Release 0.9.11

Introduce Serializer::collect_str (fixes #786)

serde/Cargo.toml

@@ -1,16 +1,16 @@
 [package]
 name = "serde"
-version = "0.9.5"
+version = "0.9.11"
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>"]
 license = "MIT/Apache-2.0"
 description = "A generic serialization/deserialization framework"
 homepage = "https://serde.rs"
 repository = "https://github.com/serde-rs/serde"
 documentation = "https://docs.serde.rs/serde/"
-readme = "../README.md"
-keywords = ["serde", "serialization"]
+keywords = ["serde", "serialization", "no_std"]
 categories = ["encoding"]
-include = ["Cargo.toml", "src/**/*.rs"]
+readme = "../README.md"
+include = ["Cargo.toml", "src/**/*.rs", "README.md", "LICENSE-APACHE", "LICENSE-MIT"]
 
 [badges]
 travis-ci = { repository = "serde-rs/serde" }
@@ -24,5 +24,11 @@ alloc = ["unstable"]
 collections = ["alloc"]
 unstable-testing = ["unstable", "std"]
 
+# to get serde_derive picked up by play.integer32.com
+playground = ["serde_derive"]
+
+[dependencies]
+serde_derive = { version = "0.9", optional = true }
+
 [dev-dependencies]
 serde_derive = "0.9"

serde/LICENSE-APACHE

@@ -0,0 +1 @@
+../LICENSE-APACHE

serde/LICENSE-MIT

@@ -0,0 +1 @@
+../LICENSE-MIT

serde/README.md

@@ -0,0 +1 @@
+../README.md

serde/src/bytes.rs

@@ -60,9 +60,7 @@ pub struct Bytes<'a> {
 impl<'a> Bytes<'a> {
     /// Wrap an existing `&[u8]`.
     pub fn new(bytes: &'a [u8]) -> Self {
-        Bytes {
-            bytes: bytes,
-        }
+        Bytes { bytes: bytes }
     }
 }
 
@@ -98,7 +96,9 @@ impl<'a> Into<&'a [u8]> for Bytes<'a> {
 impl<'a> ops::Deref for Bytes<'a> {
     type Target = [u8];
 
-    fn deref(&self) -> &[u8] { self.bytes }
+    fn deref(&self) -> &[u8] {
+        self.bytes
+    }
 }
 
 impl<'a> ser::Serialize for Bytes<'a> {
@@ -114,6 +114,7 @@ impl<'a> ser::Serialize for Bytes<'a> {
 
 #[cfg(any(feature = "std", feature = "collections"))]
 mod bytebuf {
+    use core::cmp;
     use core::ops;
     use core::fmt;
     use core::fmt::Write;
@@ -161,9 +162,7 @@ mod bytebuf {
 
         /// Wrap existing bytes in a `ByteBuf`.
         pub fn from<T: Into<Vec<u8>>>(bytes: T) -> Self {
-            ByteBuf {
-                bytes: bytes.into(),
-            }
+            ByteBuf { bytes: bytes.into() }
         }
     }
 
@@ -216,11 +215,15 @@ mod bytebuf {
     impl ops::Deref for ByteBuf {
         type Target = [u8];
 
-        fn deref(&self) -> &[u8] { &self.bytes[..] }
+        fn deref(&self) -> &[u8] {
+            &self.bytes[..]
+        }
     }
 
     impl ops::DerefMut for ByteBuf {
-        fn deref_mut(&mut self) -> &mut [u8] { &mut self.bytes[..] }
+        fn deref_mut(&mut self) -> &mut [u8] {
+            &mut self.bytes[..]
+        }
     }
 
     impl ser::Serialize for ByteBuf {
@@ -243,16 +246,16 @@ mod bytebuf {
 
         #[inline]
         fn visit_unit<E>(self) -> Result<ByteBuf, E>
-            where E: de::Error,
+            where E: de::Error
         {
             Ok(ByteBuf::new())
         }
 
         #[inline]
         fn visit_seq<V>(self, mut visitor: V) -> Result<ByteBuf, V::Error>
-            where V: de::SeqVisitor,
+            where V: de::SeqVisitor
         {
-            let (len, _) = visitor.size_hint();
+            let len = cmp::min(visitor.size_hint().0, 4096);
             let mut values = Vec::with_capacity(len);
 
             while let Some(value) = try!(visitor.visit()) {
@@ -264,26 +267,26 @@ mod bytebuf {
 
         #[inline]
         fn visit_bytes<E>(self, v: &[u8]) -> Result<ByteBuf, E>
-            where E: de::Error,
+            where E: de::Error
         {
             Ok(ByteBuf::from(v))
         }
 
         #[inline]
         fn visit_byte_buf<E>(self, v: Vec<u8>) -> Result<ByteBuf, E>
-            where E: de::Error,
+            where E: de::Error
         {
             Ok(ByteBuf::from(v))
         }
 
         fn visit_str<E>(self, v: &str) -> Result<ByteBuf, E>
-            where E: de::Error,
+            where E: de::Error
         {
             Ok(ByteBuf::from(v))
         }
 
         fn visit_string<E>(self, v: String) -> Result<ByteBuf, E>
-            where E: de::Error,
+            where E: de::Error
         {
             Ok(ByteBuf::from(v))
         }
@@ -302,7 +305,9 @@ mod bytebuf {
 ///////////////////////////////////////////////////////////////////////////////
 
 #[inline]
-fn escape_bytestring<'a>(bytes: &'a [u8]) -> iter::FlatMap<slice::Iter<'a, u8>, char::EscapeDefault, fn(&u8) -> char::EscapeDefault> {
+fn escape_bytestring<'a>
+    (bytes: &'a [u8])
+     -> iter::FlatMap<slice::Iter<'a, u8>, char::EscapeDefault, fn(&u8) -> char::EscapeDefault> {
     fn f(b: &u8) -> char::EscapeDefault {
         char::from_u32(*b as u32).unwrap().escape_default()
     }

serde/src/de/impls.rs

@@ -6,32 +6,16 @@ use std::borrow::Cow;
 use collections::borrow::Cow;
 
 #[cfg(all(feature = "collections", not(feature = "std")))]
-use collections::{
-    BinaryHeap,
-    BTreeMap,
-    BTreeSet,
-    LinkedList,
-    VecDeque,
-    Vec,
-    String,
-};
+use collections::{BinaryHeap, BTreeMap, BTreeSet, LinkedList, VecDeque, Vec, String};
 
 #[cfg(feature = "std")]
-use std::collections::{
-    HashMap,
-    HashSet,
-    BinaryHeap,
-    BTreeMap,
-    BTreeSet,
-    LinkedList,
-    VecDeque,
-};
+use std::collections::{HashMap, HashSet, BinaryHeap, BTreeMap, BTreeSet, LinkedList, VecDeque};
 
-#[cfg(feature = "collections")]
-use collections::enum_set::{CLike, EnumSet};
 #[cfg(feature = "collections")]
 use collections::borrow::ToOwned;
 
+#[cfg(any(feature = "std", feature = "collections"))]
+use core::cmp;
 use core::fmt;
 #[cfg(feature = "std")]
 use core::hash::{Hash, BuildHasher};
@@ -41,6 +25,8 @@ use std::net;
 #[cfg(feature = "std")]
 use std::path;
 use core::str;
+#[cfg(feature = "std")]
+use std::ffi::CString;
 
 #[cfg(feature = "std")]
 use std::rc::Rc;
@@ -65,19 +51,13 @@ use core::nonzero::{NonZero, Zeroable};
 #[allow(deprecated)] // required for impl Deserialize for NonZero<T>
 use core::num::Zero;
 
-use de::{
-    Deserialize,
-    Deserializer,
-    EnumVisitor,
-    Error,
-    MapVisitor,
-    SeqVisitor,
-    Unexpected,
-    VariantVisitor,
-    Visitor,
-};
+use de::{Deserialize, Deserializer, EnumVisitor, Error, MapVisitor, SeqVisitor, Unexpected,
+         VariantVisitor, Visitor};
 use de::from_primitive::FromPrimitive;
 
+#[cfg(feature = "std")]
+use bytes::ByteBuf;
+
 ///////////////////////////////////////////////////////////////////////////////
 
 /// A visitor that produces a `()`.
@@ -91,13 +71,13 @@ impl Visitor for UnitVisitor {
     }
 
     fn visit_unit<E>(self) -> Result<(), E>
-        where E: Error,
+        where E: Error
     {
         Ok(())
     }
 
     fn visit_seq<V>(self, _: V) -> Result<(), V::Error>
-        where V: SeqVisitor,
+        where V: SeqVisitor
     {
         Ok(())
     }
@@ -105,7 +85,7 @@ impl Visitor for UnitVisitor {
 
 impl Deserialize for () {
     fn deserialize<D>(deserializer: D) -> Result<(), D::Error>
-        where D: Deserializer,
+        where D: Deserializer
     {
         deserializer.deserialize_unit(UnitVisitor)
     }
@@ -124,13 +104,13 @@ impl Visitor for BoolVisitor {
     }
 
     fn visit_bool<E>(self, v: bool) -> Result<bool, E>
-        where E: Error,
+        where E: Error
     {
         Ok(v)
     }
 
     fn visit_str<E>(self, s: &str) -> Result<bool, E>
-        where E: Error,
+        where E: Error
     {
         match s.trim_matches(::utils::Pattern_White_Space) {
             "true" => Ok(true),
@@ -142,7 +122,7 @@ impl Visitor for BoolVisitor {
 
 impl Deserialize for bool {
     fn deserialize<D>(deserializer: D) -> Result<bool, D::Error>
-        where D: Deserializer,
+        where D: Deserializer
     {
         deserializer.deserialize_bool(BoolVisitor)
     }
@@ -233,14 +213,14 @@ impl Visitor for CharVisitor {
 
     #[inline]
     fn visit_char<E>(self, v: char) -> Result<char, E>
-        where E: Error,
+        where E: Error
     {
         Ok(v)
     }
 
     #[inline]
     fn visit_str<E>(self, v: &str) -> Result<char, E>
-        where E: Error,
+        where E: Error
     {
         let mut iter = v.chars();
         match (iter.next(), iter.next()) {
@@ -253,7 +233,7 @@ impl Visitor for CharVisitor {
 impl Deserialize for char {
     #[inline]
     fn deserialize<D>(deserializer: D) -> Result<char, D::Error>
-        where D: Deserializer,
+        where D: Deserializer
     {
         deserializer.deserialize_char(CharVisitor)
     }
@@ -273,25 +253,25 @@ impl Visitor for StringVisitor {
     }
 
     fn visit_str<E>(self, v: &str) -> Result<String, E>
-        where E: Error,
+        where E: Error
     {
         Ok(v.to_owned())
     }
 
     fn visit_string<E>(self, v: String) -> Result<String, E>
-        where E: Error,
+        where E: Error
     {
         Ok(v)
     }
 
     fn visit_unit<E>(self) -> Result<String, E>
-        where E: Error,
+        where E: Error
     {
         Ok(String::new())
     }
 
     fn visit_bytes<E>(self, v: &[u8]) -> Result<String, E>
-        where E: Error,
+        where E: Error
     {
         match str::from_utf8(v) {
             Ok(s) => Ok(s.to_owned()),
@@ -300,7 +280,7 @@ impl Visitor for StringVisitor {
     }
 
     fn visit_byte_buf<E>(self, v: Vec<u8>) -> Result<String, E>
-        where E: Error,
+        where E: Error
     {
         match String::from_utf8(v) {
             Ok(s) => Ok(s),
@@ -312,7 +292,7 @@ impl Visitor for StringVisitor {
 #[cfg(any(feature = "std", feature = "collections"))]
 impl Deserialize for String {
     fn deserialize<D>(deserializer: D) -> Result<String, D::Error>
-        where D: Deserializer,
+        where D: Deserializer
     {
         deserializer.deserialize_string(StringVisitor)
     }
@@ -320,13 +300,23 @@ impl Deserialize for String {
 
 ///////////////////////////////////////////////////////////////////////////////
 
+#[cfg(feature = "std")]
+impl Deserialize for CString {
+    fn deserialize<D>(deserializer: D) -> Result<CString, D::Error>
+        where D: Deserializer
+    {
+        let bytes = try!(ByteBuf::deserialize(deserializer));
+        CString::new(bytes).map_err(Error::custom)
+    }
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
 struct OptionVisitor<T> {
     marker: PhantomData<T>,
 }
 
-impl<
-    T: Deserialize,
-> Visitor for OptionVisitor<T> {
+impl<T: Deserialize> Visitor for OptionVisitor<T> {
     type Value = Option<T>;
 
     fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
@@ -335,29 +325,31 @@ impl<
 
     #[inline]
     fn visit_unit<E>(self) -> Result<Option<T>, E>
-        where E: Error,
+        where E: Error
     {
         Ok(None)
     }
 
     #[inline]
     fn visit_none<E>(self) -> Result<Option<T>, E>
-        where E: Error,
+        where E: Error
     {
         Ok(None)
     }
 
     #[inline]
     fn visit_some<D>(self, deserializer: D) -> Result<Option<T>, D::Error>
-        where D: Deserializer,
+        where D: Deserializer
     {
         Ok(Some(try!(Deserialize::deserialize(deserializer))))
     }
 }
 
-impl<T> Deserialize for Option<T> where T: Deserialize {
+impl<T> Deserialize for Option<T>
+    where T: Deserialize
+{
     fn deserialize<D>(deserializer: D) -> Result<Option<T>, D::Error>
-        where D: Deserializer,
+        where D: Deserializer
     {
         deserializer.deserialize_option(OptionVisitor { marker: PhantomData })
     }
@@ -379,7 +371,7 @@ impl<T> Visitor for PhantomDataVisitor<T> {
 
     #[inline]
     fn visit_unit<E>(self) -> Result<PhantomData<T>, E>
-        where E: Error,
+        where E: Error
     {
         Ok(PhantomData)
     }
@@ -387,7 +379,7 @@ impl<T> Visitor for PhantomDataVisitor<T> {
 
 impl<T> Deserialize for PhantomData<T> {
     fn deserialize<D>(deserializer: D) -> Result<PhantomData<T>, D::Error>
-        where D: Deserializer,
+        where D: Deserializer
     {
         let visitor = PhantomDataVisitor { marker: PhantomData };
         deserializer.deserialize_unit_struct("PhantomData", visitor)
@@ -469,7 +461,7 @@ seq_impl!(
     BinaryHeapVisitor<T: Deserialize + Ord>,
     visitor,
     BinaryHeap::new(),
-    BinaryHeap::with_capacity(visitor.size_hint().0),
+    BinaryHeap::with_capacity(cmp::min(visitor.size_hint().0, 4096)),
     BinaryHeap::push);
 
 #[cfg(any(feature = "std", feature = "collections"))]
@@ -481,15 +473,6 @@ seq_impl!(
     BTreeSet::new(),
     BTreeSet::insert);
 
-#[cfg(feature = "collections")]
-seq_impl!(
-    EnumSet<T>,
-    EnumSetVisitor<T: Deserialize + CLike>,
-    visitor,
-    EnumSet::new(),
-    EnumSet::new(),
-    EnumSet::insert);
-
 #[cfg(any(feature = "std", feature = "collections"))]
 seq_impl!(
     LinkedList<T>,
@@ -506,7 +489,7 @@ seq_impl!(
                    S: BuildHasher + Default>,
     visitor,
     HashSet::with_hasher(S::default()),
-    HashSet::with_capacity_and_hasher(visitor.size_hint().0, S::default()),
+    HashSet::with_capacity_and_hasher(cmp::min(visitor.size_hint().0, 4096), S::default()),
     HashSet::insert);
 
 #[cfg(any(feature = "std", feature = "collections"))]
@@ -515,7 +498,7 @@ seq_impl!(
     VecVisitor<T: Deserialize>,
     visitor,
     Vec::new(),
-    Vec::with_capacity(visitor.size_hint().0),
+    Vec::with_capacity(cmp::min(visitor.size_hint().0, 4096)),
     Vec::push);
 
 #[cfg(any(feature = "std", feature = "collections"))]
@@ -524,7 +507,7 @@ seq_impl!(
     VecDequeVisitor<T: Deserialize>,
     visitor,
     VecDeque::new(),
-    VecDeque::with_capacity(visitor.size_hint().0),
+    VecDeque::with_capacity(cmp::min(visitor.size_hint().0, 4096)),
     VecDeque::push_back);
 
 ///////////////////////////////////////////////////////////////////////////////
@@ -535,13 +518,13 @@ struct ArrayVisitor<A> {
 
 impl<A> ArrayVisitor<A> {
     pub fn new() -> Self {
-        ArrayVisitor {
-            marker: PhantomData,
-        }
+        ArrayVisitor { marker: PhantomData }
     }
 }
 
-impl<T> Visitor for ArrayVisitor<[T; 0]> where T: Deserialize {
+impl<T> Visitor for ArrayVisitor<[T; 0]>
+    where T: Deserialize
+{
     type Value = [T; 0];
 
     fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
@@ -550,14 +533,14 @@ impl<T> Visitor for ArrayVisitor<[T; 0]> where T: Deserialize {
 
     #[inline]
     fn visit_unit<E>(self) -> Result<[T; 0], E>
-        where E: Error,
+        where E: Error
     {
         Ok([])
     }
 
     #[inline]
     fn visit_seq<V>(self, _: V) -> Result<[T; 0], V::Error>
-        where V: SeqVisitor,
+        where V: SeqVisitor
     {
         Ok([])
     }
@@ -567,7 +550,7 @@ impl<T> Deserialize for [T; 0]
     where T: Deserialize
 {
     fn deserialize<D>(deserializer: D) -> Result<[T; 0], D::Error>
-        where D: Deserializer,
+        where D: Deserializer
     {
         deserializer.deserialize_seq_fixed_size(0, ArrayVisitor::<[T; 0]>::new())
     }
@@ -802,14 +785,14 @@ map_impl!(
                    S: BuildHasher + Default>,
     visitor,
     HashMap::with_hasher(S::default()),
-    HashMap::with_capacity_and_hasher(visitor.size_hint().0, S::default()));
+    HashMap::with_capacity_and_hasher(cmp::min(visitor.size_hint().0, 4096), S::default()));
 
 ///////////////////////////////////////////////////////////////////////////////
 
 #[cfg(feature = "std")]
 impl Deserialize for net::IpAddr {
     fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
-        where D: Deserializer,
+        where D: Deserializer
     {
         let s = try!(String::deserialize(deserializer));
         match s.parse() {
@@ -822,7 +805,7 @@ impl Deserialize for net::IpAddr {
 #[cfg(feature = "std")]
 impl Deserialize for net::Ipv4Addr {
     fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
-        where D: Deserializer,
+        where D: Deserializer
     {
         let s = try!(String::deserialize(deserializer));
         match s.parse() {
@@ -835,7 +818,7 @@ impl Deserialize for net::Ipv4Addr {
 #[cfg(feature = "std")]
 impl Deserialize for net::Ipv6Addr {
     fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
-        where D: Deserializer,
+        where D: Deserializer
     {
         let s = try!(String::deserialize(deserializer));
         match s.parse() {
@@ -850,7 +833,7 @@ impl Deserialize for net::Ipv6Addr {
 #[cfg(feature = "std")]
 impl Deserialize for net::SocketAddr {
     fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
-        where D: Deserializer,
+        where D: Deserializer
     {
         let s = try!(String::deserialize(deserializer));
         match s.parse() {
@@ -863,7 +846,7 @@ impl Deserialize for net::SocketAddr {
 #[cfg(feature = "std")]
 impl Deserialize for net::SocketAddrV4 {
     fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
-        where D: Deserializer,
+        where D: Deserializer
     {
         let s = try!(String::deserialize(deserializer));
         match s.parse() {
@@ -876,7 +859,7 @@ impl Deserialize for net::SocketAddrV4 {
 #[cfg(feature = "std")]
 impl Deserialize for net::SocketAddrV6 {
     fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
-        where D: Deserializer,
+        where D: Deserializer
     {
         let s = try!(String::deserialize(deserializer));
         match s.parse() {
@@ -900,13 +883,13 @@ impl Visitor for PathBufVisitor {
     }
 
     fn visit_str<E>(self, v: &str) -> Result<path::PathBuf, E>
-        where E: Error,
+        where E: Error
     {
         Ok(From::from(v))
     }
 
     fn visit_string<E>(self, v: String) -> Result<path::PathBuf, E>
-        where E: Error,
+        where E: Error
     {
         Ok(From::from(v))
     }
@@ -915,7 +898,7 @@ impl Visitor for PathBufVisitor {
 #[cfg(feature = "std")]
 impl Deserialize for path::PathBuf {
     fn deserialize<D>(deserializer: D) -> Result<path::PathBuf, D::Error>
-        where D: Deserializer,
+        where D: Deserializer
     {
         deserializer.deserialize_string(PathBufVisitor)
     }
@@ -926,7 +909,7 @@ impl Deserialize for path::PathBuf {
 #[cfg(any(feature = "std", feature = "alloc"))]
 impl<T: Deserialize> Deserialize for Box<T> {
     fn deserialize<D>(deserializer: D) -> Result<Box<T>, D::Error>
-        where D: Deserializer,
+        where D: Deserializer
     {
         let val = try!(Deserialize::deserialize(deserializer));
         Ok(Box::new(val))
@@ -936,7 +919,7 @@ impl<T: Deserialize> Deserialize for Box<T> {
 #[cfg(any(feature = "std", feature = "collections"))]
 impl<T: Deserialize> Deserialize for Box<[T]> {
     fn deserialize<D>(deserializer: D) -> Result<Box<[T]>, D::Error>
-        where D: Deserializer,
+        where D: Deserializer
     {
         let v: Vec<T> = try!(Deserialize::deserialize(deserializer));
         Ok(v.into_boxed_slice())
@@ -956,7 +939,7 @@ impl Deserialize for Box<str> {
 #[cfg(any(feature = "std", feature = "alloc"))]
 impl<T: Deserialize> Deserialize for Arc<T> {
     fn deserialize<D>(deserializer: D) -> Result<Arc<T>, D::Error>
-        where D: Deserializer,
+        where D: Deserializer
     {
         let val = try!(Deserialize::deserialize(deserializer));
         Ok(Arc::new(val))
@@ -966,7 +949,7 @@ impl<T: Deserialize> Deserialize for Arc<T> {
 #[cfg(any(feature = "std", feature = "alloc"))]
 impl<T: Deserialize> Deserialize for Rc<T> {
     fn deserialize<D>(deserializer: D) -> Result<Rc<T>, D::Error>
-        where D: Deserializer,
+        where D: Deserializer
     {
         let val = try!(Deserialize::deserialize(deserializer));
         Ok(Rc::new(val))
@@ -974,10 +957,13 @@ 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, {
+impl<'a, T: ?Sized> Deserialize for Cow<'a, T>
+    where T: ToOwned,
+          T::Owned: Deserialize
+{
     #[inline]
     fn deserialize<D>(deserializer: D) -> Result<Cow<'a, T>, D::Error>
-        where D: Deserializer,
+        where D: Deserializer
     {
         let val = try!(Deserialize::deserialize(deserializer));
         Ok(Cow::Owned(val))
@@ -997,13 +983,16 @@ impl<'a, T: ?Sized> Deserialize for Cow<'a, T> where T: ToOwned, T::Owned: Deser
 #[cfg(feature = "std")]
 impl Deserialize for Duration {
     fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
-        where D: Deserializer,
+        where D: Deserializer
     {
-        enum Field { Secs, Nanos };
+        enum Field {
+            Secs,
+            Nanos,
+        };
 
         impl Deserialize for Field {
             fn deserialize<D>(deserializer: D) -> Result<Field, D::Error>
-                where D: Deserializer,
+                where D: Deserializer
             {
                 struct FieldVisitor;
 
@@ -1015,7 +1004,7 @@ impl Deserialize for Duration {
                     }
 
                     fn visit_str<E>(self, value: &str) -> Result<Field, E>
-                        where E: Error,
+                        where E: Error
                     {
                         match value {
                             "secs" => Ok(Field::Secs),
@@ -1025,7 +1014,7 @@ impl Deserialize for Duration {
                     }
 
                     fn visit_bytes<E>(self, value: &[u8]) -> Result<Field, E>
-                        where E: Error,
+                        where E: Error
                     {
                         match value {
                             b"secs" => Ok(Field::Secs),
@@ -1052,7 +1041,7 @@ impl Deserialize for Duration {
             }
 
             fn visit_seq<V>(self, mut visitor: V) -> Result<Duration, V::Error>
-                where V: SeqVisitor,
+                where V: SeqVisitor
             {
                 let secs: u64 = match try!(visitor.visit()) {
                     Some(value) => value,
@@ -1070,7 +1059,7 @@ impl Deserialize for Duration {
             }
 
             fn visit_map<V>(self, mut visitor: V) -> Result<Duration, V::Error>
-                where V: MapVisitor,
+                where V: MapVisitor
             {
                 let mut secs: Option<u64> = None;
                 let mut nanos: Option<u32> = None;
@@ -1111,24 +1100,30 @@ impl Deserialize for Duration {
 
 #[cfg(feature = "unstable")]
 #[allow(deprecated)] // num::Zero is deprecated but there is no replacement
-impl<T> Deserialize for NonZero<T> where T: Deserialize + PartialEq + Zeroable + Zero {
-    fn deserialize<D>(deserializer: D) -> Result<NonZero<T>, D::Error> where D: Deserializer {
+impl<T> Deserialize for NonZero<T>
+    where T: Deserialize + PartialEq + Zeroable + Zero
+{
+    fn deserialize<D>(deserializer: D) -> Result<NonZero<T>, D::Error>
+        where D: Deserializer
+    {
         let value = try!(Deserialize::deserialize(deserializer));
         if value == Zero::zero() {
-            return Err(Error::custom("expected a non-zero value"))
-        }
-        unsafe {
-            Ok(NonZero::new(value))
+            return Err(Error::custom("expected a non-zero value"));
         }
+        unsafe { Ok(NonZero::new(value)) }
     }
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 
 
-impl<T, E> Deserialize for Result<T, E> where T: Deserialize, E: Deserialize {
+impl<T, E> Deserialize for Result<T, E>
+    where T: Deserialize,
+          E: Deserialize
+{
     fn deserialize<D>(deserializer: D) -> Result<Result<T, E>, D::Error>
-                      where D: Deserializer {
+        where D: Deserializer
+    {
         enum Field {
             Ok,
             Err,
@@ -1148,15 +1143,21 @@ impl<T, E> Deserialize for Result<T, E> where T: Deserialize, E: Deserialize {
                         formatter.write_str("`Ok` or `Err`")
                     }
 
-                    fn visit_u32<E>(self, value: u32) -> Result<Field, E> where E: Error {
+                    fn visit_u32<E>(self, value: u32) -> Result<Field, E>
+                        where E: Error
+                    {
                         match value {
                             0 => Ok(Field::Ok),
                             1 => Ok(Field::Err),
-                            _ => Err(Error::invalid_value(Unexpected::Unsigned(value as u64), &self)),
+                            _ => {
+                                Err(Error::invalid_value(Unexpected::Unsigned(value as u64), &self))
+                            }
                         }
                     }
 
-                    fn visit_str<E>(self, value: &str) -> Result<Field, E> where E: Error {
+                    fn visit_str<E>(self, value: &str) -> Result<Field, E>
+                        where E: Error
+                    {
                         match value {
                             "Ok" => Ok(Field::Ok),
                             "Err" => Ok(Field::Err),
@@ -1164,14 +1165,18 @@ impl<T, E> Deserialize for Result<T, E> where T: Deserialize, E: Deserialize {
                         }
                     }
 
-                    fn visit_bytes<E>(self, value: &[u8]) -> Result<Field, E> where E: Error {
+                    fn visit_bytes<E>(self, value: &[u8]) -> Result<Field, E>
+                        where E: Error
+                    {
                         match value {
                             b"Ok" => Ok(Field::Ok),
                             b"Err" => Ok(Field::Err),
                             _ => {
                                 match str::from_utf8(value) {
                                     Ok(value) => Err(Error::unknown_variant(value, VARIANTS)),
-                                    Err(_) => Err(Error::invalid_value(Unexpected::Bytes(value), &self)),
+                                    Err(_) => {
+                                        Err(Error::invalid_value(Unexpected::Bytes(value), &self))
+                                    }
                                 }
                             }
                         }
@@ -1219,7 +1224,7 @@ pub struct IgnoredAny;
 impl Deserialize for IgnoredAny {
     #[inline]
     fn deserialize<D>(deserializer: D) -> Result<IgnoredAny, D::Error>
-        where D: Deserializer,
+        where D: Deserializer
     {
         struct IgnoredAnyVisitor;
 
@@ -1252,7 +1257,7 @@ impl Deserialize for IgnoredAny {
 
             #[inline]
             fn visit_str<E>(self, _: &str) -> Result<IgnoredAny, E>
-                where E: Error,
+                where E: Error
             {
                 Ok(IgnoredAny)
             }
@@ -1264,14 +1269,14 @@ impl Deserialize for IgnoredAny {
 
             #[inline]
             fn visit_some<D>(self, _: D) -> Result<IgnoredAny, D::Error>
-                where D: Deserializer,
+                where D: Deserializer
             {
                 Ok(IgnoredAny)
             }
 
             #[inline]
             fn visit_newtype_struct<D>(self, _: D) -> Result<IgnoredAny, D::Error>
-                where D: Deserializer,
+                where D: Deserializer
             {
                 Ok(IgnoredAny)
             }
@@ -1283,7 +1288,7 @@ impl Deserialize for IgnoredAny {
 
             #[inline]
             fn visit_seq<V>(self, mut visitor: V) -> Result<IgnoredAny, V::Error>
-                where V: SeqVisitor,
+                where V: SeqVisitor
             {
                 while let Some(_) = try!(visitor.visit::<IgnoredAny>()) {
                     // Gobble
@@ -1293,7 +1298,7 @@ impl Deserialize for IgnoredAny {
 
             #[inline]
             fn visit_map<V>(self, mut visitor: V) -> Result<IgnoredAny, V::Error>
-                where V: MapVisitor,
+                where V: MapVisitor
             {
                 while let Some((_, _)) = try!(visitor.visit::<IgnoredAny, IgnoredAny>()) {
                     // Gobble
@@ -1303,7 +1308,7 @@ impl Deserialize for IgnoredAny {
 
             #[inline]
             fn visit_bytes<E>(self, _: &[u8]) -> Result<IgnoredAny, E>
-                where E: Error,
+                where E: Error
             {
                 Ok(IgnoredAny)
             }

serde/src/de/mod.rs

@@ -115,6 +115,8 @@ mod from_primitive;
 // Helpers used by generated code. Not public API.
 #[doc(hidden)]
 pub mod private;
+#[cfg(any(feature = "std", feature = "collections"))]
+mod content;
 
 ///////////////////////////////////////////////////////////////////////////////
 
@@ -179,7 +181,10 @@ pub trait Error: Sized + error::Error {
                 write!(formatter, "invalid type: {}, expected {}", self.unexp, self.exp)
             }
         }
-        Error::custom(InvalidType { unexp: unexp, exp: exp })
+        Error::custom(InvalidType {
+            unexp: unexp,
+            exp: exp,
+        })
     }
 
     /// Raised when a `Deserialize` receives a value of the right type but that
@@ -205,7 +210,10 @@ pub trait Error: Sized + error::Error {
                 write!(formatter, "invalid value: {}, expected {}", self.unexp, self.exp)
             }
         }
-        Error::custom(InvalidValue { unexp: unexp, exp: exp })
+        Error::custom(InvalidValue {
+            unexp: unexp,
+            exp: exp,
+        })
     }
 
     /// Raised when deserializing a sequence or map and the input data contains
@@ -227,7 +235,10 @@ pub trait Error: Sized + error::Error {
                 write!(formatter, "invalid length {}, expected {}", self.len, self.exp)
             }
         }
-        Error::custom(InvalidLength { len: len, exp: exp })
+        Error::custom(InvalidLength {
+            len: len,
+            exp: exp,
+        })
     }
 
     /// Raised when a `Deserialize` enum type received a variant with an
@@ -251,7 +262,10 @@ pub trait Error: Sized + error::Error {
                 }
             }
         }
-        Error::custom(UnknownVariant { variant: variant, expected: expected })
+        Error::custom(UnknownVariant {
+            variant: variant,
+            expected: expected,
+        })
     }
 
     /// Raised when a `Deserialize` struct type received a field with an
@@ -275,7 +289,10 @@ pub trait Error: Sized + error::Error {
                 }
             }
         }
-        Error::custom(UnknownField { field: field, expected: expected })
+        Error::custom(UnknownField {
+            field: field,
+            expected: expected,
+        })
     }
 
     /// Raised when a `Deserialize` struct type expected to receive a required
@@ -468,7 +485,9 @@ pub trait Expected {
     fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result;
 }
 
-impl<T> Expected for T where T: Visitor {
+impl<T> Expected for T
+    where T: Visitor
+{
     fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
         self.expecting(formatter)
     }
@@ -488,8 +507,8 @@ impl<'a> Display for Expected + 'a {
 
 ///////////////////////////////////////////////////////////////////////////////
 
-/// An implementation of this trait is a **data structure** that can be
-/// deserialized from any data format supported by Serde.
+/// A **data structure** that can be deserialized from any data format supported
+/// by Serde.
 ///
 /// Serde provides `Deserialize` implementations for many Rust primitive and
 /// standard library types. The complete list is [here][de]. All of these can
@@ -519,8 +538,7 @@ pub trait Deserialize: Sized {
     /// manual for more information about how to implement this method.
     ///
     /// [impl-deserialize]: https://serde.rs/impl-deserialize.html
-    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
-        where D: Deserializer;
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error> where D: Deserializer;
 }
 
 /// `DeserializeSeed` is the stateful form of the `Deserialize` trait. If you
@@ -668,8 +686,7 @@ pub trait DeserializeSeed: Sized {
 
     /// Equivalent to the more common `Deserialize::deserialize` method, except
     /// with some initial piece of data (the seed) passed in.
-    fn deserialize<D>(self, deserializer: D) -> Result<Self::Value, D::Error>
-        where D: Deserializer;
+    fn deserialize<D>(self, deserializer: D) -> Result<Self::Value, D::Error> where D: Deserializer;
 }
 
 impl<T> DeserializeSeed for PhantomData<T>
@@ -687,8 +704,8 @@ impl<T> DeserializeSeed for PhantomData<T>
 
 ///////////////////////////////////////////////////////////////////////////////
 
-/// An implementation of this trait is a **data format** that can deserialize
-/// any data structure supported by Serde.
+/// A **data format** that can deserialize any data structure supported by
+/// Serde.
 ///
 /// The role of this trait is to define the deserialization half of the Serde
 /// data model, which is a way to categorize every Rust data type into one of 28
@@ -782,56 +799,43 @@ pub trait Deserializer: Sized {
     /// `Deserializer::deserialize` means your data type will be able to
     /// deserialize from self-describing formats only, ruling out Bincode and
     /// many others.
-    fn deserialize<V>(self, visitor: V) -> Result<V::Value, Self::Error>
-        where V: Visitor;
+    fn deserialize<V>(self, visitor: V) -> Result<V::Value, Self::Error> where V: Visitor;
 
     /// Hint that the `Deserialize` type is expecting a `bool` value.
-    fn deserialize_bool<V>(self, visitor: V) -> Result<V::Value, Self::Error>
-        where V: Visitor;
+    fn deserialize_bool<V>(self, visitor: V) -> Result<V::Value, Self::Error> where V: Visitor;
 
     /// Hint that the `Deserialize` type is expecting a `u8` value.
-    fn deserialize_u8<V>(self, visitor: V) -> Result<V::Value, Self::Error>
-        where V: Visitor;
+    fn deserialize_u8<V>(self, visitor: V) -> Result<V::Value, Self::Error> where V: Visitor;
 
     /// Hint that the `Deserialize` type is expecting a `u16` value.
-    fn deserialize_u16<V>(self, visitor: V) -> Result<V::Value, Self::Error>
-        where V: Visitor;
+    fn deserialize_u16<V>(self, visitor: V) -> Result<V::Value, Self::Error> where V: Visitor;
 
     /// Hint that the `Deserialize` type is expecting a `u32` value.
-    fn deserialize_u32<V>(self, visitor: V) -> Result<V::Value, Self::Error>
-        where V: Visitor;
+    fn deserialize_u32<V>(self, visitor: V) -> Result<V::Value, Self::Error> where V: Visitor;
 
     /// Hint that the `Deserialize` type is expecting a `u64` value.
-    fn deserialize_u64<V>(self, visitor: V) -> Result<V::Value, Self::Error>
-        where V: Visitor;
+    fn deserialize_u64<V>(self, visitor: V) -> Result<V::Value, Self::Error> where V: Visitor;
 
     /// Hint that the `Deserialize` type is expecting an `i8` value.
-    fn deserialize_i8<V>(self, visitor: V) -> Result<V::Value, Self::Error>
-        where V: Visitor;
+    fn deserialize_i8<V>(self, visitor: V) -> Result<V::Value, Self::Error> where V: Visitor;
 
     /// Hint that the `Deserialize` type is expecting an `i16` value.
-    fn deserialize_i16<V>(self, visitor: V) -> Result<V::Value, Self::Error>
-        where V: Visitor;
+    fn deserialize_i16<V>(self, visitor: V) -> Result<V::Value, Self::Error> where V: Visitor;
 
     /// Hint that the `Deserialize` type is expecting an `i32` value.
-    fn deserialize_i32<V>(self, visitor: V) -> Result<V::Value, Self::Error>
-        where V: Visitor;
+    fn deserialize_i32<V>(self, visitor: V) -> Result<V::Value, Self::Error> where V: Visitor;
 
     /// Hint that the `Deserialize` type is expecting an `i64` value.
-    fn deserialize_i64<V>(self, visitor: V) -> Result<V::Value, Self::Error>
-        where V: Visitor;
+    fn deserialize_i64<V>(self, visitor: V) -> Result<V::Value, Self::Error> where V: Visitor;
 
     /// Hint that the `Deserialize` type is expecting a `f32` value.
-    fn deserialize_f32<V>(self, visitor: V) -> Result<V::Value, Self::Error>
-        where V: Visitor;
+    fn deserialize_f32<V>(self, visitor: V) -> Result<V::Value, Self::Error> where V: Visitor;
 
     /// Hint that the `Deserialize` type is expecting a `f64` value.
-    fn deserialize_f64<V>(self, visitor: V) -> Result<V::Value, Self::Error>
-        where V: Visitor;
+    fn deserialize_f64<V>(self, visitor: V) -> Result<V::Value, Self::Error> where V: Visitor;
 
     /// Hint that the `Deserialize` type is expecting a `char` value.
-    fn deserialize_char<V>(self, visitor: V) -> Result<V::Value, Self::Error>
-        where V: Visitor;
+    fn deserialize_char<V>(self, visitor: V) -> Result<V::Value, Self::Error> where V: Visitor;
 
     /// Hint that the `Deserialize` type is expecting a string value and does
     /// not benefit from taking ownership of buffered data owned by the
@@ -840,8 +844,7 @@ pub trait Deserializer: Sized {
     /// If the `Visitor` would benefit from taking ownership of `String` data,
     /// indiciate this to the `Deserializer` by using `deserialize_string`
     /// instead.
-    fn deserialize_str<V>(self, visitor: V) -> Result<V::Value, Self::Error>
-        where V: Visitor;
+    fn deserialize_str<V>(self, visitor: V) -> Result<V::Value, Self::Error> where V: Visitor;
 
     /// Hint that the `Deserialize` type is expecting a string value and would
     /// benefit from taking ownership of buffered data owned by the
@@ -850,18 +853,16 @@ pub trait Deserializer: Sized {
     /// If the `Visitor` would not benefit from taking ownership of `String`
     /// data, indicate that to the `Deserializer` by using `deserialize_str`
     /// instead.
-    fn deserialize_string<V>(self, visitor: V) -> Result<V::Value, Self::Error>
-        where V: Visitor;
+    fn deserialize_string<V>(self, visitor: V) -> Result<V::Value, Self::Error> where V: Visitor;
 
     /// Hint that the `Deserialize` type is expecting a byte array and does not
     /// benefit from taking ownership of buffered data owned by the
     /// `Deserializer`.
     ///
-    /// If the `Visitor would benefit from taking ownership of `Vec<u8>` data,
+    /// If the `Visitor` would benefit from taking ownership of `Vec<u8>` data,
     /// indicate this to the `Deserializer` by using `deserialize_byte_buf`
     /// instead.
-    fn deserialize_bytes<V>(self, visitor: V) -> Result<V::Value, Self::Error>
-        where V: Visitor;
+    fn deserialize_bytes<V>(self, visitor: V) -> Result<V::Value, Self::Error> where V: Visitor;
 
     /// Hint that the `Deserialize` type is expecting a byte array and would
     /// benefit from taking ownership of buffered data owned by the
@@ -870,44 +871,43 @@ pub trait Deserializer: Sized {
     /// If the `Visitor` would not benefit from taking ownership of `Vec<u8>`
     /// data, indicate that to the `Deserializer` by using `deserialize_bytes`
     /// instead.
-    fn deserialize_byte_buf<V>(self, visitor: V) -> Result<V::Value, Self::Error>
-        where V: Visitor;
+    fn deserialize_byte_buf<V>(self, visitor: V) -> Result<V::Value, Self::Error> where V: Visitor;
 
     /// Hint that the `Deserialize` type is expecting an optional value.
     ///
     /// This allows deserializers that encode an optional value as a nullable
     /// value to convert the null value into `None` and a regular value into
     /// `Some(value)`.
-    fn deserialize_option<V>(self, visitor: V) -> Result<V::Value, Self::Error>
-        where V: Visitor;
+    fn deserialize_option<V>(self, visitor: V) -> Result<V::Value, Self::Error> where V: Visitor;
 
     /// Hint that the `Deserialize` type is expecting a unit value.
-    fn deserialize_unit<V>(self, visitor: V) -> Result<V::Value, Self::Error>
-        where V: Visitor;
+    fn deserialize_unit<V>(self, visitor: V) -> Result<V::Value, Self::Error> where V: Visitor;
 
     /// Hint that the `Deserialize` type is expecting a unit struct with a
     /// particular name.
     fn deserialize_unit_struct<V>(self,
                                   name: &'static str,
-                                  visitor: V) -> Result<V::Value, Self::Error>
+                                  visitor: V)
+                                  -> Result<V::Value, Self::Error>
         where V: Visitor;
 
     /// Hint that the `Deserialize` type is expecting a newtype struct with a
     /// particular name.
     fn deserialize_newtype_struct<V>(self,
                                      name: &'static str,
-                                     visitor: V) -> Result<V::Value, Self::Error>
+                                     visitor: V)
+                                     -> Result<V::Value, Self::Error>
         where V: Visitor;
 
     /// Hint that the `Deserialize` type is expecting a sequence of values.
-    fn deserialize_seq<V>(self, visitor: V) -> Result<V::Value, Self::Error>
-        where V: Visitor;
+    fn deserialize_seq<V>(self, visitor: V) -> Result<V::Value, Self::Error> where V: Visitor;
 
     /// Hint that the `Deserialize` type is expecting a sequence of values and
     /// knows how many values there are without looking at the serialized data.
     fn deserialize_seq_fixed_size<V>(self,
                                      len: usize,
-                                     visitor: V) -> Result<V::Value, Self::Error>
+                                     visitor: V)
+                                     -> Result<V::Value, Self::Error>
         where V: Visitor;
 
     /// Hint that the `Deserialize` type is expecting a tuple value with a
@@ -920,19 +920,20 @@ pub trait Deserializer: Sized {
     fn deserialize_tuple_struct<V>(self,
                                    name: &'static str,
                                    len: usize,
-                                   visitor: V) -> Result<V::Value, Self::Error>
+                                   visitor: V)
+                                   -> Result<V::Value, Self::Error>
         where V: Visitor;
 
     /// Hint that the `Deserialize` type is expecting a map of key-value pairs.
-    fn deserialize_map<V>(self, visitor: V) -> Result<V::Value, Self::Error>
-        where V: Visitor;
+    fn deserialize_map<V>(self, visitor: V) -> Result<V::Value, Self::Error> where V: Visitor;
 
     /// Hint that the `Deserialize` type is expecting a struct with a particular
     /// name and fields.
     fn deserialize_struct<V>(self,
                              name: &'static str,
                              fields: &'static [&'static str],
-                             visitor: V) -> Result<V::Value, Self::Error>
+                             visitor: V)
+                             -> Result<V::Value, Self::Error>
         where V: Visitor;
 
     /// Hint that the `Deserialize` type is expecting the name of a struct
@@ -945,7 +946,8 @@ pub trait Deserializer: Sized {
     fn deserialize_enum<V>(self,
                            name: &'static str,
                            variants: &'static [&'static str],
-                           visitor: V) -> Result<V::Value, Self::Error>
+                           visitor: V)
+                           -> Result<V::Value, Self::Error>
         where V: Visitor;
 
     /// Hint that the `Deserialize` type needs to deserialize a value whose type
@@ -1014,77 +1016,77 @@ pub trait Visitor: Sized {
 
     /// Deserialize a `bool` into a `Value`.
     fn visit_bool<E>(self, v: bool) -> Result<Self::Value, E>
-        where E: Error,
+        where E: Error
     {
         Err(Error::invalid_type(Unexpected::Bool(v), &self))
     }
 
     /// Deserialize an `i8` into a `Value`.
     fn visit_i8<E>(self, v: i8) -> Result<Self::Value, E>
-        where E: Error,
+        where E: Error
     {
         self.visit_i64(v as i64)
     }
 
     /// Deserialize an `i16` into a `Value`.
     fn visit_i16<E>(self, v: i16) -> Result<Self::Value, E>
-        where E: Error,
+        where E: Error
     {
         self.visit_i64(v as i64)
     }
 
     /// Deserialize an `i32` into a `Value`.
     fn visit_i32<E>(self, v: i32) -> Result<Self::Value, E>
-        where E: Error,
+        where E: Error
     {
         self.visit_i64(v as i64)
     }
 
     /// Deserialize an `i64` into a `Value`.
     fn visit_i64<E>(self, v: i64) -> Result<Self::Value, E>
-        where E: Error,
+        where E: Error
     {
         Err(Error::invalid_type(Unexpected::Signed(v), &self))
     }
 
     /// Deserialize a `u8` into a `Value`.
     fn visit_u8<E>(self, v: u8) -> Result<Self::Value, E>
-        where E: Error,
+        where E: Error
     {
         self.visit_u64(v as u64)
     }
 
     /// Deserialize a `u16` into a `Value`.
     fn visit_u16<E>(self, v: u16) -> Result<Self::Value, E>
-        where E: Error,
+        where E: Error
     {
         self.visit_u64(v as u64)
     }
 
     /// Deserialize a `u32` into a `Value`.
     fn visit_u32<E>(self, v: u32) -> Result<Self::Value, E>
-        where E: Error,
+        where E: Error
     {
         self.visit_u64(v as u64)
     }
 
     /// Deserialize a `u64` into a `Value`.
     fn visit_u64<E>(self, v: u64) -> Result<Self::Value, E>
-        where E: Error,
+        where E: Error
     {
         Err(Error::invalid_type(Unexpected::Unsigned(v), &self))
     }
 
     /// Deserialize a `f32` into a `Value`.
     fn visit_f32<E>(self, v: f32) -> Result<Self::Value, E>
-        where E: Error,
+        where E: Error
     {
         self.visit_f64(v as f64)
     }
 
     /// Deserialize a `f64` into a `Value`.
     fn visit_f64<E>(self, v: f64) -> Result<Self::Value, E>
-        where E: Error,
+        where E: Error
     {
         Err(Error::invalid_type(Unexpected::Float(v), &self))
     }
@@ -1092,7 +1094,7 @@ pub trait Visitor: Sized {
     /// Deserialize a `char` into a `Value`.
     #[inline]
     fn visit_char<E>(self, v: char) -> Result<Self::Value, E>
-        where E: Error,
+        where E: Error
     {
         self.visit_str(::utils::encode_utf8(v).as_str())
     }
@@ -1108,7 +1110,7 @@ pub trait Visitor: Sized {
     /// It is never correct to implement `visit_string` without implementing
     /// `visit_str`. Implement neither, both, or just `visit_str`.
     fn visit_str<E>(self, v: &str) -> Result<Self::Value, E>
-        where E: Error,
+        where E: Error
     {
         Err(Error::invalid_type(Unexpected::Str(v), &self))
     }
@@ -1130,28 +1132,28 @@ pub trait Visitor: Sized {
     #[inline]
     #[cfg(any(feature = "std", feature = "collections"))]
     fn visit_string<E>(self, v: String) -> Result<Self::Value, E>
-        where E: Error,
+        where E: Error
     {
         self.visit_str(&v)
     }
 
     /// Deserialize a `()` into a `Value`.
     fn visit_unit<E>(self) -> Result<Self::Value, E>
-        where E: Error,
+        where E: Error
     {
         Err(Error::invalid_type(Unexpected::Unit, &self))
     }
 
     /// Deserialize an absent optional `Value`.
     fn visit_none<E>(self) -> Result<Self::Value, E>
-        where E: Error,
+        where E: Error
     {
         Err(Error::invalid_type(Unexpected::Option, &self))
     }
 
     /// Deserialize a present optional `Value`.
     fn visit_some<D>(self, deserializer: D) -> Result<Self::Value, D::Error>
-        where D: Deserializer,
+        where D: Deserializer
     {
         let _ = deserializer;
         Err(Error::invalid_type(Unexpected::Option, &self))
@@ -1159,7 +1161,7 @@ pub trait Visitor: Sized {
 
     /// Deserialize `Value` as a newtype struct.
     fn visit_newtype_struct<D>(self, deserializer: D) -> Result<Self::Value, D::Error>
-        where D: Deserializer,
+        where D: Deserializer
     {
         let _ = deserializer;
         Err(Error::invalid_type(Unexpected::NewtypeStruct, &self))
@@ -1167,7 +1169,7 @@ pub trait Visitor: Sized {
 
     /// Deserialize `Value` as a sequence of elements.
     fn visit_seq<V>(self, visitor: V) -> Result<Self::Value, V::Error>
-        where V: SeqVisitor,
+        where V: SeqVisitor
     {
         let _ = visitor;
         Err(Error::invalid_type(Unexpected::Seq, &self))
@@ -1175,7 +1177,7 @@ pub trait Visitor: Sized {
 
     /// Deserialize `Value` as a key-value map.
     fn visit_map<V>(self, visitor: V) -> Result<Self::Value, V::Error>
-        where V: MapVisitor,
+        where V: MapVisitor
     {
         let _ = visitor;
         Err(Error::invalid_type(Unexpected::Map, &self))
@@ -1183,7 +1185,7 @@ pub trait Visitor: Sized {
 
     /// Deserialize `Value` as an enum.
     fn visit_enum<V>(self, visitor: V) -> Result<Self::Value, V::Error>
-        where V: EnumVisitor,
+        where V: EnumVisitor
     {
         let _ = visitor;
         Err(Error::invalid_type(Unexpected::Enum, &self))
@@ -1200,7 +1202,7 @@ pub trait Visitor: Sized {
     /// It is never correct to implement `visit_byte_buf` without implementing
     /// `visit_bytes`. Implement neither, both, or just `visit_bytes`.
     fn visit_bytes<E>(self, v: &[u8]) -> Result<Self::Value, E>
-        where E: Error,
+        where E: Error
     {
         let _ = v;
         Err(Error::invalid_type(Unexpected::Bytes(v), &self))
@@ -1223,7 +1225,7 @@ pub trait Visitor: Sized {
     /// `Vec<u8>`.
     #[cfg(any(feature = "std", feature = "collections"))]
     fn visit_byte_buf<E>(self, v: Vec<u8>) -> Result<Self::Value, E>
-        where E: Error,
+        where E: Error
     {
         self.visit_bytes(&v)
     }
@@ -1267,7 +1269,9 @@ pub trait SeqVisitor {
     }
 }
 
-impl<'a, V> SeqVisitor for &'a mut V where V: SeqVisitor {
+impl<'a, V> SeqVisitor for &'a mut V
+    where V: SeqVisitor
+{
     type Error = V::Error;
 
     #[inline]
@@ -1324,7 +1328,10 @@ pub trait MapVisitor {
     /// `Deserialize` implementations should typically use `MapVisitor::visit`
     /// instead.
     #[inline]
-    fn visit_seed<K, V>(&mut self, kseed: K, vseed: V) -> Result<Option<(K::Value, V::Value)>, Self::Error>
+    fn visit_seed<K, V>(&mut self,
+                        kseed: K,
+                        vseed: V)
+                        -> Result<Option<(K::Value, V::Value)>, Self::Error>
         where K: DeserializeSeed,
               V: DeserializeSeed
     {
@@ -1333,7 +1340,7 @@ pub trait MapVisitor {
                 let value = try!(self.visit_value_seed(vseed));
                 Ok(Some((key, value)))
             }
-            None => Ok(None)
+            None => Ok(None),
         }
     }
 
@@ -1368,7 +1375,7 @@ pub trait MapVisitor {
     #[inline]
     fn visit<K, V>(&mut self) -> Result<Option<(K, V)>, Self::Error>
         where K: Deserialize,
-              V: Deserialize,
+              V: Deserialize
     {
         self.visit_seed(PhantomData, PhantomData)
     }
@@ -1380,7 +1387,9 @@ pub trait MapVisitor {
     }
 }
 
-impl<'a, V_> MapVisitor for &'a mut V_ where V_: MapVisitor {
+impl<'a, V_> MapVisitor for &'a mut V_
+    where V_: MapVisitor
+{
     type Error = V_::Error;
 
     #[inline]
@@ -1398,7 +1407,10 @@ impl<'a, V_> MapVisitor for &'a mut V_ where V_: MapVisitor {
     }
 
     #[inline]
-    fn visit_seed<K, V>(&mut self, kseed: K, vseed: V) -> Result<Option<(K::Value, V::Value)>, Self::Error>
+    fn visit_seed<K, V>(&mut self,
+                        kseed: K,
+                        vseed: V)
+                        -> Result<Option<(K::Value, V::Value)>, Self::Error>
         where K: DeserializeSeed,
               V: DeserializeSeed
     {
@@ -1408,7 +1420,7 @@ impl<'a, V_> MapVisitor for &'a mut V_ where V_: MapVisitor {
     #[inline]
     fn visit<K, V>(&mut self) -> Result<Option<(K, V)>, V_::Error>
         where K: Deserialize,
-              V: Deserialize,
+              V: Deserialize
     {
         (**self).visit()
     }
@@ -1444,7 +1456,7 @@ pub trait EnumVisitor: Sized {
     type Error: Error;
     /// The `Visitor` that will be used to deserialize the content of the enum
     /// variant.
-    type Variant: VariantVisitor<Error=Self::Error>;
+    type Variant: VariantVisitor<Error = Self::Error>;
 
     /// `visit_variant` is called to identify which variant to deserialize.
     ///
@@ -1537,9 +1549,7 @@ pub trait VariantVisitor: Sized {
     ///     Err(Error::invalid_type(unexp, &"tuple variant"))
     /// }
     /// ```
-    fn visit_tuple<V>(self,
-                      len: usize,
-                      visitor: V) -> Result<V::Value, Self::Error>
+    fn visit_tuple<V>(self, len: usize, visitor: V) -> Result<V::Value, Self::Error>
         where V: Visitor;
 
     /// Called when deserializing a struct-like variant.
@@ -1562,7 +1572,8 @@ pub trait VariantVisitor: Sized {
     /// ```
     fn visit_struct<V>(self,
                        fields: &'static [&'static str],
-                       visitor: V) -> Result<V::Value, Self::Error>
+                       visitor: V)
+                       -> Result<V::Value, Self::Error>
         where V: Visitor;
 }
 

serde/src/de/private.rs

@@ -2,6 +2,11 @@ use core::marker::PhantomData;
 
 use de::{Deserialize, Deserializer, Error, Visitor};
 
+#[cfg(any(feature = "std", feature = "collections"))]
+pub use de::content::{Content, ContentRefDeserializer, ContentDeserializer, TaggedContentVisitor,
+                      TagOrContentField, TagOrContentFieldVisitor, InternallyTaggedUnitVisitor,
+                      UntaggedUnitVisitor};
+
 /// If the missing field is of type `Option<T>` then treat is as `None`,
 /// otherwise it is an error.
 pub fn missing_field<V, E>(field: &'static str) -> Result<V, E>

serde/src/de/value.rs

@@ -1,31 +1,15 @@
 //! This module supports deserializing from primitives with the `ValueDeserializer` trait.
 
 #[cfg(feature = "std")]
-use std::collections::{
-    BTreeMap,
-    BTreeSet,
-    HashMap,
-    HashSet,
-    btree_map,
-    btree_set,
-    hash_map,
-    hash_set,
-};
+use std::collections::{BTreeMap, BTreeSet, HashMap, HashSet, btree_map, btree_set, hash_map,
+                       hash_set};
 #[cfg(feature = "std")]
 use std::borrow::Cow;
 #[cfg(feature = "std")]
 use std::vec;
 
 #[cfg(all(feature = "collections", not(feature = "std")))]
-use collections::{
-    BTreeMap,
-    BTreeSet,
-    Vec,
-    String,
-    btree_map,
-    btree_set,
-    vec,
-};
+use collections::{BTreeMap, BTreeSet, Vec, String, btree_map, btree_set, vec};
 #[cfg(all(feature = "collections", not(feature = "std")))]
 use collections::borrow::Cow;
 #[cfg(all(feature = "collections", not(feature = "std")))]
@@ -41,7 +25,7 @@ use std::error;
 use error;
 
 use core::fmt::{self, Display};
-use core::iter::{self,  Iterator};
+use core::iter::{self, Iterator};
 use core::marker::PhantomData;
 
 use de::{self, Expected, SeqVisitor};
@@ -63,16 +47,12 @@ type ErrorImpl = ();
 impl de::Error for Error {
     #[cfg(any(feature = "std", feature = "collections"))]
     fn custom<T: Display>(msg: T) -> Self {
-        Error {
-            err: msg.to_string().into_boxed_str(),
-        }
+        Error { err: msg.to_string().into_boxed_str() }
     }
 
     #[cfg(not(any(feature = "std", feature = "collections")))]
     fn custom<T: Display>(_msg: T) -> Self {
-        Error {
-            err: (),
-        }
+        Error { err: () }
     }
 }
 
@@ -105,7 +85,7 @@ impl error::Error for Error {
 /// This trait converts primitive types into a deserializer.
 pub trait ValueDeserializer<E: de::Error = Error> {
     /// The actual deserializer type.
-    type Deserializer: de::Deserializer<Error=E>;
+    type Deserializer: de::Deserializer<Error = E>;
 
     /// Convert this value into a deserializer.
     fn into_deserializer(self) -> Self::Deserializer;
@@ -114,14 +94,12 @@ pub trait ValueDeserializer<E: de::Error = Error> {
 ///////////////////////////////////////////////////////////////////////////////
 
 impl<E> ValueDeserializer<E> for ()
-    where E: de::Error,
+    where E: de::Error
 {
     type Deserializer = UnitDeserializer<E>;
 
     fn into_deserializer(self) -> UnitDeserializer<E> {
-        UnitDeserializer {
-            marker: PhantomData,
-        }
+        UnitDeserializer { marker: PhantomData }
     }
 }
 
@@ -142,13 +120,13 @@ impl<E> de::Deserializer for UnitDeserializer<E>
     }
 
     fn deserialize<V>(self, visitor: V) -> Result<V::Value, Self::Error>
-        where V: de::Visitor,
+        where V: de::Visitor
     {
         visitor.visit_unit()
     }
 
     fn deserialize_option<V>(self, visitor: V) -> Result<V::Value, Self::Error>
-        where V: de::Visitor,
+        where V: de::Visitor
     {
         visitor.visit_none()
     }
@@ -221,7 +199,7 @@ pub struct StrDeserializer<'a, E> {
 }
 
 impl<'a, E> ValueDeserializer<E> for &'a str
-    where E: de::Error,
+    where E: de::Error
 {
     type Deserializer = StrDeserializer<'a, E>;
 
@@ -234,21 +212,22 @@ impl<'a, E> ValueDeserializer<E> for &'a str
 }
 
 impl<'a, E> de::Deserializer for StrDeserializer<'a, E>
-    where E: de::Error,
+    where E: de::Error
 {
     type Error = E;
 
     fn deserialize<V>(self, visitor: V) -> Result<V::Value, Self::Error>
-        where V: de::Visitor,
+        where V: de::Visitor
     {
         visitor.visit_str(self.value)
     }
 
     fn deserialize_enum<V>(self,
-                     _name: &str,
-                     _variants: &'static [&'static str],
-                     visitor: V) -> Result<V::Value, Self::Error>
-        where V: de::Visitor,
+                           _name: &str,
+                           _variants: &'static [&'static str],
+                           visitor: V)
+                           -> Result<V::Value, Self::Error>
+        where V: de::Visitor
     {
         visitor.visit_enum(self)
     }
@@ -261,13 +240,13 @@ impl<'a, E> de::Deserializer for StrDeserializer<'a, E>
 }
 
 impl<'a, E> de::EnumVisitor for StrDeserializer<'a, E>
-    where E: de::Error,
+    where E: de::Error
 {
     type Error = E;
     type Variant = private::UnitOnly<E>;
 
     fn visit_variant_seed<T>(self, seed: T) -> Result<(T::Value, Self::Variant), Self::Error>
-        where T: de::DeserializeSeed,
+        where T: de::DeserializeSeed
     {
         seed.deserialize(self).map(private::unit_only)
     }
@@ -284,7 +263,7 @@ pub struct StringDeserializer<E> {
 
 #[cfg(any(feature = "std", feature = "collections"))]
 impl<E> ValueDeserializer<E> for String
-    where E: de::Error,
+    where E: de::Error
 {
     type Deserializer = StringDeserializer<E>;
 
@@ -298,21 +277,22 @@ impl<E> ValueDeserializer<E> for String
 
 #[cfg(any(feature = "std", feature = "collections"))]
 impl<E> de::Deserializer for StringDeserializer<E>
-    where E: de::Error,
+    where E: de::Error
 {
     type Error = E;
 
     fn deserialize<V>(self, visitor: V) -> Result<V::Value, Self::Error>
-        where V: de::Visitor,
+        where V: de::Visitor
     {
         visitor.visit_string(self.value)
     }
 
     fn deserialize_enum<V>(self,
-                     _name: &str,
-                     _variants: &'static [&'static str],
-                     visitor: V) -> Result<V::Value, Self::Error>
-        where V: de::Visitor,
+                           _name: &str,
+                           _variants: &'static [&'static str],
+                           visitor: V)
+                           -> Result<V::Value, Self::Error>
+        where V: de::Visitor
     {
         visitor.visit_enum(self)
     }
@@ -326,13 +306,13 @@ impl<E> de::Deserializer for StringDeserializer<E>
 
 #[cfg(any(feature = "std", feature = "collections"))]
 impl<'a, E> de::EnumVisitor for StringDeserializer<E>
-    where E: de::Error,
+    where E: de::Error
 {
     type Error = E;
     type Variant = private::UnitOnly<E>;
 
     fn visit_variant_seed<T>(self, seed: T) -> Result<(T::Value, Self::Variant), Self::Error>
-        where T: de::DeserializeSeed,
+        where T: de::DeserializeSeed
     {
         seed.deserialize(self).map(private::unit_only)
     }
@@ -349,7 +329,7 @@ pub struct CowStrDeserializer<'a, E> {
 
 #[cfg(any(feature = "std", feature = "collections"))]
 impl<'a, E> ValueDeserializer<E> for Cow<'a, str>
-    where E: de::Error,
+    where E: de::Error
 {
     type Deserializer = CowStrDeserializer<'a, E>;
 
@@ -363,12 +343,12 @@ impl<'a, E> ValueDeserializer<E> for Cow<'a, str>
 
 #[cfg(any(feature = "std", feature = "collections"))]
 impl<'a, E> de::Deserializer for CowStrDeserializer<'a, E>
-    where E: de::Error,
+    where E: de::Error
 {
     type Error = E;
 
     fn deserialize<V>(self, visitor: V) -> Result<V::Value, Self::Error>
-        where V: de::Visitor,
+        where V: de::Visitor
     {
         match self.value {
             Cow::Borrowed(string) => visitor.visit_str(string),
@@ -377,10 +357,11 @@ impl<'a, E> de::Deserializer for CowStrDeserializer<'a, E>
     }
 
     fn deserialize_enum<V>(self,
-                     _name: &str,
-                     _variants: &'static [&'static str],
-                     visitor: V) -> Result<V::Value, Self::Error>
-        where V: de::Visitor,
+                           _name: &str,
+                           _variants: &'static [&'static str],
+                           visitor: V)
+                           -> Result<V::Value, Self::Error>
+        where V: de::Visitor
     {
         visitor.visit_enum(self)
     }
@@ -394,13 +375,13 @@ impl<'a, E> de::Deserializer for CowStrDeserializer<'a, E>
 
 #[cfg(any(feature = "std", feature = "collections"))]
 impl<'a, E> de::EnumVisitor for CowStrDeserializer<'a, E>
-    where E: de::Error,
+    where E: de::Error
 {
     type Error = E;
     type Variant = private::UnitOnly<E>;
 
     fn visit_variant_seed<T>(self, seed: T) -> Result<(T::Value, Self::Variant), Self::Error>
-        where T: de::DeserializeSeed,
+        where T: de::DeserializeSeed
     {
         seed.deserialize(self).map(private::unit_only)
     }
@@ -417,7 +398,7 @@ pub struct SeqDeserializer<I, E> {
 
 impl<I, E> SeqDeserializer<I, E>
     where I: Iterator,
-          E: de::Error,
+          E: de::Error
 {
     /// Construct a new `SeqDeserializer<I>`.
     pub fn new(iter: I) -> Self {
@@ -428,7 +409,9 @@ impl<I, E> SeqDeserializer<I, E>
         }
     }
 
-    fn end(&mut self) -> Result<(), E> {
+    /// Check for remaining elements after passing a `SeqDeserializer` to
+    /// `Visitor::visit_seq`.
+    pub fn end(mut self) -> Result<(), E> {
         let mut remaining = 0;
         while self.iter.next().is_some() {
             remaining += 1;
@@ -444,14 +427,14 @@ impl<I, E> SeqDeserializer<I, E>
 }
 
 impl<I, T, E> de::Deserializer for SeqDeserializer<I, E>
-    where I: Iterator<Item=T>,
+    where I: Iterator<Item = T>,
           T: ValueDeserializer<E>,
-          E: de::Error,
+          E: de::Error
 {
     type Error = E;
 
     fn deserialize<V>(mut self, visitor: V) -> Result<V::Value, Self::Error>
-        where V: de::Visitor,
+        where V: de::Visitor
     {
         let v = try!(visitor.visit_seq(&mut self));
         try!(self.end());
@@ -466,9 +449,9 @@ impl<I, T, E> de::Deserializer for SeqDeserializer<I, E>
 }
 
 impl<I, T, E> de::SeqVisitor for SeqDeserializer<I, E>
-    where I: Iterator<Item=T>,
+    where I: Iterator<Item = T>,
           T: ValueDeserializer<E>,
-          E: de::Error,
+          E: de::Error
 {
     type Error = E;
 
@@ -506,7 +489,7 @@ impl Expected for ExpectedInSeq {
 #[cfg(any(feature = "std", feature = "collections"))]
 impl<T, E> ValueDeserializer<E> for Vec<T>
     where T: ValueDeserializer<E>,
-          E: de::Error,
+          E: de::Error
 {
     type Deserializer = SeqDeserializer<vec::IntoIter<T>, E>;
 
@@ -518,7 +501,7 @@ 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,
+          E: de::Error
 {
     type Deserializer = SeqDeserializer<btree_set::IntoIter<T>, E>;
 
@@ -530,7 +513,7 @@ 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,
+          E: de::Error
 {
     type Deserializer = SeqDeserializer<hash_set::IntoIter<T>, E>;
 
@@ -549,20 +532,20 @@ pub struct SeqVisitorDeserializer<V_, E> {
 
 impl<V_, E> SeqVisitorDeserializer<V_, E>
     where V_: de::SeqVisitor<Error = E>,
-          E: de::Error,
+          E: de::Error
 {
     /// Construct a new `SeqVisitorDeserializer<V_, E>`.
     pub fn new(visitor: V_) -> Self {
-        SeqVisitorDeserializer{
+        SeqVisitorDeserializer {
             visitor: visitor,
-            marker: PhantomData
+            marker: PhantomData,
         }
     }
 }
 
 impl<V_, E> de::Deserializer for SeqVisitorDeserializer<V_, E>
     where V_: de::SeqVisitor<Error = E>,
-          E: de::Error,
+          E: de::Error
 {
     type Error = E;
 
@@ -585,7 +568,7 @@ pub struct MapDeserializer<I, E>
           I::Item: private::Pair,
           <I::Item as private::Pair>::First: ValueDeserializer<E>,
           <I::Item as private::Pair>::Second: ValueDeserializer<E>,
-          E: de::Error,
+          E: de::Error
 {
     iter: iter::Fuse<I>,
     value: Option<<I::Item as private::Pair>::Second>,
@@ -598,7 +581,7 @@ impl<I, E> MapDeserializer<I, E>
           I::Item: private::Pair,
           <I::Item as private::Pair>::First: ValueDeserializer<E>,
           <I::Item as private::Pair>::Second: ValueDeserializer<E>,
-          E: de::Error,
+          E: de::Error
 {
     /// Construct a new `MapDeserializer<I, K, V, E>`.
     pub fn new(iter: I) -> Self {
@@ -610,17 +593,9 @@ impl<I, E> MapDeserializer<I, E>
         }
     }
 
-    fn next_pair(&mut self) -> Option<(<I::Item as private::Pair>::First, <I::Item as private::Pair>::Second)> {
-        match self.iter.next() {
-            Some(kv) => {
-                self.count += 1;
-                Some(private::Pair::split(kv))
-            }
-            None => None,
-        }
-    }
-
-    fn end(&mut self) -> Result<(), E> {
+    /// Check for remaining elements after passing a `MapDeserializer` to
+    /// `Visitor::visit_map`.
+    pub fn end(mut self) -> Result<(), E> {
         let mut remaining = 0;
         while self.iter.next().is_some() {
             remaining += 1;
@@ -633,6 +608,18 @@ impl<I, E> MapDeserializer<I, E>
             Err(de::Error::invalid_length(self.count + remaining, &ExpectedInMap(self.count)))
         }
     }
+
+    fn next_pair
+        (&mut self)
+         -> Option<(<I::Item as private::Pair>::First, <I::Item as private::Pair>::Second)> {
+        match self.iter.next() {
+            Some(kv) => {
+                self.count += 1;
+                Some(private::Pair::split(kv))
+            }
+            None => None,
+        }
+    }
 }
 
 impl<I, E> de::Deserializer for MapDeserializer<I, E>
@@ -640,12 +627,12 @@ impl<I, E> de::Deserializer for MapDeserializer<I, E>
           I::Item: private::Pair,
           <I::Item as private::Pair>::First: ValueDeserializer<E>,
           <I::Item as private::Pair>::Second: ValueDeserializer<E>,
-          E: de::Error,
+          E: de::Error
 {
     type Error = E;
 
     fn deserialize<V_>(mut self, visitor: V_) -> Result<V_::Value, Self::Error>
-        where V_: de::Visitor,
+        where V_: de::Visitor
     {
         let value = try!(visitor.visit_map(&mut self));
         try!(self.end());
@@ -653,15 +640,18 @@ impl<I, E> de::Deserializer for MapDeserializer<I, E>
     }
 
     fn deserialize_seq<V_>(mut self, visitor: V_) -> Result<V_::Value, Self::Error>
-        where V_: de::Visitor,
+        where V_: de::Visitor
     {
         let value = try!(visitor.visit_seq(&mut self));
         try!(self.end());
         Ok(value)
     }
 
-    fn deserialize_seq_fixed_size<V_>(self, _len: usize, visitor: V_) -> Result<V_::Value, Self::Error>
-        where V_: de::Visitor,
+    fn deserialize_seq_fixed_size<V_>(self,
+                                      _len: usize,
+                                      visitor: V_)
+                                      -> Result<V_::Value, Self::Error>
+        where V_: de::Visitor
     {
         self.deserialize_seq(visitor)
     }
@@ -678,12 +668,12 @@ impl<I, E> de::MapVisitor for MapDeserializer<I, E>
           I::Item: private::Pair,
           <I::Item as private::Pair>::First: ValueDeserializer<E>,
           <I::Item as private::Pair>::Second: ValueDeserializer<E>,
-          E: de::Error,
+          E: de::Error
 {
     type Error = E;
 
     fn visit_key_seed<T>(&mut self, seed: T) -> Result<Option<T::Value>, Self::Error>
-        where T: de::DeserializeSeed,
+        where T: de::DeserializeSeed
     {
         match self.next_pair() {
             Some((key, value)) => {
@@ -695,7 +685,7 @@ impl<I, E> de::MapVisitor for MapDeserializer<I, E>
     }
 
     fn visit_value_seed<T>(&mut self, seed: T) -> Result<T::Value, Self::Error>
-        where T: de::DeserializeSeed,
+        where T: de::DeserializeSeed
     {
         let value = self.value.take();
         // Panic because this indicates a bug in the program rather than an
@@ -704,7 +694,10 @@ impl<I, E> de::MapVisitor for MapDeserializer<I, E>
         seed.deserialize(value.into_deserializer())
     }
 
-    fn visit_seed<TK, TV>(&mut self, kseed: TK, vseed: TV) -> Result<Option<(TK::Value, TV::Value)>, Self::Error>
+    fn visit_seed<TK, TV>(&mut self,
+                          kseed: TK,
+                          vseed: TV)
+                          -> Result<Option<(TK::Value, TV::Value)>, Self::Error>
         where TK: de::DeserializeSeed,
               TV: de::DeserializeSeed
     {
@@ -714,7 +707,7 @@ impl<I, E> de::MapVisitor for MapDeserializer<I, E>
                 let value = try!(vseed.deserialize(value.into_deserializer()));
                 Ok(Some((key, value)))
             }
-            None => Ok(None)
+            None => Ok(None),
         }
     }
 
@@ -728,12 +721,12 @@ impl<I, E> de::SeqVisitor for MapDeserializer<I, E>
           I::Item: private::Pair,
           <I::Item as private::Pair>::First: ValueDeserializer<E>,
           <I::Item as private::Pair>::Second: ValueDeserializer<E>,
-          E: de::Error,
+          E: de::Error
 {
     type Error = E;
 
     fn visit_seed<T>(&mut self, seed: T) -> Result<Option<T::Value>, Self::Error>
-        where T: de::DeserializeSeed,
+        where T: de::DeserializeSeed
     {
         match self.next_pair() {
             Some((k, v)) => {
@@ -767,13 +760,13 @@ impl<A, B, E> de::Deserializer for PairDeserializer<A, B, E>
     }
 
     fn deserialize<V>(self, visitor: V) -> Result<V::Value, Self::Error>
-        where V: de::Visitor,
+        where V: de::Visitor
     {
         self.deserialize_seq(visitor)
     }
 
     fn deserialize_seq<V>(self, visitor: V) -> Result<V::Value, Self::Error>
-        where V: de::Visitor,
+        where V: de::Visitor
     {
         let mut pair_visitor = PairVisitor(Some(self.0), Some(self.1), PhantomData);
         let pair = try!(visitor.visit_seq(&mut pair_visitor));
@@ -788,7 +781,7 @@ impl<A, B, E> de::Deserializer for PairDeserializer<A, B, E>
     }
 
     fn deserialize_seq_fixed_size<V>(self, len: usize, visitor: V) -> Result<V::Value, Self::Error>
-        where V: de::Visitor,
+        where V: de::Visitor
     {
         if len == 2 {
             self.deserialize_seq(visitor)
@@ -805,12 +798,12 @@ struct PairVisitor<A, B, E>(Option<A>, Option<B>, PhantomData<E>);
 impl<A, B, E> de::SeqVisitor for PairVisitor<A, B, E>
     where A: ValueDeserializer<E>,
           B: ValueDeserializer<E>,
-          E: de::Error,
+          E: de::Error
 {
     type Error = E;
 
     fn visit_seed<T>(&mut self, seed: T) -> Result<Option<T::Value>, Self::Error>
-        where T: de::DeserializeSeed,
+        where T: de::DeserializeSeed
     {
         if let Some(k) = self.0.take() {
             seed.deserialize(k.into_deserializer()).map(Some)
@@ -851,7 +844,7 @@ impl Expected for ExpectedInMap {
 impl<K, V, E> ValueDeserializer<E> for BTreeMap<K, V>
     where K: ValueDeserializer<E> + Eq + Ord,
           V: ValueDeserializer<E>,
-          E: de::Error,
+          E: de::Error
 {
     type Deserializer = MapDeserializer<btree_map::IntoIter<K, V>, E>;
 
@@ -864,7 +857,7 @@ impl<K, V, E> ValueDeserializer<E> for BTreeMap<K, V>
 impl<K, V, E> ValueDeserializer<E> for HashMap<K, V>
     where K: ValueDeserializer<E> + Eq + Hash,
           V: ValueDeserializer<E>,
-          E: de::Error,
+          E: de::Error
 {
     type Deserializer = MapDeserializer<hash_map::IntoIter<K, V>, E>;
 
@@ -883,20 +876,20 @@ pub struct MapVisitorDeserializer<V_, E> {
 
 impl<V_, E> MapVisitorDeserializer<V_, E>
     where V_: de::MapVisitor<Error = E>,
-          E: de::Error,
+          E: de::Error
 {
     /// Construct a new `MapVisitorDeserializer<V_, E>`.
     pub fn new(visitor: V_) -> Self {
-        MapVisitorDeserializer{
+        MapVisitorDeserializer {
             visitor: visitor,
-            marker: PhantomData
+            marker: PhantomData,
         }
     }
 }
 
 impl<V_, E> de::Deserializer for MapVisitorDeserializer<V_, E>
     where V_: de::MapVisitor<Error = E>,
-          E: de::Error,
+          E: de::Error
 {
     type Error = E;
 
@@ -914,7 +907,7 @@ impl<V_, E> de::Deserializer for MapVisitorDeserializer<V_, E>
 ///////////////////////////////////////////////////////////////////////////////
 
 impl<'a, E> ValueDeserializer<E> for bytes::Bytes<'a>
-    where E: de::Error,
+    where E: de::Error
 {
     type Deserializer = BytesDeserializer<'a, E>;
 
@@ -938,7 +931,7 @@ impl<'a, E> de::Deserializer for BytesDeserializer<'a, E>
     type Error = E;
 
     fn deserialize<V>(self, visitor: V) -> Result<V::Value, Self::Error>
-        where V: de::Visitor,
+        where V: de::Visitor
     {
         visitor.visit_bytes(self.value)
     }
@@ -954,7 +947,7 @@ 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,
+    where E: de::Error
 {
     type Deserializer = ByteBufDeserializer<E>;
 
@@ -975,12 +968,12 @@ pub struct ByteBufDeserializer<E> {
 
 #[cfg(any(feature = "std", feature = "collections"))]
 impl<E> de::Deserializer for ByteBufDeserializer<E>
-    where E: de::Error,
+    where E: de::Error
 {
     type Error = E;
 
     fn deserialize<V>(self, visitor: V) -> Result<V::Value, Self::Error>
-        where V: de::Visitor,
+        where V: de::Visitor
     {
         visitor.visit_byte_buf(self.value)
     }
@@ -1016,14 +1009,12 @@ mod private {
         }
 
         fn visit_newtype_seed<T>(self, _seed: T) -> Result<T::Value, Self::Error>
-            where T: de::DeserializeSeed,
+            where T: de::DeserializeSeed
         {
             Err(de::Error::invalid_type(Unexpected::UnitVariant, &"newtype variant"))
         }
 
-        fn visit_tuple<V>(self,
-                          _len: usize,
-                          _visitor: V) -> Result<V::Value, Self::Error>
+        fn visit_tuple<V>(self, _len: usize, _visitor: V) -> Result<V::Value, Self::Error>
             where V: de::Visitor
         {
             Err(de::Error::invalid_type(Unexpected::UnitVariant, &"tuple variant"))
@@ -1031,7 +1022,8 @@ mod private {
 
         fn visit_struct<V>(self,
                            _fields: &'static [&'static str],
-                           _visitor: V) -> Result<V::Value, Self::Error>
+                           _visitor: V)
+                           -> Result<V::Value, Self::Error>
             where V: de::Visitor
         {
             Err(de::Error::invalid_type(Unexpected::UnitVariant, &"struct variant"))
@@ -1049,6 +1041,8 @@ mod private {
     impl<A, B> Pair for (A, B) {
         type First = A;
         type Second = B;
-        fn split(self) -> (A, B) { self }
+        fn split(self) -> (A, B) {
+            self
+        }
     }
 }

serde/src/error.rs

@@ -11,5 +11,7 @@ pub trait Error: Debug + Display {
     fn description(&self) -> &str;
 
     /// The lower-level cause of this error, if any.
-    fn cause(&self) -> Option<&Error> { None }
+    fn cause(&self) -> Option<&Error> {
+        None
+    }
 }

serde/src/export.rs

@@ -9,7 +9,8 @@ use collections::borrow::Cow;
 pub use core::default::Default;
 pub use core::fmt;
 pub use core::marker::PhantomData;
-pub use core::result::Result;
+pub use core::option::Option::{self, None, Some};
+pub use core::result::Result::{self, Ok, Err};
 
 #[cfg(any(feature = "collections", feature = "std"))]
 pub fn from_utf8_lossy(bytes: &[u8]) -> Cow<str> {

serde/src/iter.rs

@@ -4,13 +4,13 @@ use std::io;
 use std::iter::Peekable;
 
 /// Iterator over a byte stream that tracks the current position's line and column.
-pub struct LineColIterator<Iter: Iterator<Item=io::Result<u8>>> {
+pub struct LineColIterator<Iter: Iterator<Item = io::Result<u8>>> {
     iter: Iter,
     line: usize,
     col: usize,
 }
 
-impl<Iter: Iterator<Item=io::Result<u8>>> LineColIterator<Iter> {
+impl<Iter: Iterator<Item = io::Result<u8>>> LineColIterator<Iter> {
     /// Construct a new `LineColIterator<Iter>`.
     pub fn new(iter: Iter) -> LineColIterator<Iter> {
         LineColIterator {
@@ -21,27 +21,39 @@ impl<Iter: Iterator<Item=io::Result<u8>>> LineColIterator<Iter> {
     }
 
     /// Report the current line inside the iterator.
-    pub fn line(&self) -> usize { self.line }
+    pub fn line(&self) -> usize {
+        self.line
+    }
 
     /// Report the current column inside the iterator.
-    pub fn col(&self) -> usize { self.col }
+    pub fn col(&self) -> usize {
+        self.col
+    }
 
     /// Gets a reference to the underlying iterator.
-    pub fn get_ref(&self) -> &Iter { &self.iter }
+    pub fn get_ref(&self) -> &Iter {
+        &self.iter
+    }
 
     /// Gets a mutable reference to the underlying iterator.
-    pub fn get_mut(&mut self) -> &mut Iter { &mut self.iter }
+    pub fn get_mut(&mut self) -> &mut Iter {
+        &mut self.iter
+    }
 
     /// Unwraps this `LineColIterator`, returning the underlying iterator.
-    pub fn into_inner(self) -> Iter { self.iter }
+    pub fn into_inner(self) -> Iter {
+        self.iter
+    }
 }
 
-impl<Iter: Iterator<Item=io::Result<u8>>> LineColIterator<Peekable<Iter>> {
+impl<Iter: Iterator<Item = io::Result<u8>>> LineColIterator<Peekable<Iter>> {
     /// peeks at the next value
-    pub fn peek(&mut self) -> Option<&io::Result<u8>> { self.iter.peek() }
+    pub fn peek(&mut self) -> Option<&io::Result<u8>> {
+        self.iter.peek()
+    }
 }
 
-impl<Iter: Iterator<Item=io::Result<u8>>> Iterator for LineColIterator<Iter> {
+impl<Iter: Iterator<Item = io::Result<u8>>> Iterator for LineColIterator<Iter> {
     type Item = io::Result<u8>;
     fn next(&mut self) -> Option<io::Result<u8>> {
         match self.iter.next() {
@@ -50,11 +62,11 @@ impl<Iter: Iterator<Item=io::Result<u8>>> Iterator for LineColIterator<Iter> {
                 self.line += 1;
                 self.col = 0;
                 Some(Ok(b'\n'))
-            },
+            }
             Some(Ok(c)) => {
                 self.col += 1;
                 Some(Ok(c))
-            },
+            }
             Some(Err(e)) => Some(Err(e)),
         }
     }

serde/src/lib.rs

@@ -61,9 +61,9 @@
 
 #![doc(html_root_url="https://docs.serde.rs")]
 #![cfg_attr(not(feature = "std"), no_std)]
-#![cfg_attr(feature = "unstable", feature(nonzero, inclusive_range, zero_one))]
+#![cfg_attr(feature = "unstable", feature(inclusive_range, nonzero, specialization, zero_one))]
 #![cfg_attr(feature = "alloc", feature(alloc))]
-#![cfg_attr(feature = "collections", feature(collections, enumset))]
+#![cfg_attr(feature = "collections", feature(collections))]
 #![cfg_attr(feature = "cargo-clippy", allow(linkedlist, type_complexity, doc_markdown))]
 #![deny(missing_docs)]
 
@@ -79,12 +79,14 @@ extern crate core as actual_core;
 #[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, cell, default, result};
+                  usize, f32, f64, char, str, num, slice, iter, cell, default, result, option};
     #[cfg(feature = "unstable")]
     pub use actual_core::nonzero;
 }
 
+#[doc(inline)]
 pub use ser::{Serialize, Serializer};
+#[doc(inline)]
 pub use de::{Deserialize, Deserializer};
 
 #[macro_use]

serde/src/macros.rs

@@ -188,3 +188,35 @@ macro_rules! forward_to_deserialize {
         $(forward_to_deserialize_helper!{$func})*
     };
 }
+
+/// Seralize the `$value` that implements Display as a string,
+/// when that string is statically known to never have more than
+/// a constant `$MAX_LEN` bytes.
+///
+/// Panics if the Display impl tries to write more than `$MAX_LEN` bytes.
+#[cfg(feature = "std")]
+// Not exported
+macro_rules! serialize_display_bounded_length {
+    ($value: expr, $MAX_LEN: expr, $serializer: expr) => {
+        {
+            use std::io::Write;
+            let mut buffer: [u8; $MAX_LEN] = unsafe { ::std::mem::uninitialized() };
+            let remaining_len;
+            {
+                let mut remaining = &mut buffer[..];
+                write!(remaining, "{}", $value).unwrap();
+                remaining_len = remaining.len()
+            }
+            let written_len = buffer.len() - remaining_len;
+            let written = &buffer[..written_len];
+
+            // write! only provides std::fmt::Formatter to Display implementations,
+            // which has methods write_str and write_char but no method to write arbitrary bytes.
+            // Therefore, `written` is well-formed in UTF-8.
+            let written_str = unsafe {
+                ::std::str::from_utf8_unchecked(written)
+            };
+            $serializer.serialize_str(written_str)
+        }
+    }
+}

serde/src/ser/content.rs

@@ -0,0 +1,635 @@
+use core::marker::PhantomData;
+
+#[cfg(all(not(feature = "std"), feature = "collections"))]
+use collections::{String, Vec};
+
+#[cfg(all(feature = "alloc", not(feature = "std")))]
+use alloc::boxed::Box;
+
+#[cfg(feature = "collections")]
+use collections::borrow::ToOwned;
+
+use ser::{self, Serialize, Serializer};
+
+pub struct SerializeTupleVariantAsMapValue<M> {
+    map: M,
+    name: &'static str,
+    fields: Vec<Content>,
+}
+
+impl<M> SerializeTupleVariantAsMapValue<M> {
+    pub fn new(map: M, name: &'static str, len: usize) -> Self {
+        SerializeTupleVariantAsMapValue {
+            map: map,
+            name: name,
+            fields: Vec::with_capacity(len),
+        }
+    }
+}
+
+impl<M> ser::SerializeTupleVariant for SerializeTupleVariantAsMapValue<M>
+    where M: ser::SerializeMap
+{
+    type Ok = M::Ok;
+    type Error = M::Error;
+
+    fn serialize_field<T: ?Sized + Serialize>(&mut self,
+                                              value: &T)
+                                              -> Result<(), M::Error>
+    {
+        let value = try!(value.serialize(ContentSerializer::<M::Error>::new()));
+        self.fields.push(value);
+        Ok(())
+    }
+
+    fn end(mut self) -> Result<M::Ok, M::Error> {
+        try!(self.map.serialize_value(&Content::TupleStruct(self.name, self.fields)));
+        self.map.end()
+    }
+}
+
+pub struct SerializeStructVariantAsMapValue<M> {
+    map: M,
+    name: &'static str,
+    fields: Vec<(&'static str, Content)>,
+}
+
+impl<M> SerializeStructVariantAsMapValue<M> {
+    pub fn new(map: M, name: &'static str, len: usize) -> Self {
+        SerializeStructVariantAsMapValue {
+            map: map,
+            name: name,
+            fields: Vec::with_capacity(len),
+        }
+    }
+}
+
+impl<M> ser::SerializeStructVariant for SerializeStructVariantAsMapValue<M>
+    where M: ser::SerializeMap
+{
+    type Ok = M::Ok;
+    type Error = M::Error;
+
+    fn serialize_field<T: ?Sized + Serialize>(&mut self,
+                                              key: &'static str,
+                                              value: &T)
+                                              -> Result<(), M::Error>
+    {
+        let value = try!(value.serialize(ContentSerializer::<M::Error>::new()));
+        self.fields.push((key, value));
+        Ok(())
+    }
+
+    fn end(mut self) -> Result<M::Ok, M::Error> {
+        try!(self.map.serialize_value(&Content::Struct(self.name, self.fields)));
+        self.map.end()
+    }
+}
+
+#[derive(Debug)]
+enum Content {
+    Bool(bool),
+
+    U8(u8),
+    U16(u16),
+    U32(u32),
+    U64(u64),
+
+    I8(i8),
+    I16(i16),
+    I32(i32),
+    I64(i64),
+
+    F32(f32),
+    F64(f64),
+
+    Char(char),
+    String(String),
+    Bytes(Vec<u8>),
+
+    None,
+    Some(Box<Content>),
+
+    Unit,
+    UnitStruct(&'static str),
+    UnitVariant(&'static str, usize, &'static str),
+    NewtypeStruct(&'static str, Box<Content>),
+    NewtypeVariant(&'static str, usize, &'static str, Box<Content>),
+
+    Seq(Vec<Content>),
+    SeqFixedSize(Vec<Content>),
+    Tuple(Vec<Content>),
+    TupleStruct(&'static str, Vec<Content>),
+    TupleVariant(&'static str, usize, &'static str, Vec<Content>),
+    Map(Vec<(Content, Content)>),
+    Struct(&'static str, Vec<(&'static str, Content)>),
+    StructVariant(&'static str, usize, &'static str, Vec<(&'static str, Content)>),
+}
+
+impl Serialize for Content {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+        where S: Serializer
+    {
+        match *self {
+            Content::Bool(b) => serializer.serialize_bool(b),
+            Content::U8(u) => serializer.serialize_u8(u),
+            Content::U16(u) => serializer.serialize_u16(u),
+            Content::U32(u) => serializer.serialize_u32(u),
+            Content::U64(u) => serializer.serialize_u64(u),
+            Content::I8(i) => serializer.serialize_i8(i),
+            Content::I16(i) => serializer.serialize_i16(i),
+            Content::I32(i) => serializer.serialize_i32(i),
+            Content::I64(i) => serializer.serialize_i64(i),
+            Content::F32(f) => serializer.serialize_f32(f),
+            Content::F64(f) => serializer.serialize_f64(f),
+            Content::Char(c) => serializer.serialize_char(c),
+            Content::String(ref s) => serializer.serialize_str(s),
+            Content::Bytes(ref b) => serializer.serialize_bytes(b),
+            Content::None => serializer.serialize_none(),
+            Content::Some(ref c) => serializer.serialize_some(&**c),
+            Content::Unit => serializer.serialize_unit(),
+            Content::UnitStruct(n) => serializer.serialize_unit_struct(n),
+            Content::UnitVariant(n, i, v) => serializer.serialize_unit_variant(n, i, v),
+            Content::NewtypeStruct(n, ref c) => serializer.serialize_newtype_struct(n, &**c),
+            Content::NewtypeVariant(n, i, v, ref c) => serializer.serialize_newtype_variant(n, i, v, &**c),
+            Content::Seq(ref elements) => elements.serialize(serializer),
+            Content::SeqFixedSize(ref elements) => {
+                use ser::SerializeSeq;
+                let mut seq = try!(serializer.serialize_seq_fixed_size(elements.len()));
+                for e in elements {
+                    try!(seq.serialize_element(e));
+                }
+                seq.end()
+            }
+            Content::Tuple(ref elements) => {
+                use ser::SerializeTuple;
+                let mut tuple = try!(serializer.serialize_tuple(elements.len()));
+                for e in elements {
+                    try!(tuple.serialize_element(e));
+                }
+                tuple.end()
+            }
+            Content::TupleStruct(n, ref fields) => {
+                use ser::SerializeTupleStruct;
+                let mut ts = try!(serializer.serialize_tuple_struct(n, fields.len()));
+                for f in fields {
+                    try!(ts.serialize_field(f));
+                }
+                ts.end()
+            }
+            Content::TupleVariant(n, i, v, ref fields) => {
+                use ser::SerializeTupleVariant;
+                let mut tv = try!(serializer.serialize_tuple_variant(n, i, v, fields.len()));
+                for f in fields {
+                    try!(tv.serialize_field(f));
+                }
+                tv.end()
+            }
+            Content::Map(ref entries) => {
+                use ser::SerializeMap;
+                let mut map = try!(serializer.serialize_map(Some(entries.len())));
+                for &(ref k, ref v) in entries {
+                    try!(map.serialize_entry(k, v));
+                }
+                map.end()
+            }
+            Content::Struct(n, ref fields) => {
+                use ser::SerializeStruct;
+                let mut s = try!(serializer.serialize_struct(n, fields.len()));
+                for &(k, ref v) in fields {
+                    try!(s.serialize_field(k, v));
+                }
+                s.end()
+            }
+            Content::StructVariant(n, i, v, ref fields) => {
+                use ser::SerializeStructVariant;
+                let mut sv = try!(serializer.serialize_struct_variant(n, i, v, fields.len()));
+                for &(k, ref v) in fields {
+                    try!(sv.serialize_field(k, v));
+                }
+                sv.end()
+            }
+        }
+    }
+}
+
+struct ContentSerializer<E> {
+    error: PhantomData<E>,
+}
+
+impl<E> ContentSerializer<E> {
+    fn new() -> Self {
+        ContentSerializer {
+            error: PhantomData,
+        }
+    }
+}
+
+impl<E> Serializer for ContentSerializer<E>
+    where E: ser::Error
+{
+    type Ok = Content;
+    type Error = E;
+
+    type SerializeSeq = SerializeSeq<E>;
+    type SerializeTuple = SerializeTuple<E>;
+    type SerializeTupleStruct = SerializeTupleStruct<E>;
+    type SerializeTupleVariant = SerializeTupleVariant<E>;
+    type SerializeMap = SerializeMap<E>;
+    type SerializeStruct = SerializeStruct<E>;
+    type SerializeStructVariant = SerializeStructVariant<E>;
+
+    fn serialize_bool(self, v: bool) -> Result<Content, E> {
+        Ok(Content::Bool(v))
+    }
+
+    fn serialize_i8(self, v: i8) -> Result<Content, E> {
+        Ok(Content::I8(v))
+    }
+
+    fn serialize_i16(self, v: i16) -> Result<Content, E> {
+        Ok(Content::I16(v))
+    }
+
+    fn serialize_i32(self, v: i32) -> Result<Content, E> {
+        Ok(Content::I32(v))
+    }
+
+    fn serialize_i64(self, v: i64) -> Result<Content, E> {
+        Ok(Content::I64(v))
+    }
+
+    fn serialize_u8(self, v: u8) -> Result<Content, E> {
+        Ok(Content::U8(v))
+    }
+
+    fn serialize_u16(self, v: u16) -> Result<Content, E> {
+        Ok(Content::U16(v))
+    }
+
+    fn serialize_u32(self, v: u32) -> Result<Content, E> {
+        Ok(Content::U32(v))
+    }
+
+    fn serialize_u64(self, v: u64) -> Result<Content, E> {
+        Ok(Content::U64(v))
+    }
+
+    fn serialize_f32(self, v: f32) -> Result<Content, E> {
+        Ok(Content::F32(v))
+    }
+
+    fn serialize_f64(self, v: f64) -> Result<Content, E> {
+        Ok(Content::F64(v))
+    }
+
+    fn serialize_char(self, v: char) -> Result<Content, E> {
+        Ok(Content::Char(v))
+    }
+
+    fn serialize_str(self, value: &str) -> Result<Content, E> {
+        Ok(Content::String(value.to_owned()))
+    }
+
+    fn serialize_bytes(self, value: &[u8]) -> Result<Content, E> {
+        Ok(Content::Bytes(value.to_owned()))
+    }
+
+    fn serialize_none(self) -> Result<Content, E> {
+        Ok(Content::None)
+    }
+
+    fn serialize_some<T: ?Sized + Serialize>(self,
+                                             value: &T)
+                                             -> Result<Content, E> {
+        Ok(Content::Some(Box::new(try!(value.serialize(self)))))
+    }
+
+    fn serialize_unit(self) -> Result<Content, E> {
+        Ok(Content::Unit)
+    }
+
+    fn serialize_unit_struct(self,
+                             name: &'static str)
+                             -> Result<Content, E> {
+        Ok(Content::UnitStruct(name))
+    }
+
+    fn serialize_unit_variant(self,
+                              name: &'static str,
+                              variant_index: usize,
+                              variant: &'static str)
+                              -> Result<Content, E> {
+        Ok(Content::UnitVariant(name, variant_index, variant))
+    }
+
+    fn serialize_newtype_struct<T: ?Sized + Serialize>(self,
+                                                       name: &'static str,
+                                                       value: &T)
+                                                       -> Result<Content, E> {
+        Ok(Content::NewtypeStruct(name, Box::new(try!(value.serialize(self)))))
+    }
+
+    fn serialize_newtype_variant<T: ?Sized + Serialize>(self,
+                                                        name: &'static str,
+                                                        variant_index: usize,
+                                                        variant: &'static str,
+                                                        value: &T)
+                                                        -> Result<Content, E> {
+        Ok(Content::NewtypeVariant(name, variant_index, variant, Box::new(try!(value.serialize(self)))))
+    }
+
+    fn serialize_seq(self,
+                     len: Option<usize>)
+                     -> Result<Self::SerializeSeq, E> {
+        Ok(SerializeSeq {
+            fixed_size: false,
+            elements: Vec::with_capacity(len.unwrap_or(0)),
+            error: PhantomData,
+        })
+    }
+
+    fn serialize_seq_fixed_size(self,
+                                size: usize)
+                                -> Result<Self::SerializeSeq, E> {
+        Ok(SerializeSeq {
+            fixed_size: true,
+            elements: Vec::with_capacity(size),
+            error: PhantomData,
+        })
+    }
+
+    fn serialize_tuple(self,
+                       len: usize)
+                       -> Result<Self::SerializeTuple, E> {
+        Ok(SerializeTuple {
+            elements: Vec::with_capacity(len),
+            error: PhantomData,
+        })
+    }
+
+    fn serialize_tuple_struct(self,
+                              name: &'static str,
+                              len: usize)
+                              -> Result<Self::SerializeTupleStruct, E> {
+        Ok(SerializeTupleStruct {
+            name: name,
+            fields: Vec::with_capacity(len),
+            error: PhantomData,
+        })
+    }
+
+    fn serialize_tuple_variant(self,
+                               name: &'static str,
+                               variant_index: usize,
+                               variant: &'static str,
+                               len: usize)
+                               -> Result<Self::SerializeTupleVariant, E> {
+        Ok(SerializeTupleVariant {
+            name: name,
+            variant_index: variant_index,
+            variant: variant,
+            fields: Vec::with_capacity(len),
+            error: PhantomData,
+        })
+    }
+
+    fn serialize_map(self,
+                     len: Option<usize>)
+                     -> Result<Self::SerializeMap, E> {
+        Ok(SerializeMap {
+            entries: Vec::with_capacity(len.unwrap_or(0)),
+            key: None,
+            error: PhantomData,
+        })
+    }
+
+    fn serialize_struct(self,
+                        name: &'static str,
+                        len: usize)
+                        -> Result<Self::SerializeStruct, E> {
+        Ok(SerializeStruct {
+            name: name,
+            fields: Vec::with_capacity(len),
+            error: PhantomData,
+        })
+    }
+
+    fn serialize_struct_variant(self,
+                                name: &'static str,
+                                variant_index: usize,
+                                variant: &'static str,
+                                len: usize)
+                                -> Result<Self::SerializeStructVariant, E> {
+        Ok(SerializeStructVariant {
+            name: name,
+            variant_index: variant_index,
+            variant: variant,
+            fields: Vec::with_capacity(len),
+            error: PhantomData,
+        })
+    }
+}
+
+struct SerializeSeq<E> {
+    fixed_size: bool,
+    elements: Vec<Content>,
+    error: PhantomData<E>,
+}
+
+impl<E> ser::SerializeSeq for SerializeSeq<E>
+    where E: ser::Error
+{
+    type Ok = Content;
+    type Error = E;
+
+    fn serialize_element<T: ?Sized + Serialize>(&mut self,
+                                                value: &T)
+                                                -> Result<(), E> {
+        let value = try!(value.serialize(ContentSerializer::<E>::new()));
+        self.elements.push(value);
+        Ok(())
+    }
+
+    fn end(self) -> Result<Content, E> {
+        Ok(if self.fixed_size {
+            Content::SeqFixedSize(self.elements)
+        } else {
+            Content::Seq(self.elements)
+        })
+    }
+}
+
+struct SerializeTuple<E> {
+    elements: Vec<Content>,
+    error: PhantomData<E>,
+}
+
+impl<E> ser::SerializeTuple for SerializeTuple<E>
+    where E: ser::Error
+{
+    type Ok = Content;
+    type Error = E;
+
+    fn serialize_element<T: ?Sized + Serialize>(&mut self,
+                                                value: &T)
+                                                -> Result<(), E> {
+        let value = try!(value.serialize(ContentSerializer::<E>::new()));
+        self.elements.push(value);
+        Ok(())
+    }
+
+    fn end(self) -> Result<Content, E> {
+        Ok(Content::Tuple(self.elements))
+    }
+}
+
+struct SerializeTupleStruct<E> {
+    name: &'static str,
+    fields: Vec<Content>,
+    error: PhantomData<E>,
+}
+
+impl<E> ser::SerializeTupleStruct for SerializeTupleStruct<E>
+    where E: ser::Error
+{
+    type Ok = Content;
+    type Error = E;
+
+    fn serialize_field<T: ?Sized + Serialize>(&mut self,
+                                              value: &T)
+                                              -> Result<(), E> {
+        let value = try!(value.serialize(ContentSerializer::<E>::new()));
+        self.fields.push(value);
+        Ok(())
+    }
+
+    fn end(self) -> Result<Content, E> {
+        Ok(Content::TupleStruct(self.name, self.fields))
+    }
+}
+
+struct SerializeTupleVariant<E> {
+    name: &'static str,
+    variant_index: usize,
+    variant: &'static str,
+    fields: Vec<Content>,
+    error: PhantomData<E>,
+}
+
+impl<E> ser::SerializeTupleVariant for SerializeTupleVariant<E>
+    where E: ser::Error
+{
+    type Ok = Content;
+    type Error = E;
+
+    fn serialize_field<T: ?Sized + Serialize>(&mut self,
+                                              value: &T)
+                                              -> Result<(), E> {
+        let value = try!(value.serialize(ContentSerializer::<E>::new()));
+        self.fields.push(value);
+        Ok(())
+    }
+
+    fn end(self) -> Result<Content, E> {
+        Ok(Content::TupleVariant(self.name, self.variant_index, self.variant, self.fields))
+    }
+}
+
+struct SerializeMap<E> {
+    entries: Vec<(Content, Content)>,
+    key: Option<Content>,
+    error: PhantomData<E>,
+}
+
+impl<E> ser::SerializeMap for SerializeMap<E>
+    where E: ser::Error
+{
+    type Ok = Content;
+    type Error = E;
+
+    fn serialize_key<T: ?Sized + Serialize>(&mut self,
+                                            key: &T)
+                                            -> Result<(), E> {
+        let key = try!(key.serialize(ContentSerializer::<E>::new()));
+        self.key = Some(key);
+        Ok(())
+    }
+
+    fn serialize_value<T: ?Sized + Serialize>(&mut self,
+                                              value: &T)
+                                              -> Result<(), E> {
+        let key = self.key.take().expect("serialize_value called before serialize_key");
+        let value = try!(value.serialize(ContentSerializer::<E>::new()));
+        self.entries.push((key, value));
+        Ok(())
+    }
+
+    fn end(self) -> Result<Content, E> {
+        Ok(Content::Map(self.entries))
+    }
+
+    fn serialize_entry<K: ?Sized + Serialize, V: ?Sized + Serialize>(&mut self,
+                                                                     key: &K,
+                                                                     value: &V)
+                                                                     -> Result<(), E> {
+        let key = try!(key.serialize(ContentSerializer::<E>::new()));
+        let value = try!(value.serialize(ContentSerializer::<E>::new()));
+        self.entries.push((key, value));
+        Ok(())
+    }
+}
+
+struct SerializeStruct<E> {
+    name: &'static str,
+    fields: Vec<(&'static str, Content)>,
+    error: PhantomData<E>,
+}
+
+impl<E> ser::SerializeStruct for SerializeStruct<E>
+    where E: ser::Error
+{
+    type Ok = Content;
+    type Error = E;
+
+    fn serialize_field<T: ?Sized + Serialize>(&mut self,
+                                              key: &'static str,
+                                              value: &T)
+                                              -> Result<(), E> {
+        let value = try!(value.serialize(ContentSerializer::<E>::new()));
+        self.fields.push((key, value));
+        Ok(())
+    }
+
+    fn end(self) -> Result<Content, E> {
+        Ok(Content::Struct(self.name, self.fields))
+    }
+}
+
+struct SerializeStructVariant<E> {
+    name: &'static str,
+    variant_index: usize,
+    variant: &'static str,
+    fields: Vec<(&'static str, Content)>,
+    error: PhantomData<E>,
+}
+
+impl<E> ser::SerializeStructVariant for SerializeStructVariant<E>
+    where E: ser::Error
+{
+    type Ok = Content;
+    type Error = E;
+
+    fn serialize_field<T: ?Sized + Serialize>(&mut self,
+                                              key: &'static str,
+                                              value: &T)
+                                              -> Result<(), E> {
+        let value = try!(value.serialize(ContentSerializer::<E>::new()));
+        self.fields.push((key, value));
+        Ok(())
+    }
+
+    fn end(self) -> Result<Content, E> {
+        Ok(Content::StructVariant(self.name, self.variant_index, self.variant, self.fields))
+    }
+}

serde/src/ser/impls.rs

@@ -4,28 +4,10 @@ use std::borrow::Cow;
 use collections::borrow::Cow;
 
 #[cfg(feature = "std")]
-use std::collections::{
-    BinaryHeap,
-    BTreeMap,
-    BTreeSet,
-    LinkedList,
-    HashMap,
-    HashSet,
-    VecDeque,
-};
+use std::collections::{BinaryHeap, BTreeMap, BTreeSet, LinkedList, HashMap, HashSet, VecDeque};
 #[cfg(all(feature = "collections", not(feature = "std")))]
-use collections::{
-    BinaryHeap,
-    BTreeMap,
-    BTreeSet,
-    LinkedList,
-    VecDeque,
-    String,
-    Vec,
-};
+use collections::{BinaryHeap, BTreeMap, BTreeSet, LinkedList, VecDeque, String, Vec};
 
-#[cfg(feature = "collections")]
-use collections::enum_set::{CLike, EnumSet};
 #[cfg(feature = "collections")]
 use collections::borrow::ToOwned;
 
@@ -40,6 +22,8 @@ use core::ops;
 #[cfg(feature = "std")]
 use std::path;
 #[cfg(feature = "std")]
+use std::ffi::{CString, CStr};
+#[cfg(feature = "std")]
 use std::rc::Rc;
 #[cfg(all(feature = "alloc", not(feature = "std")))]
 use alloc::rc::Rc;
@@ -59,18 +43,10 @@ use core::marker::PhantomData;
 #[cfg(feature = "unstable")]
 use core::nonzero::{NonZero, Zeroable};
 
-use super::{
-    Serialize,
-    SerializeSeq,
-    SerializeTuple,
-    Serializer,
-};
-#[cfg(any(feature = "std", feature = "unstable"))]
+use super::{Serialize, SerializeSeq, SerializeTuple, Serializer};
+#[cfg(feature = "std")]
 use super::Error;
 
-#[cfg(feature = "unstable")]
-use super::Iterator;
-
 ///////////////////////////////////////////////////////////////////////////////
 
 macro_rules! impl_visit {
@@ -106,7 +82,7 @@ impl_visit!(char, serialize_char);
 impl Serialize for str {
     #[inline]
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
-        where S: Serializer,
+        where S: Serializer
     {
         serializer.serialize_str(self)
     }
@@ -116,7 +92,7 @@ impl Serialize for str {
 impl Serialize for String {
     #[inline]
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
-        where S: Serializer,
+        where S: Serializer
     {
         (&self[..]).serialize(serializer)
     }
@@ -124,12 +100,34 @@ impl Serialize for String {
 
 ///////////////////////////////////////////////////////////////////////////////
 
+#[cfg(feature = "std")]
+impl Serialize for CStr {
+    #[inline]
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+        where S: Serializer
+    {
+        serializer.serialize_bytes(self.to_bytes())
+    }
+}
+
+#[cfg(feature = "std")]
+impl Serialize for CString {
+    #[inline]
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+        where S: Serializer
+    {
+        serializer.serialize_bytes(self.to_bytes())
+    }
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
 impl<T> Serialize for Option<T>
     where T: Serialize
 {
     #[inline]
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
-        where S: Serializer,
+        where S: Serializer
     {
         match *self {
             Some(ref value) => serializer.serialize_some(value),
@@ -143,30 +141,12 @@ impl<T> Serialize for Option<T>
 impl<T> Serialize for PhantomData<T> {
     #[inline]
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
-        where S: Serializer,
+        where S: Serializer
     {
         serializer.serialize_unit_struct("PhantomData")
     }
 }
 
-
-///////////////////////////////////////////////////////////////////////////////
-
-impl<T> Serialize for [T]
-    where T: Serialize,
-{
-    #[inline]
-    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
-        where S: Serializer,
-    {
-        let mut seq = try!(serializer.serialize_seq(Some(self.len())));
-        for e in self {
-            try!(seq.serialize_element(e));
-        }
-        seq.end()
-    }
-}
-
 ///////////////////////////////////////////////////////////////////////////////
 
 macro_rules! array_impls {
@@ -222,48 +202,23 @@ array_impls!(32);
 
 ///////////////////////////////////////////////////////////////////////////////
 
-#[cfg(feature = "unstable")]
-impl<'a, I> Serialize for Iterator<I>
-    where I: IntoIterator, <I as IntoIterator>::Item: Serialize
-{
-    #[inline]
-    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
-        where S: Serializer,
-    {
-        // FIXME: use specialization to prevent invalidating the object in case of clonable iterators?
-        let iter = match self.data.borrow_mut().take() {
-            Some(iter) => iter.into_iter(),
-            None => return Err(Error::custom("Iterator used twice")),
-        };
-        let size = match iter.size_hint() {
-            (lo, Some(hi)) if lo == hi => Some(lo),
-            _ => None,
-        };
-        let mut seq = try!(serializer.serialize_seq(size));
-        for e in iter {
-            try!(seq.serialize_element(&e));
-        }
-        seq.end()
-    }
-}
-
-///////////////////////////////////////////////////////////////////////////////
-
 macro_rules! serialize_seq {
     () => {
         #[inline]
         fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
             where S: Serializer,
         {
-            let mut seq = try!(serializer.serialize_seq(Some(self.len())));
-            for e in self {
-                try!(seq.serialize_element(&e));
-            }
-            seq.end()
+            serializer.collect_seq(self)
         }
     }
 }
 
+impl<T> Serialize for [T]
+    where T: Serialize
+{
+    serialize_seq!();
+}
+
 #[cfg(any(feature = "std", feature = "collections"))]
 impl<T> Serialize for BinaryHeap<T>
     where T: Serialize + Ord
@@ -273,14 +228,7 @@ impl<T> Serialize for BinaryHeap<T>
 
 #[cfg(any(feature = "std", feature = "collections"))]
 impl<T> Serialize for BTreeSet<T>
-    where T: Serialize + Ord,
-{
-    serialize_seq!();
-}
-
-#[cfg(feature = "collections")]
-impl<T> Serialize for EnumSet<T>
-    where T: Serialize + CLike
+    where T: Serialize + Ord
 {
     serialize_seq!();
 }
@@ -288,14 +236,14 @@ impl<T> Serialize for EnumSet<T>
 #[cfg(feature = "std")]
 impl<T, H> Serialize for HashSet<T, H>
     where T: Serialize + Eq + Hash,
-          H: BuildHasher,
+          H: BuildHasher
 {
     serialize_seq!();
 }
 
 #[cfg(any(feature = "std", feature = "collections"))]
 impl<T> Serialize for LinkedList<T>
-    where T: Serialize,
+    where T: Serialize
 {
     serialize_seq!();
 }
@@ -317,11 +265,11 @@ impl<T> Serialize for VecDeque<T>
 #[cfg(feature = "unstable")]
 impl<A> Serialize for ops::Range<A>
     where ops::Range<A>: ExactSizeIterator + iter::Iterator<Item = A> + Clone,
-          A: Serialize,
+          A: Serialize
 {
     #[inline]
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
-        where S: Serializer,
+        where S: Serializer
     {
         let mut seq = try!(serializer.serialize_seq(Some(self.len())));
         for e in self.clone() {
@@ -334,11 +282,11 @@ impl<A> Serialize for ops::Range<A>
 #[cfg(feature = "unstable")]
 impl<A> Serialize for ops::RangeInclusive<A>
     where ops::RangeInclusive<A>: ExactSizeIterator + iter::Iterator<Item = A> + Clone,
-          A: Serialize,
+          A: Serialize
 {
     #[inline]
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
-        where S: Serializer,
+        where S: Serializer
     {
         let mut seq = try!(serializer.serialize_seq(Some(self.len())));
         for e in self.clone() {
@@ -353,7 +301,7 @@ impl<A> Serialize for ops::RangeInclusive<A>
 impl Serialize for () {
     #[inline]
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
-        where S: Serializer,
+        where S: Serializer
     {
         serializer.serialize_unit()
     }
@@ -565,12 +513,7 @@ macro_rules! serialize_map {
         fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
             where S: Serializer,
         {
-            use super::SerializeMap;
-            let mut map = try!(serializer.serialize_map(Some(self.len())));
-            for (k, v) in self {
-                try!(map.serialize_entry(k, v));
-            }
-            map.end()
+            serializer.collect_map(self)
         }
     }
 }
@@ -578,7 +521,7 @@ macro_rules! serialize_map {
 #[cfg(any(feature = "std", feature = "collections"))]
 impl<K, V> Serialize for BTreeMap<K, V>
     where K: Serialize + Ord,
-          V: Serialize,
+          V: Serialize
 {
     serialize_map!();
 }
@@ -587,26 +530,30 @@ impl<K, V> Serialize for BTreeMap<K, V>
 impl<K, V, H> Serialize for HashMap<K, V, H>
     where K: Serialize + Eq + Hash,
           V: Serialize,
-          H: BuildHasher,
+          H: BuildHasher
 {
     serialize_map!();
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 
-impl<'a, T: ?Sized> Serialize for &'a T where T: Serialize {
+impl<'a, T: ?Sized> Serialize for &'a T
+    where T: Serialize
+{
     #[inline]
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
-        where S: Serializer,
+        where S: Serializer
     {
         (**self).serialize(serializer)
     }
 }
 
-impl<'a, T: ?Sized> Serialize for &'a mut T where T: Serialize {
+impl<'a, T: ?Sized> Serialize for &'a mut T
+    where T: Serialize
+{
     #[inline]
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
-        where S: Serializer,
+        where S: Serializer
     {
         (**self).serialize(serializer)
     }
@@ -618,7 +565,7 @@ impl<T: ?Sized> Serialize for Box<T>
 {
     #[inline]
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
-        where S: Serializer,
+        where S: Serializer
     {
         (**self).serialize(serializer)
     }
@@ -630,7 +577,7 @@ impl<T> Serialize for Rc<T>
 {
     #[inline]
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
-        where S: Serializer,
+        where S: Serializer
     {
         (**self).serialize(serializer)
     }
@@ -642,7 +589,7 @@ impl<T> Serialize for Arc<T>
 {
     #[inline]
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
-        where S: Serializer,
+        where S: Serializer
     {
         (**self).serialize(serializer)
     }
@@ -654,7 +601,7 @@ impl<'a, T: ?Sized> Serialize for Cow<'a, T>
 {
     #[inline]
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
-        where S: Serializer,
+        where S: Serializer
     {
         (**self).serialize(serializer)
     }
@@ -670,9 +617,7 @@ impl<T, E> Serialize for Result<T, E>
         where S: Serializer
     {
         match *self {
-            Result::Ok(ref value) => {
-                serializer.serialize_newtype_variant("Result", 0, "Ok", value)
-            }
+            Result::Ok(ref value) => serializer.serialize_newtype_variant("Result", 0, "Ok", value),
             Result::Err(ref value) => {
                 serializer.serialize_newtype_variant("Result", 1, "Err", value)
             }
@@ -685,7 +630,7 @@ impl<T, E> Serialize for Result<T, E>
 #[cfg(feature = "std")]
 impl Serialize for Duration {
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
-        where S: Serializer,
+        where S: Serializer
     {
         use super::SerializeStruct;
         let mut state = try!(serializer.serialize_struct("Duration", 2));
@@ -700,27 +645,34 @@ impl Serialize for Duration {
 #[cfg(feature = "std")]
 impl Serialize for net::IpAddr {
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
-        where S: Serializer,
+        where S: Serializer
     {
-        self.to_string().serialize(serializer)
+        match *self {
+            net::IpAddr::V4(ref a) => a.serialize(serializer),
+            net::IpAddr::V6(ref a) => a.serialize(serializer),
+        }
     }
 }
 
 #[cfg(feature = "std")]
 impl Serialize for net::Ipv4Addr {
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
-        where S: Serializer,
+        where S: Serializer
     {
-        self.to_string().serialize(serializer)
+        /// "101.102.103.104".len()
+        const MAX_LEN: usize = 15;
+        serialize_display_bounded_length!(self, MAX_LEN, serializer)
     }
 }
 
 #[cfg(feature = "std")]
 impl Serialize for net::Ipv6Addr {
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
-        where S: Serializer,
+        where S: Serializer
     {
-        self.to_string().serialize(serializer)
+        /// "1000:1002:1003:1004:1005:1006:1007:1008".len()
+        const MAX_LEN: usize = 39;
+        serialize_display_bounded_length!(self, MAX_LEN, serializer)
     }
 }
 
@@ -729,7 +681,7 @@ impl Serialize for net::Ipv6Addr {
 #[cfg(feature = "std")]
 impl Serialize for net::SocketAddr {
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
-        where S: Serializer,
+        where S: Serializer
     {
         match *self {
             net::SocketAddr::V4(ref addr) => addr.serialize(serializer),
@@ -741,18 +693,22 @@ impl Serialize for net::SocketAddr {
 #[cfg(feature = "std")]
 impl Serialize for net::SocketAddrV4 {
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
-        where S: Serializer,
+        where S: Serializer
     {
-        self.to_string().serialize(serializer)
+        /// "101.102.103.104:65000".len()
+        const MAX_LEN: usize = 21;
+        serialize_display_bounded_length!(self, MAX_LEN, serializer)
     }
 }
 
 #[cfg(feature = "std")]
 impl Serialize for net::SocketAddrV6 {
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
-        where S: Serializer,
+        where S: Serializer
     {
-        self.to_string().serialize(serializer)
+        /// "[1000:1002:1003:1004:1005:1006:1007:1008]:65000".len()
+        const MAX_LEN: usize = 47;
+        serialize_display_bounded_length!(self, MAX_LEN, serializer)
     }
 }
 
@@ -761,7 +717,7 @@ impl Serialize for net::SocketAddrV6 {
 #[cfg(feature = "std")]
 impl Serialize for path::Path {
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
-        where S: Serializer,
+        where S: Serializer
     {
         match self.to_str() {
             Some(s) => s.serialize(serializer),
@@ -773,7 +729,7 @@ impl Serialize for path::Path {
 #[cfg(feature = "std")]
 impl Serialize for path::PathBuf {
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
-        where S: Serializer,
+        where S: Serializer
     {
         self.as_path().serialize(serializer)
     }

serde/src/ser/impossible.rs

@@ -2,17 +2,8 @@
 
 use core::marker::PhantomData;
 
-use ser::{
-    self,
-    Serialize,
-    SerializeSeq,
-    SerializeTuple,
-    SerializeTupleStruct,
-    SerializeTupleVariant,
-    SerializeMap,
-    SerializeStruct,
-    SerializeStructVariant,
-};
+use ser::{self, Serialize, SerializeSeq, SerializeTuple, SerializeTupleStruct,
+          SerializeTupleVariant, SerializeMap, SerializeStruct, SerializeStructVariant};
 
 /// Helper type for implementing a `Serializer` that does not support
 /// serializing one of the compound types.
@@ -50,14 +41,12 @@ pub struct Impossible<Ok, E> {
 enum Void {}
 
 impl<Ok, E> SerializeSeq for Impossible<Ok, E>
-    where E: ser::Error,
+    where E: ser::Error
 {
     type Ok = Ok;
     type Error = E;
 
-    fn serialize_element<T: ?Sized + Serialize>(&mut self,
-                                                _value: &T)
-                                                -> Result<(), E> {
+    fn serialize_element<T: ?Sized + Serialize>(&mut self, _value: &T) -> Result<(), E> {
         match self.void {}
     }
 
@@ -67,14 +56,12 @@ impl<Ok, E> SerializeSeq for Impossible<Ok, E>
 }
 
 impl<Ok, E> SerializeTuple for Impossible<Ok, E>
-    where E: ser::Error,
+    where E: ser::Error
 {
     type Ok = Ok;
     type Error = E;
 
-    fn serialize_element<T: ?Sized + Serialize>(&mut self,
-                                                _value: &T)
-                                                -> Result<(), E> {
+    fn serialize_element<T: ?Sized + Serialize>(&mut self, _value: &T) -> Result<(), E> {
         match self.void {}
     }
 
@@ -84,14 +71,12 @@ impl<Ok, E> SerializeTuple for Impossible<Ok, E>
 }
 
 impl<Ok, E> SerializeTupleStruct for Impossible<Ok, E>
-    where E: ser::Error,
+    where E: ser::Error
 {
     type Ok = Ok;
     type Error = E;
 
-    fn serialize_field<T: ?Sized + Serialize>(&mut self,
-                                              _value: &T)
-                                              -> Result<(), E> {
+    fn serialize_field<T: ?Sized + Serialize>(&mut self, _value: &T) -> Result<(), E> {
         match self.void {}
     }
 
@@ -101,14 +86,12 @@ impl<Ok, E> SerializeTupleStruct for Impossible<Ok, E>
 }
 
 impl<Ok, E> SerializeTupleVariant for Impossible<Ok, E>
-    where E: ser::Error,
+    where E: ser::Error
 {
     type Ok = Ok;
     type Error = E;
 
-    fn serialize_field<T: ?Sized + Serialize>(&mut self,
-                                              _value: &T)
-                                              -> Result<(), E> {
+    fn serialize_field<T: ?Sized + Serialize>(&mut self, _value: &T) -> Result<(), E> {
         match self.void {}
     }
 
@@ -118,20 +101,16 @@ impl<Ok, E> SerializeTupleVariant for Impossible<Ok, E>
 }
 
 impl<Ok, E> SerializeMap for Impossible<Ok, E>
-    where E: ser::Error,
+    where E: ser::Error
 {
     type Ok = Ok;
     type Error = E;
 
-    fn serialize_key<T: ?Sized + Serialize>(&mut self,
-                                                 _key: &T)
-                                            -> Result<(), E> {
+    fn serialize_key<T: ?Sized + Serialize>(&mut self, _key: &T) -> Result<(), E> {
         match self.void {}
     }
 
-    fn serialize_value<T: ?Sized + Serialize>(&mut self,
-                                              _value: &T)
-                                              -> Result<(), E> {
+    fn serialize_value<T: ?Sized + Serialize>(&mut self, _value: &T) -> Result<(), E> {
         match self.void {}
     }
 
@@ -141,13 +120,13 @@ impl<Ok, E> SerializeMap for Impossible<Ok, E>
 }
 
 impl<Ok, E> SerializeStruct for Impossible<Ok, E>
-    where E: ser::Error,
+    where E: ser::Error
 {
     type Ok = Ok;
     type Error = E;
 
     fn serialize_field<T: ?Sized + Serialize>(&mut self,
-                                                   _key: &'static str,
+                                              _key: &'static str,
                                               _value: &T)
                                               -> Result<(), E> {
         match self.void {}
@@ -159,13 +138,13 @@ impl<Ok, E> SerializeStruct for Impossible<Ok, E>
 }
 
 impl<Ok, E> SerializeStructVariant for Impossible<Ok, E>
-    where E: ser::Error,
+    where E: ser::Error
 {
     type Ok = Ok;
     type Error = E;
 
     fn serialize_field<T: ?Sized + Serialize>(&mut self,
-                                                   _key: &'static str,
+                                              _key: &'static str,
                                               _value: &T)
                                               -> Result<(), E> {
         match self.void {}

serde/src/ser/mod.rs

@@ -98,14 +98,22 @@ use std::error;
 #[cfg(not(feature = "std"))]
 use error;
 
-#[cfg(feature = "unstable")]
-use core::cell::RefCell;
-
+#[cfg(all(feature = "collections", not(feature = "std")))]
+use collections::string::String;
 use core::fmt::Display;
+#[cfg(any(feature = "std", feature = "collections"))]
+use core::fmt::Write;
+use core::iter::IntoIterator;
 
 mod impls;
 mod impossible;
 
+// Helpers used by generated code. Not public API.
+#[doc(hidden)]
+pub mod private;
+#[cfg(any(feature = "std", feature = "collections"))]
+mod content;
+
 pub use self::impossible::Impossible;
 
 ///////////////////////////////////////////////////////////////////////////////
@@ -141,8 +149,8 @@ pub trait Error: Sized + error::Error {
 
 ///////////////////////////////////////////////////////////////////////////////
 
-/// An implementation of this trait is a **data structure** that can be
-/// serialized into any data format supported by Serde.
+/// A **data structure** that can be serialized into any data format supported
+/// by Serde.
 ///
 /// Serde provides `Serialize` implementations for many Rust primitive and
 /// standard library types. The complete list is [here][ser]. All of these can
@@ -172,14 +180,12 @@ pub trait Serialize {
     /// for more information about how to implement this method.
     ///
     /// [impl-serialize]: https://serde.rs/impl-serialize.html
-    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
-        where S: Serializer;
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error> where S: Serializer;
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 
-/// An implementation of this trait is a **data format** that can serialize any
-/// data structure supported by Serde.
+/// A **data format** that can serialize any data structure supported by Serde.
 ///
 /// The role of this trait is to define the serialization half of the Serde data
 /// model, which is a way to categorize every Rust data structure into one of 28
@@ -239,7 +245,7 @@ pub trait Serialize {
 /// is the `serde_json::value::Serializer` (distinct from the main `serde_json`
 /// serializer) that produces a `serde_json::Value` data structure in memory as
 /// output.
-pub trait Serializer {
+pub trait Serializer: Sized {
     /// The output type produced by this `Serializer` during successful
     /// serialization. Most serializers that produce text or binary output
     /// should set `Ok = ()` and serialize into an `io::Write` or buffer
@@ -253,31 +259,31 @@ pub trait Serializer {
 
     /// Type returned from `serialize_seq` and `serialize_seq_fixed_size` for
     /// serializing the content of the sequence.
-    type SerializeSeq: SerializeSeq<Ok=Self::Ok, Error=Self::Error>;
+    type SerializeSeq: SerializeSeq<Ok = Self::Ok, Error = Self::Error>;
 
     /// Type returned from `serialize_tuple` for serializing the content of the
     /// tuple.
-    type SerializeTuple: SerializeTuple<Ok=Self::Ok, Error=Self::Error>;
+    type SerializeTuple: SerializeTuple<Ok = Self::Ok, Error = Self::Error>;
 
     /// Type returned from `serialize_tuple_struct` for serializing the content
     /// of the tuple struct.
-    type SerializeTupleStruct: SerializeTupleStruct<Ok=Self::Ok, Error=Self::Error>;
+    type SerializeTupleStruct: SerializeTupleStruct<Ok = Self::Ok, Error = Self::Error>;
 
     /// Type returned from `serialize_tuple_variant` for serializing the content
     /// of the tuple variant.
-    type SerializeTupleVariant: SerializeTupleVariant<Ok=Self::Ok, Error=Self::Error>;
+    type SerializeTupleVariant: SerializeTupleVariant<Ok = Self::Ok, Error = Self::Error>;
 
     /// Type returned from `serialize_map` for serializing the content of the
     /// map.
-    type SerializeMap: SerializeMap<Ok=Self::Ok, Error=Self::Error>;
+    type SerializeMap: SerializeMap<Ok = Self::Ok, Error = Self::Error>;
 
     /// Type returned from `serialize_struct` for serializing the content of the
     /// struct.
-    type SerializeStruct: SerializeStruct<Ok=Self::Ok, Error=Self::Error>;
+    type SerializeStruct: SerializeStruct<Ok = Self::Ok, Error = Self::Error>;
 
     /// Type returned from `serialize_struct_variant` for serializing the
     /// content of the struct variant.
-    type SerializeStructVariant: SerializeStructVariant<Ok=Self::Ok, Error=Self::Error>;
+    type SerializeStructVariant: SerializeStructVariant<Ok = Self::Ok, Error = Self::Error>;
 
     /// Serialize a `bool` value.
     fn serialize_bool(self, v: bool) -> Result<Self::Ok, Self::Error>;
@@ -370,10 +376,7 @@ pub trait Serializer {
     fn serialize_none(self) -> Result<Self::Ok, Self::Error>;
 
     /// Serialize a `Some(T)` value.
-    fn serialize_some<T: ?Sized + Serialize>(
-        self,
-        value: &T,
-    ) -> Result<Self::Ok, Self::Error>;
+    fn serialize_some<T: ?Sized + Serialize>(self, value: &T) -> Result<Self::Ok, Self::Error>;
 
     /// Serialize a `()` value.
     fn serialize_unit(self) -> Result<Self::Ok, Self::Error>;
@@ -381,10 +384,7 @@ pub trait Serializer {
     /// Serialize a unit struct like `struct Unit` or `PhantomData<T>`.
     ///
     /// A reasonable implementation would be to forward to `serialize_unit`.
-    fn serialize_unit_struct(
-        self,
-        name: &'static str,
-    ) -> Result<Self::Ok, Self::Error>;
+    fn serialize_unit_struct(self, name: &'static str) -> Result<Self::Ok, Self::Error>;
 
     /// Serialize a unit variant like `E::A` in `enum E { A, B }`.
     ///
@@ -400,12 +400,11 @@ pub trait Serializer {
     ///     E::B => serializer.serialize_unit_variant("E", 1, "B"),
     /// }
     /// ```
-    fn serialize_unit_variant(
-        self,
-        name: &'static str,
-        variant_index: usize,
-        variant: &'static str,
-    ) -> Result<Self::Ok, Self::Error>;
+    fn serialize_unit_variant(self,
+                              name: &'static str,
+                              variant_index: usize,
+                              variant: &'static str)
+                              -> Result<Self::Ok, Self::Error>;
 
     /// Serialize a newtype struct like `struct Millimeters(u8)`.
     ///
@@ -416,11 +415,10 @@ pub trait Serializer {
     /// ```rust,ignore
     /// serializer.serialize_newtype_struct("Millimeters", &self.0)
     /// ```
-    fn serialize_newtype_struct<T: ?Sized + Serialize>(
-        self,
-        name: &'static str,
-        value: &T,
-    ) -> Result<Self::Ok, Self::Error>;
+    fn serialize_newtype_struct<T: ?Sized + Serialize>(self,
+                                                       name: &'static str,
+                                                       value: &T)
+                                                       -> Result<Self::Ok, Self::Error>;
 
     /// Serialize a newtype variant like `E::N` in `enum E { N(u8) }`.
     ///
@@ -433,13 +431,12 @@ pub trait Serializer {
     ///     E::N(ref n) => serializer.serialize_newtype_variant("E", 0, "N", n),
     /// }
     /// ```
-    fn serialize_newtype_variant<T: ?Sized + Serialize>(
-        self,
-        name: &'static str,
-        variant_index: usize,
-        variant: &'static str,
-        value: &T,
-    ) -> Result<Self::Ok, Self::Error>;
+    fn serialize_newtype_variant<T: ?Sized + Serialize>(self,
+                                                        name: &'static str,
+                                                        variant_index: usize,
+                                                        variant: &'static str,
+                                                        value: &T)
+                                                        -> Result<Self::Ok, Self::Error>;
 
     /// Begin to serialize a dynamically sized sequence. This call must be
     /// followed by zero or more calls to `serialize_element`, then a call to
@@ -456,10 +453,7 @@ pub trait Serializer {
     /// }
     /// seq.end()
     /// ```
-    fn serialize_seq(
-        self,
-        len: Option<usize>,
-    ) -> Result<Self::SerializeSeq, Self::Error>;
+    fn serialize_seq(self, len: Option<usize>) -> Result<Self::SerializeSeq, Self::Error>;
 
     /// Begin to serialize a statically sized sequence whose length will be
     /// known at deserialization time without looking at the serialized data.
@@ -473,25 +467,19 @@ pub trait Serializer {
     /// }
     /// seq.end()
     /// ```
-    fn serialize_seq_fixed_size(
-        self,
-        size: usize,
-    ) -> Result<Self::SerializeSeq, Self::Error>;
+    fn serialize_seq_fixed_size(self, size: usize) -> Result<Self::SerializeSeq, Self::Error>;
 
     /// Begin to serialize a tuple. This call must be followed by zero or more
-    /// calls to `serialize_field`, then a call to `end`.
+    /// calls to `serialize_element`, then a call to `end`.
     ///
     /// ```rust,ignore
     /// let mut tup = serializer.serialize_tuple(3)?;
-    /// tup.serialize_field(&self.0)?;
-    /// tup.serialize_field(&self.1)?;
-    /// tup.serialize_field(&self.2)?;
+    /// tup.serialize_element(&self.0)?;
+    /// tup.serialize_element(&self.1)?;
+    /// tup.serialize_element(&self.2)?;
     /// tup.end()
     /// ```
-    fn serialize_tuple(
-        self,
-        len: usize,
-    ) -> Result<Self::SerializeTuple, Self::Error>;
+    fn serialize_tuple(self, len: usize) -> Result<Self::SerializeTuple, Self::Error>;
 
     /// Begin to serialize a tuple struct like `struct Rgb(u8, u8, u8)`. This
     /// call must be followed by zero or more calls to `serialize_field`, then a
@@ -507,11 +495,10 @@ pub trait Serializer {
     /// ts.serialize_field(&self.2)?;
     /// ts.end()
     /// ```
-    fn serialize_tuple_struct(
-        self,
-        name: &'static str,
-        len: usize,
-    ) -> Result<Self::SerializeTupleStruct, Self::Error>;
+    fn serialize_tuple_struct(self,
+                              name: &'static str,
+                              len: usize)
+                              -> Result<Self::SerializeTupleStruct, Self::Error>;
 
     /// Begin to serialize a tuple variant like `E::T` in `enum E { T(u8, u8)
     /// }`. This call must be followed by zero or more calls to
@@ -531,13 +518,12 @@ pub trait Serializer {
     ///     }
     /// }
     /// ```
-    fn serialize_tuple_variant(
-        self,
-        name: &'static str,
-        variant_index: usize,
-        variant: &'static str,
-        len: usize,
-    ) -> Result<Self::SerializeTupleVariant, Self::Error>;
+    fn serialize_tuple_variant(self,
+                               name: &'static str,
+                               variant_index: usize,
+                               variant: &'static str,
+                               len: usize)
+                               -> Result<Self::SerializeTupleVariant, Self::Error>;
 
     /// Begin to serialize a map. This call must be followed by zero or more
     /// calls to `serialize_key` and `serialize_value`, then a call to `end`.
@@ -553,10 +539,7 @@ pub trait Serializer {
     /// }
     /// map.end()
     /// ```
-    fn serialize_map(
-        self,
-        len: Option<usize>,
-    ) -> Result<Self::SerializeMap, Self::Error>;
+    fn serialize_map(self, len: Option<usize>) -> Result<Self::SerializeMap, Self::Error>;
 
     /// Begin to serialize a struct like `struct Rgb { r: u8, g: u8, b: u8 }`.
     /// This call must be followed by zero or more calls to `serialize_field`,
@@ -572,11 +555,10 @@ pub trait Serializer {
     /// struc.serialize_field("b", &self.b)?;
     /// struc.end()
     /// ```
-    fn serialize_struct(
-        self,
-        name: &'static str,
-        len: usize,
-    ) -> Result<Self::SerializeStruct, Self::Error>;
+    fn serialize_struct(self,
+                        name: &'static str,
+                        len: usize)
+                        -> Result<Self::SerializeStruct, Self::Error>;
 
     /// Begin to serialize a struct variant like `E::S` in `enum E { S { r: u8,
     /// g: u8, b: u8 } }`. This call must be followed by zero or more calls to
@@ -597,13 +579,111 @@ pub trait Serializer {
     ///     }
     /// }
     /// ```
-    fn serialize_struct_variant(
-        self,
-        name: &'static str,
-        variant_index: usize,
-        variant: &'static str,
-        len: usize,
-    ) -> Result<Self::SerializeStructVariant, Self::Error>;
+    fn serialize_struct_variant(self,
+                                name: &'static str,
+                                variant_index: usize,
+                                variant: &'static str,
+                                len: usize)
+                                -> Result<Self::SerializeStructVariant, Self::Error>;
+
+    /// Collect an iterator as a sequence.
+    ///
+    /// The default implementation serializes each item yielded by the iterator
+    /// using `Self::SerializeSeq`. Implementors should not need to override
+    /// this method.
+    fn collect_seq<I>(self, iter: I) -> Result<Self::Ok, Self::Error>
+        where I: IntoIterator,
+              <I as IntoIterator>::Item: Serialize
+    {
+        let iter = iter.into_iter();
+        let mut serializer = try!(self.serialize_seq(iter.len_hint()));
+        for item in iter {
+            try!(serializer.serialize_element(&item));
+        }
+        serializer.end()
+    }
+
+    /// Collect an iterator as a map.
+    ///
+    /// The default implementation serializes each pair yielded by the iterator
+    /// using `Self::SerializeMap`. Implementors should not need to override
+    /// this method.
+    fn collect_map<K, V, I>(self, iter: I) -> Result<Self::Ok, Self::Error>
+        where K: Serialize,
+              V: Serialize,
+              I: IntoIterator<Item = (K, V)>
+    {
+        let iter = iter.into_iter();
+        let mut serializer = try!(self.serialize_map(iter.len_hint()));
+        for (key, value) in iter {
+            try!(serializer.serialize_entry(&key, &value));
+        }
+        serializer.end()
+    }
+
+    /// Serialize a string produced by an implementation of `Display`.
+    ///
+    /// The default implementation builds a heap-allocated `String` and
+    /// delegates to `serialize_str`. Serializers are encouraged to provide a
+    /// more efficient implementation if possible.
+    ///
+    /// ```rust
+    /// # use serde::{Serialize, Serializer};
+    /// # struct DateTime;
+    /// # impl DateTime {
+    /// #     fn naive_local(&self) -> () { () }
+    /// #     fn offset(&self) -> () { () }
+    /// # }
+    /// impl Serialize for DateTime {
+    ///     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    ///         where S: Serializer
+    ///     {
+    ///         serializer.collect_str(&format_args!("{:?}{:?}",
+    ///                                              self.naive_local(),
+    ///                                              self.offset()))
+    ///     }
+    /// }
+    /// ```
+    #[cfg(any(feature = "std", feature = "collections"))]
+    fn collect_str<T: ?Sized>(self, value: &T) -> Result<Self::Ok, Self::Error>
+        where T: Display,
+    {
+        let mut string = String::new();
+        write!(string, "{}", value).unwrap();
+        self.serialize_str(&string)
+    }
+
+    /// Serialize a string produced by an implementation of `Display`.
+    ///
+    /// The default implementation returns an error unconditionally when
+    /// compiled with `no_std`.
+    ///
+    /// ```rust
+    /// # use serde::{Serialize, Serializer};
+    /// # struct DateTime;
+    /// # impl DateTime {
+    /// #     fn naive_local(&self) -> () { () }
+    /// #     fn offset(&self) -> () { () }
+    /// # }
+    /// impl Serialize for DateTime {
+    ///     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    ///         where S: Serializer
+    ///     {
+    ///         serializer.collect_str(&format_args!("{:?}{:?}",
+    ///                                              self.naive_local(),
+    ///                                              self.offset()))
+    ///     }
+    /// }
+    /// ```
+    #[cfg(not(any(feature = "std", feature = "collections")))]
+    fn collect_str<T: ?Sized>(self, value: &T) -> Result<Self::Ok, Self::Error>
+        where T: Display,
+    {
+        // TODO https://github.com/serde-rs/serde/issues/805
+        // Remove this impl and force no_std formats to implement collect_str.
+        let _ = value;
+        Err(Error::custom("this no_std format does not support serializing strings with collect_str"))
+    }
 }
 
 /// Returned from `Serializer::serialize_seq` and
@@ -634,9 +714,9 @@ pub trait SerializeSeq {
 ///
 /// ```rust,ignore
 /// let mut tup = serializer.serialize_tuple(3)?;
-/// tup.serialize_field(&self.0)?;
-/// tup.serialize_field(&self.1)?;
-/// tup.serialize_field(&self.2)?;
+/// tup.serialize_element(&self.0)?;
+/// tup.serialize_element(&self.1)?;
+/// tup.serialize_element(&self.2)?;
 /// tup.end()
 /// ```
 pub trait SerializeTuple {
@@ -737,11 +817,10 @@ pub trait SerializeMap {
     /// `serialize_value`. This is appropriate for serializers that do not care
     /// about performance or are not able to optimize `serialize_entry` any
     /// better than this.
-    fn serialize_entry<K: ?Sized + Serialize, V: ?Sized + Serialize>(
-        &mut self,
-        key: &K,
-        value: &V,
-    ) -> Result<(), Self::Error> {
+    fn serialize_entry<K: ?Sized + Serialize, V: ?Sized + Serialize>(&mut self,
+                                                                     key: &K,
+                                                                     value: &V)
+                                                                     -> Result<(), Self::Error> {
         try!(self.serialize_key(key));
         self.serialize_value(value)
     }
@@ -767,7 +846,10 @@ pub trait SerializeStruct {
     type Error: Error;
 
     /// Serialize a struct field.
-    fn serialize_field<T: ?Sized + Serialize>(&mut self, key: &'static str, value: &T) -> Result<(), Self::Error>;
+    fn serialize_field<T: ?Sized + Serialize>(&mut self,
+                                              key: &'static str,
+                                              value: &T)
+                                              -> Result<(), Self::Error>;
 
     /// Finish serializing a struct.
     fn end(self) -> Result<Self::Ok, Self::Error>;
@@ -794,32 +876,41 @@ pub trait SerializeStructVariant {
     type Error: Error;
 
     /// Serialize a struct variant field.
-    fn serialize_field<T: ?Sized + Serialize>(&mut self, key: &'static str, value: &T) -> Result<(), Self::Error>;
+    fn serialize_field<T: ?Sized + Serialize>(&mut self,
+                                              key: &'static str,
+                                              value: &T)
+                                              -> Result<(), Self::Error>;
 
     /// Finish serializing a struct variant.
     fn end(self) -> Result<Self::Ok, Self::Error>;
 }
 
-/// A wrapper type for iterators that implements `Serialize` for iterators whose
-/// items implement `Serialize`. Don't use multiple times. Create new versions
-/// of this with the `serde::ser::iterator` function every time you want to
-/// serialize an iterator.
-#[cfg(feature = "unstable")]
-pub struct Iterator<I>
-    where <I as IntoIterator>::Item: Serialize,
-          I: IntoIterator
-{
-    data: RefCell<Option<I>>,
+trait LenHint: Iterator {
+    fn len_hint(&self) -> Option<usize>;
 }
 
-/// Create a wrapper type that can be passed to any function expecting a
-/// `Serialize` and will serialize the given iterator as a sequence.
-#[cfg(feature = "unstable")]
-pub fn iterator<I>(iter: I) -> Iterator<I>
-    where <I as IntoIterator>::Item: Serialize,
-          I: IntoIterator
-{
-    Iterator {
-        data: RefCell::new(Some(iter)),
+impl<I: Iterator> LenHint for I {
+    #[cfg(not(feature = "unstable"))]
+    fn len_hint(&self) -> Option<usize> {
+        iterator_len_hint(self)
+    }
+
+    #[cfg(feature = "unstable")]
+    default fn len_hint(&self) -> Option<usize> {
+        iterator_len_hint(self)
+    }
+}
+
+#[cfg(feature = "unstable")]
+impl<I: ExactSizeIterator> LenHint for I {
+    fn len_hint(&self) -> Option<usize> {
+        Some(self.len())
+    }
+}
+
+fn iterator_len_hint<I: Iterator>(iter: &I) -> Option<usize> {
+    match iter.size_hint() {
+        (lo, Some(hi)) if lo == hi => Some(lo),
+        _ => None,
     }
 }

serde/src/ser/private.rs

@@ -0,0 +1,313 @@
+use core::fmt::{self, Display};
+
+use ser::{self, Serialize, Serializer, SerializeMap, SerializeStruct, Impossible};
+
+#[cfg(any(feature = "std", feature = "collections"))]
+use ser::content::{SerializeTupleVariantAsMapValue, SerializeStructVariantAsMapValue};
+
+/// Not public API.
+pub fn serialize_tagged_newtype<S, T>(serializer: S,
+                                      type_ident: &'static str,
+                                      variant_ident: &'static str,
+                                      tag: &'static str,
+                                      variant_name: &'static str,
+                                      value: &T)
+                                      -> Result<S::Ok, S::Error>
+    where S: Serializer,
+          T: Serialize
+{
+    value.serialize(TaggedSerializer {
+        type_ident: type_ident,
+        variant_ident: variant_ident,
+        tag: tag,
+        variant_name: variant_name,
+        delegate: serializer,
+    })
+}
+
+struct TaggedSerializer<S> {
+    type_ident: &'static str,
+    variant_ident: &'static str,
+    tag: &'static str,
+    variant_name: &'static str,
+    delegate: S,
+}
+
+enum Unsupported {
+    Boolean,
+    Integer,
+    Float,
+    Char,
+    String,
+    ByteArray,
+    Optional,
+    Unit,
+    UnitStruct,
+    Sequence,
+    Tuple,
+    TupleStruct,
+    #[cfg(not(any(feature = "std", feature = "collections")))]
+    Enum,
+}
+
+impl Display for Unsupported {
+    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            Unsupported::Boolean => formatter.write_str("a boolean"),
+            Unsupported::Integer => formatter.write_str("an integer"),
+            Unsupported::Float => formatter.write_str("a float"),
+            Unsupported::Char => formatter.write_str("a char"),
+            Unsupported::String => formatter.write_str("a string"),
+            Unsupported::ByteArray => formatter.write_str("a byte array"),
+            Unsupported::Optional => formatter.write_str("an optional"),
+            Unsupported::Unit => formatter.write_str("unit"),
+            Unsupported::UnitStruct => formatter.write_str("a unit struct"),
+            Unsupported::Sequence => formatter.write_str("a sequence"),
+            Unsupported::Tuple => formatter.write_str("a tuple"),
+            Unsupported::TupleStruct => formatter.write_str("a tuple struct"),
+            #[cfg(not(any(feature = "std", feature = "collections")))]
+            Unsupported::Enum => formatter.write_str("an enum"),
+        }
+    }
+}
+
+struct Error {
+    type_ident: &'static str,
+    variant_ident: &'static str,
+    ty: Unsupported,
+}
+
+impl Display for Error {
+    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+        write!(formatter,
+               "cannot serialize tagged newtype variant {}::{} containing {}",
+               self.type_ident, self.variant_ident, self.ty)
+    }
+}
+
+impl<S> TaggedSerializer<S>
+    where S: Serializer
+{
+    fn bad_type(self, what: Unsupported) -> S::Error {
+        ser::Error::custom(Error {
+            type_ident: self.type_ident,
+            variant_ident: self.variant_ident,
+            ty: what,
+        })
+    }
+}
+
+impl<S> Serializer for TaggedSerializer<S>
+    where S: Serializer
+{
+    type Ok = S::Ok;
+    type Error = S::Error;
+
+    type SerializeSeq = Impossible<S::Ok, S::Error>;
+    type SerializeTuple = Impossible<S::Ok, S::Error>;
+    type SerializeTupleStruct = Impossible<S::Ok, S::Error>;
+    type SerializeMap = S::SerializeMap;
+    type SerializeStruct = S::SerializeStruct;
+
+    #[cfg(not(any(feature = "std", feature = "collections")))]
+    type SerializeTupleVariant = Impossible<S::Ok, S::Error>;
+    #[cfg(any(feature = "std", feature = "collections"))]
+    type SerializeTupleVariant = SerializeTupleVariantAsMapValue<S::SerializeMap>;
+
+    #[cfg(not(any(feature = "std", feature = "collections")))]
+    type SerializeStructVariant = Impossible<S::Ok, S::Error>;
+    #[cfg(any(feature = "std", feature = "collections"))]
+    type SerializeStructVariant = SerializeStructVariantAsMapValue<S::SerializeMap>;
+
+    fn serialize_bool(self, _: bool) -> Result<Self::Ok, Self::Error> {
+        Err(self.bad_type(Unsupported::Boolean))
+    }
+
+    fn serialize_i8(self, _: i8) -> Result<Self::Ok, Self::Error> {
+        Err(self.bad_type(Unsupported::Integer))
+    }
+
+    fn serialize_i16(self, _: i16) -> Result<Self::Ok, Self::Error> {
+        Err(self.bad_type(Unsupported::Integer))
+    }
+
+    fn serialize_i32(self, _: i32) -> Result<Self::Ok, Self::Error> {
+        Err(self.bad_type(Unsupported::Integer))
+    }
+
+    fn serialize_i64(self, _: i64) -> Result<Self::Ok, Self::Error> {
+        Err(self.bad_type(Unsupported::Integer))
+    }
+
+    fn serialize_u8(self, _: u8) -> Result<Self::Ok, Self::Error> {
+        Err(self.bad_type(Unsupported::Integer))
+    }
+
+    fn serialize_u16(self, _: u16) -> Result<Self::Ok, Self::Error> {
+        Err(self.bad_type(Unsupported::Integer))
+    }
+
+    fn serialize_u32(self, _: u32) -> Result<Self::Ok, Self::Error> {
+        Err(self.bad_type(Unsupported::Integer))
+    }
+
+    fn serialize_u64(self, _: u64) -> Result<Self::Ok, Self::Error> {
+        Err(self.bad_type(Unsupported::Integer))
+    }
+
+    fn serialize_f32(self, _: f32) -> Result<Self::Ok, Self::Error> {
+        Err(self.bad_type(Unsupported::Float))
+    }
+
+    fn serialize_f64(self, _: f64) -> Result<Self::Ok, Self::Error> {
+        Err(self.bad_type(Unsupported::Float))
+    }
+
+    fn serialize_char(self, _: char) -> Result<Self::Ok, Self::Error> {
+        Err(self.bad_type(Unsupported::Char))
+    }
+
+    fn serialize_str(self, _: &str) -> Result<Self::Ok, Self::Error> {
+        Err(self.bad_type(Unsupported::String))
+    }
+
+    fn serialize_bytes(self, _: &[u8]) -> Result<Self::Ok, Self::Error> {
+        Err(self.bad_type(Unsupported::ByteArray))
+    }
+
+    fn serialize_none(self) -> Result<Self::Ok, Self::Error> {
+        Err(self.bad_type(Unsupported::Optional))
+    }
+
+    fn serialize_some<T: ?Sized>(self, _: &T) -> Result<Self::Ok, Self::Error>
+        where T: Serialize
+    {
+        Err(self.bad_type(Unsupported::Optional))
+    }
+
+    fn serialize_unit(self) -> Result<Self::Ok, Self::Error> {
+        Err(self.bad_type(Unsupported::Unit))
+    }
+
+    fn serialize_unit_struct(self, _: &'static str) -> Result<Self::Ok, Self::Error> {
+        Err(self.bad_type(Unsupported::UnitStruct))
+    }
+
+    fn serialize_unit_variant(self,
+                              _: &'static str,
+                              _: usize,
+                              inner_variant: &'static str)
+                              -> Result<Self::Ok, Self::Error> {
+        let mut map = try!(self.delegate.serialize_map(Some(2)));
+        try!(map.serialize_entry(self.tag, self.variant_name));
+        try!(map.serialize_entry(inner_variant, &()));
+        map.end()
+    }
+
+    fn serialize_newtype_struct<T: ?Sized>(self,
+                                           _: &'static str,
+                                           value: &T)
+                                           -> Result<Self::Ok, Self::Error>
+        where T: Serialize
+    {
+        value.serialize(self)
+    }
+
+    fn serialize_newtype_variant<T: ?Sized>(self,
+                                            _: &'static str,
+                                            _: usize,
+                                            inner_variant: &'static str,
+                                            inner_value: &T)
+                                            -> Result<Self::Ok, Self::Error>
+        where T: Serialize
+    {
+        let mut map = try!(self.delegate.serialize_map(Some(2)));
+        try!(map.serialize_entry(self.tag, self.variant_name));
+        try!(map.serialize_entry(inner_variant, inner_value));
+        map.end()
+    }
+
+    fn serialize_seq(self, _: Option<usize>) -> Result<Self::SerializeSeq, Self::Error> {
+        Err(self.bad_type(Unsupported::Sequence))
+    }
+
+    fn serialize_seq_fixed_size(self, _: usize) -> Result<Self::SerializeSeq, Self::Error> {
+        Err(self.bad_type(Unsupported::Sequence))
+    }
+
+    fn serialize_tuple(self, _: usize) -> Result<Self::SerializeTuple, Self::Error> {
+        Err(self.bad_type(Unsupported::Tuple))
+    }
+
+    fn serialize_tuple_struct(self,
+                              _: &'static str,
+                              _: usize)
+                              -> Result<Self::SerializeTupleStruct, Self::Error> {
+        Err(self.bad_type(Unsupported::TupleStruct))
+    }
+
+    #[cfg(not(any(feature = "std", feature = "collections")))]
+    fn serialize_tuple_variant(self,
+                               _: &'static str,
+                               _: usize,
+                               _: &'static str,
+                               _: usize)
+                               -> Result<Self::SerializeTupleVariant, Self::Error> {
+        // Lack of push-based serialization means we need to buffer the content
+        // of the tuple variant, so it requires std.
+        Err(self.bad_type(Unsupported::Enum))
+    }
+
+    #[cfg(any(feature = "std", feature = "collections"))]
+    fn serialize_tuple_variant(self,
+                               _: &'static str,
+                               _: usize,
+                               inner_variant: &'static str,
+                               len: usize)
+                               -> Result<Self::SerializeTupleVariant, Self::Error> {
+        let mut map = try!(self.delegate.serialize_map(Some(2)));
+        try!(map.serialize_entry(self.tag, self.variant_name));
+        try!(map.serialize_key(inner_variant));
+        Ok(SerializeTupleVariantAsMapValue::new(map, inner_variant, len))
+    }
+
+    fn serialize_map(self, len: Option<usize>) -> Result<Self::SerializeMap, Self::Error> {
+        let mut map = try!(self.delegate.serialize_map(len.map(|len| len + 1)));
+        try!(map.serialize_entry(self.tag, self.variant_name));
+        Ok(map)
+    }
+
+    fn serialize_struct(self,
+                        name: &'static str,
+                        len: usize)
+                        -> Result<Self::SerializeStruct, Self::Error> {
+        let mut state = try!(self.delegate.serialize_struct(name, len + 1));
+        try!(state.serialize_field(self.tag, self.variant_name));
+        Ok(state)
+    }
+
+    #[cfg(not(any(feature = "std", feature = "collections")))]
+    fn serialize_struct_variant(self,
+                                _: &'static str,
+                                _: usize,
+                                _: &'static str,
+                                _: usize)
+                                -> Result<Self::SerializeStructVariant, Self::Error> {
+        // Lack of push-based serialization means we need to buffer the content
+        // of the struct variant, so it requires std.
+        Err(self.bad_type(Unsupported::Enum))
+    }
+
+    #[cfg(any(feature = "std", feature = "collections"))]
+    fn serialize_struct_variant(self,
+                                _: &'static str,
+                                _: usize,
+                                inner_variant: &'static str,
+                                len: usize)
+                                -> Result<Self::SerializeStructVariant, Self::Error> {
+        let mut map = try!(self.delegate.serialize_map(Some(2)));
+        try!(map.serialize_entry(self.tag, self.variant_name));
+        try!(map.serialize_key(inner_variant));
+        Ok(SerializeStructVariantAsMapValue::new(map, inner_variant, len))
+    }
+}

serde/src/utils.rs

@@ -1,12 +1,12 @@
 //! Private utility functions
 
-const TAG_CONT: u8    = 0b1000_0000;
-const TAG_TWO_B: u8   = 0b1100_0000;
+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;
+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 {
@@ -21,17 +21,20 @@ pub fn encode_utf8(c: char) -> EncodeUtf8 {
         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[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[2] = (code >> 6 & 0x3F) as u8 | TAG_CONT;
         buf[3] = (code & 0x3F) as u8 | TAG_CONT;
         0
     };
-    EncodeUtf8 { buf: buf, pos: pos }
+    EncodeUtf8 {
+        buf: buf,
+        pos: pos,
+    }
 }
 
 pub struct EncodeUtf8 {
@@ -47,23 +50,22 @@ impl EncodeUtf8 {
 }
 
 #[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}')
-];
+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 {
+    r.binary_search_by(|&(lo, hi)| if c < lo {
             Greater
         } else if hi < c {
             Less
         } else {
             Equal
-        }
-    })
-    .is_ok()
+        })
+        .is_ok()
 }
 
 #[allow(non_snake_case)]

serde_codegen_internals/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "serde_codegen_internals"
-version = "0.12.1"
+version = "0.14.1"
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>"]
 license = "MIT/Apache-2.0"
 description = "AST representation used by Serde codegen. Unstable."
@@ -8,10 +8,11 @@ homepage = "https://serde.rs"
 repository = "https://github.com/serde-rs/serde"
 documentation = "https://docs.serde.rs/serde_codegen_internals/"
 keywords = ["serde", "serialization"]
-include = ["Cargo.toml", "src/**/*.rs"]
+readme = "../README.md"
+include = ["Cargo.toml", "src/**/*.rs", "README.md", "LICENSE-APACHE", "LICENSE-MIT"]
 
 [dependencies]
-syn = "0.11"
+syn = { version = "0.11", default-features = false, features = ["parsing"] }
 
 [badges]
 travis-ci = { repository = "serde-rs/serde" }

serde_codegen_internals/LICENSE-APACHE

@@ -0,0 +1 @@
+../LICENSE-APACHE

serde_codegen_internals/LICENSE-MIT

@@ -0,0 +1 @@
+../LICENSE-MIT

serde_codegen_internals/README.md

@@ -0,0 +1 @@
+../README.md

serde_codegen_internals/src/ast.rs

@@ -38,16 +38,30 @@ impl<'a> Item<'a> {
     pub fn from_ast(cx: &Ctxt, item: &'a syn::MacroInput) -> Item<'a> {
         let attrs = attr::Item::from_ast(cx, item);
 
-        let body = match item.body {
-            syn::Body::Enum(ref variants) => {
-                Body::Enum(enum_from_ast(cx, variants))
-            }
+        let mut body = match item.body {
+            syn::Body::Enum(ref variants) => Body::Enum(enum_from_ast(cx, variants)),
             syn::Body::Struct(ref variant_data) => {
                 let (style, fields) = struct_from_ast(cx, variant_data);
                 Body::Struct(style, fields)
             }
         };
 
+        match body {
+            Body::Enum(ref mut variants) => {
+                for ref mut variant in variants {
+                    variant.attrs.rename_by_rule(attrs.rename_all());
+                    for ref mut field in &mut variant.fields {
+                        field.attrs.rename_by_rule(variant.attrs.rename_all());
+                    }
+                }
+            }
+            Body::Struct(_, ref mut fields) => {
+                for field in fields {
+                    field.attrs.rename_by_rule(attrs.rename_all());
+                }
+            }
+        }
+
         Item {
             ident: item.ident.clone(),
             attrs: attrs,
@@ -58,15 +72,13 @@ impl<'a> Item<'a> {
 }
 
 impl<'a> Body<'a> {
-    pub fn all_fields(&'a self) -> Box<Iterator<Item=&'a Field<'a>> + 'a> {
+    pub fn all_fields(&'a self) -> Box<Iterator<Item = &'a Field<'a>> + 'a> {
         match *self {
             Body::Enum(ref variants) => {
                 Box::new(variants.iter()
-                             .flat_map(|variant| variant.fields.iter()))
-            }
-            Body::Struct(_, ref fields) => {
-                Box::new(fields.iter())
+                    .flat_map(|variant| variant.fields.iter()))
             }
+            Body::Struct(_, ref fields) => Box::new(fields.iter()),
         }
     }
 }
@@ -87,18 +99,12 @@ fn enum_from_ast<'a>(cx: &Ctxt, variants: &'a [syn::Variant]) -> Vec<Variant<'a>
 
 fn struct_from_ast<'a>(cx: &Ctxt, data: &'a syn::VariantData) -> (Style, Vec<Field<'a>>) {
     match *data {
-        syn::VariantData::Struct(ref fields) => {
-            (Style::Struct, fields_from_ast(cx, fields))
-        }
+        syn::VariantData::Struct(ref fields) => (Style::Struct, fields_from_ast(cx, fields)),
         syn::VariantData::Tuple(ref fields) if fields.len() == 1 => {
             (Style::Newtype, fields_from_ast(cx, fields))
         }
-        syn::VariantData::Tuple(ref fields) => {
-            (Style::Tuple, fields_from_ast(cx, fields))
-        }
-        syn::VariantData::Unit => {
-            (Style::Unit, Vec::new())
-        }
+        syn::VariantData::Tuple(ref fields) => (Style::Tuple, fields_from_ast(cx, fields)),
+        syn::VariantData::Unit => (Style::Unit, Vec::new()),
     }
 }
 

serde_codegen_internals/src/attr.rs

@@ -2,6 +2,7 @@ use Ctxt;
 use syn;
 use syn::MetaItem::{List, NameValue, Word};
 use syn::NestedMetaItem::{Literal, MetaItem};
+use std::str::FromStr;
 
 // This module handles parsing of `#[serde(...)]` attributes. The entrypoints
 // are `attr::Item::from_ast`, `attr::Variant::from_ast`, and
@@ -11,6 +12,8 @@ use syn::NestedMetaItem::{Literal, MetaItem};
 // user will see errors simultaneously for all bad attributes in the crate
 // rather than just the first.
 
+pub use case::RenameRule;
+
 struct Attr<'c, T> {
     cx: &'c Ctxt,
     name: &'static str,
@@ -90,8 +93,43 @@ impl Name {
 pub struct Item {
     name: Name,
     deny_unknown_fields: bool,
+    default: Default,
+    rename_all: RenameRule,
     ser_bound: Option<Vec<syn::WherePredicate>>,
     de_bound: Option<Vec<syn::WherePredicate>>,
+    tag: EnumTag,
+}
+
+/// Styles of representing an enum.
+#[derive(Debug)]
+pub enum EnumTag {
+    /// The default.
+    ///
+    /// ```json
+    /// {"variant1": {"key1": "value1", "key2": "value2"}}
+    /// ```
+    External,
+
+    /// `#[serde(tag = "type")]`
+    ///
+    /// ```json
+    /// {"type": "variant1", "key1": "value1", "key2": "value2"}
+    /// ```
+    Internal { tag: String },
+
+    /// `#[serde(tag = "t", content = "c")]`
+    ///
+    /// ```json
+    /// {"t": "variant1", "c": {"key1": "value1", "key2": "value2"}}
+    /// ```
+    Adjacent { tag: String, content: String },
+
+    /// `#[serde(untagged)]`
+    ///
+    /// ```json
+    /// {"key1": "value1", "key2": "value2"}
+    /// ```
+    None,
 }
 
 impl Item {
@@ -100,8 +138,13 @@ impl Item {
         let mut ser_name = Attr::none(cx, "rename");
         let mut de_name = Attr::none(cx, "rename");
         let mut deny_unknown_fields = BoolAttr::none(cx, "deny_unknown_fields");
+        let mut default = Attr::none(cx, "default");
+        let mut rename_all = Attr::none(cx, "rename_all");
         let mut ser_bound = Attr::none(cx, "bound");
         let mut de_bound = Attr::none(cx, "bound");
+        let mut untagged = BoolAttr::none(cx, "untagged");
+        let mut internal_tag = Attr::none(cx, "tag");
+        let mut content = Attr::none(cx, "content");
 
         for meta_items in item.attrs.iter().filter_map(get_serde_meta_items) {
             for meta_item in meta_items {
@@ -122,14 +165,57 @@ impl Item {
                         }
                     }
 
+                    // Parse `#[serde(rename_all="foo")]`
+                    MetaItem(NameValue(ref name, ref lit)) if name == "rename_all" => {
+                        if let Ok(s) = get_string_from_lit(cx, name.as_ref(), name.as_ref(), lit) {
+                            match RenameRule::from_str(&s) {
+                                Ok(rename_rule) => rename_all.set(rename_rule),
+                                Err(()) => {
+                                    cx.error(format!("unknown rename rule for #[serde(rename_all \
+                                                      = {:?})]",
+                                                     s))
+                                }
+                            }
+                        }
+                    }
+
                     // Parse `#[serde(deny_unknown_fields)]`
                     MetaItem(Word(ref name)) if name == "deny_unknown_fields" => {
                         deny_unknown_fields.set_true();
                     }
 
+                    // Parse `#[serde(default)]`
+                    MetaItem(Word(ref name)) if name == "default" => {
+                        match item.body {
+                            syn::Body::Struct(syn::VariantData::Struct(_)) => {
+                                default.set(Default::Default);
+                            }
+                            _ => {
+                                cx.error("#[serde(default)] can only be used on structs \
+                                          with named fields")
+                            }
+                        }
+                    }
+
+                    // Parse `#[serde(default="...")]`
+                    MetaItem(NameValue(ref name, ref lit)) if name == "default" => {
+                        if let Ok(path) = parse_lit_into_path(cx, name.as_ref(), lit) {
+                            match item.body {
+                                syn::Body::Struct(syn::VariantData::Struct(_)) => {
+                                    default.set(Default::Path(path));
+                                }
+                                _ => {
+                                    cx.error("#[serde(default = \"...\")] can only be used \
+                                              on structs with named fields")
+                                }
+                            }
+                        }
+                    }
+
                     // Parse `#[serde(bound="D: Serialize")]`
                     MetaItem(NameValue(ref name, ref lit)) if name == "bound" => {
-                        if let Ok(where_predicates) = parse_lit_into_where(cx, name.as_ref(), name.as_ref(), lit) {
+                        if let Ok(where_predicates) =
+                            parse_lit_into_where(cx, name.as_ref(), name.as_ref(), lit) {
                             ser_bound.set(where_predicates.clone());
                             de_bound.set(where_predicates);
                         }
@@ -143,6 +229,47 @@ impl Item {
                         }
                     }
 
+                    // Parse `#[serde(untagged)]`
+                    MetaItem(Word(ref name)) if name == "untagged" => {
+                        match item.body {
+                            syn::Body::Enum(_) => {
+                                untagged.set_true();
+                            }
+                            syn::Body::Struct(_) => {
+                                cx.error("#[serde(untagged)] can only be used on enums")
+                            }
+                        }
+                    }
+
+                    // Parse `#[serde(tag = "type")]`
+                    MetaItem(NameValue(ref name, ref lit)) if name == "tag" => {
+                        if let Ok(s) = get_string_from_lit(cx, name.as_ref(), name.as_ref(), lit) {
+                            match item.body {
+                                syn::Body::Enum(_) => {
+                                    internal_tag.set(s);
+                                }
+                                syn::Body::Struct(_) => {
+                                    cx.error("#[serde(tag = \"...\")] can only be used on enums")
+                                }
+                            }
+                        }
+                    }
+
+                    // Parse `#[serde(content = "c")]`
+                    MetaItem(NameValue(ref name, ref lit)) if name == "content" => {
+                        if let Ok(s) = get_string_from_lit(cx, name.as_ref(), name.as_ref(), lit) {
+                            match item.body {
+                                syn::Body::Enum(_) => {
+                                    content.set(s);
+                                }
+                                syn::Body::Struct(_) => {
+                                    cx.error("#[serde(content = \"...\")] can only be used on \
+                                              enums")
+                                }
+                            }
+                        }
+                    }
+
                     MetaItem(ref meta_item) => {
                         cx.error(format!("unknown serde container attribute `{}`",
                                          meta_item.name()));
@@ -155,14 +282,63 @@ impl Item {
             }
         }
 
+        let tag = match (untagged.get(), internal_tag.get(), content.get()) {
+            (false, None, None) => EnumTag::External,
+            (true, None, None) => EnumTag::None,
+            (false, Some(tag), None) => {
+                // Check that there are no tuple variants.
+                if let syn::Body::Enum(ref variants) = item.body {
+                    for variant in variants {
+                        match variant.data {
+                            syn::VariantData::Struct(_) |
+                            syn::VariantData::Unit => {}
+                            syn::VariantData::Tuple(ref fields) => {
+                                if fields.len() != 1 {
+                                    cx.error("#[serde(tag = \"...\")] cannot be used with tuple \
+                                              variants");
+                                    break;
+                                }
+                            }
+                        }
+                    }
+                }
+                EnumTag::Internal { tag: tag }
+            }
+            (true, Some(_), None) => {
+                cx.error("enum cannot be both untagged and internally tagged");
+                EnumTag::External // doesn't matter, will error
+            }
+            (false, None, Some(_)) => {
+                cx.error("#[serde(tag = \"...\", content = \"...\")] must be used together");
+                EnumTag::External
+            }
+            (true, None, Some(_)) => {
+                cx.error("untagged enum cannot have #[serde(content = \"...\")]");
+                EnumTag::External
+            }
+            (false, Some(tag), Some(content)) => {
+                EnumTag::Adjacent {
+                    tag: tag,
+                    content: content,
+                }
+            }
+            (true, Some(_), Some(_)) => {
+                cx.error("untagged enum cannot have #[serde(tag = \"...\", content = \"...\")]");
+                EnumTag::External
+            }
+        };
+
         Item {
             name: Name {
                 serialize: ser_name.get().unwrap_or_else(|| item.ident.to_string()),
                 deserialize: de_name.get().unwrap_or_else(|| item.ident.to_string()),
             },
             deny_unknown_fields: deny_unknown_fields.get(),
+            default: default.get().unwrap_or(Default::None),
+            rename_all: rename_all.get().unwrap_or(RenameRule::None),
             ser_bound: ser_bound.get(),
             de_bound: de_bound.get(),
+            tag: tag,
         }
     }
 
@@ -170,10 +346,18 @@ impl Item {
         &self.name
     }
 
+    pub fn rename_all(&self) -> &RenameRule {
+        &self.rename_all
+    }
+
     pub fn deny_unknown_fields(&self) -> bool {
         self.deny_unknown_fields
     }
 
+    pub fn default(&self) -> &Default {
+        &self.default
+    }
+
     pub fn ser_bound(&self) -> Option<&[syn::WherePredicate]> {
         self.ser_bound.as_ref().map(|vec| &vec[..])
     }
@@ -181,12 +365,19 @@ impl Item {
     pub fn de_bound(&self) -> Option<&[syn::WherePredicate]> {
         self.de_bound.as_ref().map(|vec| &vec[..])
     }
+
+    pub fn tag(&self) -> &EnumTag {
+        &self.tag
+    }
 }
 
 /// Represents variant attribute information
 #[derive(Debug)]
 pub struct Variant {
     name: Name,
+    ser_renamed: bool,
+    de_renamed: bool,
+    rename_all: RenameRule,
     skip_deserializing: bool,
     skip_serializing: bool,
 }
@@ -197,6 +388,7 @@ impl Variant {
         let mut de_name = Attr::none(cx, "rename");
         let mut skip_deserializing = BoolAttr::none(cx, "skip_deserializing");
         let mut skip_serializing = BoolAttr::none(cx, "skip_serializing");
+        let mut rename_all = Attr::none(cx, "rename_all");
 
         for meta_items in variant.attrs.iter().filter_map(get_serde_meta_items) {
             for meta_item in meta_items {
@@ -216,6 +408,21 @@ impl Variant {
                             de_name.set_opt(de);
                         }
                     }
+
+                    // Parse `#[serde(rename_all="foo")]`
+                    MetaItem(NameValue(ref name, ref lit)) if name == "rename_all" => {
+                        if let Ok(s) = get_string_from_lit(cx, name.as_ref(), name.as_ref(), lit) {
+                            match RenameRule::from_str(&s) {
+                                Ok(rename_rule) => rename_all.set(rename_rule),
+                                Err(()) => {
+                                    cx.error(format!("unknown rename rule for #[serde(rename_all \
+                                                      = {:?})]",
+                                                     s))
+                                }
+                            }
+                        }
+                    }
+
                     // Parse `#[serde(skip_deserializing)]`
                     MetaItem(Word(ref name)) if name == "skip_deserializing" => {
                         skip_deserializing.set_true();
@@ -226,8 +433,7 @@ impl Variant {
                     }
 
                     MetaItem(ref meta_item) => {
-                        cx.error(format!("unknown serde variant attribute `{}`",
-                                         meta_item.name()));
+                        cx.error(format!("unknown serde variant attribute `{}`", meta_item.name()));
                     }
 
                     Literal(_) => {
@@ -237,11 +443,18 @@ impl Variant {
             }
         }
 
+        let ser_name = ser_name.get();
+        let ser_renamed = ser_name.is_some();
+        let de_name = de_name.get();
+        let de_renamed = de_name.is_some();
         Variant {
             name: Name {
-                serialize: ser_name.get().unwrap_or_else(|| variant.ident.to_string()),
-                deserialize: de_name.get().unwrap_or_else(|| variant.ident.to_string()),
+                serialize: ser_name.unwrap_or_else(|| variant.ident.to_string()),
+                deserialize: de_name.unwrap_or_else(|| variant.ident.to_string()),
             },
+            ser_renamed: ser_renamed,
+            de_renamed: de_renamed,
+            rename_all: rename_all.get().unwrap_or(RenameRule::None),
             skip_deserializing: skip_deserializing.get(),
             skip_serializing: skip_serializing.get(),
         }
@@ -251,6 +464,19 @@ impl Variant {
         &self.name
     }
 
+    pub fn rename_by_rule(&mut self, rule: &RenameRule) {
+        if !self.ser_renamed {
+            self.name.serialize = rule.apply_to_variant(&self.name.serialize);
+        }
+        if !self.de_renamed {
+            self.name.deserialize = rule.apply_to_variant(&self.name.deserialize);
+        }
+    }
+
+    pub fn rename_all(&self) -> &RenameRule {
+        &self.rename_all
+    }
+
     pub fn skip_deserializing(&self) -> bool {
         self.skip_deserializing
     }
@@ -264,10 +490,12 @@ impl Variant {
 #[derive(Debug)]
 pub struct Field {
     name: Name,
+    ser_renamed: bool,
+    de_renamed: bool,
     skip_serializing: bool,
     skip_deserializing: bool,
     skip_serializing_if: Option<syn::Path>,
-    default: FieldDefault,
+    default: Default,
     serialize_with: Option<syn::Path>,
     deserialize_with: Option<syn::Path>,
     ser_bound: Option<Vec<syn::WherePredicate>>,
@@ -276,7 +504,7 @@ pub struct Field {
 
 /// Represents the default to use for a field when deserializing.
 #[derive(Debug, PartialEq)]
-pub enum FieldDefault {
+pub enum Default {
     /// Field must always be specified because it does not have a default.
     None,
     /// The default is given by `std::default::Default::default()`.
@@ -287,9 +515,7 @@ pub enum FieldDefault {
 
 impl Field {
     /// Extract out the `#[serde(...)]` attributes from a struct field.
-    pub fn from_ast(cx: &Ctxt,
-                    index: usize,
-                    field: &syn::Field) -> Self {
+    pub fn from_ast(cx: &Ctxt, index: usize, field: &syn::Field) -> Self {
         let mut ser_name = Attr::none(cx, "rename");
         let mut de_name = Attr::none(cx, "rename");
         let mut skip_serializing = BoolAttr::none(cx, "skip_serializing");
@@ -327,13 +553,13 @@ impl Field {
 
                     // Parse `#[serde(default)]`
                     MetaItem(Word(ref name)) if name == "default" => {
-                        default.set(FieldDefault::Default);
+                        default.set(Default::Default);
                     }
 
                     // Parse `#[serde(default="...")]`
                     MetaItem(NameValue(ref name, ref lit)) if name == "default" => {
                         if let Ok(path) = parse_lit_into_path(cx, name.as_ref(), lit) {
-                            default.set(FieldDefault::Path(path));
+                            default.set(Default::Path(path));
                         }
                     }
 
@@ -368,9 +594,22 @@ impl Field {
                         }
                     }
 
+                    // Parse `#[serde(with="...")]`
+                    MetaItem(NameValue(ref name, ref lit)) if name == "with" => {
+                        if let Ok(path) = parse_lit_into_path(cx, name.as_ref(), lit) {
+                            let mut ser_path = path.clone();
+                            ser_path.segments.push("serialize".into());
+                            serialize_with.set(ser_path);
+                            let mut de_path = path;
+                            de_path.segments.push("deserialize".into());
+                            deserialize_with.set(de_path);
+                        }
+                    }
+
                     // Parse `#[serde(bound="D: Serialize")]`
                     MetaItem(NameValue(ref name, ref lit)) if name == "bound" => {
-                        if let Ok(where_predicates) = parse_lit_into_where(cx, name.as_ref(), name.as_ref(), lit) {
+                        if let Ok(where_predicates) =
+                            parse_lit_into_where(cx, name.as_ref(), name.as_ref(), lit) {
                             ser_bound.set(where_predicates.clone());
                             de_bound.set(where_predicates);
                         }
@@ -385,8 +624,7 @@ impl Field {
                     }
 
                     MetaItem(ref meta_item) => {
-                        cx.error(format!("unknown serde field attribute `{}`",
-                                         meta_item.name()));
+                        cx.error(format!("unknown serde field attribute `{}`", meta_item.name()));
                     }
 
                     Literal(_) => {
@@ -399,18 +637,24 @@ impl Field {
         // Is skip_deserializing, initialize the field to Default::default()
         // unless a different default is specified by `#[serde(default="...")]`
         if skip_deserializing.0.value.is_some() {
-            default.set_if_none(FieldDefault::Default);
+            default.set_if_none(Default::Default);
         }
 
+        let ser_name = ser_name.get();
+        let ser_renamed = ser_name.is_some();
+        let de_name = de_name.get();
+        let de_renamed = de_name.is_some();
         Field {
             name: Name {
-                serialize: ser_name.get().unwrap_or_else(|| ident.clone()),
-                deserialize: de_name.get().unwrap_or(ident),
+                serialize: ser_name.unwrap_or_else(|| ident.clone()),
+                deserialize: de_name.unwrap_or(ident),
             },
+            ser_renamed: ser_renamed,
+            de_renamed: de_renamed,
             skip_serializing: skip_serializing.get(),
             skip_deserializing: skip_deserializing.get(),
             skip_serializing_if: skip_serializing_if.get(),
-            default: default.get().unwrap_or(FieldDefault::None),
+            default: default.get().unwrap_or(Default::None),
             serialize_with: serialize_with.get(),
             deserialize_with: deserialize_with.get(),
             ser_bound: ser_bound.get(),
@@ -422,6 +666,15 @@ impl Field {
         &self.name
     }
 
+    pub fn rename_by_rule(&mut self, rule: &RenameRule) {
+        if !self.ser_renamed {
+            self.name.serialize = rule.apply_to_field(&self.name.serialize);
+        }
+        if !self.de_renamed {
+            self.name.deserialize = rule.apply_to_field(&self.name.deserialize);
+        }
+    }
+
     pub fn skip_serializing(&self) -> bool {
         self.skip_serializing
     }
@@ -434,7 +687,7 @@ impl Field {
         self.skip_serializing_if.as_ref()
     }
 
-    pub fn default(&self) -> &FieldDefault {
+    pub fn default(&self) -> &Default {
         &self.default
     }
 
@@ -457,13 +710,12 @@ impl Field {
 
 type SerAndDe<T> = (Option<T>, Option<T>);
 
-fn get_ser_and_de<T, F>(
-    cx: &Ctxt,
-    attr_name: &'static str,
-    items: &[syn::NestedMetaItem],
-    f: F
-) -> Result<SerAndDe<T>, ()>
-    where F: Fn(&Ctxt, &str, &str, &syn::Lit) -> Result<T, ()>,
+fn get_ser_and_de<T, F>(cx: &Ctxt,
+                        attr_name: &'static str,
+                        items: &[syn::NestedMetaItem],
+                        f: F)
+                        -> Result<SerAndDe<T>, ()>
+    where F: Fn(&Ctxt, &str, &str, &syn::Lit) -> Result<T, ()>
 {
     let mut ser_item = Attr::none(cx, attr_name);
     let mut de_item = Attr::none(cx, attr_name);
@@ -483,7 +735,8 @@ fn get_ser_and_de<T, F>(
             }
 
             _ => {
-                cx.error(format!("malformed {0} attribute, expected `{0}(serialize = ..., deserialize = ...)`",
+                cx.error(format!("malformed {0} attribute, expected `{0}(serialize = ..., \
+                                  deserialize = ...)`",
                                  attr_name));
                 return Err(());
             }
@@ -493,35 +746,34 @@ fn get_ser_and_de<T, F>(
     Ok((ser_item.get(), de_item.get()))
 }
 
-fn get_renames(
-    cx: &Ctxt,
-    items: &[syn::NestedMetaItem],
-) -> Result<SerAndDe<String>, ()> {
+fn get_renames(cx: &Ctxt, items: &[syn::NestedMetaItem]) -> Result<SerAndDe<String>, ()> {
     get_ser_and_de(cx, "rename", items, get_string_from_lit)
 }
 
-fn get_where_predicates(
-    cx: &Ctxt,
-    items: &[syn::NestedMetaItem],
-) -> Result<SerAndDe<Vec<syn::WherePredicate>>, ()> {
+fn get_where_predicates(cx: &Ctxt,
+                        items: &[syn::NestedMetaItem])
+                        -> Result<SerAndDe<Vec<syn::WherePredicate>>, ()> {
     get_ser_and_de(cx, "bound", items, parse_lit_into_where)
 }
 
 pub fn get_serde_meta_items(attr: &syn::Attribute) -> Option<Vec<syn::NestedMetaItem>> {
     match attr.value {
-        List(ref name, ref items) if name == "serde" => {
-            Some(items.iter().cloned().collect())
-        }
-        _ => None
+        List(ref name, ref items) if name == "serde" => Some(items.iter().cloned().collect()),
+        _ => None,
     }
 }
 
-fn get_string_from_lit(cx: &Ctxt, attr_name: &str, meta_item_name: &str, lit: &syn::Lit) -> Result<String, ()> {
+fn get_string_from_lit(cx: &Ctxt,
+                       attr_name: &str,
+                       meta_item_name: &str,
+                       lit: &syn::Lit)
+                       -> Result<String, ()> {
     if let syn::Lit::Str(ref s, _) = *lit {
         Ok(s.clone())
     } else {
         cx.error(format!("expected serde {} attribute to be a string: `{} = \"...\"`",
-                         attr_name, meta_item_name));
+                         attr_name,
+                         meta_item_name));
         Err(())
     }
 }
@@ -531,7 +783,11 @@ fn parse_lit_into_path(cx: &Ctxt, attr_name: &str, lit: &syn::Lit) -> Result<syn
     syn::parse_path(&string).map_err(|err| cx.error(err))
 }
 
-fn parse_lit_into_where(cx: &Ctxt, attr_name: &str, meta_item_name: &str, lit: &syn::Lit) -> Result<Vec<syn::WherePredicate>, ()> {
+fn parse_lit_into_where(cx: &Ctxt,
+                        attr_name: &str,
+                        meta_item_name: &str,
+                        lit: &syn::Lit)
+                        -> Result<Vec<syn::WherePredicate>, ()> {
     let string = try!(get_string_from_lit(cx, attr_name, meta_item_name, lit));
     if string.is_empty() {
         return Ok(Vec::new());

serde_codegen_internals/src/case.rs

@@ -0,0 +1,115 @@
+use std::ascii::AsciiExt;
+use std::str::FromStr;
+
+use self::RenameRule::*;
+
+#[derive(Debug, PartialEq)]
+pub enum RenameRule {
+    /// Don't apply a default rename rule.
+    None,
+    /// Rename direct children to "PascalCase" style, as typically used for enum variants.
+    PascalCase,
+    /// Rename direct children to "camelCase" style.
+    CamelCase,
+    /// Rename direct children to "snake_case" style, as commonly used for fields.
+    SnakeCase,
+    /// Rename direct children to "SCREAMING_SNAKE_CASE" style, as commonly used for constants.
+    ScreamingSnakeCase,
+    /// Rename direct children to "kebab-case" style.
+    KebabCase,
+}
+
+impl RenameRule {
+    pub fn apply_to_variant(&self, variant: &str) -> String {
+        match *self {
+            None | PascalCase => variant.to_owned(),
+            CamelCase => variant[..1].to_ascii_lowercase() + &variant[1..],
+            SnakeCase => {
+                let mut snake = String::new();
+                for (i, ch) in variant.char_indices() {
+                    if i > 0 && ch.is_uppercase() {
+                        snake.push('_');
+                    }
+                    snake.push(ch.to_ascii_lowercase());
+                }
+                snake
+            }
+            ScreamingSnakeCase => SnakeCase.apply_to_variant(variant).to_ascii_uppercase(),
+            KebabCase => SnakeCase.apply_to_variant(variant).replace('_', "-"),
+        }
+    }
+
+    pub fn apply_to_field(&self, field: &str) -> String {
+        match *self {
+            None | SnakeCase => field.to_owned(),
+            PascalCase => {
+                let mut pascal = String::new();
+                let mut capitalize = true;
+                for ch in field.chars() {
+                    if ch == '_' {
+                        capitalize = true;
+                    } else if capitalize {
+                        pascal.push(ch.to_ascii_uppercase());
+                        capitalize = false;
+                    } else {
+                        pascal.push(ch);
+                    }
+                }
+                pascal
+            }
+            CamelCase => {
+                let pascal = PascalCase.apply_to_field(field);
+                pascal[..1].to_ascii_lowercase() + &pascal[1..]
+            }
+            ScreamingSnakeCase => field.to_ascii_uppercase(),
+            KebabCase => field.replace('_', "-"),
+        }
+    }
+}
+
+impl FromStr for RenameRule {
+    type Err = ();
+
+    fn from_str(rename_all_str: &str) -> Result<Self, Self::Err> {
+        match rename_all_str {
+            "PascalCase" => Ok(PascalCase),
+            "camelCase" => Ok(CamelCase),
+            "snake_case" => Ok(SnakeCase),
+            "SCREAMING_SNAKE_CASE" => Ok(ScreamingSnakeCase),
+            "kebab-case" => Ok(KebabCase),
+            _ => Err(()),
+        }
+    }
+}
+
+#[test]
+fn rename_variants() {
+    for &(original, camel, snake, screaming, kebab) in
+        &[("Outcome", "outcome", "outcome", "OUTCOME", "outcome"),
+          ("VeryTasty", "veryTasty", "very_tasty", "VERY_TASTY", "very-tasty"),
+          ("A", "a", "a", "A", "a"),
+          ("Z42", "z42", "z42", "Z42", "z42")] {
+        assert_eq!(None.apply_to_variant(original), original);
+        assert_eq!(PascalCase.apply_to_variant(original), original);
+        assert_eq!(CamelCase.apply_to_variant(original), camel);
+        assert_eq!(SnakeCase.apply_to_variant(original), snake);
+        assert_eq!(ScreamingSnakeCase.apply_to_variant(original), screaming);
+        assert_eq!(KebabCase.apply_to_variant(original), kebab);
+    }
+}
+
+#[test]
+fn rename_fields() {
+    for &(original, pascal, camel, screaming, kebab) in
+        &[("outcome", "Outcome", "outcome", "OUTCOME", "outcome"),
+          ("very_tasty", "VeryTasty", "veryTasty", "VERY_TASTY", "very-tasty"),
+          ("a", "A", "a", "A", "a"),
+          ("z42", "Z42", "z42", "Z42", "z42")] {
+        assert_eq!(None.apply_to_field(original), original);
+        assert_eq!(PascalCase.apply_to_field(original), pascal);
+        assert_eq!(CamelCase.apply_to_field(original), camel);
+        assert_eq!(SnakeCase.apply_to_field(original), original);
+        assert_eq!(ScreamingSnakeCase.apply_to_field(original), screaming);
+        assert_eq!(KebabCase.apply_to_field(original), kebab);
+    }
+}

serde_codegen_internals/src/ctxt.rs

@@ -8,9 +8,7 @@ pub struct Ctxt {
 
 impl Ctxt {
     pub fn new() -> Self {
-        Ctxt {
-            errors: RefCell::new(Some(Vec::new())),
-        }
+        Ctxt { errors: RefCell::new(Some(Vec::new())) }
     }
 
     pub fn error<T: Display>(&self, msg: T) {

serde_codegen_internals/src/lib.rs

@@ -5,3 +5,5 @@ pub mod attr;
 
 mod ctxt;
 pub use ctxt::Ctxt;
+
+mod case;

serde_derive/Cargo.toml

@@ -1,14 +1,15 @@
 [package]
 name = "serde_derive"
-version = "0.9.5"
+version = "0.9.11"
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>"]
 license = "MIT/Apache-2.0"
 description = "Macros 1.1 implementation of #[derive(Serialize, Deserialize)]"
 homepage = "https://serde.rs"
 repository = "https://github.com/serde-rs/serde"
 documentation = "https://serde.rs/codegen.html"
-keywords = ["serde", "serialization"]
-include = ["Cargo.toml", "src/**/*.rs"]
+keywords = ["serde", "serialization", "no_std"]
+readme = "../README.md"
+include = ["Cargo.toml", "src/**/*.rs", "README.md", "LICENSE-APACHE", "LICENSE-MIT"]
 
 [features]
 unstable = []
@@ -22,5 +23,5 @@ proc-macro = true
 
 [dependencies]
 quote = "0.3.8"
-serde_codegen_internals = { version = "=0.12.1", default-features = false, path = "../serde_codegen_internals" }
-syn = { version = "0.11", features = ["aster", "visit"] }
+serde_codegen_internals = { version = "=0.14.1", default-features = false, path = "../serde_codegen_internals" }
+syn = { version = "0.11", features = ["visit"] }

serde_derive/LICENSE-APACHE

@@ -0,0 +1 @@
+../LICENSE-APACHE

serde_derive/LICENSE-MIT

@@ -0,0 +1 @@
+../LICENSE-MIT

serde_derive/README.md

@@ -0,0 +1 @@
+../README.md

serde_derive/src/bound.rs

@@ -1,46 +1,71 @@
 use std::collections::HashSet;
 
-use syn::{self, aster, visit};
+use syn::{self, visit};
 
 use internals::ast::Item;
 use internals::attr;
 
+macro_rules! path {
+    ($first:ident $(:: $rest:ident)*) => {
+        syn::Path {
+            global: false,
+            segments: vec![
+                stringify!($first).into(),
+                $(
+                    stringify!($rest).into(),
+                )*
+            ],
+        }
+    };
+
+    (::$first:ident $(:: $rest:ident)*) => {
+        syn::Path {
+            global: true,
+            segments: vec![
+                stringify!($first).into(),
+                $(
+                    stringify!($rest).into(),
+                )*
+            ],
+        }
+    };
+}
+
 // Remove the default from every type parameter because in the generated impls
 // they look like associated types: "error: associated type bindings are not
 // allowed here".
 pub fn without_defaults(generics: &syn::Generics) -> syn::Generics {
     syn::Generics {
-        ty_params: generics.ty_params.iter().map(|ty_param| {
-            syn::TyParam {
-                default: None,
-                .. ty_param.clone()
-            }}).collect(),
-        .. generics.clone()
+        ty_params: generics.ty_params
+            .iter()
+            .map(|ty_param| syn::TyParam { default: None, ..ty_param.clone() })
+            .collect(),
+        ..generics.clone()
     }
 }
 
-pub fn with_where_predicates(
-    generics: &syn::Generics,
-    predicates: &[syn::WherePredicate],
-) -> syn::Generics {
-    aster::from_generics(generics.clone())
-        .with_predicates(predicates.to_vec())
-        .build()
+pub fn with_where_predicates(generics: &syn::Generics,
+                             predicates: &[syn::WherePredicate])
+                             -> syn::Generics {
+    let mut generics = generics.clone();
+    generics.where_clause.predicates.extend_from_slice(predicates);
+    generics
 }
 
-pub fn with_where_predicates_from_fields<F>(
-    item: &Item,
-    generics: &syn::Generics,
-    from_field: F,
-) -> syn::Generics
-    where F: Fn(&attr::Field) -> Option<&[syn::WherePredicate]>,
+pub fn with_where_predicates_from_fields<F>(item: &Item,
+                                            generics: &syn::Generics,
+                                            from_field: F)
+                                            -> syn::Generics
+    where F: Fn(&attr::Field) -> Option<&[syn::WherePredicate]>
 {
-    aster::from_generics(generics.clone())
-        .with_predicates(
-            item.body.all_fields()
-                .flat_map(|field| from_field(&field.attrs))
-                .flat_map(|predicates| predicates.to_vec()))
-        .build()
+    let predicates = item.body
+        .all_fields()
+        .flat_map(|field| from_field(&field.attrs))
+        .flat_map(|predicates| predicates.to_vec());
+
+    let mut generics = generics.clone();
+    generics.where_clause.predicates.extend(predicates);
+    generics
 }
 
 // Puts the given bound on any generic type parameters that are used in fields
@@ -54,13 +79,12 @@ pub fn with_where_predicates_from_fields<F>(
 //         #[serde(skip_serializing)]
 //         c: C,
 //     }
-pub fn with_bound<F>(
-    item: &Item,
-    generics: &syn::Generics,
-    filter: F,
-    bound: &syn::Path,
-) -> syn::Generics
-    where F: Fn(&attr::Field) -> bool,
+pub fn with_bound<F>(item: &Item,
+                     generics: &syn::Generics,
+                     filter: F,
+                     bound: &syn::Path)
+                     -> syn::Generics
+    where F: Fn(&attr::Field) -> bool
 {
     struct FindTyParams {
         // Set of all generic type parameters on the current struct (A, B, C in
@@ -90,11 +114,13 @@ pub fn with_bound<F>(
         }
     }
 
-    let all_ty_params: HashSet<_> = generics.ty_params.iter()
+    let all_ty_params: HashSet<_> = generics.ty_params
+        .iter()
         .map(|ty_param| ty_param.ident.clone())
         .collect();
 
-    let relevant_tys = item.body.all_fields()
+    let relevant_tys = item.body
+        .all_fields()
         .filter(|&field| filter(&field.attrs))
         .map(|field| &field.ty);
 
@@ -106,16 +132,97 @@ pub fn with_bound<F>(
         visit::walk_ty(&mut visitor, ty);
     }
 
-    aster::from_generics(generics.clone())
-        .with_predicates(
-            generics.ty_params.iter()
-                .map(|ty_param| ty_param.ident.clone())
-                .filter(|id| visitor.relevant_ty_params.contains(id))
-                .map(|id| aster::where_predicate()
-                    // the type parameter that is being bounded e.g. T
-                    .bound().build(aster::ty().id(id))
-                    // the bound e.g. Serialize
-                    .bound().trait_(bound.clone()).build()
-                    .build()))
-        .build()
+    let new_predicates = generics.ty_params
+        .iter()
+        .map(|ty_param| ty_param.ident.clone())
+        .filter(|id| visitor.relevant_ty_params.contains(id))
+        .map(|id| {
+            syn::WherePredicate::BoundPredicate(syn::WhereBoundPredicate {
+                bound_lifetimes: Vec::new(),
+                // the type parameter that is being bounded e.g. T
+                bounded_ty: syn::Ty::Path(None, id.into()),
+                // the bound e.g. Serialize
+                bounds: vec![syn::TyParamBound::Trait(
+                    syn::PolyTraitRef {
+                        bound_lifetimes: Vec::new(),
+                        trait_ref: bound.clone(),
+                    },
+                    syn::TraitBoundModifier::None
+                )],
+            })
+        });
+
+    let mut generics = generics.clone();
+    generics.where_clause.predicates.extend(new_predicates);
+    generics
+}
+
+pub fn with_self_bound(item: &Item,
+                       generics: &syn::Generics,
+                       bound: &syn::Path)
+                       -> syn::Generics
+{
+    let mut generics = generics.clone();
+    generics.where_clause.predicates.push(
+        syn::WherePredicate::BoundPredicate(syn::WhereBoundPredicate {
+            bound_lifetimes: Vec::new(),
+            // the type that is being bounded e.g. MyStruct<'a, T>
+            bounded_ty: type_of_item(item),
+            // the bound e.g. Default
+            bounds: vec![syn::TyParamBound::Trait(
+                syn::PolyTraitRef {
+                    bound_lifetimes: Vec::new(),
+                    trait_ref: bound.clone(),
+                },
+                syn::TraitBoundModifier::None
+            )],
+        })
+    );
+    generics
+}
+
+pub fn with_lifetime_bound(generics: &syn::Generics,
+                           lifetime: &str)
+                           -> syn::Generics {
+    let mut generics = generics.clone();
+
+    for lifetime_def in &mut generics.lifetimes {
+        lifetime_def.bounds.push(syn::Lifetime::new(lifetime));
+    }
+
+    for ty_param in &mut generics.ty_params {
+        ty_param.bounds.push(syn::TyParamBound::Region(syn::Lifetime::new(lifetime)));
+    }
+
+    generics.lifetimes.push(syn::LifetimeDef {
+        attrs: Vec::new(),
+        lifetime: syn::Lifetime::new(lifetime),
+        bounds: Vec::new(),
+    });
+
+    generics
+}
+
+fn type_of_item(item: &Item) -> syn::Ty {
+    syn::Ty::Path(None, syn::Path {
+        global: false,
+        segments: vec![
+            syn::PathSegment {
+                ident: item.ident.clone(),
+                parameters: syn::PathParameters::AngleBracketed(syn::AngleBracketedParameterData {
+                    lifetimes: item.generics
+                                    .lifetimes
+                                    .iter()
+                                    .map(|def| def.lifetime.clone())
+                                    .collect(),
+                    types: item.generics
+                                .ty_params
+                                .iter()
+                                .map(|param| syn::Ty::Path(None, param.ident.clone().into()))
+                                .collect(),
+                    bindings: Vec::new(),
+                }),
+            }
+        ]
+    })
 }

serde_derive/src/fragment.rs

@@ -0,0 +1,67 @@
+use quote::{Tokens, ToTokens};
+
+pub enum Fragment {
+    /// Tokens that can be used as an expression.
+    Expr(Tokens),
+    /// Tokens that can be used inside a block. The surrounding curly braces are
+    /// not part of these tokens.
+    Block(Tokens),
+}
+
+macro_rules! quote_expr {
+    ($($tt:tt)*) => {
+        $crate::fragment::Fragment::Expr(quote!($($tt)*))
+    }
+}
+
+macro_rules! quote_block {
+    ($($tt:tt)*) => {
+        $crate::fragment::Fragment::Block(quote!($($tt)*))
+    }
+}
+
+/// Interpolate a fragment in place of an expression. This involves surrounding
+/// Block fragments in curly braces.
+pub struct Expr(pub Fragment);
+impl ToTokens for Expr {
+    fn to_tokens(&self, out: &mut Tokens) {
+        match self.0 {
+            Fragment::Expr(ref expr) => expr.to_tokens(out),
+            Fragment::Block(ref block) => {
+                out.append("{");
+                block.to_tokens(out);
+                out.append("}");
+            }
+        }
+    }
+}
+
+/// Interpolate a fragment as the statements of a block.
+pub struct Stmts(pub Fragment);
+impl ToTokens for Stmts {
+    fn to_tokens(&self, out: &mut Tokens) {
+        match self.0 {
+            Fragment::Expr(ref expr) => expr.to_tokens(out),
+            Fragment::Block(ref block) => block.to_tokens(out),
+        }
+    }
+}
+
+/// Interpolate a fragment as the value part of a `match` expression. This
+/// involves putting a comma after expressions and curly braces around blocks.
+pub struct Match(pub Fragment);
+impl ToTokens for Match {
+    fn to_tokens(&self, out: &mut Tokens) {
+        match self.0 {
+            Fragment::Expr(ref expr) => {
+                expr.to_tokens(out);
+                out.append(",");
+            }
+            Fragment::Block(ref block) => {
+                out.append("{");
+                block.to_tokens(out);
+                out.append("}");
+            }
+        }
+    }
+}

serde_derive/src/lib.rs

@@ -13,9 +13,13 @@ extern crate serde_codegen_internals as internals;
 extern crate proc_macro;
 use proc_macro::TokenStream;
 
+#[macro_use]
 mod bound;
-mod de;
+#[macro_use]
+mod fragment;
+
 mod ser;
+mod de;
 
 #[proc_macro_derive(Serialize, attributes(serde))]
 pub fn derive_serialize(input: TokenStream) -> TokenStream {

serde_test/Cargo.toml

@@ -1,15 +1,15 @@
 [package]
 name = "serde_test"
-version = "0.9.5"
+version = "0.9.11"
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>"]
 license = "MIT/Apache-2.0"
 description = "Token De/Serializer for testing De/Serialize implementations"
 homepage = "https://serde.rs"
 repository = "https://github.com/serde-rs/serde"
 documentation = "https://docs.serde.rs/serde_test/"
-readme = "../README.md"
 keywords = ["serde", "serialization"]
-include = ["Cargo.toml", "src/**/*.rs"]
+readme = "../README.md"
+include = ["Cargo.toml", "src/**/*.rs", "README.md", "LICENSE-APACHE", "LICENSE-MIT"]
 
 [dependencies]
 serde = { version = "0.9", path = "../serde" }

serde_test/LICENSE-APACHE

@@ -0,0 +1 @@
+../LICENSE-APACHE

serde_test/LICENSE-MIT

@@ -0,0 +1 @@
+../LICENSE-MIT

serde_test/README.md

@@ -0,0 +1 @@
+../README.md

serde_test/src/assert.rs

@@ -7,24 +7,26 @@ use token::Token;
 
 use std::fmt::Debug;
 
+/// Runs both `assert_ser_tokens` and `assert_de_tokens`.
 pub fn assert_tokens<T>(value: &T, tokens: &[Token<'static>])
-    where T: Serialize + Deserialize + PartialEq + Debug,
+    where T: Serialize + Deserialize + PartialEq + Debug
 {
     assert_ser_tokens(value, tokens);
     assert_de_tokens(value, tokens);
 }
 
+/// Asserts that `value` serializes to the given `tokens`.
 pub fn assert_ser_tokens<T>(value: &T, tokens: &[Token])
-    where T: Serialize,
+    where T: Serialize
 {
     let mut ser = Serializer::new(tokens.iter());
     assert_eq!(Serialize::serialize(value, &mut ser), Ok(()));
     assert_eq!(ser.next_token(), None);
 }
 
-/// Expect an error serializing `T`.
+/// Asserts that `value` serializes to the given `tokens`, and then yields `error`.
 pub fn assert_ser_tokens_error<T>(value: &T, tokens: &[Token], error: Error)
-    where T: Serialize + PartialEq + Debug,
+    where T: Serialize + PartialEq + Debug
 {
     let mut ser = Serializer::new(tokens.iter());
     let v: Result<(), Error> = Serialize::serialize(value, &mut ser);
@@ -32,8 +34,9 @@ pub fn assert_ser_tokens_error<T>(value: &T, tokens: &[Token], error: Error)
     assert_eq!(ser.next_token(), None);
 }
 
+/// Asserts that the given `tokens` deserialize into `value`.
 pub fn assert_de_tokens<T>(value: &T, tokens: &[Token<'static>])
-    where T: Deserialize + PartialEq + Debug,
+    where T: Deserialize + PartialEq + Debug
 {
     let mut de = Deserializer::new(tokens.to_vec().into_iter());
     let v: Result<T, Error> = Deserialize::deserialize(&mut de);
@@ -41,9 +44,9 @@ pub fn assert_de_tokens<T>(value: &T, tokens: &[Token<'static>])
     assert_eq!(de.next_token(), None);
 }
 
-/// Expect an error deserializing tokens into a `T`.
+/// Asserts that the given `tokens` yield `error` when deserializing.
 pub fn assert_de_tokens_error<T>(tokens: &[Token<'static>], error: Error)
-    where T: Deserialize + PartialEq + Debug,
+    where T: Deserialize + PartialEq + Debug
 {
     let mut de = Deserializer::new(tokens.to_vec().into_iter());
     let v: Result<T, Error> = Deserialize::deserialize(&mut de);

serde_test/src/error.rs

@@ -5,11 +5,19 @@ use serde::{ser, de};
 
 use token::Token;
 
+/// Error returned by the test `Serializer` and `Deserializer`.
 #[derive(Clone, PartialEq, Debug)]
 pub enum Error {
+    /// A custom error.
     Message(String),
+
+    /// `Deserialize` was expecting a struct of one name, and another was found.
     InvalidName(&'static str),
+
+    /// `Serialize` generated a token that didn't match the test.
     UnexpectedToken(Token<'static>),
+
+    /// The expected token list was too short.
     EndOfTokens,
 }
 

serde_test/src/lib.rs

@@ -1,13 +1,9 @@
+#[macro_use]
 extern crate serde;
 
 mod assert;
-pub use assert::{
-    assert_tokens,
-    assert_ser_tokens,
-    assert_ser_tokens_error,
-    assert_de_tokens,
-    assert_de_tokens_error,
-};
+pub use assert::{assert_tokens, assert_ser_tokens, assert_ser_tokens_error, assert_de_tokens,
+                 assert_de_tokens_error};
 
 mod ser;
 pub use ser::Serializer;

serde_test/src/ser.rs

@@ -5,16 +5,18 @@ use serde::{ser, Serialize};
 use error::Error;
 use token::Token;
 
+/// A `Serializer` that ensures that a value serializes to a given list of tokens.
 pub struct Serializer<'a, I>
-    where I: Iterator<Item=&'a Token<'a>>,
+    where I: Iterator<Item = &'a Token<'a>>
 {
     tokens: I,
     phantom: PhantomData<&'a Token<'a>>,
 }
 
 impl<'a, I> Serializer<'a, I>
-    where I: Iterator<Item=&'a Token<'a>>,
+    where I: Iterator<Item = &'a Token<'a>>
 {
+    /// Creates the serializer.
     pub fn new(tokens: I) -> Serializer<'a, I> {
         Serializer {
             tokens: tokens,
@@ -22,13 +24,14 @@ impl<'a, I> Serializer<'a, I>
         }
     }
 
+    /// Pulls the next token off of the serializer, ignoring it.
     pub fn next_token(&mut self) -> Option<&'a Token<'a>> {
         self.tokens.next()
     }
 }
 
 impl<'s, 'a, I> ser::Serializer for &'s mut Serializer<'a, I>
-    where I: Iterator<Item=&'a Token<'a>>,
+    where I: Iterator<Item = &'a Token<'a>>
 {
     type Ok = ();
     type Error = Error;
@@ -124,15 +127,14 @@ impl<'s, 'a, I> ser::Serializer for &'s mut Serializer<'a, I>
     fn serialize_unit_variant(self,
                               name: &str,
                               _variant_index: usize,
-                              variant: &str) -> Result<(), Error> {
+                              variant: &str)
+                              -> Result<(), Error> {
         assert_eq!(self.tokens.next(), Some(&Token::EnumUnit(name, variant)));
         Ok(())
     }
 
-    fn serialize_newtype_struct<T: ?Sized>(self,
-                                           name: &'static str,
-                                           value: &T) -> Result<(), Error>
-        where T: Serialize,
+    fn serialize_newtype_struct<T: ?Sized>(self, name: &'static str, value: &T) -> Result<(), Error>
+        where T: Serialize
     {
         assert_eq!(self.tokens.next(), Some(&Token::StructNewType(name)));
         value.serialize(self)
@@ -142,8 +144,9 @@ impl<'s, 'a, I> ser::Serializer for &'s mut Serializer<'a, I>
                                             name: &str,
                                             _variant_index: usize,
                                             variant: &str,
-                                            value: &T) -> Result<(), Error>
-        where T: Serialize,
+                                            value: &T)
+                                            -> Result<(), Error>
+        where T: Serialize
     {
         assert_eq!(self.tokens.next(), Some(&Token::EnumNewType(name, variant)));
         value.serialize(self)
@@ -155,7 +158,7 @@ impl<'s, 'a, I> ser::Serializer for &'s mut Serializer<'a, I>
     }
 
     fn serialize_some<T: ?Sized>(self, value: &T) -> Result<(), Error>
-        where T: Serialize,
+        where T: Serialize
     {
         assert_eq!(self.tokens.next(), Some(&Token::Option(true)));
         value.serialize(self)
@@ -177,7 +180,8 @@ impl<'s, 'a, I> ser::Serializer for &'s mut Serializer<'a, I>
     }
 
     fn serialize_tuple_struct(self, name: &'static str, len: usize) -> Result<Self, Error> {
-        assert_eq!(self.tokens.next(), Some(&Token::TupleStructStart(name, len)));
+        assert_eq!(self.tokens.next(),
+                   Some(&Token::TupleStructStart(name, len)));
         Ok(self)
     }
 
@@ -185,9 +189,10 @@ impl<'s, 'a, I> ser::Serializer for &'s mut Serializer<'a, I>
                                name: &str,
                                _variant_index: usize,
                                variant: &str,
-                               len: usize) -> Result<Self, Error>
-    {
-        assert_eq!(self.tokens.next(), Some(&Token::EnumSeqStart(name, variant, len)));
+                               len: usize)
+                               -> Result<Self, Error> {
+        assert_eq!(self.tokens.next(),
+                   Some(&Token::EnumSeqStart(name, variant, len)));
         Ok(self)
     }
 
@@ -205,15 +210,16 @@ impl<'s, 'a, I> ser::Serializer for &'s mut Serializer<'a, I>
                                 name: &str,
                                 _variant_index: usize,
                                 variant: &str,
-                                len: usize) -> Result<Self, Error>
-    {
-        assert_eq!(self.tokens.next(), Some(&Token::EnumMapStart(name, variant, len)));
+                                len: usize)
+                                -> Result<Self, Error> {
+        assert_eq!(self.tokens.next(),
+                   Some(&Token::EnumMapStart(name, variant, len)));
         Ok(self)
     }
 }
 
 impl<'s, 'a, I> ser::SerializeSeq for &'s mut Serializer<'a, I>
-    where I: Iterator<Item=&'a Token<'a>>,
+    where I: Iterator<Item = &'a Token<'a>>
 {
     type Ok = ();
     type Error = Error;
@@ -232,7 +238,7 @@ impl<'s, 'a, I> ser::SerializeSeq for &'s mut Serializer<'a, I>
 }
 
 impl<'s, 'a, I> ser::SerializeTuple for &'s mut Serializer<'a, I>
-    where I: Iterator<Item=&'a Token<'a>>,
+    where I: Iterator<Item = &'a Token<'a>>
 {
     type Ok = ();
     type Error = Error;
@@ -251,7 +257,7 @@ impl<'s, 'a, I> ser::SerializeTuple for &'s mut Serializer<'a, I>
 }
 
 impl<'s, 'a, I> ser::SerializeTupleStruct for &'s mut Serializer<'a, I>
-    where I: Iterator<Item=&'a Token<'a>>,
+    where I: Iterator<Item = &'a Token<'a>>
 {
     type Ok = ();
     type Error = Error;
@@ -270,7 +276,7 @@ impl<'s, 'a, I> ser::SerializeTupleStruct for &'s mut Serializer<'a, I>
 }
 
 impl<'s, 'a, I> ser::SerializeTupleVariant for &'s mut Serializer<'a, I>
-    where I: Iterator<Item=&'a Token<'a>>,
+    where I: Iterator<Item = &'a Token<'a>>
 {
     type Ok = ();
     type Error = Error;
@@ -289,17 +295,21 @@ impl<'s, 'a, I> ser::SerializeTupleVariant for &'s mut Serializer<'a, I>
 }
 
 impl<'s, 'a, I> ser::SerializeMap for &'s mut Serializer<'a, I>
-    where I: Iterator<Item=&'a Token<'a>>,
+    where I: Iterator<Item = &'a Token<'a>>
 {
     type Ok = ();
     type Error = Error;
 
-    fn serialize_key<T: ?Sized>(&mut self, key: &T) -> Result<(), Self::Error> where T: Serialize {
+    fn serialize_key<T: ?Sized>(&mut self, key: &T) -> Result<(), Self::Error>
+        where T: Serialize
+    {
         assert_eq!(self.tokens.next(), Some(&Token::MapSep));
         key.serialize(&mut **self)
     }
 
-    fn serialize_value<T: ?Sized>(&mut self, value: &T) -> Result<(), Self::Error> where T: Serialize {
+    fn serialize_value<T: ?Sized>(&mut self, value: &T) -> Result<(), Self::Error>
+        where T: Serialize
+    {
         value.serialize(&mut **self)
     }
 
@@ -310,12 +320,17 @@ impl<'s, 'a, I> ser::SerializeMap for &'s mut Serializer<'a, I>
 }
 
 impl<'s, 'a, I> ser::SerializeStruct for &'s mut Serializer<'a, I>
-    where I: Iterator<Item=&'a Token<'a>>,
+    where I: Iterator<Item = &'a Token<'a>>
 {
     type Ok = ();
     type Error = Error;
 
-    fn serialize_field<T: ?Sized>(&mut self, key: &'static str, value: &T) -> Result<(), Self::Error> where T: Serialize {
+    fn serialize_field<T: ?Sized>(&mut self,
+                                  key: &'static str,
+                                  value: &T)
+                                  -> Result<(), Self::Error>
+        where T: Serialize
+    {
         assert_eq!(self.tokens.next(), Some(&Token::StructSep));
         try!(key.serialize(&mut **self));
         value.serialize(&mut **self)
@@ -328,12 +343,17 @@ impl<'s, 'a, I> ser::SerializeStruct for &'s mut Serializer<'a, I>
 }
 
 impl<'s, 'a, I> ser::SerializeStructVariant for &'s mut Serializer<'a, I>
-    where I: Iterator<Item=&'a Token<'a>>,
+    where I: Iterator<Item = &'a Token<'a>>
 {
     type Ok = ();
     type Error = Error;
 
-    fn serialize_field<T: ?Sized>(&mut self, key: &'static str, value: &T) -> Result<(), Self::Error> where T: Serialize {
+    fn serialize_field<T: ?Sized>(&mut self,
+                                  key: &'static str,
+                                  value: &T)
+                                  -> Result<(), Self::Error>
+        where T: Serialize
+    {
         assert_eq!(self.tokens.next(), Some(&Token::EnumMapSep));
         try!(key.serialize(&mut **self));
         value.serialize(&mut **self)

serde_test/src/token.rs

@@ -1,59 +1,170 @@
 #[derive(Clone, PartialEq, Debug)]
 pub enum Token<'a> {
+    /// A serialized `bool`.
     Bool(bool),
+
+    /// A serialized `i8`.
     I8(i8),
+
+    /// A serialized `i16`.
     I16(i16),
+
+    /// A serialized `i32`.
     I32(i32),
+
+    /// A serialized `i64`.
     I64(i64),
+
+    /// A serialized `u8`.
     U8(u8),
+
+    /// A serialized `u16`.
     U16(u16),
+
+    /// A serialized `u32`.
     U32(u32),
+
+    /// A serialized `u64`.
     U64(u64),
+
+    /// A serialized `f32`.
     F32(f32),
+
+    /// A serialized `f64`.
     F64(f64),
+
+    /// A serialized `char`.
     Char(char),
+
+    /// A serialized `str`.
     Str(&'a str),
+
+    /// A serialized `String`.
     String(String),
+
+    /// A serialized `[u8]`
     Bytes(&'a [u8]),
+
+    /// A serialized `ByteBuf`
     ByteBuf(Vec<u8>),
 
+    /// The header to a serialized `Option<T>`.
+    ///
+    /// `None` is serialized as `Option(false)`, while `Some` is serialized as `Option(true)`, then
+    /// the value contained in the option.
     Option(bool),
 
+    /// A serialized `()`.
     Unit,
+
+    /// A serialized unit struct of the given name.
     UnitStruct(&'a str),
 
+    /// The header to a serialized newtype struct of the given name.
+    ///
+    /// Newtype structs are serialized with this header, followed by the value contained in the
+    /// newtype struct.
     StructNewType(&'a str),
 
+    /// The header to an enum of the given name.
+    ///
+    /// This token is only used for deserializers, and ensures that the following tokens are read as
+    /// an enum. Because this is never emitted by serializers, calling `assert_ser_tokens` or
+    /// `assert_tokens` will fail if this token is used.
+    ///
+    /// TODO: Trash this.
     EnumStart(&'a str),
+
+    /// A unit variant of an enum of the given name, of the given name.
+    ///
+    /// The first string represents the name of the enum, and the second represents the name of the
+    /// variant.
     EnumUnit(&'a str, &'a str),
+
+    /// The header to a newtype variant of an enum of the given name, of the given name.
+    ///
+    /// The first string represents the name of the enum, and the second represents the name of the
+    /// variant. The value contained within this enum works the same as `StructNewType`.
     EnumNewType(&'a str, &'a str),
 
+    /// The header to a sequence of the given length.
+    ///
+    /// These are serialized via `serialize_seq`, which takes an optional length. After this
+    /// header is a list of elements, followed by `SeqEnd`.
     SeqStart(Option<usize>),
+
+    /// The header to an array of the given length.
+    ///
+    /// These are serialized via `serialize_seq_fized_size`, which requires a length. After this
+    /// header is a list of elements, followed by `SeqEnd`.
     SeqArrayStart(usize),
+
+    /// A separator, which occurs *before* every element in a sequence.
+    ///
+    /// Elements in sequences are represented by a `SeqSep`, followed by the value of the element.
     SeqSep,
+
+    /// An indicator of the end of a sequence.
     SeqEnd,
 
+    /// The header to a tuple of the given length, similar to `SeqArrayStart`.
     TupleStart(usize),
+
+    /// A separator, similar to `SeqSep`.
     TupleSep,
+
+    /// An indicator of the end of a tuple, similar to `SeqEnd`.
     TupleEnd,
 
+    /// The header to a tuple struct of the given name and length.
     TupleStructStart(&'a str, usize),
+
+    /// A separator, similar to `TupleSep`.
     TupleStructSep,
+
+    /// An indicator of the end of a tuple struct, similar to `TupleEnd`.
     TupleStructEnd,
 
+    /// The header to a map of the given length.
+    ///
+    /// These are serialized via `serialize_map`, which takes an optional length. After this header
+    /// is a list of key-value pairs, followed by `MapEnd`.
     MapStart(Option<usize>),
+
+    /// A separator, which occurs *before* every key-value pair in a map.
+    ///
+    /// Elements in maps are represented by a `MapSep`, followed by a serialized key, followed
+    /// by a serialized value.
     MapSep,
+
+    /// An indicator of the end of a map.
     MapEnd,
 
+    /// The header of a struct of the given name and length, similar to `MapStart`.
     StructStart(&'a str, usize),
+
+    /// A separator, similar to `MapSep`.
     StructSep,
+
+    /// An indicator of the end of a struct, similar to `MapEnd`.
     StructEnd,
 
+    /// The header to a tuple variant of an enum of the given name, of the given name and length.
     EnumSeqStart(&'a str, &'a str, usize),
+
+    /// A separator, similar to `TupleSep`.
     EnumSeqSep,
+
+    /// An indicator of the end of a tuple variant, similar to `TupleEnd`.
     EnumSeqEnd,
 
+    /// The header of a struct variant of an enum of the given name, of the given name and length,
+    /// similar to `StructStart`.
     EnumMapStart(&'a str, &'a str, usize),
+
+    /// A separator, similar to `StructSep`.
     EnumMapSep,
+
+    /// An indicator of the end of a struct, similar to `StructEnd`.
     EnumMapEnd,
 }

test_suite/Cargo.toml

@@ -2,20 +2,10 @@
 name = "serde_test_suite"
 version = "0.0.0"
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>"]
-license = "MIT/Apache-2.0"
-description = "A generic serialization/deserialization framework"
-homepage = "https://serde.rs"
-repository = "https://github.com/serde-rs/serde"
-documentation = "https://docs.serde.rs/serde/"
-readme = "README.md"
-keywords = ["serialization"]
 publish = false
 
 [features]
-unstable-testing = [
-    "compiletest_rs",
-    "serde/unstable-testing",
-]
+unstable-testing = ["compiletest_rs"]
 
 [dev-dependencies]
 fnv = "1.0"
@@ -26,7 +16,3 @@ serde_test = { path = "../serde_test" }
 
 [dependencies]
 compiletest_rs = { version = "0.2", optional = true }
-
-[[test]]
-name = "test"
-path = "tests/test.rs"

test_suite/tests/compile-fail/default-attribute/enum.rs

@@ -0,0 +1,8 @@
+#[macro_use]
+extern crate serde_derive;
+
+#[derive(Deserialize)] //~ ERROR: proc-macro derive panicked
+#[serde(default)] //~^ HELP: #[serde(default)] can only be used on structs
+enum E {
+    S { f: u8 },
+}

test_suite/tests/compile-fail/default-attribute/nameless_struct_fields.rs

@@ -0,0 +1,8 @@
+#[macro_use]
+extern crate serde_derive;
+
+#[derive(Deserialize)] //~ ERROR: proc-macro derive panicked
+#[serde(default)] //~^ HELP: #[serde(default)] can only be used on structs
+struct T(u8, u8);
+
+fn main() { }

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

@@ -1,7 +1,7 @@
 #[macro_use]
 extern crate serde_derive;
 
-#[derive(Serialize)] //~ ERROR: custom derive attribute panicked
+#[derive(Serialize)] //~ ERROR: proc-macro derive panicked
 struct S {
     #[serde(rename="x", serialize="y")] //~^^ HELP: unknown serde field attribute `serialize`
     x: (),

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

@@ -1,7 +1,7 @@
 #[macro_use]
 extern crate serde_derive;
 
-#[derive(Serialize)] //~ ERROR: custom derive attribute panicked
+#[derive(Serialize)] //~ ERROR: proc-macro derive panicked
 struct S {
     #[serde(rename="x")]
     #[serde(rename(deserialize="y"))] //~^^^ HELP: duplicate serde attribute `rename`

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

@@ -1,7 +1,7 @@
 #[macro_use]
 extern crate serde_derive;
 
-#[derive(Serialize)] //~ ERROR: custom derive attribute panicked
+#[derive(Serialize)] //~ ERROR: proc-macro derive panicked
 struct S {
     #[serde(rename(serialize="x"), rename(serialize="y"))] //~^^ HELP: duplicate serde attribute `rename`
     x: (),

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

@@ -1,7 +1,7 @@
 #[macro_use]
 extern crate serde_derive;
 
-#[derive(Serialize)] //~ ERROR: custom derive attribute panicked
+#[derive(Serialize)] //~ ERROR: proc-macro derive panicked
 struct S {
     #[serde(rename(serialize="x"))]
     #[serde(rename="y")] //~^^^ HELP: duplicate serde attribute `rename`

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

@@ -1,7 +1,7 @@
 #[macro_use]
 extern crate serde_derive;
 
-#[derive(Serialize)] //~ ERROR: custom derive attribute panicked
+#[derive(Serialize)] //~ ERROR: proc-macro derive panicked
 struct S {
     #[serde(rename(serialize="x", serialize="y"))] //~^^ HELP: duplicate serde attribute `rename`
     x: (),

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

@@ -1,7 +1,7 @@
 #[macro_use]
 extern crate serde_derive;
 
-#[derive(Serialize)] //~ ERROR: custom derive attribute panicked
+#[derive(Serialize)] //~ ERROR: proc-macro derive panicked
 struct S {
     #[serde(rename(serialize="x"))]
     #[serde(rename(serialize="y"))] //~^^^ HELP: duplicate serde attribute `rename`

test_suite/tests/compile-fail/duplicate-attribute/with-and-serialize-with.rs

@@ -0,0 +1,10 @@
+#[macro_use]
+extern crate serde_derive;
+
+#[derive(Serialize)] //~ ERROR: proc-macro derive panicked
+struct S {
+    #[serde(with = "w", serialize_with = "s")] //~^^ HELP: duplicate serde attribute `serialize_with`
+    x: (),
+}
+
+fn main() {}

test_suite/tests/compile-fail/enum-representation/internal-tuple-variant.rs

@@ -0,0 +1,10 @@
+#[macro_use]
+extern crate serde_derive;
+
+#[derive(Serialize)] //~ ERROR: proc-macro derive panicked
+#[serde(tag = "type")] //~^ HELP: #[serde(tag = "...")] cannot be used with tuple variants
+enum E {
+    Tuple(u8, u8),
+}
+
+fn main() {}

test_suite/tests/compile-fail/enum-representation/internally-tagged-struct.rs

@@ -0,0 +1,8 @@
+#[macro_use]
+extern crate serde_derive;
+
+#[derive(Serialize)] //~ ERROR: proc-macro derive panicked
+#[serde(tag = "type")] //~^ HELP: #[serde(tag = "...")] can only be used on enums
+struct S;
+
+fn main() {}

test_suite/tests/compile-fail/enum-representation/untagged-and-internal.rs

@@ -0,0 +1,12 @@
+#[macro_use]
+extern crate serde_derive;
+
+#[derive(Serialize)] //~ ERROR: proc-macro derive panicked
+#[serde(untagged)]
+#[serde(tag = "type")] //~^^ HELP: enum cannot be both untagged and internally tagged
+enum E {
+    A(u8),
+    B(String),
+}
+
+fn main() {}

test_suite/tests/compile-fail/enum-representation/untagged-struct.rs

@@ -0,0 +1,8 @@
+#[macro_use]
+extern crate serde_derive;
+
+#[derive(Serialize)] //~ ERROR: proc-macro derive panicked
+#[serde(untagged)] //~^ HELP: #[serde(untagged)] can only be used on enums
+struct S;
+
+fn main() {}

test_suite/tests/compile-fail/str_ref_deser.rs

@@ -1,7 +1,7 @@
 #[macro_use]
 extern crate serde_derive;
 
-#[derive(Serialize, Deserialize)] //~ ERROR: custom derive attribute panicked
+#[derive(Serialize, Deserialize)] //~ ERROR: proc-macro derive panicked
 struct Test<'a> {
     s: &'a str, //~^^ HELP: Serde does not support deserializing fields of type &str
 }

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

@@ -1,7 +1,7 @@
 #[macro_use]
 extern crate serde_derive;
 
-#[derive(Serialize)] //~ ERROR: custom derive attribute panicked
+#[derive(Serialize)] //~ ERROR: proc-macro derive panicked
 #[serde(abc="xyz")] //~^ HELP: unknown serde container attribute `abc`
 struct A {
     x: u32,

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

@@ -1,7 +1,7 @@
 #[macro_use]
 extern crate serde_derive;
 
-#[derive(Serialize)] //~ ERROR: custom derive attribute panicked
+#[derive(Serialize)] //~ ERROR: proc-macro derive panicked
 struct C {
     #[serde(abc="xyz")] //~^^ HELP: unknown serde field attribute `abc`
     x: u32,

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

@@ -1,7 +1,7 @@
 #[macro_use]
 extern crate serde_derive;
 
-#[derive(Serialize)] //~ ERROR: custom derive attribute panicked
+#[derive(Serialize)] //~ ERROR: proc-macro derive panicked
 enum E {
     #[serde(abc="xyz")] //~^^ HELP: unknown serde variant attribute `abc`
     V,

test_suite/tests/compiletest.rs

@@ -1,3 +1,5 @@
+#![cfg(feature = "unstable-testing")]
+
 extern crate compiletest_rs as compiletest;
 
 use std::env;

test_suite/tests/test.rs

@@ -1,23 +0,0 @@
-#![cfg_attr(feature = "unstable-testing", feature(test, non_ascii_idents))]
-
-#[cfg(feature = "unstable-testing")]
-extern crate test;
-
-#[macro_use]
-extern crate serde_derive;
-
-extern crate serde;
-extern crate serde_test;
-
-#[macro_use]
-mod macros;
-
-mod test_annotations;
-mod test_bytes;
-mod test_de;
-mod test_gen;
-mod test_macros;
-mod test_ser;
-
-#[cfg(feature = "unstable-testing")]
-mod compiletest;

test_suite/tests/test_annotations.rs

@@ -1,3 +1,6 @@
+#[macro_use]
+extern crate serde_derive;
+
 extern crate serde;
 use self::serde::{Serialize, Serializer, Deserialize, Deserializer};
 

test_suite/tests/test_bytes.rs

@@ -1,4 +1,7 @@
+extern crate serde;
 use serde::bytes::{ByteBuf, Bytes};
+
+extern crate serde_test;
 use serde_test::{assert_tokens, assert_ser_tokens, assert_de_tokens, Token};
 
 #[test]

test_suite/tests/test_de.rs

@@ -1,8 +1,14 @@
+#[macro_use]
+extern crate serde_derive;
+
 use std::collections::{BTreeMap, BTreeSet, HashMap, HashSet};
 use std::net;
 use std::path::PathBuf;
 use std::time::Duration;
+use std::default::Default;
+use std::ffi::CString;
 
+extern crate serde;
 use serde::Deserialize;
 
 extern crate fnv;
@@ -16,6 +22,9 @@ use self::serde_test::{
     assert_de_tokens_error,
 };
 
+#[macro_use]
+mod macros;
+
 //////////////////////////////////////////////////////////////////////////
 
 #[derive(Copy, Clone, PartialEq, Debug, Deserialize)]
@@ -40,6 +49,22 @@ struct StructDenyUnknown {
     b: i32,
 }
 
+#[derive(PartialEq, Debug, Deserialize)]
+#[serde(default)]
+struct StructDefault<T> {
+    a: i32,
+    b: T,
+}
+
+impl Default for StructDefault<String> {
+    fn default() -> Self {
+        StructDefault {
+            a: 100,
+            b: "default".to_string(),
+        }
+    }
+}
+
 #[derive(PartialEq, Debug, Deserialize)]
 struct StructSkipAll {
     #[serde(skip_deserializing)]
@@ -225,7 +250,7 @@ declare_tests! {
         ],
         () => &[
             Token::TupleStructStart("Anything", 0),
-            Token::SeqEnd,
+            Token::TupleStructEnd,
         ],
     }
     test_unit_struct {
@@ -330,7 +355,7 @@ declare_tests! {
         ],
         BTreeSet::<isize>::new() => &[
             Token::TupleStructStart("Anything", 0),
-            Token::SeqEnd,
+            Token::TupleStructEnd,
         ],
     }
     test_hashset {
@@ -358,7 +383,7 @@ declare_tests! {
         ],
         HashSet::<isize>::new() => &[
             Token::TupleStructStart("Anything", 0),
-            Token::SeqEnd,
+            Token::TupleStructEnd,
         ],
         hashset![FnvHasher @ 1, 2, 3] => &[
             Token::SeqStart(Some(3)),
@@ -408,7 +433,7 @@ declare_tests! {
         ],
         Vec::<isize>::new() => &[
             Token::TupleStructStart("Anything", 0),
-            Token::SeqEnd,
+            Token::TupleStructEnd,
         ],
     }
     test_array {
@@ -472,7 +497,7 @@ declare_tests! {
         ],
         [0; 0] => &[
             Token::TupleStructStart("Anything", 0),
-            Token::SeqEnd,
+            Token::TupleStructEnd,
         ],
     }
     test_tuple {
@@ -564,7 +589,7 @@ declare_tests! {
         ],
         BTreeMap::<isize, isize>::new() => &[
             Token::StructStart("Anything", 0),
-            Token::MapEnd,
+            Token::StructEnd,
         ],
     }
     test_hashmap {
@@ -618,7 +643,7 @@ declare_tests! {
         ],
         HashMap::<isize, isize>::new() => &[
             Token::StructStart("Anything", 0),
-            Token::MapEnd,
+            Token::StructEnd,
         ],
         hashmap![FnvHasher @ 1 => 2, 3 => 4] => &[
             Token::MapStart(Some(2)),
@@ -728,6 +753,23 @@ declare_tests! {
             Token::StructEnd,
         ],
     }
+    test_struct_default {
+        StructDefault { a: 50, b: "overwritten".to_string() } => &[
+            Token::StructStart("StructDefault", 1),
+                Token::StructSep,
+                Token::Str("a"),
+                Token::I32(50),
+
+                Token::StructSep,
+                Token::Str("b"),
+                Token::String("overwritten".to_string()),
+            Token::StructEnd,
+        ],
+        StructDefault { a: 100, b: "default".to_string() } => &[
+            Token::StructStart("StructDefault", 0),
+            Token::StructEnd,
+        ],
+    }
     test_enum_unit {
         Enum::Unit => &[
             Token::EnumUnit("Enum", "Unit"),
@@ -837,6 +879,11 @@ declare_tests! {
             Token::String("/usr/local/lib".to_owned()),
         ],
     }
+    test_cstring {
+        CString::new("abc").unwrap() => &[
+            Token::Bytes(b"abc"),
+        ],
+    }
 }
 
 #[cfg(feature = "unstable")]
@@ -954,4 +1001,16 @@ declare_error_tests! {
         ],
         Error::Message("invalid length 1, expected an array of length 3".into()),
     }
+    test_cstring_internal_null<CString> {
+        &[
+            Token::Bytes(b"a\0c"),
+        ],
+        Error::Message("nul byte found in provided data at position: 1".into()),
+    }
+    test_cstring_internal_null_end<CString> {
+        &[
+            Token::Bytes(b"ac\0"),
+        ],
+        Error::Message("nul byte found in provided data at position: 2".into()),
+    }
 }

test_suite/tests/test_gen.rs

@@ -2,17 +2,26 @@
 // successfully when there are a variety of generics and non-(de)serializable
 // types involved.
 
+#![cfg_attr(feature = "unstable-testing", feature(non_ascii_idents))]
+
+#[macro_use]
+extern crate serde_derive;
+
 extern crate serde;
 use self::serde::ser::{Serialize, Serializer};
 use self::serde::de::{Deserialize, Deserializer};
 
 use std::borrow::Cow;
 use std::marker::PhantomData;
+use std::result::Result as StdResult;
 
 // Try to trip up the generated code if it fails to use fully qualified paths.
 #[allow(dead_code)]
 struct Result;
-use std::result::Result as StdResult;
+#[allow(dead_code)]
+struct Ok;
+#[allow(dead_code)]
+struct Err;
 
 //////////////////////////////////////////////////////////////////////////
 
@@ -26,6 +35,14 @@ fn test_gen() {
     }
     assert::<With<i32>>();
 
+    #[derive(Serialize, Deserialize)]
+    struct WithTogether<T> {
+        t: T,
+        #[serde(with="both_x")]
+        x: X,
+    }
+    assert::<WithTogether<i32>>();
+
     #[derive(Serialize, Deserialize)]
     struct WithRef<'a, T: 'a> {
         #[serde(skip_deserializing)]
@@ -303,16 +320,20 @@ trait DeserializeWith: Sized {
 }
 
 // Implements neither Serialize nor Deserialize
-struct X;
+pub struct X;
 
-fn ser_x<S: Serializer>(_: &X, _: S) -> StdResult<S::Ok, S::Error> {
+pub fn ser_x<S: Serializer>(_: &X, _: S) -> StdResult<S::Ok, S::Error> {
     unimplemented!()
 }
 
-fn de_x<D: Deserializer>(_: D) -> StdResult<X, D::Error> {
+pub fn de_x<D: Deserializer>(_: D) -> StdResult<X, D::Error> {
     unimplemented!()
 }
 
+mod both_x {
+    pub use super::{ser_x as serialize, de_x as deserialize};
+}
+
 impl SerializeWith for X {
     fn serialize_with<S: Serializer>(_: &Self, _: S) -> StdResult<S::Ok, S::Error> {
         unimplemented!()

test_suite/tests/test_macros.rs

@@ -1,11 +1,17 @@
+#[macro_use]
+extern crate serde_derive;
+
 extern crate serde_test;
 use self::serde_test::{
+    Error,
     Token,
     assert_tokens,
     assert_ser_tokens,
     assert_de_tokens,
+    assert_de_tokens_error,
 };
 
+use std::collections::BTreeMap;
 use std::marker::PhantomData;
 
 // That tests that the derived Serialize implementation doesn't trigger
@@ -625,3 +631,683 @@ fn test_enum_state_field() {
         ]
     );
 }
+
+#[test]
+fn test_untagged_enum() {
+    #[derive(Debug, PartialEq, Serialize, Deserialize)]
+    #[serde(untagged)]
+    enum Untagged {
+        A {
+            a: u8,
+        },
+        B {
+            b: u8,
+        },
+        C,
+        D(u8),
+        E(String),
+        F(u8, u8),
+    }
+
+    assert_tokens(
+        &Untagged::A { a: 1 },
+        &[
+            Token::StructStart("Untagged", 1),
+
+            Token::StructSep,
+            Token::Str("a"),
+            Token::U8(1),
+
+            Token::StructEnd,
+        ]
+    );
+
+    assert_tokens(
+        &Untagged::B { b: 2 },
+        &[
+            Token::StructStart("Untagged", 1),
+
+            Token::StructSep,
+            Token::Str("b"),
+            Token::U8(2),
+
+            Token::StructEnd,
+        ]
+    );
+
+    assert_tokens(
+        &Untagged::C,
+        &[
+            Token::Unit,
+        ]
+    );
+
+    assert_tokens(
+        &Untagged::D(4),
+        &[
+            Token::U8(4),
+        ]
+    );
+    assert_tokens(
+        &Untagged::E("e".to_owned()),
+        &[
+            Token::Str("e"),
+        ]
+    );
+
+    assert_tokens(
+        &Untagged::F(1, 2),
+        &[
+            Token::TupleStart(2),
+
+            Token::TupleSep,
+            Token::U8(1),
+
+            Token::TupleSep,
+            Token::U8(2),
+
+            Token::TupleEnd,
+        ]
+    );
+
+    assert_de_tokens_error::<Untagged>(
+        &[
+            Token::Option(false),
+        ],
+        Error::Message("data did not match any variant of untagged enum Untagged".to_owned()),
+    );
+
+    assert_de_tokens_error::<Untagged>(
+        &[
+            Token::TupleStart(1),
+
+            Token::TupleSep,
+            Token::U8(1),
+
+            Token::TupleEnd,
+        ],
+        Error::Message("data did not match any variant of untagged enum Untagged".to_owned()),
+    );
+
+    assert_de_tokens_error::<Untagged>(
+        &[
+            Token::TupleStart(3),
+
+            Token::TupleSep,
+            Token::U8(1),
+
+            Token::TupleSep,
+            Token::U8(2),
+
+            Token::TupleSep,
+            Token::U8(3),
+
+            Token::TupleEnd,
+        ],
+        Error::Message("data did not match any variant of untagged enum Untagged".to_owned()),
+    );
+}
+
+#[test]
+fn test_internally_tagged_enum() {
+    #[derive(Debug, PartialEq, Serialize, Deserialize)]
+    struct Newtype(BTreeMap<String, String>);
+
+    #[derive(Debug, PartialEq, Serialize, Deserialize)]
+    struct Struct {
+        f: u8,
+    }
+
+    #[derive(Debug, PartialEq, Serialize, Deserialize)]
+    #[serde(tag = "type")]
+    enum InternallyTagged {
+        A {
+            a: u8,
+        },
+        B {
+            b: u8,
+        },
+        C,
+        D(BTreeMap<String, String>),
+        E(Newtype),
+        F(Struct),
+    }
+
+    assert_tokens(
+        &InternallyTagged::A { a: 1 },
+        &[
+            Token::StructStart("InternallyTagged", 2),
+
+            Token::StructSep,
+            Token::Str("type"),
+            Token::Str("A"),
+
+            Token::StructSep,
+            Token::Str("a"),
+            Token::U8(1),
+
+            Token::StructEnd,
+        ]
+    );
+
+    assert_tokens(
+        &InternallyTagged::B { b: 2 },
+        &[
+            Token::StructStart("InternallyTagged", 2),
+
+            Token::StructSep,
+            Token::Str("type"),
+            Token::Str("B"),
+
+            Token::StructSep,
+            Token::Str("b"),
+            Token::U8(2),
+
+            Token::StructEnd,
+        ]
+    );
+
+    assert_tokens(
+        &InternallyTagged::C,
+        &[
+            Token::StructStart("InternallyTagged", 1),
+
+            Token::StructSep,
+            Token::Str("type"),
+            Token::Str("C"),
+
+            Token::StructEnd,
+        ]
+    );
+
+    assert_tokens(
+        &InternallyTagged::D(BTreeMap::new()),
+        &[
+            Token::MapStart(Some(1)),
+
+            Token::MapSep,
+            Token::Str("type"),
+            Token::Str("D"),
+
+            Token::MapEnd,
+        ]
+    );
+
+    assert_tokens(
+        &InternallyTagged::E(Newtype(BTreeMap::new())),
+        &[
+            Token::MapStart(Some(1)),
+
+            Token::MapSep,
+            Token::Str("type"),
+            Token::Str("E"),
+
+            Token::MapEnd,
+        ]
+    );
+
+    assert_tokens(
+        &InternallyTagged::F(Struct { f: 6 }),
+        &[
+            Token::StructStart("Struct", 2),
+
+            Token::StructSep,
+            Token::Str("type"),
+            Token::Str("F"),
+
+            Token::StructSep,
+            Token::Str("f"),
+            Token::U8(6),
+
+            Token::StructEnd,
+        ]
+    );
+
+    assert_de_tokens_error::<InternallyTagged>(
+        &[
+            Token::MapStart(Some(0)),
+            Token::MapEnd,
+        ],
+        Error::Message("missing field `type`".to_owned()),
+    );
+
+    assert_de_tokens_error::<InternallyTagged>(
+        &[
+            Token::MapStart(Some(1)),
+
+            Token::MapSep,
+            Token::Str("type"),
+            Token::Str("Z"),
+
+            Token::MapEnd,
+        ],
+        Error::Message("unknown variant `Z`, expected one of `A`, `B`, `C`, `D`, `E`, `F`".to_owned()),
+    );
+}
+
+#[test]
+fn test_adjacently_tagged_enum() {
+    #[derive(Debug, PartialEq, Serialize, Deserialize)]
+    #[serde(tag = "t", content = "c")]
+    enum AdjacentlyTagged<T> {
+        Unit,
+        Newtype(T),
+        Tuple(u8, u8),
+        Struct { f: u8 },
+    }
+
+    // unit with no content
+    assert_tokens(
+        &AdjacentlyTagged::Unit::<u8>,
+        &[
+            Token::StructStart("AdjacentlyTagged", 1),
+
+            Token::StructSep,
+            Token::Str("t"),
+            Token::Str("Unit"),
+
+            Token::StructEnd,
+        ]
+    );
+
+    // unit with tag first
+    assert_de_tokens(
+        &AdjacentlyTagged::Unit::<u8>,
+        &[
+            Token::StructStart("AdjacentlyTagged", 1),
+
+            Token::StructSep,
+            Token::Str("t"),
+            Token::Str("Unit"),
+
+            Token::StructSep,
+            Token::Str("c"),
+            Token::Unit,
+
+            Token::StructEnd,
+        ]
+    );
+
+    // unit with content first
+    assert_de_tokens(
+        &AdjacentlyTagged::Unit::<u8>,
+        &[
+            Token::StructStart("AdjacentlyTagged", 1),
+
+            Token::StructSep,
+            Token::Str("c"),
+            Token::Unit,
+
+            Token::StructSep,
+            Token::Str("t"),
+            Token::Str("Unit"),
+
+            Token::StructEnd,
+        ]
+    );
+
+    // newtype with tag first
+    assert_tokens(
+        &AdjacentlyTagged::Newtype::<u8>(1),
+        &[
+            Token::StructStart("AdjacentlyTagged", 2),
+
+            Token::StructSep,
+            Token::Str("t"),
+            Token::Str("Newtype"),
+
+            Token::StructSep,
+            Token::Str("c"),
+            Token::U8(1),
+
+            Token::StructEnd,
+        ]
+    );
+
+    // newtype with content first
+    assert_de_tokens(
+        &AdjacentlyTagged::Newtype::<u8>(1),
+        &[
+            Token::StructStart("AdjacentlyTagged", 2),
+
+            Token::StructSep,
+            Token::Str("c"),
+            Token::U8(1),
+
+            Token::StructSep,
+            Token::Str("t"),
+            Token::Str("Newtype"),
+
+            Token::StructEnd,
+        ]
+    );
+
+    // tuple with tag first
+    assert_tokens(
+        &AdjacentlyTagged::Tuple::<u8>(1, 1),
+        &[
+            Token::StructStart("AdjacentlyTagged", 2),
+
+            Token::StructSep,
+            Token::Str("t"),
+            Token::Str("Tuple"),
+
+            Token::StructSep,
+            Token::Str("c"),
+            Token::TupleStart(2),
+            Token::TupleSep,
+            Token::U8(1),
+            Token::TupleSep,
+            Token::U8(1),
+            Token::TupleEnd,
+
+            Token::StructEnd,
+        ]
+    );
+
+    // tuple with content first
+    assert_de_tokens(
+        &AdjacentlyTagged::Tuple::<u8>(1, 1),
+        &[
+            Token::StructStart("AdjacentlyTagged", 2),
+
+            Token::StructSep,
+            Token::Str("c"),
+            Token::TupleStart(2),
+            Token::TupleSep,
+            Token::U8(1),
+            Token::TupleSep,
+            Token::U8(1),
+            Token::TupleEnd,
+
+            Token::StructSep,
+            Token::Str("t"),
+            Token::Str("Tuple"),
+
+            Token::StructEnd,
+        ]
+    );
+
+    // struct with tag first
+    assert_tokens(
+        &AdjacentlyTagged::Struct::<u8> { f: 1 },
+        &[
+            Token::StructStart("AdjacentlyTagged", 2),
+
+            Token::StructSep,
+            Token::Str("t"),
+            Token::Str("Struct"),
+
+            Token::StructSep,
+            Token::Str("c"),
+            Token::StructStart("Struct", 1),
+            Token::StructSep,
+            Token::Str("f"),
+            Token::U8(1),
+            Token::StructEnd,
+
+            Token::StructEnd,
+        ]
+    );
+
+    // struct with content first
+    assert_de_tokens(
+        &AdjacentlyTagged::Struct::<u8> { f: 1 },
+        &[
+            Token::StructStart("AdjacentlyTagged", 2),
+
+            Token::StructSep,
+            Token::Str("c"),
+            Token::StructStart("Struct", 1),
+            Token::StructSep,
+            Token::Str("f"),
+            Token::U8(1),
+            Token::StructEnd,
+
+            Token::StructSep,
+            Token::Str("t"),
+            Token::Str("Struct"),
+
+            Token::StructEnd,
+        ]
+    );
+}
+
+#[test]
+fn test_enum_in_internally_tagged_enum() {
+    #[derive(Debug, PartialEq, Serialize, Deserialize)]
+    #[serde(tag = "type")]
+    enum Outer {
+        Inner(Inner),
+    }
+
+    #[derive(Debug, PartialEq, Serialize, Deserialize)]
+    enum Inner {
+        Unit,
+        Newtype(u8),
+        Tuple(u8, u8),
+        Struct { f: u8 },
+    }
+
+    assert_tokens(
+        &Outer::Inner(Inner::Unit),
+        &[
+            Token::MapStart(Some(2)),
+
+            Token::MapSep,
+            Token::Str("type"),
+            Token::Str("Inner"),
+
+            Token::MapSep,
+            Token::Str("Unit"),
+            Token::Unit,
+
+            Token::MapEnd,
+        ]
+    );
+
+    assert_tokens(
+        &Outer::Inner(Inner::Newtype(1)),
+        &[
+            Token::MapStart(Some(2)),
+
+            Token::MapSep,
+            Token::Str("type"),
+            Token::Str("Inner"),
+
+            Token::MapSep,
+            Token::Str("Newtype"),
+            Token::U8(1),
+
+            Token::MapEnd,
+        ]
+    );
+
+    assert_tokens(
+        &Outer::Inner(Inner::Tuple(1, 1)),
+        &[
+            Token::MapStart(Some(2)),
+
+            Token::MapSep,
+            Token::Str("type"),
+            Token::Str("Inner"),
+
+            Token::MapSep,
+            Token::Str("Tuple"),
+            Token::TupleStructStart("Tuple", 2),
+            Token::TupleStructSep,
+            Token::U8(1),
+            Token::TupleStructSep,
+            Token::U8(1),
+            Token::TupleStructEnd,
+
+            Token::MapEnd,
+        ]
+    );
+
+    assert_tokens(
+        &Outer::Inner(Inner::Struct { f: 1 }),
+        &[
+            Token::MapStart(Some(2)),
+
+            Token::MapSep,
+            Token::Str("type"),
+            Token::Str("Inner"),
+
+            Token::MapSep,
+            Token::Str("Struct"),
+            Token::StructStart("Struct", 1),
+            Token::StructSep,
+            Token::Str("f"),
+            Token::U8(1),
+            Token::StructEnd,
+
+            Token::MapEnd,
+        ]
+    );
+}
+
+#[test]
+fn test_enum_in_untagged_enum() {
+    #[derive(Debug, PartialEq, Serialize, Deserialize)]
+    #[serde(untagged)]
+    enum Outer {
+        Inner(Inner),
+    }
+
+    #[derive(Debug, PartialEq, Serialize, Deserialize)]
+    enum Inner {
+        Unit,
+        Newtype(u8),
+        Tuple(u8, u8),
+        Struct { f: u8 },
+    }
+
+    assert_tokens(
+        &Outer::Inner(Inner::Unit),
+        &[
+            Token::EnumUnit("Inner", "Unit"),
+        ]
+    );
+
+    assert_tokens(
+        &Outer::Inner(Inner::Newtype(1)),
+        &[
+            Token::EnumNewType("Inner", "Newtype"),
+            Token::U8(1),
+        ]
+    );
+
+    assert_tokens(
+        &Outer::Inner(Inner::Tuple(1, 1)),
+        &[
+            Token::EnumSeqStart("Inner", "Tuple", 2),
+
+            Token::EnumSeqSep,
+            Token::U8(1),
+            Token::EnumSeqSep,
+            Token::U8(1),
+
+            Token::EnumSeqEnd,
+        ]
+    );
+
+    assert_tokens(
+        &Outer::Inner(Inner::Struct { f: 1 }),
+        &[
+            Token::EnumMapStart("Inner", "Struct", 1),
+
+            Token::EnumMapSep,
+            Token::Str("f"),
+            Token::U8(1),
+
+            Token::EnumMapEnd,
+        ]
+    );
+}
+
+#[test]
+fn test_rename_all() {
+    #[derive(Serialize, Deserialize, Debug, PartialEq)]
+    #[serde(rename_all = "snake_case")]
+    enum E {
+        #[serde(rename_all = "camelCase")]
+        Serialize {
+            serialize: bool,
+            serialize_seq: bool,
+        },
+        #[serde(rename_all = "kebab-case")]
+        SerializeSeq {
+            serialize: bool,
+            serialize_seq: bool,
+        },
+        #[serde(rename_all = "SCREAMING_SNAKE_CASE")]
+        SerializeMap {
+            serialize: bool,
+            serialize_seq: bool,
+        },
+    }
+
+    #[derive(Serialize, Deserialize, Debug, PartialEq)]
+    #[serde(rename_all = "PascalCase")]
+    struct S {
+        serialize: bool,
+        serialize_seq: bool,
+    }
+
+    assert_tokens(
+        &E::Serialize { serialize: true, serialize_seq: true },
+        &[
+            Token::EnumMapStart("E", "serialize", 2),
+            Token::EnumMapSep,
+            Token::Str("serialize"),
+            Token::Bool(true),
+            Token::EnumMapSep,
+            Token::Str("serializeSeq"),
+            Token::Bool(true),
+            Token::EnumMapEnd,
+        ]
+    );
+
+    assert_tokens(
+        &E::SerializeSeq { serialize: true, serialize_seq: true },
+        &[
+            Token::EnumMapStart("E", "serialize_seq", 2),
+            Token::EnumMapSep,
+            Token::Str("serialize"),
+            Token::Bool(true),
+            Token::EnumMapSep,
+            Token::Str("serialize-seq"),
+            Token::Bool(true),
+            Token::EnumMapEnd,
+        ]
+    );
+
+    assert_tokens(
+        &E::SerializeMap { serialize: true, serialize_seq: true },
+        &[
+            Token::EnumMapStart("E", "serialize_map", 2),
+            Token::EnumMapSep,
+            Token::Str("SERIALIZE"),
+            Token::Bool(true),
+            Token::EnumMapSep,
+            Token::Str("SERIALIZE_SEQ"),
+            Token::Bool(true),
+            Token::EnumMapEnd,
+        ]
+    );
+
+    assert_tokens(
+        &S { serialize: true, serialize_seq: true },
+        &[
+            Token::StructStart("S", 2),
+            Token::StructSep,
+            Token::Str("Serialize"),
+            Token::Bool(true),
+            Token::StructSep,
+            Token::Str("SerializeSeq"),
+            Token::Bool(true),
+            Token::StructEnd,
+        ]
+    );
+}

test_suite/tests/test_ser.rs

@@ -1,8 +1,14 @@
+#[macro_use]
+extern crate serde_derive;
+
 use std::collections::{BTreeMap, HashMap, HashSet};
 use std::net;
 use std::path::{Path, PathBuf};
 use std::str;
 use std::time::Duration;
+use std::ffi::CString;
+
+extern crate serde;
 
 extern crate serde_test;
 use self::serde_test::{
@@ -18,6 +24,9 @@ use self::fnv::FnvHasher;
 #[cfg(feature = "unstable")]
 use serde::ser::iterator;
 
+#[macro_use]
+mod macros;
+
 //////////////////////////////////////////////////////////////////////////
 
 #[derive(Serialize)]
@@ -381,6 +390,16 @@ declare_tests! {
             Token::Str("/usr/local/lib"),
         ],
     }
+    test_cstring {
+        CString::new("abc").unwrap() => &[
+            Token::Bytes(b"abc"),
+        ],
+    }
+    test_cstr {
+        (&*CString::new("abc").unwrap()) => &[
+            Token::Bytes(b"abc"),
+        ],
+    }
 }