////////////////////////////////////////////////////////////////////
 
+#[cfg(feature = "std")]
 impl Serialize for path::Path {
     fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
         where S: Serializer,
@@ -765,6 +816,7 @@ impl Serialize for path::Path {
     }
 }
 
+#[cfg(feature = "std")]
 impl Serialize for path::PathBuf {
     fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
         where S: Serializer,

serde/src/ser/mod.rs

@@ -1,6 +1,12 @@
 //! Generic serialization framework.
 
+#[cfg(feature = "std")]
 use std::error;
+#[cfg(not(feature = "std"))]
+use error;
+
+#[cfg(all(feature = "collections", not(feature = "std")))]
+use collections::String;
 
 pub mod impls;
 
@@ -10,8 +16,13 @@ pub mod impls;
 /// `Serializer` error.
 pub trait Error: Sized + error::Error {
     /// Raised when there is general error when deserializing 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.
+    #[cfg(all(not(feature = "std"), not(feature = "collections")))]
+    fn custom<T: Into<&'static str>>(msg: T) -> Self;
+
     /// Raised when a `Serialize` was passed an incorrect value.
     fn invalid_value(msg: &str) -> Self {
         Error::custom(format!("invalid value: {}", msg))
@@ -115,9 +126,7 @@ pub trait Serializer {
     /// single character.
     #[inline]
     fn serialize_char(&mut self, v: char) -> Result<(), Self::Error> {
-        // FIXME: this allocation is required in order to be compatible with stable rust, which
+        self.serialize_str(::utils::encode_utf8(v).as_str())
-        // doesn't support encoding a `char` into a stack buffer.
-        self.serialize_str(&v.to_string())
     }
 
     /// Serializes a `&str`.

serde/src/utils.rs

@@ -0,0 +1,72 @@
+//! Private utility functions
+
+const TAG_CONT: u8    = 0b1000_0000;
+const TAG_TWO_B: u8   = 0b1100_0000;
+const TAG_THREE_B: u8 = 0b1110_0000;
+const TAG_FOUR_B: u8  = 0b1111_0000;
+const MAX_ONE_B: u32   =     0x80;
+const MAX_TWO_B: u32   =    0x800;
+const MAX_THREE_B: u32 =  0x10000;
+
+#[inline]
+pub fn encode_utf8(c: char) -> EncodeUtf8 {
+    let code = c as u32;
+    let mut buf = [0; 4];
+    let pos = if code < MAX_ONE_B {
+        buf[3] = code as u8;
+        3
+    } else if code < MAX_TWO_B {
+        buf[2] = (code >> 6 & 0x1F) as u8 | TAG_TWO_B;
+        buf[3] = (code & 0x3F) as u8 | TAG_CONT;
+        2
+    } else if code < MAX_THREE_B {
+        buf[1] = (code >> 12 & 0x0F) as u8 | TAG_THREE_B;
+        buf[2] = (code >>  6 & 0x3F) as u8 | TAG_CONT;
+        buf[3] = (code & 0x3F) as u8 | TAG_CONT;
+        1
+    } else {
+        buf[0] = (code >> 18 & 0x07) as u8 | TAG_FOUR_B;
+        buf[1] = (code >> 12 & 0x3F) as u8 | TAG_CONT;
+        buf[2] = (code >>  6 & 0x3F) as u8 | TAG_CONT;
+        buf[3] = (code & 0x3F) as u8 | TAG_CONT;
+        0
+    };
+    EncodeUtf8 { buf: buf, pos: pos }
+}
+
+pub struct EncodeUtf8 {
+    buf: [u8; 4],
+    pos: usize,
+}
+
+impl EncodeUtf8 {
+    // FIXME: use this from_utf8_unchecked, since we know it can never fail
+    pub fn as_str(&self) -> &str {
+        ::core::str::from_utf8(&self.buf[self.pos..]).unwrap()
+    }
+}
+
+#[allow(non_upper_case_globals)]
+const Pattern_White_Space_table: &'static [(char, char)] = &[
+    ('\u{9}', '\u{d}'), ('\u{20}', '\u{20}'), ('\u{85}', '\u{85}'), ('\u{200e}', '\u{200f}'),
+    ('\u{2028}', '\u{2029}')
+];
+
+fn bsearch_range_table(c: char, r: &'static [(char, char)]) -> bool {
+    use core::cmp::Ordering::{Equal, Less, Greater};
+    r.binary_search_by(|&(lo, hi)| {
+        if c < lo {
+            Greater
+        } else if hi < c {
+            Less
+        } else {
+            Equal
+        }
+    })
+    .is_ok()
+}
+
+#[allow(non_snake_case)]
+pub fn Pattern_White_Space(c: char) -> bool {
+    bsearch_range_table(c, Pattern_White_Space_table)
+}

serde_codegen/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "serde_codegen"
-version = "0.7.4"
+version = "0.7.7"
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>"]
 license = "MIT/Apache-2.0"
 description = "Macros to auto-generate implementations for the serde framework"
@@ -8,6 +8,7 @@ repository = "https://github.com/serde-rs/serde"
 documentation = "https://github.com/serde-rs/serde"
 keywords = ["serde", "serialization"]
 build = "build.rs"
+include = ["Cargo.toml", "build.rs", "src/**/*.rs"]
 
 [features]
 default = ["with-syntex"]
@@ -16,13 +17,13 @@ nightly-testing = ["clippy"]
 with-syntex = ["quasi/with-syntex", "quasi_codegen", "quasi_codegen/with-syntex", "syntex", "syntex_syntax"]
 
 [build-dependencies]
-quasi_codegen = { version = "^0.10.0", optional = true }
+quasi_codegen = { version = "^0.11.0", optional = true }
-syntex = { version = "^0.31.0", optional = true }
+syntex = { version = "^0.33.0", optional = true }
 
 [dependencies]
-aster = { version = "^0.16.0", default-features = false }
+aster = { version = "^0.17.0", default-features = false }
 clippy = { version = "^0.*", optional = true }
-quasi = { version = "^0.10.0", default-features = false }
+quasi = { version = "^0.11.0", default-features = false }
-quasi_macros = { version = "^0.10.0", optional = true }
+quasi_macros = { version = "^0.11.0", optional = true }
-syntex = { version = "^0.32.0", optional = true }
+syntex = { version = "^0.33.0", optional = true }
-syntex_syntax = { version = "^0.32.0", optional = true }
+syntex_syntax = { version = "^0.33.0", optional = true }

serde_codegen/src/attr.rs

@@ -177,36 +177,32 @@ pub struct FieldAttrs {
     name: Name,
     skip_serializing_field: bool,
     skip_deserializing_field: bool,
-    skip_serializing_field_if: Option<P<ast::Expr>>,
+    skip_serializing_if: Option<ast::Path>,
     default_expr_if_missing: Option<P<ast::Expr>>,
-    serialize_with: Option<P<ast::Expr>>,
+    serialize_with: Option<ast::Path>,
-    deserialize_with: P<ast::Expr>,
+    deserialize_with: Option<ast::Path>,
 }
 
 impl FieldAttrs {
     /// Extract out the `#[serde(...)]` attributes from a struct field.
     pub fn from_field(cx: &ExtCtxt,
-                      container_ty: &P<ast::Ty>,
+                      index: usize,
-                      generics: &ast::Generics,
+                      field: &ast::StructField) -> Result<Self, Error> {
-                      field: &ast::StructField,
-                      is_enum: bool) -> Result<Self, Error> {
         let builder = AstBuilder::new();
 
         let field_ident = match field.ident {
             Some(ident) => ident,
-            None => { cx.span_bug(field.span, "struct field has no name?") }
+            None => builder.id(index.to_string()),
         };
 
-        let identity = quote_expr!(cx, |x| x);
-
         let mut field_attrs = FieldAttrs {
             name: Name::new(field_ident),
             skip_serializing_field: false,
             skip_deserializing_field: false,
-            skip_serializing_field_if: None,
+            skip_serializing_if: None,
             default_expr_if_missing: None,
             serialize_with: None,
-            deserialize_with: identity,
+            deserialize_with: None,
         };
 
         for meta_items in field.attrs.iter().filter_map(get_serde_meta_items) {
@@ -262,39 +258,20 @@ impl FieldAttrs {
 
                     // Parse `#[serde(skip_serializing_if="...")]`
                     ast::MetaItemKind::NameValue(ref name, ref lit) if name == &"skip_serializing_if" => {
-                        let expr = wrap_skip_serializing(
+                        let path = try!(parse_lit_into_path(cx, name, lit));
-                            field_ident,
+                        field_attrs.skip_serializing_if = Some(path);
-                            try!(parse_lit_into_path(cx, name, lit)),
-                            is_enum,
-                        );
-
-                        field_attrs.skip_serializing_field_if = Some(expr);
                     }
 
                     // Parse `#[serde(serialize_with="...")]`
                     ast::MetaItemKind::NameValue(ref name, ref lit) if name == &"serialize_with" => {
-                        let expr = wrap_serialize_with(
+                        let path = try!(parse_lit_into_path(cx, name, lit));
-                            cx,
+                        field_attrs.serialize_with = Some(path);
-                            container_ty,
-                            generics,
-                            field_ident,
-                            try!(parse_lit_into_path(cx, name, lit)),
-                            is_enum,
-                        );
-
-                        field_attrs.serialize_with = Some(expr);
                     }
 
                     // Parse `#[serde(deserialize_with="...")]`
                     ast::MetaItemKind::NameValue(ref name, ref lit) if name == &"deserialize_with" => {
-                        let expr = wrap_deserialize_with(
+                        let path = try!(parse_lit_into_path(cx, name, lit));
-                            cx,
+                        field_attrs.deserialize_with = Some(path);
-                            &field.ty,
-                            generics,
-                            try!(parse_lit_into_path(cx, name, lit)),
-                        );
-
-                        field_attrs.deserialize_with = expr;
                     }
 
                     _ => {
@@ -316,22 +293,6 @@ impl FieldAttrs {
         &self.name
     }
 
-    /// Predicate for using a field's default value
-    pub fn expr_is_missing(&self) -> P<ast::Expr> {
-        match self.default_expr_if_missing {
-            Some(ref expr) => expr.clone(),
-            None => {
-                let name = self.name.deserialize_name_expr();
-                AstBuilder::new().expr()
-                    .try()
-                    .method_call("missing_field").id("visitor")
-                        .with_arg(name)
-                        .build()
-            }
-        }
-    }
-
-    /// Predicate for ignoring a field when serializing a value
     pub fn skip_serializing_field(&self) -> bool {
         self.skip_serializing_field
     }
@@ -340,28 +301,35 @@ impl FieldAttrs {
         self.skip_deserializing_field
     }
 
-    pub fn skip_serializing_field_if(&self) -> Option<&P<ast::Expr>> {
+    pub fn skip_serializing_if(&self) -> Option<&ast::Path> {
-        self.skip_serializing_field_if.as_ref()
+        self.skip_serializing_if.as_ref()
     }
 
-    pub fn serialize_with(&self) -> Option<&P<ast::Expr>> {
+    pub fn default_expr_if_missing(&self) -> Option<&P<ast::Expr>> {
+        self.default_expr_if_missing.as_ref()
+    }
+
+    pub fn serialize_with(&self) -> Option<&ast::Path> {
         self.serialize_with.as_ref()
     }
 
-    pub fn deserialize_with(&self) -> &P<ast::Expr> {
+    pub fn deserialize_with(&self) -> Option<&ast::Path> {
-        &self.deserialize_with
+        self.deserialize_with.as_ref()
     }
 }
 
 
-/// Extract out the `#[serde(...)]` attributes from a struct field.
+/// Zip together fields and `#[serde(...)]` attributes on those fields.
-pub fn get_struct_field_attrs(cx: &ExtCtxt,
+pub fn fields_with_attrs<'a>(
-                              container_ty: &P<ast::Ty>,
+    cx: &ExtCtxt,
-                              generics: &ast::Generics,
+    fields: &'a [ast::StructField],
-                              fields: &[ast::StructField],
+) -> Result<Vec<(&'a ast::StructField, FieldAttrs)>, Error> {
-                              is_enum: bool) -> Result<Vec<FieldAttrs>, Error> {
     fields.iter()
-        .map(|field| FieldAttrs::from_field(cx, container_ty, generics, field, is_enum))
+        .enumerate()
+        .map(|(i, field)| {
+            let attrs = try!(FieldAttrs::from_field(cx, i, field));
+            Ok((field, attrs))
+        })
         .collect()
 }
 
@@ -515,133 +483,3 @@ fn wrap_default(path: ast::Path) -> P<ast::Expr> {
         .build_path(path)
         .build()
 }
-
-/// This function wraps the expression in `#[serde(skip_serializing_if="...")]` in a trait to
-/// prevent it from accessing the internal `Serialize` state.
-fn wrap_skip_serializing(field_ident: ast::Ident,
-                         path: ast::Path,
-                         is_enum: bool) -> P<ast::Expr> {
-    let builder = AstBuilder::new();
-
-    let expr = builder.expr()
-        .field(field_ident)
-        .field("value")
-        .self_();
-
-    let expr = if is_enum {
-        expr
-    } else {
-        builder.expr().ref_().build(expr)
-    };
-
-    builder.expr().call()
-        .build_path(path)
-        .arg().build(expr)
-        .build()
-}
-
-/// This function wraps the expression in `#[serde(serialize_with="...")]` in a trait to
-/// prevent it from accessing the internal `Serialize` state.
-fn wrap_serialize_with(cx: &ExtCtxt,
-                       container_ty: &P<ast::Ty>,
-                       generics: &ast::Generics,
-                       field_ident: ast::Ident,
-                       path: ast::Path,
-                       is_enum: bool) -> P<ast::Expr> {
-    let builder = AstBuilder::new();
-
-    let expr = builder.expr()
-        .field(field_ident)
-        .self_();
-
-    let expr = if is_enum {
-        expr
-    } else {
-        builder.expr().ref_().build(expr)
-    };
-
-    let expr = builder.expr().call()
-        .build_path(path)
-        .arg().build(expr)
-        .arg()
-            .id("serializer")
-        .build();
-
-    let where_clause = &generics.where_clause;
-
-    quote_expr!(cx, {
-        trait __SerdeSerializeWith {
-            fn __serde_serialize_with<S>(&self, serializer: &mut S) -> Result<(), S::Error>
-                where S: _serde::ser::Serializer;
-        }
-
-        impl<'a, T> __SerdeSerializeWith for &'a T
-            where T: 'a + __SerdeSerializeWith,
-        {
-            fn __serde_serialize_with<S>(&self, serializer: &mut S) -> Result<(), S::Error>
-                where S: _serde::ser::Serializer
-            {
-                (**self).__serde_serialize_with(serializer)
-            }
-        }
-
-        impl $generics __SerdeSerializeWith for $container_ty $where_clause {
-            fn __serde_serialize_with<S>(&self, serializer: &mut S) -> Result<(), S::Error>
-                where S: _serde::ser::Serializer
-            {
-                $expr
-            }
-        }
-
-        struct __SerdeSerializeWithStruct<'a, T: 'a> {
-            value: &'a T,
-        }
-
-        impl<'a, T> _serde::ser::Serialize for __SerdeSerializeWithStruct<'a, T>
-            where T: 'a + __SerdeSerializeWith
-        {
-            fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
-                where S: _serde::ser::Serializer
-            {
-                self.value.__serde_serialize_with(serializer)
-            }
-        }
-
-        __SerdeSerializeWithStruct {
-            value: &self.value,
-        }
-    })
-}
-
-/// This function wraps the expression in `#[serde(deserialize_with="...")]` in a trait to prevent
-/// it from accessing the internal `Deserialize` state.
-fn wrap_deserialize_with(cx: &ExtCtxt,
-                         field_ty: &P<ast::Ty>,
-                         generics: &ast::Generics,
-                         path: ast::Path) -> P<ast::Expr> {
-    // Quasi-quoting doesn't do a great job of expanding generics into paths, so manually build it.
-    let ty_path = AstBuilder::new().path()
-        .segment("__SerdeDeserializeWithStruct")
-            .with_generics(generics.clone())
-            .build()
-        .build();
-
-    let where_clause = &generics.where_clause;
-
-    quote_expr!(cx, ({
-        struct __SerdeDeserializeWithStruct $generics $where_clause {
-            value: $field_ty,
-        }
-
-        impl $generics _serde::de::Deserialize for $ty_path $where_clause {
-            fn deserialize<D>(deserializer: &mut D) -> ::std::result::Result<Self, D::Error>
-                where D: _serde::de::Deserializer
-            {
-                let value = try!($path(deserializer));
-                Ok(__SerdeDeserializeWithStruct { value: value })
-            }
-        }
-
-        |visit: $ty_path| visit.value
-    }))
-}

serde_codegen/src/bound.rs

@@ -139,9 +139,9 @@ fn contains_generic(ty: &ast::Ty, generics: &ast::Generics) -> bool {
 //
 //    impl<'a, T> Serialize for Test<'a, T>
 //        where T: Serialize { ... }
-fn strip_reference(ty: &P<ast::Ty>) -> &P<ast::Ty> {
+fn strip_reference(mut ty: &P<ast::Ty>) -> &P<ast::Ty> {
-    match ty.node {
+    while let ast::TyKind::Rptr(_, ref mut_ty) = ty.node {
-        ast::TyKind::Rptr(_, ref mut_ty) => &mut_ty.ty,
+        ty = &mut_ty.ty;
-        _ => ty
     }
+    ty
 }

serde_codegen/src/de.rs

@@ -9,7 +9,6 @@ use syntax::ast::{
 };
 use syntax::codemap::Span;
 use syntax::ext::base::{Annotatable, ExtCtxt};
-use syntax::ext::build::AstBuilder;
 use syntax::parse::token::InternedString;
 use syntax::ptr::P;
 
@@ -113,22 +112,7 @@ fn deserialized_by_us(field: &ast::StructField) -> bool {
                     return false
                 }
                 ast::MetaItemKind::NameValue(ref name, _) if name == &"deserialize_with" => {
-                    // TODO: For now we require `T: Deserialize` even if the
+                    return false
-                    // field has `deserialize_with`. The reason is the signature
-                    // of serde::de::MapVisitor::missing_field which looks like:
-                    //
-                    // fn missing_field<T>(...) -> Result<T, Self::Error> where T: Deserialize
-                    //
-                    // So in order to use missing_field, the type must have the
-                    // `T: Deserialize` bound. Some formats rely on this bound
-                    // because they treat missing fields as unit.
-                    //
-                    // Long-term the fix would be to change the signature of
-                    // missing_field so it can, for example, use the
-                    // `deserialize_with` function to visit a unit in place of
-                    // the missing field.
-                    //
-                    // See https://github.com/serde-rs/serde/issues/259
                 }
                 _ => {}
             }
@@ -218,28 +202,19 @@ fn deserialize_item_struct(
                 container_attrs,
             )
         }
-        ast::VariantData::Tuple(ref fields, _) if fields.len() == 1 => {
-            deserialize_newtype_struct(
-                cx,
-                &builder,
-                item.ident,
-                impl_generics,
-                ty,
-                container_attrs,
-            )
-        }
         ast::VariantData::Tuple(ref fields, _) => {
             if fields.iter().any(|field| field.ident.is_some()) {
                 cx.span_bug(span, "tuple struct has named fields")
             }
 
-            deserialize_tuple_struct(
+            deserialize_tuple(
                 cx,
                 &builder,
                 item.ident,
+                None,
                 impl_generics,
                 ty,
-                fields.len(),
+                fields,
                 container_attrs,
             )
         }
@@ -252,6 +227,7 @@ fn deserialize_item_struct(
                 cx,
                 &builder,
                 item.ident,
+                None,
                 impl_generics,
                 ty,
                 fields,
@@ -356,15 +332,15 @@ fn deserialize_unit_struct(
             type Value = $type_ident;
 
             #[inline]
-            fn visit_unit<E>(&mut self) -> ::std::result::Result<$type_ident, E>
+            fn visit_unit<__E>(&mut self) -> ::std::result::Result<$type_ident, __E>
-                where E: _serde::de::Error,
+                where __E: _serde::de::Error,
             {
                 Ok($type_ident)
             }
 
             #[inline]
-            fn visit_seq<V>(&mut self, mut visitor: V) -> ::std::result::Result<$type_ident, V::Error>
+            fn visit_seq<__V>(&mut self, mut visitor: __V) -> ::std::result::Result<$type_ident, __V::Error>
-                where V: _serde::de::SeqVisitor,
+                where __V: _serde::de::SeqVisitor,
             {
                 try!(visitor.end());
                 self.visit_unit()
@@ -375,12 +351,14 @@ fn deserialize_unit_struct(
     }))
 }
 
-fn deserialize_newtype_struct(
+fn deserialize_tuple(
     cx: &ExtCtxt,
     builder: &aster::AstBuilder,
     type_ident: Ident,
+    variant_ident: Option<Ident>,
     impl_generics: &ast::Generics,
     ty: P<ast::Ty>,
+    fields: &[ast::StructField],
     container_attrs: &attr::ContainerAttrs,
 ) -> Result<P<ast::Expr>, Error> {
     let where_clause = &impl_generics.where_clause;
@@ -392,67 +370,50 @@ fn deserialize_newtype_struct(
         vec![deserializer_ty_arg(builder)],
     ));
 
-    let visit_seq_expr = deserialize_seq(
+    let is_enum = variant_ident.is_some();
+    let type_path = match variant_ident {
+        Some(variant_ident) => builder.path().id(type_ident).id(variant_ident).build(),
+        None => builder.path().id(type_ident).build(),
+    };
+
+    let nfields = fields.len();
+    let fields_with_attrs = try!(attr::fields_with_attrs(cx, fields));
+
+    let visit_newtype_struct = if !is_enum && nfields == 1 {
+        Some(try!(deserialize_newtype_struct(
+            cx,
+            builder,
+            type_ident,
+            &type_path,
+            impl_generics,
+            &fields_with_attrs[0],
+        )))
+    } else {
+        None
+    };
+
+    let visit_seq_expr = try!(deserialize_seq(
         cx,
         builder,
-        builder.path().id(type_ident).build(),
+        type_ident,
-        1,
+        type_path,
-    );
-
-    let type_name = container_attrs.name().deserialize_name_expr();
-
-    Ok(quote_expr!(cx, {
-        $visitor_item
-
-        impl $visitor_generics _serde::de::Visitor for $visitor_ty $where_clause {
-            type Value = $ty;
-
-            #[inline]
-            fn visit_newtype_struct<D>(&mut self, deserializer: &mut D) -> ::std::result::Result<Self::Value, D::Error>
-                where D: _serde::de::Deserializer,
-            {
-                let value = try!(_serde::de::Deserialize::deserialize(deserializer));
-                Ok($type_ident(value))
-            }
-
-            #[inline]
-            fn visit_seq<__V>(&mut self, mut visitor: __V) -> ::std::result::Result<$ty, __V::Error>
-                where __V: _serde::de::SeqVisitor,
-            {
-                $visit_seq_expr
-            }
-        }
-
-        deserializer.deserialize_newtype_struct($type_name, $visitor_expr)
-    }))
-}
-
-fn deserialize_tuple_struct(
-    cx: &ExtCtxt,
-    builder: &aster::AstBuilder,
-    type_ident: Ident,
-    impl_generics: &ast::Generics,
-    ty: P<ast::Ty>,
-    fields: usize,
-    container_attrs: &attr::ContainerAttrs,
-) -> Result<P<ast::Expr>, Error> {
-    let where_clause = &impl_generics.where_clause;
-
-    let (visitor_item, visitor_ty, visitor_expr, visitor_generics) = try!(deserialize_visitor(
-        builder,
         impl_generics,
-        vec![deserializer_ty_param(builder)],
+        &fields_with_attrs,
-        vec![deserializer_ty_arg(builder)],
+        false,
     ));
 
-    let visit_seq_expr = deserialize_seq(
+    let dispatch = if is_enum {
-        cx,
+        quote_expr!(cx,
-        builder,
+            visitor.visit_tuple($nfields, $visitor_expr))
-        builder.path().id(type_ident).build(),
+    } else if nfields == 1 {
-        fields,
+        let type_name = container_attrs.name().deserialize_name_expr();
-    );
+        quote_expr!(cx,
-
+            deserializer.deserialize_newtype_struct($type_name, $visitor_expr))
-    let type_name = container_attrs.name().deserialize_name_expr();
+    } else {
+        let type_name = container_attrs.name().deserialize_name_expr();
+        quote_expr!(cx,
+            deserializer.deserialize_tuple_struct($type_name, $nfields, $visitor_expr))
+    };
 
     Ok(quote_expr!(cx, {
         $visitor_item
@@ -460,6 +421,8 @@ fn deserialize_tuple_struct(
         impl $visitor_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,
@@ -468,64 +431,47 @@ fn deserialize_tuple_struct(
             }
         }
 
-        deserializer.deserialize_tuple_struct($type_name, $fields, $visitor_expr)
+        $dispatch
     }))
 }
 
 fn deserialize_seq(
     cx: &ExtCtxt,
     builder: &aster::AstBuilder,
-    struct_path: ast::Path,
+    type_ident: Ident,
-    fields: usize,
+    type_path: ast::Path,
-) -> P<ast::Expr> {
+    impl_generics: &ast::Generics,
-    let let_values: Vec<ast::Stmt> = (0 .. fields)
-        .map(|i| {
-            let name = builder.id(format!("__field{}", i));
-            quote_stmt!(cx,
-                let $name = match try!(visitor.visit()) {
-                    Some(value) => { value },
-                    None => {
-                        return Err(_serde::de::Error::end_of_stream());
-                    }
-                };
-            ).unwrap()
-        })
-        .collect();
-
-    let result = builder.expr().call()
-        .build_path(struct_path)
-        .with_args((0 .. fields).map(|i| builder.expr().id(format!("__field{}", i))))
-        .build();
-
-    quote_expr!(cx, {
-        $let_values
-
-        try!(visitor.end());
-
-        Ok($result)
-    })
-}
-
-fn deserialize_struct_as_seq(
-    cx: &ExtCtxt,
-    builder: &aster::AstBuilder,
-    struct_path: ast::Path,
     fields: &[(&ast::StructField, attr::FieldAttrs)],
+    is_struct: bool,
 ) -> Result<P<ast::Expr>, Error> {
     let let_values: Vec<_> = fields.iter()
         .enumerate()
-        .map(|(i, &(_, ref attrs))| {
+        .map(|(i, &(field, ref attrs))| {
             let name = builder.id(format!("__field{}", i));
             if attrs.skip_deserializing_field() {
-                let default = attrs.expr_is_missing();
+                let default = expr_is_missing(cx, attrs);
                 quote_stmt!(cx,
                     let $name = $default;
                 ).unwrap()
             } else {
-                let deserialize_with = attrs.deserialize_with();
+                let visit = match attrs.deserialize_with() {
+                    None => {
+                        let field_ty = &field.ty;
+                        quote_expr!(cx, try!(visitor.visit::<$field_ty>()))
+                    }
+                    Some(path) => {
+                        let (wrapper, wrapper_impl, wrapper_ty) = wrap_deserialize_with(
+                            cx, builder, type_ident, impl_generics, &field.ty, path);
+                        quote_expr!(cx, {
+                            $wrapper
+                            $wrapper_impl
+                            try!(visitor.visit::<$wrapper_ty>()).map(|wrap| wrap.value)
+                        })
+                    }
+                };
                 quote_stmt!(cx,
-                    let $name = match try!(visitor.visit()) {
+                    let $name = match $visit {
-                        Some(value) => { $deserialize_with(value) },
+                        Some(value) => { value },
                         None => {
                             return Err(_serde::de::Error::end_of_stream());
                         }
@@ -535,23 +481,30 @@ fn deserialize_struct_as_seq(
         })
         .collect();
 
-    let result = builder.expr().struct_path(struct_path)
+    let result = if is_struct {
-        .with_id_exprs(
+        builder.expr().struct_path(type_path)
-            fields.iter()
+            .with_id_exprs(
-                .enumerate()
+                fields.iter()
-                .map(|(i, &(field, _))| {
+                    .enumerate()
-                    (
+                    .map(|(i, &(field, _))| {
-                        match field.ident {
+                        (
-                            Some(name) => name.clone(),
+                            match field.ident {
-                            None => {
+                                Some(name) => name.clone(),
-                                cx.span_bug(field.span, "struct contains unnamed fields")
+                                None => {
-                            }
+                                    cx.span_bug(field.span, "struct contains unnamed fields")
-                        },
+                                }
-                        builder.expr().id(format!("__field{}", i)),
+                            },
-                    )
+                            builder.expr().id(format!("__field{}", i)),
-                })
+                        )
-        )
+                    })
-        .build();
+            )
+            .build()
+    } else {
+        builder.expr().call()
+            .build_path(type_path)
+            .with_args((0..fields.len()).map(|i| builder.expr().id(format!("__field{}", i))))
+            .build()
+    };
 
     Ok(quote_expr!(cx, {
         $let_values
@@ -562,10 +515,46 @@ fn deserialize_struct_as_seq(
     }))
 }
 
+fn deserialize_newtype_struct(
+    cx: &ExtCtxt,
+    builder: &aster::AstBuilder,
+    type_ident: Ident,
+    type_path: &ast::Path,
+    impl_generics: &ast::Generics,
+    field: &(&ast::StructField, attr::FieldAttrs),
+) -> Result<Vec<ast::TokenTree>, Error> {
+    let &(field, ref attrs) = field;
+    let value = match attrs.deserialize_with() {
+        None => {
+            let field_ty = &field.ty;
+            quote_expr!(cx,
+                try!(<$field_ty as _serde::Deserialize>::deserialize(__e)))
+        }
+        Some(path) => {
+            let (wrapper, wrapper_impl, wrapper_ty) = wrap_deserialize_with(
+                cx, builder, type_ident, impl_generics, &field.ty, path);
+            quote_expr!(cx, {
+                $wrapper
+                $wrapper_impl
+                try!(<$wrapper_ty as _serde::Deserialize>::deserialize(__e)).value
+            })
+        }
+    };
+    Ok(quote_tokens!(cx,
+        #[inline]
+        fn visit_newtype_struct<__E>(&mut self, __e: &mut __E) -> ::std::result::Result<Self::Value, __E::Error>
+            where __E: _serde::de::Deserializer,
+        {
+            Ok($type_path($value))
+        }
+    ))
+}
+
 fn deserialize_struct(
     cx: &ExtCtxt,
     builder: &aster::AstBuilder,
     type_ident: Ident,
+    variant_ident: Option<Ident>,
     impl_generics: &ast::Generics,
     ty: P<ast::Ty>,
     fields: &[ast::StructField],
@@ -580,26 +569,42 @@ fn deserialize_struct(
         vec![deserializer_ty_arg(builder)],
     ));
 
-    let type_path = builder.path().id(type_ident).build();
+    let type_path = match variant_ident {
+        Some(variant_ident) => builder.path().id(type_ident).id(variant_ident).build(),
+        None => builder.path().id(type_ident).build(),
+    };
 
-    let fields_with_attrs = try!(fields_with_attrs(cx, impl_generics, &ty, fields, false));
+    let fields_with_attrs = try!(attr::fields_with_attrs(cx, fields));
 
-    let visit_seq_expr = try!(deserialize_struct_as_seq(
+    let visit_seq_expr = try!(deserialize_seq(
         cx,
         builder,
+        type_ident,
         type_path.clone(),
+        impl_generics,
         &fields_with_attrs,
+        true,
     ));
 
     let (field_visitor, fields_stmt, visit_map_expr) = try!(deserialize_struct_visitor(
         cx,
         builder,
+        type_ident,
         type_path.clone(),
+        impl_generics,
         &fields_with_attrs,
         container_attrs,
     ));
 
-    let type_name = container_attrs.name().deserialize_name_expr();
+    let is_enum = variant_ident.is_some();
+    let dispatch = if is_enum {
+        quote_expr!(cx,
+            visitor.visit_struct(FIELDS, $visitor_expr))
+    } else {
+        let type_name = container_attrs.name().deserialize_name_expr();
+        quote_expr!(cx,
+            deserializer.deserialize_struct($type_name, FIELDS, $visitor_expr))
+    };
 
     Ok(quote_expr!(cx, {
         $field_visitor
@@ -626,7 +631,7 @@ fn deserialize_struct(
 
         $fields_stmt
 
-        deserializer.deserialize_struct($type_name, FIELDS, $visitor_expr)
+        $dispatch
     }))
 }
 
@@ -747,29 +752,34 @@ fn deserialize_variant(
                 Ok($type_ident::$variant_ident)
             }))
         }
-        ast::VariantData::Tuple(ref args, _) if args.len() == 1 => {
+        ast::VariantData::Tuple(ref fields, _) if fields.len() == 1 => {
-            Ok(quote_expr!(cx, {
+            deserialize_newtype_variant(
-                let val = try!(visitor.visit_newtype());
-                Ok($type_ident::$variant_ident(val))
-            }))
-        }
-        ast::VariantData::Tuple(ref fields, _) => {
-            deserialize_tuple_variant(
                 cx,
                 builder,
                 type_ident,
                 variant_ident,
                 generics,
-                ty,
+                &fields[0],
-                fields.len(),
             )
         }
-        ast::VariantData::Struct(ref fields, _) => {
+        ast::VariantData::Tuple(ref fields, _) => {
-            deserialize_struct_variant(
+            deserialize_tuple(
                 cx,
                 builder,
                 type_ident,
-                variant_ident,
+                Some(variant_ident),
+                generics,
+                ty,
+                fields,
+                container_attrs,
+            )
+        }
+        ast::VariantData::Struct(ref fields, _) => {
+            deserialize_struct(
+                cx,
+                builder,
+                type_ident,
+                Some(variant_ident),
                 generics,
                 ty,
                 fields,
@@ -779,116 +789,31 @@ fn deserialize_variant(
     }
 }
 
-fn deserialize_tuple_variant(
+fn deserialize_newtype_variant(
     cx: &ExtCtxt,
     builder: &aster::AstBuilder,
-    type_ident: ast::Ident,
+    type_ident: Ident,
-    variant_ident: ast::Ident,
+    variant_ident: Ident,
-    generics: &ast::Generics,
+    impl_generics: &ast::Generics,
-    ty: P<ast::Ty>,
+    field: &ast::StructField,
-    fields: usize,
 ) -> Result<P<ast::Expr>, Error> {
-    let where_clause = &generics.where_clause;
+    let attrs = try!(attr::FieldAttrs::from_field(cx, 0, field));
-
+    let visit = match attrs.deserialize_with() {
-    let (visitor_item, visitor_ty, visitor_expr, visitor_generics) = try!(deserialize_visitor(
+        None => {
-        builder,
+            let field_ty = &field.ty;
-        generics,
+            quote_expr!(cx, try!(visitor.visit_newtype::<$field_ty>()))
-        vec![deserializer_ty_param(builder)],
-        vec![deserializer_ty_arg(builder)],
-    ));
-
-    let visit_seq_expr = deserialize_seq(
-        cx,
-        builder,
-        builder.path().id(type_ident).id(variant_ident).build(),
-        fields,
-    );
-
-    Ok(quote_expr!(cx, {
-        $visitor_item
-
-        impl $visitor_generics _serde::de::Visitor for $visitor_ty $where_clause {
-            type Value = $ty;
-
-            fn visit_seq<__V>(&mut self, mut visitor: __V) -> ::std::result::Result<$ty, __V::Error>
-                where __V: _serde::de::SeqVisitor,
-            {
-                $visit_seq_expr
-            }
         }
-
+        Some(path) => {
-        visitor.visit_tuple($fields, $visitor_expr)
+            let (wrapper, wrapper_impl, wrapper_ty) = wrap_deserialize_with(
-    }))
+                cx, builder, type_ident, impl_generics, &field.ty, path);
-}
+            quote_expr!(cx, {
-
+                $wrapper
-fn deserialize_struct_variant(
+                $wrapper_impl
-    cx: &ExtCtxt,
+                try!(visitor.visit_newtype::<$wrapper_ty>()).value
-    builder: &aster::AstBuilder,
+            })
-    type_ident: ast::Ident,
-    variant_ident: ast::Ident,
-    generics: &ast::Generics,
-    ty: P<ast::Ty>,
-    fields: &[ast::StructField],
-    container_attrs: &attr::ContainerAttrs,
-) -> Result<P<ast::Expr>, Error> {
-    let where_clause = &generics.where_clause;
-
-    let type_path = builder.path()
-        .id(type_ident)
-        .id(variant_ident)
-        .build();
-
-    let fields_with_attrs = try!(fields_with_attrs(cx, generics, &ty, fields, true));
-
-    let visit_seq_expr = try!(deserialize_struct_as_seq(
-        cx,
-        builder,
-        type_path.clone(),
-        &fields_with_attrs,
-    ));
-
-    let (field_visitor, fields_stmt, field_expr) = try!(deserialize_struct_visitor(
-        cx,
-        builder,
-        type_path,
-        &fields_with_attrs,
-        container_attrs,
-    ));
-
-    let (visitor_item, visitor_ty, visitor_expr, visitor_generics) = try!(deserialize_visitor(
-        builder,
-        generics,
-        vec![deserializer_ty_param(builder)],
-        vec![deserializer_ty_arg(builder)],
-    ));
-
-    Ok(quote_expr!(cx, {
-        $field_visitor
-
-        $visitor_item
-
-        impl $visitor_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,
-            {
-                $visit_seq_expr
-            }
-
-            #[inline]
-            fn visit_map<__V>(&mut self, mut visitor: __V) -> ::std::result::Result<$ty, __V::Error>
-                where __V: _serde::de::MapVisitor,
-            {
-                $field_expr
-            }
         }
-
+    };
-        $fields_stmt
+    Ok(quote_expr!(cx, Ok($type_ident::$variant_ident($visit))))
-
-        visitor.visit_struct(FIELDS, $visitor_expr)
-    }))
 }
 
 fn deserialize_field_visitor(
@@ -1008,13 +933,11 @@ fn deserialize_field_visitor(
     let impl_item = quote_item!(cx,
         impl _serde::de::Deserialize for __Field {
             #[inline]
-            fn deserialize<D>(deserializer: &mut D) -> ::std::result::Result<__Field, D::Error>
+            fn deserialize<__D>(deserializer: &mut __D) -> ::std::result::Result<__Field, __D::Error>
-                where D: _serde::de::Deserializer,
+                where __D: _serde::de::Deserializer,
             {
-                use std::marker::PhantomData;
+                struct __FieldVisitor<__D> {
-
+                    phantom: ::std::marker::PhantomData<__D>
-                struct __FieldVisitor<D> {
-                    phantom: PhantomData<D>
                 }
 
                 impl<__D> _serde::de::Visitor for __FieldVisitor<__D>
@@ -1022,26 +945,30 @@ fn deserialize_field_visitor(
                 {
                     type Value = __Field;
 
-                    fn visit_usize<E>(&mut self, value: usize) -> ::std::result::Result<__Field, E>
+                    fn visit_usize<__E>(&mut self, value: usize) -> ::std::result::Result<__Field, __E>
-                        where E: _serde::de::Error,
+                        where __E: _serde::de::Error,
                     {
                         $index_body
                     }
 
-                    fn visit_str<E>(&mut self, value: &str) -> ::std::result::Result<__Field, E>
+                    fn visit_str<__E>(&mut self, value: &str) -> ::std::result::Result<__Field, __E>
-                        where E: _serde::de::Error,
+                        where __E: _serde::de::Error,
                     {
                         $str_body
                     }
 
-                    fn visit_bytes<E>(&mut self, value: &[u8]) -> ::std::result::Result<__Field, E>
+                    fn visit_bytes<__E>(&mut self, value: &[u8]) -> ::std::result::Result<__Field, __E>
-                        where E: _serde::de::Error,
+                        where __E: _serde::de::Error,
                     {
                         $bytes_body
                     }
                 }
 
-                deserializer.deserialize_struct_field(__FieldVisitor::<D>{ phantom: PhantomData })
+                deserializer.deserialize_struct_field(
+                    __FieldVisitor::<__D>{
+                        phantom: ::std::marker::PhantomData
+                    }
+                )
             }
         }
     ).unwrap();
@@ -1052,7 +979,9 @@ fn deserialize_field_visitor(
 fn deserialize_struct_visitor(
     cx: &ExtCtxt,
     builder: &aster::AstBuilder,
+    type_ident: Ident,
     struct_path: ast::Path,
+    impl_generics: &ast::Generics,
     fields: &[(&ast::StructField, attr::FieldAttrs)],
     container_attrs: &attr::ContainerAttrs,
 ) -> Result<(Vec<P<ast::Item>>, ast::Stmt, P<ast::Expr>), Error> {
@@ -1071,7 +1000,9 @@ fn deserialize_struct_visitor(
     let visit_map_expr = try!(deserialize_map(
         cx,
         builder,
+        type_ident,
         struct_path,
+        impl_generics,
         fields,
         container_attrs,
     ));
@@ -1100,7 +1031,9 @@ fn deserialize_struct_visitor(
 fn deserialize_map(
     cx: &ExtCtxt,
     builder: &aster::AstBuilder,
+    type_ident: Ident,
     struct_path: ast::Path,
+    impl_generics: &ast::Generics,
     fields: &[(&ast::StructField, attr::FieldAttrs)],
     container_attrs: &attr::ContainerAttrs,
 ) -> Result<P<ast::Expr>, Error> {
@@ -1114,17 +1047,40 @@ fn deserialize_map(
     // Declare each field that will be deserialized.
     let let_values: Vec<ast::Stmt> = fields_attrs_names.iter()
         .filter(|&&(_, ref attrs, _)| !attrs.skip_deserializing_field())
-        .map(|&(_, _, name)| quote_stmt!(cx, let mut $name = None;).unwrap())
+        .map(|&(field, _, name)| {
+            let field_ty = &field.ty;
+            quote_stmt!(cx, let mut $name: Option<$field_ty> = None;).unwrap()
+        })
         .collect();
 
     // Match arms to extract a value for a field.
     let value_arms = fields_attrs_names.iter()
         .filter(|&&(_, ref attrs, _)| !attrs.skip_deserializing_field())
-        .map(|&(_, ref attrs, name)| {
+        .map(|&(field, ref attrs, name)| {
-            let deserialize_with = attrs.deserialize_with();
+            let deser_name = attrs.name().deserialize_name();
+            let name_str = builder.expr().lit().str(deser_name);
+
+            let visit = match attrs.deserialize_with() {
+                None => {
+                    let field_ty = &field.ty;
+                    quote_expr!(cx, try!(visitor.visit_value::<$field_ty>()))
+                }
+                Some(path) => {
+                    let (wrapper, wrapper_impl, wrapper_ty) = wrap_deserialize_with(
+                        cx, builder, type_ident, impl_generics, &field.ty, path);
+                    quote_expr!(cx, ({
+                        $wrapper
+                        $wrapper_impl
+                        try!(visitor.visit_value::<$wrapper_ty>()).value
+                    }))
+                }
+            };
             quote_arm!(cx,
                 __Field::$name => {
-                    $name = Some($deserialize_with(try!(visitor.visit_value())));
+                    if $name.is_some() {
+                        return Err(<__V::Error as _serde::de::Error>::duplicate_field($name_str));
+                    }
+                    $name = Some($visit);
                 }
             )
         })
@@ -1155,7 +1111,7 @@ fn deserialize_map(
     let extract_values = fields_attrs_names.iter()
         .filter(|&&(_, ref attrs, _)| !attrs.skip_deserializing_field())
         .map(|&(_, ref attrs, name)| {
-            let missing_expr = attrs.expr_is_missing();
+            let missing_expr = expr_is_missing(cx, attrs);
 
             Ok(quote_stmt!(cx,
                 let $name = match $name {
@@ -1180,7 +1136,7 @@ fn deserialize_map(
                             }
                         },
                         if attrs.skip_deserializing_field() {
-                            attrs.expr_is_missing()
+                            expr_is_missing(cx, attrs)
                         } else {
                             builder.expr().id(name)
                         }
@@ -1192,7 +1148,7 @@ fn deserialize_map(
     Ok(quote_expr!(cx, {
         $let_values
 
-        while let Some(key) = try!(visitor.visit_key()) {
+        while let Some(key) = try!(visitor.visit_key::<__Field>()) {
             match key {
                 $value_arms
                 $skipped_arms
@@ -1208,17 +1164,73 @@ fn deserialize_map(
     }))
 }
 
-fn fields_with_attrs<'a>(
+/// This function wraps the expression in `#[serde(deserialize_with="...")]` in
+/// a trait to prevent it from accessing the internal `Deserialize` state.
+fn wrap_deserialize_with(
     cx: &ExtCtxt,
-    generics: &ast::Generics,
+    builder: &aster::AstBuilder,
-    ty: &P<ast::Ty>,
+    type_ident: Ident,
-    fields: &'a [ast::StructField],
+    impl_generics: &ast::Generics,
-    is_enum: bool
+    field_ty: &P<ast::Ty>,
-) -> Result<Vec<(&'a ast::StructField, attr::FieldAttrs)>, Error> {
+    deserialize_with: &ast::Path,
-    fields.iter()
+) -> (ast::Stmt, ast::Stmt, ast::Path) {
-        .map(|field| {
+    // Quasi-quoting doesn't do a great job of expanding generics into paths,
-            let attrs = try!(attr::FieldAttrs::from_field(cx, &ty, generics, field, is_enum));
+    // so manually build it.
-            Ok((field, attrs))
+    let wrapper_ty = builder.path()
-        })
+        .segment("__SerdeDeserializeWithStruct")
-        .collect()
+            .with_generics(impl_generics.clone())
+            .build()
+        .build();
+
+    let where_clause = &impl_generics.where_clause;
+
+    let phantom_ty = builder.path()
+        .segment(type_ident)
+            .with_generics(builder.from_generics(impl_generics.clone())
+                .strip_ty_params()
+                .build())
+            .build()
+        .build();
+
+    (
+        quote_stmt!(cx,
+            struct __SerdeDeserializeWithStruct $impl_generics $where_clause {
+                value: $field_ty,
+                phantom: ::std::marker::PhantomData<$phantom_ty>,
+            }
+        ).unwrap(),
+        quote_stmt!(cx,
+            impl $impl_generics _serde::de::Deserialize for $wrapper_ty $where_clause {
+                fn deserialize<__D>(__d: &mut __D) -> ::std::result::Result<Self, __D::Error>
+                    where __D: _serde::de::Deserializer
+                {
+                    let value = try!($deserialize_with(__d));
+                    Ok(__SerdeDeserializeWithStruct {
+                        value: value,
+                        phantom: ::std::marker::PhantomData,
+                    })
+                }
+            }
+        ).unwrap(),
+        wrapper_ty,
+    )
+}
+
+fn expr_is_missing(
+    cx: &ExtCtxt,
+    attrs: &attr::FieldAttrs,
+) -> P<ast::Expr> {
+    if let Some(expr) = attrs.default_expr_if_missing() {
+        return expr.clone();
+    }
+    let name = attrs.name().deserialize_name_expr();
+    match attrs.deserialize_with() {
+        None => {
+            quote_expr!(cx, try!(visitor.missing_field($name)))
+        }
+        Some(_) => {
+            quote_expr!(cx, return Err(
+                <__V::Error as _serde::de::Error>::missing_field($name)))
+        }
+    }
 }

serde_codegen/src/ser.rs

@@ -185,6 +185,10 @@ fn serialize_item_struct(
         ast::VariantData::Tuple(ref fields, _) if fields.len() == 1 => {
             serialize_newtype_struct(
                 cx,
+                &builder,
+                impl_generics,
+                ty,
+                &fields[0],
                 container_attrs,
             )
         }
@@ -198,7 +202,7 @@ fn serialize_item_struct(
                 &builder,
                 impl_generics,
                 ty,
-                fields.len(),
+                fields,
                 container_attrs,
             )
         }
@@ -232,12 +236,24 @@ fn serialize_unit_struct(
 
 fn serialize_newtype_struct(
     cx: &ExtCtxt,
+    builder: &aster::AstBuilder,
+    impl_generics: &ast::Generics,
+    container_ty: P<ast::Ty>,
+    field: &ast::StructField,
     container_attrs: &attr::ContainerAttrs,
 ) -> Result<P<ast::Expr>, Error> {
     let type_name = container_attrs.name().serialize_name_expr();
 
+    let attrs = try!(attr::FieldAttrs::from_field(cx, 0, field));
+
+    let mut field_expr = quote_expr!(cx, &self.0);
+    if let Some(path) = attrs.serialize_with() {
+        field_expr = wrap_serialize_with(cx, builder,
+            &container_ty, impl_generics, &field.ty, path, field_expr);
+    }
+
     Ok(quote_expr!(cx,
-        _serializer.serialize_newtype_struct($type_name, &self.0)
+        _serializer.serialize_newtype_struct($type_name, $field_expr)
     ))
 }
 
@@ -246,10 +262,10 @@ fn serialize_tuple_struct(
     builder: &aster::AstBuilder,
     impl_generics: &ast::Generics,
     ty: P<ast::Ty>,
-    fields: usize,
+    fields: &[ast::StructField],
     container_attrs: &attr::ContainerAttrs,
 ) -> Result<P<ast::Expr>, Error> {
-    let (visitor_struct, visitor_impl) = serialize_tuple_struct_visitor(
+    let (visitor_struct, visitor_impl) = try!(serialize_tuple_struct_visitor(
         cx,
         builder,
         ty.clone(),
@@ -260,7 +276,8 @@ fn serialize_tuple_struct(
         builder.id("serialize_tuple_struct_elt"),
         fields,
         impl_generics,
-    );
+        false,
+    ));
 
     let type_name = container_attrs.name().serialize_name_expr();
 
@@ -362,12 +379,8 @@ fn serialize_variant(
 
     match variant.node.data {
         ast::VariantData::Unit(_) => {
-            let pat = builder.pat().path()
-                .id(type_ident).id(variant_ident)
-                .build();
-
             Ok(quote_arm!(cx,
-                $pat => {
+                $type_ident::$variant_ident => {
                     _serde::ser::Serializer::serialize_unit_variant(
                         _serializer,
                         $type_name,
@@ -378,23 +391,19 @@ fn serialize_variant(
             ))
         },
         ast::VariantData::Tuple(ref fields, _) if fields.len() == 1 => {
-            let field = builder.id("__simple_value");
+            let expr = try!(serialize_newtype_variant(
-            let field = builder.pat().ref_id(field);
+                cx,
-            let pat = builder.pat().enum_()
+                builder,
-                .id(type_ident).id(variant_ident).build()
+                type_name,
-                .with_pats(Some(field).into_iter())
+                variant_index,
-                .build();
+                variant_name,
+                ty,
+                generics,
+                &fields[0],
+            ));
 
             Ok(quote_arm!(cx,
-                $pat => {
+                $type_ident::$variant_ident(ref __simple_value) => { $expr }
-                    _serde::ser::Serializer::serialize_newtype_variant(
-                        _serializer,
-                        $type_name,
-                        $variant_index,
-                        $variant_name,
-                        __simple_value,
-                    )
-                }
             ))
         },
         ast::VariantData::Tuple(ref fields, _) => {
@@ -410,7 +419,7 @@ fn serialize_variant(
                 )
                 .build();
 
-            let expr = serialize_tuple_variant(
+            let expr = try!(serialize_tuple_variant(
                 cx,
                 builder,
                 type_name,
@@ -420,7 +429,7 @@ fn serialize_variant(
                 ty,
                 fields,
                 field_names,
-            );
+            ));
 
             Ok(quote_arm!(cx,
                 $pat => { $expr }
@@ -468,6 +477,35 @@ fn serialize_variant(
     }
 }
 
+fn serialize_newtype_variant(
+    cx: &ExtCtxt,
+    builder: &aster::AstBuilder,
+    type_name: P<ast::Expr>,
+    variant_index: usize,
+    variant_name: P<ast::Expr>,
+    container_ty: P<ast::Ty>,
+    generics: &ast::Generics,
+    field: &ast::StructField,
+) -> Result<P<ast::Expr>, Error> {
+    let attrs = try!(attr::FieldAttrs::from_field(cx, 0, field));
+
+    let mut field_expr = quote_expr!(cx, __simple_value);
+    if let Some(path) = attrs.serialize_with() {
+        field_expr = wrap_serialize_with(cx, builder,
+            &container_ty, generics, &field.ty, path, field_expr);
+    }
+
+    Ok(quote_expr!(cx,
+        _serde::ser::Serializer::serialize_newtype_variant(
+            _serializer,
+            $type_name,
+            $variant_index,
+            $variant_name,
+            $field_expr,
+        )
+    ))
+}
+
 fn serialize_tuple_variant(
     cx: &ExtCtxt,
     builder: &aster::AstBuilder,
@@ -478,7 +516,7 @@ fn serialize_tuple_variant(
     structure_ty: P<ast::Ty>,
     fields: &[ast::StructField],
     field_names: Vec<Ident>,
-) -> P<ast::Expr> {
+) -> Result<P<ast::Expr>, Error> {
     let variant_ty = builder.ty().tuple()
         .with_tys(
             fields.iter().map(|field| {
@@ -490,15 +528,16 @@ fn serialize_tuple_variant(
         )
         .build();
 
-    let (visitor_struct, visitor_impl) = serialize_tuple_struct_visitor(
+    let (visitor_struct, visitor_impl) = try!(serialize_tuple_struct_visitor(
         cx,
         builder,
         structure_ty.clone(),
         variant_ty,
         builder.id("serialize_tuple_variant_elt"),
-        fields.len(),
+        fields,
         generics,
-    );
+        true,
+    ));
 
     let value_expr = builder.expr().tuple()
         .with_exprs(
@@ -508,7 +547,7 @@ fn serialize_tuple_variant(
         )
         .build();
 
-    quote_expr!(cx, {
+    Ok(quote_expr!(cx, {
         $visitor_struct
         $visitor_impl
         _serializer.serialize_tuple_variant($type_name, $variant_index, $variant_name, Visitor {
@@ -516,7 +555,7 @@ fn serialize_tuple_variant(
             state: 0,
             _structure_ty: ::std::marker::PhantomData::<&$structure_ty>,
         })
-    })
+    }))
 }
 
 fn serialize_struct_variant(
@@ -614,20 +653,33 @@ fn serialize_tuple_struct_visitor(
     structure_ty: P<ast::Ty>,
     variant_ty: P<ast::Ty>,
     serializer_method: ast::Ident,
-    fields: usize,
+    fields: &[ast::StructField],
-    generics: &ast::Generics
+    generics: &ast::Generics,
-) -> (P<ast::Item>, P<ast::Item>) {
+    is_enum: bool,
-    let arms: Vec<ast::Arm> = (0 .. fields)
+) -> Result<(P<ast::Item>, P<ast::Item>), Error> {
-        .map(|i| {
+    let fields_with_attrs = try!(attr::fields_with_attrs(cx, fields));
-            let expr = builder.expr().method_call(serializer_method)
+
-                .id("_serializer")
+    let arms: Vec<_> = fields_with_attrs.iter()
-                .arg().ref_().tup_field(i).field("value").self_()
+        .enumerate()
-                .build();
+        .map(|(i, &(field, ref attrs))| {
+            let mut field_expr = builder.expr().tup_field(i).field("value").self_();
+            if !is_enum {
+                field_expr = quote_expr!(cx, &$field_expr);
+            }
+
+            let continue_if_skip = attrs.skip_serializing_if()
+                .map(|path| quote_stmt!(cx, if $path($field_expr) { continue }));
+
+            if let Some(path) = attrs.serialize_with() {
+                field_expr = wrap_serialize_with(cx, builder,
+                    &structure_ty, generics, &field.ty, path, field_expr);
+            }
 
             quote_arm!(cx,
                 $i => {
                     self.state += 1;
-                    Ok(Some(try!($expr)))
+                    $continue_if_skip
+                    Ok(Some(try!(_serializer.$serializer_method($field_expr))))
                 }
             )
         })
@@ -644,7 +696,9 @@ fn serialize_tuple_struct_visitor(
         .strip_bounds()
         .build();
 
-    (
+    let nfields = fields.len();
+
+    Ok((
         quote_item!(cx,
             struct Visitor $visitor_impl_generics $where_clause {
                 state: usize,
@@ -658,8 +712,8 @@ fn serialize_tuple_struct_visitor(
             for Visitor $visitor_generics
             $where_clause {
                 #[inline]
-                fn visit<S>(&mut self, _serializer: &mut S) -> ::std::result::Result<Option<()>, S::Error>
+                fn visit<__S>(&mut self, _serializer: &mut __S) -> ::std::result::Result<Option<()>, __S::Error>
-                    where S: _serde::ser::Serializer
+                    where __S: _serde::ser::Serializer
                 {
                     match self.state {
                         $arms
@@ -669,11 +723,11 @@ fn serialize_tuple_struct_visitor(
 
                 #[inline]
                 fn len(&self) -> Option<usize> {
-                    Some($fields)
+                    Some($nfields)
                 }
             }
         ).unwrap(),
-    )
+    ))
 }
 
 fn serialize_struct_visitor(
@@ -686,28 +740,27 @@ fn serialize_struct_visitor(
     generics: &ast::Generics,
     is_enum: bool,
 ) -> Result<(P<ast::Item>, P<ast::Item>), Error> {
-    let field_attrs = try!(
+    let fields_with_attrs = try!(attr::fields_with_attrs(cx, fields));
-        attr::get_struct_field_attrs(cx, &structure_ty, generics, fields, is_enum)
-    );
 
-    let arms: Vec<ast::Arm> = fields.iter().zip(field_attrs.iter())
+    let arms: Vec<ast::Arm> = fields_with_attrs.iter()
-        .filter(|&(_, ref field_attr)| !field_attr.skip_serializing_field())
+        .filter(|&&(_, ref attrs)| !attrs.skip_serializing_field())
         .enumerate()
-        .map(|(i, (ref field, ref field_attr))| {
+        .map(|(i, &(field, ref attrs))| {
-            let name = field.ident.expect("struct has unnamed 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 key_expr = field_attr.name().serialize_name_expr();
+            let key_expr = attrs.name().serialize_name_expr();
 
-            let stmt = if let Some(expr) = field_attr.skip_serializing_field_if() {
+            let continue_if_skip = attrs.skip_serializing_if()
-                    Some(quote_stmt!(cx, if $expr { continue; }))
+                .map(|path| quote_stmt!(cx, if $path($field_expr) { continue }));
-            } else {
-                None
-            };
 
-            let field_expr = match field_attr.serialize_with() {
+            if let Some(path) = attrs.serialize_with() {
-                Some(expr) => expr.clone(),
+                field_expr = wrap_serialize_with(cx, builder,
-                None => quote_expr!(cx, &self.value.$name),
+                    &structure_ty, generics, &field.ty, path, field_expr)
-            };
+            }
 
             let expr = quote_expr!(cx,
                 _serializer.$serializer_method($key_expr, $field_expr)
@@ -716,7 +769,7 @@ fn serialize_struct_visitor(
             quote_arm!(cx,
                 $i => {
                     self.state += 1;
-                    $stmt
+                    $continue_if_skip
                     return Ok(Some(try!($expr)));
                 }
             )
@@ -734,16 +787,18 @@ fn serialize_struct_visitor(
         .strip_bounds()
         .build();
 
-    let len = field_attrs.iter()
+    let len = fields_with_attrs.iter()
-        .filter(|field_attr| !field_attr.skip_serializing_field())
+        .filter(|&&(_, ref attrs)| !attrs.skip_serializing_field())
-        .map(|field_attr| {
+        .map(|&(field, ref attrs)| {
-            match field_attr.skip_serializing_field_if() {
+            let ident = field.ident.expect("struct has unnamed fields");
-                Some(expr) => {
+            let mut field_expr = quote_expr!(cx, self.value.$ident);
-                    quote_expr!(cx, if $expr { 0 } else { 1 })
+            if !is_enum {
-                }
+                field_expr = quote_expr!(cx, &$field_expr);
-                None => {
+            }
-                    quote_expr!(cx, 1)
+
-                }
+            match 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));
@@ -763,8 +818,8 @@ fn serialize_struct_visitor(
             for Visitor $visitor_generics
             $where_clause {
                 #[inline]
-                fn visit<S>(&mut self, _serializer: &mut S) -> ::std::result::Result<Option<()>, S::Error>
+                fn visit<__S>(&mut self, _serializer: &mut __S) -> ::std::result::Result<Option<()>, __S::Error>
-                    where S: _serde::ser::Serializer,
+                    where __S: _serde::ser::Serializer,
                 {
                     loop {
                         match self.state {
@@ -782,3 +837,46 @@ fn serialize_struct_visitor(
         ).unwrap(),
     ))
 }
+
+fn wrap_serialize_with(
+    cx: &ExtCtxt,
+    builder: &aster::AstBuilder,
+    container_ty: &P<ast::Ty>,
+    generics: &ast::Generics,
+    field_ty: &P<ast::Ty>,
+    path: &ast::Path,
+    value: P<ast::Expr>,
+) -> P<ast::Expr> {
+    let where_clause = &generics.where_clause;
+
+    let wrapper_generics = builder.from_generics(generics.clone())
+        .add_lifetime_bound("'__a")
+        .lifetime_name("'__a")
+        .build();
+
+    let wrapper_ty = builder.path()
+        .segment("__SerializeWith")
+            .with_generics(wrapper_generics.clone())
+            .build()
+        .build();
+
+    quote_expr!(cx, {
+        struct __SerializeWith $wrapper_generics $where_clause {
+            value: &'__a $field_ty,
+            phantom: ::std::marker::PhantomData<$container_ty>,
+        }
+
+        impl $wrapper_generics _serde::ser::Serialize for $wrapper_ty $where_clause {
+            fn serialize<__S>(&self, __s: &mut __S) -> Result<(), __S::Error>
+                where __S: _serde::ser::Serializer
+            {
+                $path(self.value, __s)
+            }
+        }
+
+        __SerializeWith {
+            value: $value,
+            phantom: ::std::marker::PhantomData::<$container_ty>,
+        }
+    })
+}

serde_macros/Cargo.toml

@@ -1,12 +1,13 @@
 [package]
 name = "serde_macros"
-version = "0.7.4"
+version = "0.7.7"
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>"]
 license = "MIT/Apache-2.0"
 description = "Macros to auto-generate implementations for the serde framework"
 repository = "https://github.com/serde-rs/serde"
 documentation = "https://github.com/serde-rs/serde"
 keywords = ["serde", "serialization"]
+include = ["Cargo.toml", "src/**/*.rs"]
 
 [lib]
 name = "serde_macros"
@@ -17,12 +18,12 @@ nightly-testing = ["clippy", "serde/nightly-testing", "serde_codegen/nightly-tes
 
 [dependencies]
 clippy = { version = "^0.*", optional = true }
-serde_codegen = { version = "^0.7.4", path = "../serde_codegen", default-features = false, features = ["nightly"] }
+serde_codegen = { version = "^0.7.7", path = "../serde_codegen", default-features = false, features = ["nightly"] }
 
 [dev-dependencies]
 compiletest_rs = "^0.1.1"
 rustc-serialize = "^0.3.16"
-serde = { version = "^0.7.4", path = "../serde" }
+serde = { version = "^0.7.7", path = "../serde" }
 
 [[test]]
 name = "test"

serde_tests/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "serde_tests"
-version = "0.7.1"
+version = "0.7.6"
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>"]
 license = "MIT/Apache-2.0"
 description = "A generic serialization/deserialization framework"
@@ -14,14 +14,14 @@ build = "build.rs"
 nightly-testing = ["clippy", "serde/nightly-testing", "serde_codegen/nightly-testing"]
 
 [build-dependencies]
-syntex = { version = "^0.32.0" }
+syntex = { version = "^0.33.0" }
-syntex_syntax = { version = "^0.32.0" }
+syntex_syntax = { version = "^0.33.0" }
 serde_codegen = { version = "*", path = "../serde_codegen", features = ["with-syntex"] }
 
 [dev-dependencies]
 rustc-serialize = "^0.3.16"
 serde = { version = "*", path = "../serde" }
-syntex = "^0.32.0"
+syntex = "^0.33.0"
 
 [dependencies]
 clippy = { version = "^0.*", optional = true }

serde_tests/benches/bench_enum.rs

@@ -1,9 +1,9 @@
 use test::Bencher;
 use std::error;
 use std::fmt;
-use rustc_serialize::{Decoder, Decodable};
+use rustc_serialize::Decodable;
 use serde;
-use serde::de::{Deserializer, Deserialize};
+use serde::de::Deserialize;
 
 //////////////////////////////////////////////////////////////////////////////
 

serde_tests/benches/bench_struct.rs

@@ -3,10 +3,10 @@ use test::Bencher;
 use std::fmt;
 use std::error;
 
-use rustc_serialize::{Decoder, Decodable};
+use rustc_serialize::Decodable;
 
 use serde;
-use serde::de::{Deserializer, Deserialize};
+use serde::de::Deserialize;
 
 //////////////////////////////////////////////////////////////////////////////
 

serde_tests/tests/test.rs.in

@@ -6,5 +6,6 @@ mod token;
 mod test_annotations;
 mod test_bytes;
 mod test_de;
+mod test_gen;
 mod test_macros;
 mod test_ser;

serde_tests/tests/test_annotations.rs

@@ -237,6 +237,14 @@ impl Default for NotDeserializeStruct {
     }
 }
 
+impl DeserializeWith for NotDeserializeStruct {
+    fn deserialize_with<D>(_: &mut D) -> Result<Self, D::Error>
+        where D: Deserializer
+    {
+        panic!()
+    }
+}
+
 // Does not implement Deserialize.
 #[derive(Debug, PartialEq)]
 enum NotDeserializeEnum { Trouble }
@@ -248,13 +256,15 @@ impl MyDefault for NotDeserializeEnum {
 }
 
 #[derive(Debug, PartialEq, Deserialize)]
-struct ContainsNotDeserialize<A, B, C: MyDefault> {
+struct ContainsNotDeserialize<A, B, C: DeserializeWith, E: MyDefault> {
     #[serde(skip_deserializing)]
     a: A,
     #[serde(skip_deserializing, default)]
     b: B,
-    #[serde(skip_deserializing, default="MyDefault::my_default")]
+    #[serde(deserialize_with="DeserializeWith::deserialize_with", default)]
     c: C,
+    #[serde(skip_deserializing, default="MyDefault::my_default")]
+    e: E,
 }
 
 // Tests that a struct field does not need to implement Deserialize if it is
@@ -266,7 +276,8 @@ fn test_elt_not_deserialize() {
         &ContainsNotDeserialize {
             a: NotDeserializeStruct(123),
             b: NotDeserializeStruct(123),
-            c: NotDeserializeEnum::Trouble,
+            c: NotDeserializeStruct(123),
+            e: NotDeserializeEnum::Trouble,
         },
         vec![
             Token::StructStart("ContainsNotDeserialize", Some(3)),

serde_tests/tests/test_de.rs

@@ -2,9 +2,6 @@ use std::collections::{BTreeMap, BTreeSet, HashMap, HashSet};
 use std::net;
 use std::path::PathBuf;
 
-extern crate serde;
-use self::serde::de::{Deserializer, Visitor};
-
 use token::{
     Error,
     Token,
@@ -725,4 +722,32 @@ declare_error_tests! {
         ],
         Error::UnexpectedToken(Token::SeqSep),
     }
+    test_duplicate_field_struct<Struct> {
+        vec![
+            Token::MapStart(Some(3)),
+                Token::MapSep,
+                Token::Str("a"),
+                Token::I32(1),
+
+                Token::MapSep,
+                Token::Str("a"),
+                Token::I32(3),
+            Token::MapEnd,
+        ],
+        Error::DuplicateFieldError("a"),
+    }
+    test_duplicate_field_enum<Enum> {
+        vec![
+            Token::EnumMapStart("Enum", "Map", Some(3)),
+                Token::EnumMapSep,
+                Token::Str("a"),
+                Token::I32(1),
+
+                Token::EnumMapSep,
+                Token::Str("a"),
+                Token::I32(3),
+            Token::EnumMapEnd,
+        ],
+        Error::DuplicateFieldError("a"),
+    }
 }

serde_tests/tests/test_gen.rs

@@ -0,0 +1,83 @@
+// These just test that serde_codegen is able to produce code that compiles
+// successfully when there are a variety of generics and non-(de)serializable
+// types involved.
+
+extern crate serde;
+use self::serde::ser::{Serialize, Serializer};
+use self::serde::de::{Deserialize, Deserializer};
+
+//////////////////////////////////////////////////////////////////////////
+
+#[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 {
+        t: T,
+        #[serde(serialize_with="ser_x", deserialize_with="de_x")]
+        x: X },
+}
+
+#[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 Newtype(
+    #[serde(serialize_with="ser_x", deserialize_with="de_x")]
+    X
+);
+
+#[derive(Serialize, Deserialize)]
+struct Tuple<T>(
+    T,
+    #[serde(serialize_with="ser_x", deserialize_with="de_x")]
+    X,
+);
+
+//////////////////////////////////////////////////////////////////////////
+
+// 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!() }
+

serde_tests/tests/token.rs

@@ -410,6 +410,7 @@ pub enum Error {
     UnknownFieldError(String),
     UnknownVariantError(String),
     MissingFieldError(&'static str),
+    DuplicateFieldError(&'static str),
     InvalidName(&'static str),
     InvalidValue(String),
     UnexpectedToken(Token<'static>),
@@ -429,6 +430,10 @@ impl de::Error for Error {
 
     fn end_of_stream() -> Error { Error::EndOfStreamError }
 
+    fn invalid_value(msg: &str) -> Error {
+        Error::InvalidValue(msg.to_owned())
+    }
+
     fn unknown_field(field: &str) -> Error {
         Error::UnknownFieldError(field.to_owned())
     }
@@ -440,6 +445,10 @@ impl de::Error for Error {
     fn missing_field(field: &'static str) -> Error {
         Error::MissingFieldError(field)
     }
+
+    fn duplicate_field(field: &'static str) -> Error {
+        Error::DuplicateFieldError(field)
+    }
 }
 
 impl fmt::Display for Error {