Release 1.0.42

Mark error construction as cold code

serde/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "serde"
-version = "1.0.38" # remember to update html_root_url
+version = "1.0.42" # remember to update html_root_url
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>", "David Tolnay <dtolnay@gmail.com>"]
 license = "MIT/Apache-2.0"
 description = "A generic serialization/deserialization framework"

serde/src/de/mod.rs

@@ -196,6 +196,7 @@ macro_rules! declare_error_trait {
             /// For example if we try to deserialize a String out of a JSON file
             /// containing an integer, the unexpected type is the integer and the
             /// expected type is the string.
+            #[cold]
             fn invalid_type(unexp: Unexpected, exp: &Expected) -> Self {
                 Error::custom(format_args!("invalid type: {}, expected {}", unexp, exp))
             }
@@ -213,6 +214,7 @@ macro_rules! declare_error_trait {
             /// For example if we try to deserialize a String out of some binary data
             /// that is not valid UTF-8, the unexpected value is the bytes and the
             /// expected value is a string.
+            #[cold]
             fn invalid_value(unexp: Unexpected, exp: &Expected) -> Self {
                 Error::custom(format_args!("invalid value: {}, expected {}", unexp, exp))
             }
@@ -226,12 +228,14 @@ macro_rules! declare_error_trait {
             /// The `exp` argument provides information about what data was being
             /// expected. For example `exp` might say that a tuple of size 6 was
             /// expected.
+            #[cold]
             fn invalid_length(len: usize, exp: &Expected) -> Self {
                 Error::custom(format_args!("invalid length {}, expected {}", len, exp))
             }
 
             /// Raised when a `Deserialize` enum type received a variant with an
             /// unrecognized name.
+            #[cold]
             fn unknown_variant(variant: &str, expected: &'static [&'static str]) -> Self {
                 if expected.is_empty() {
                     Error::custom(format_args!("unknown variant `{}`, there are no variants",
@@ -245,6 +249,7 @@ macro_rules! declare_error_trait {
 
             /// Raised when a `Deserialize` struct type received a field with an
             /// unrecognized name.
+            #[cold]
             fn unknown_field(field: &str, expected: &'static [&'static str]) -> Self {
                 if expected.is_empty() {
                     Error::custom(format_args!("unknown field `{}`, there are no fields",
@@ -259,12 +264,14 @@ macro_rules! declare_error_trait {
             /// Raised when a `Deserialize` struct type expected to receive a required
             /// field with a particular name but that field was not present in the
             /// input.
+            #[cold]
             fn missing_field(field: &'static str) -> Self {
                 Error::custom(format_args!("missing field `{}`", field))
             }
 
             /// Raised when a `Deserialize` struct type received more than one of the
             /// same field.
+            #[cold]
             fn duplicate_field(field: &'static str) -> Self {
                 Error::custom(format_args!("duplicate field `{}`", field))
             }

serde/src/de/value.rs

@@ -58,6 +58,7 @@ type ErrorImpl = ();
 
 impl de::Error for Error {
     #[cfg(any(feature = "std", feature = "alloc"))]
+    #[cold]
     fn custom<T>(msg: T) -> Self
     where
         T: Display,
@@ -68,6 +69,7 @@ impl de::Error for Error {
     }
 
     #[cfg(not(any(feature = "std", feature = "alloc")))]
+    #[cold]
     fn custom<T>(msg: T) -> Self
     where
         T: Display,
@@ -78,6 +80,7 @@ impl de::Error for Error {
 }
 
 impl ser::Error for Error {
+    #[cold]
     fn custom<T>(msg: T) -> Self
     where
         T: Display,
@@ -652,11 +655,8 @@ where
 {
     /// 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;
-        }
+    pub fn end(self) -> Result<(), E> {
+        let remaining = self.iter.count();
         if remaining == 0 {
             Ok(())
         } else {
@@ -849,11 +849,8 @@ where
 {
     /// 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;
-        }
+    pub fn end(self) -> Result<(), E> {
+        let remaining = self.iter.count();
         if remaining == 0 {
             Ok(())
         } else {

serde/src/lib.rs

@@ -79,7 +79,7 @@
 ////////////////////////////////////////////////////////////////////////////////
 
 // Serde types in rustdoc of other crates get linked to here.
-#![doc(html_root_url = "https://docs.rs/serde/1.0.38")]
+#![doc(html_root_url = "https://docs.rs/serde/1.0.42")]
 // Support using Serde without the standard library!
 #![cfg_attr(not(feature = "std"), no_std)]
 // Unstable functionality only if the user asks for it. For tracking and

serde/src/private/de.rs

@@ -229,8 +229,8 @@ mod content {
     use lib::*;
 
     use super::size_hint;
-    use de::{self, Deserialize, DeserializeSeed, Deserializer, EnumAccess, MapAccess, SeqAccess,
-             Unexpected, Visitor};
+    use de::{self, Deserialize, DeserializeSeed, Deserializer, EnumAccess, Expected, MapAccess,
+             SeqAccess, Unexpected, Visitor};
 
     /// Used from generated code to buffer the contents of the Deserializer when
     /// deserializing untagged enums and internally tagged enums.
@@ -277,6 +277,7 @@ mod content {
             }
         }
 
+        #[cold]
         fn unexpected(&self) -> Unexpected {
             match *self {
                 Content::Bool(b) => Unexpected::Bool(b),
@@ -1013,6 +1014,62 @@ mod content {
         err: PhantomData<E>,
     }
 
+    impl<'de, E> ContentDeserializer<'de, E>
+    where
+        E: de::Error,
+    {
+        #[cold]
+        fn invalid_type(self, exp: &Expected) -> E {
+            de::Error::invalid_type(self.content.unexpected(), exp)
+        }
+
+        fn deserialize_integer<V>(self, visitor: V) -> Result<V::Value, E>
+        where
+            V: Visitor<'de>,
+        {
+            match self.content {
+                Content::U8(v) => visitor.visit_u8(v),
+                Content::U16(v) => visitor.visit_u16(v),
+                Content::U32(v) => visitor.visit_u32(v),
+                Content::U64(v) => visitor.visit_u64(v),
+                Content::I8(v) => visitor.visit_i8(v),
+                Content::I16(v) => visitor.visit_i16(v),
+                Content::I32(v) => visitor.visit_i32(v),
+                Content::I64(v) => visitor.visit_i64(v),
+                _ => Err(self.invalid_type(&visitor)),
+            }
+        }
+    }
+
+    fn visit_content_seq<'de, V, E>(content: Vec<Content<'de>>, visitor: V) -> Result<V::Value, E>
+    where
+        V: Visitor<'de>,
+        E: de::Error,
+    {
+        let seq = content.into_iter().map(ContentDeserializer::new);
+        let mut seq_visitor = de::value::SeqDeserializer::new(seq);
+        let value = try!(visitor.visit_seq(&mut seq_visitor));
+        try!(seq_visitor.end());
+        Ok(value)
+    }
+
+    fn visit_content_map<'de, V, E>(
+        content: Vec<(Content<'de>, Content<'de>)>,
+        visitor: V,
+    ) -> Result<V::Value, E>
+    where
+        V: Visitor<'de>,
+        E: de::Error,
+    {
+        let map = content
+            .into_iter()
+            .map(|(k, v)| (ContentDeserializer::new(k), ContentDeserializer::new(v)));
+        let mut map_visitor = de::value::MapDeserializer::new(map);
+        let value = try!(visitor.visit_map(&mut map_visitor));
+        try!(map_visitor.end());
+        Ok(value)
+    }
+
     /// Used when deserializing an internally tagged enum because the content will
     /// be used exactly once.
     impl<'de, E> Deserializer<'de> for ContentDeserializer<'de, E>
@@ -1046,21 +1103,152 @@ mod content {
                 Content::None => visitor.visit_none(),
                 Content::Some(v) => visitor.visit_some(ContentDeserializer::new(*v)),
                 Content::Newtype(v) => visitor.visit_newtype_struct(ContentDeserializer::new(*v)),
-                Content::Seq(v) => {
-                    let seq = v.into_iter().map(ContentDeserializer::new);
-                    let mut seq_visitor = de::value::SeqDeserializer::new(seq);
-                    let value = try!(visitor.visit_seq(&mut seq_visitor));
-                    try!(seq_visitor.end());
-                    Ok(value)
-                }
-                Content::Map(v) => {
-                    let map = v.into_iter()
-                        .map(|(k, v)| (ContentDeserializer::new(k), ContentDeserializer::new(v)));
-                    let mut map_visitor = de::value::MapDeserializer::new(map);
-                    let value = try!(visitor.visit_map(&mut map_visitor));
-                    try!(map_visitor.end());
-                    Ok(value)
-                }
+                Content::Seq(v) => visit_content_seq(v, visitor),
+                Content::Map(v) => visit_content_map(v, visitor),
+            }
+        }
+
+        fn deserialize_bool<V>(self, visitor: V) -> Result<V::Value, Self::Error>
+        where
+            V: Visitor<'de>,
+        {
+            match self.content {
+                Content::Bool(v) => visitor.visit_bool(v),
+                _ => Err(self.invalid_type(&visitor)),
+            }
+        }
+
+        fn deserialize_i8<V>(self, visitor: V) -> Result<V::Value, Self::Error>
+        where
+            V: Visitor<'de>,
+        {
+            self.deserialize_integer(visitor)
+        }
+
+        fn deserialize_i16<V>(self, visitor: V) -> Result<V::Value, Self::Error>
+        where
+            V: Visitor<'de>,
+        {
+            self.deserialize_integer(visitor)
+        }
+
+        fn deserialize_i32<V>(self, visitor: V) -> Result<V::Value, Self::Error>
+        where
+            V: Visitor<'de>,
+        {
+            self.deserialize_integer(visitor)
+        }
+
+        fn deserialize_i64<V>(self, visitor: V) -> Result<V::Value, Self::Error>
+        where
+            V: Visitor<'de>,
+        {
+            self.deserialize_integer(visitor)
+        }
+
+        fn deserialize_u8<V>(self, visitor: V) -> Result<V::Value, Self::Error>
+        where
+            V: Visitor<'de>,
+        {
+            self.deserialize_integer(visitor)
+        }
+
+        fn deserialize_u16<V>(self, visitor: V) -> Result<V::Value, Self::Error>
+        where
+            V: Visitor<'de>,
+        {
+            self.deserialize_integer(visitor)
+        }
+
+        fn deserialize_u32<V>(self, visitor: V) -> Result<V::Value, Self::Error>
+        where
+            V: Visitor<'de>,
+        {
+            self.deserialize_integer(visitor)
+        }
+
+        fn deserialize_u64<V>(self, visitor: V) -> Result<V::Value, Self::Error>
+        where
+            V: Visitor<'de>,
+        {
+            self.deserialize_integer(visitor)
+        }
+
+        fn deserialize_f32<V>(self, visitor: V) -> Result<V::Value, Self::Error>
+        where
+            V: Visitor<'de>,
+        {
+            match self.content {
+                Content::F32(v) => visitor.visit_f32(v),
+                Content::F64(v) => visitor.visit_f64(v),
+                Content::U64(v) => visitor.visit_u64(v),
+                Content::I64(v) => visitor.visit_i64(v),
+                _ => Err(self.invalid_type(&visitor)),
+            }
+        }
+
+        fn deserialize_f64<V>(self, visitor: V) -> Result<V::Value, Self::Error>
+        where
+            V: Visitor<'de>,
+        {
+            match self.content {
+                Content::F64(v) => visitor.visit_f64(v),
+                Content::U64(v) => visitor.visit_u64(v),
+                Content::I64(v) => visitor.visit_i64(v),
+                _ => Err(self.invalid_type(&visitor)),
+            }
+        }
+
+        fn deserialize_char<V>(self, visitor: V) -> Result<V::Value, Self::Error>
+        where
+            V: Visitor<'de>,
+        {
+            match self.content {
+                Content::Char(v) => visitor.visit_char(v),
+                Content::String(v) => visitor.visit_string(v),
+                Content::Str(v) => visitor.visit_borrowed_str(v),
+                _ => Err(self.invalid_type(&visitor)),
+            }
+        }
+
+        fn deserialize_str<V>(self, visitor: V) -> Result<V::Value, Self::Error>
+        where
+            V: Visitor<'de>,
+        {
+            self.deserialize_string(visitor)
+        }
+
+        fn deserialize_string<V>(self, visitor: V) -> Result<V::Value, Self::Error>
+        where
+            V: Visitor<'de>,
+        {
+            match self.content {
+                Content::String(v) => visitor.visit_string(v),
+                Content::Str(v) => visitor.visit_borrowed_str(v),
+                Content::ByteBuf(v) => visitor.visit_byte_buf(v),
+                Content::Bytes(v) => visitor.visit_borrowed_bytes(v),
+                _ => Err(self.invalid_type(&visitor)),
+            }
+        }
+
+        fn deserialize_bytes<V>(self, visitor: V) -> Result<V::Value, Self::Error>
+        where
+            V: Visitor<'de>,
+        {
+            self.deserialize_byte_buf(visitor)
+        }
+
+        fn deserialize_byte_buf<V>(self, visitor: V) -> Result<V::Value, Self::Error>
+        where
+            V: Visitor<'de>,
+        {
+            match self.content {
+                Content::String(v) => visitor.visit_string(v),
+                Content::Str(v) => visitor.visit_borrowed_str(v),
+                Content::ByteBuf(v) => visitor.visit_byte_buf(v),
+                Content::Bytes(v) => visitor.visit_borrowed_bytes(v),
+                Content::Seq(v) => visit_content_seq(v, visitor),
+                _ => Err(self.invalid_type(&visitor)),
             }
         }
 
@@ -1076,6 +1264,44 @@ mod content {
             }
         }
 
+        fn deserialize_unit<V>(self, visitor: V) -> Result<V::Value, Self::Error>
+        where
+            V: Visitor<'de>,
+        {
+            match self.content {
+                Content::Unit => visitor.visit_unit(),
+                _ => Err(self.invalid_type(&visitor)),
+            }
+        }
+
+        fn deserialize_unit_struct<V>(
+            self,
+            _name: &'static str,
+            visitor: V,
+        ) -> Result<V::Value, Self::Error>
+        where
+            V: Visitor<'de>,
+        {
+            match self.content {
+                // As a special case, allow deserializing untagged newtype
+                // variant containing unit struct.
+                //
+                //     #[derive(Deserialize)]
+                //     struct Info;
+                //
+                //     #[derive(Deserialize)]
+                //     #[serde(tag = "topic")]
+                //     enum Message {
+                //         Info(Info),
+                //     }
+                //
+                // We want {"topic":"Info"} to deserialize even though
+                // ordinarily unit structs do not deserialize from empty map.
+                Content::Map(ref v) if v.is_empty() => visitor.visit_unit(),
+                _ => self.deserialize_any(visitor),
+            }
+        }
+
         fn deserialize_newtype_struct<V>(
             self,
             _name: &str,
@@ -1087,6 +1313,61 @@ mod content {
             visitor.visit_newtype_struct(self)
         }
 
+        fn deserialize_seq<V>(self, visitor: V) -> Result<V::Value, Self::Error>
+        where
+            V: Visitor<'de>,
+        {
+            match self.content {
+                Content::Seq(v) => visit_content_seq(v, visitor),
+                _ => Err(self.invalid_type(&visitor)),
+            }
+        }
+
+        fn deserialize_tuple<V>(self, _len: usize, visitor: V) -> Result<V::Value, Self::Error>
+        where
+            V: Visitor<'de>,
+        {
+            self.deserialize_seq(visitor)
+        }
+
+        fn deserialize_tuple_struct<V>(
+            self,
+            _name: &'static str,
+            _len: usize,
+            visitor: V,
+        ) -> Result<V::Value, Self::Error>
+        where
+            V: Visitor<'de>,
+        {
+            self.deserialize_seq(visitor)
+        }
+
+        fn deserialize_map<V>(self, visitor: V) -> Result<V::Value, Self::Error>
+        where
+            V: Visitor<'de>,
+        {
+            match self.content {
+                Content::Map(v) => visit_content_map(v, visitor),
+                _ => Err(self.invalid_type(&visitor)),
+            }
+        }
+
+        fn deserialize_struct<V>(
+            self,
+            _name: &'static str,
+            _fields: &'static [&'static str],
+            visitor: V,
+        ) -> Result<V::Value, Self::Error>
+        where
+            V: Visitor<'de>,
+        {
+            match self.content {
+                Content::Seq(v) => visit_content_seq(v, visitor),
+                Content::Map(v) => visit_content_map(v, visitor),
+                _ => Err(self.invalid_type(&visitor)),
+            }
+        }
+
         fn deserialize_enum<V>(
             self,
             _name: &str,
@@ -1129,38 +1410,23 @@ mod content {
             visitor.visit_enum(EnumDeserializer::new(variant, value))
         }
 
-        fn deserialize_unit_struct<V>(
-            self,
-            _name: &'static str,
-            visitor: V,
-        ) -> Result<V::Value, Self::Error>
+        fn deserialize_identifier<V>(self, visitor: V) -> Result<V::Value, Self::Error>
         where
             V: Visitor<'de>,
         {
             match self.content {
-                // As a special case, allow deserializing untagged newtype
-                // variant containing unit struct.
-                //
-                //     #[derive(Deserialize)]
-                //     struct Info;
-                //
-                //     #[derive(Deserialize)]
-                //     #[serde(tag = "topic")]
-                //     enum Message {
-                //         Info(Info),
-                //     }
-                //
-                // We want {"topic":"Info"} to deserialize even though
-                // ordinarily unit structs do not deserialize from empty map.
-                Content::Map(ref v) if v.is_empty() => visitor.visit_unit(),
-                _ => self.deserialize_any(visitor),
+                Content::String(v) => visitor.visit_string(v),
+                Content::Str(v) => visitor.visit_borrowed_str(v),
+                _ => Err(self.invalid_type(&visitor)),
             }
         }
 
-        forward_to_deserialize_any! {
-            bool i8 i16 i32 i64 u8 u16 u32 u64 f32 f64 char str string bytes
-            byte_buf unit seq tuple tuple_struct map struct identifier
-            ignored_any
+        fn deserialize_ignored_any<V>(self, visitor: V) -> Result<V::Value, Self::Error>
+        where
+            V: Visitor<'de>,
+        {
+            drop(self);
+            visitor.visit_unit()
         }
     }
 
@@ -1452,6 +1718,68 @@ mod content {
         err: PhantomData<E>,
     }
 
+    impl<'a, 'de, E> ContentRefDeserializer<'a, 'de, E>
+    where
+        E: de::Error,
+    {
+        #[cold]
+        fn invalid_type(self, exp: &Expected) -> E {
+            de::Error::invalid_type(self.content.unexpected(), exp)
+        }
+
+        fn deserialize_integer<V>(self, visitor: V) -> Result<V::Value, E>
+        where
+            V: Visitor<'de>,
+        {
+            match *self.content {
+                Content::U8(v) => visitor.visit_u8(v),
+                Content::U16(v) => visitor.visit_u16(v),
+                Content::U32(v) => visitor.visit_u32(v),
+                Content::U64(v) => visitor.visit_u64(v),
+                Content::I8(v) => visitor.visit_i8(v),
+                Content::I16(v) => visitor.visit_i16(v),
+                Content::I32(v) => visitor.visit_i32(v),
+                Content::I64(v) => visitor.visit_i64(v),
+                _ => Err(self.invalid_type(&visitor)),
+            }
+        }
+    }
+
+    fn visit_content_seq_ref<'a, 'de, V, E>(
+        content: &'a [Content<'de>],
+        visitor: V,
+    ) -> Result<V::Value, E>
+    where
+        V: Visitor<'de>,
+        E: de::Error,
+    {
+        let seq = content.into_iter().map(ContentRefDeserializer::new);
+        let mut seq_visitor = de::value::SeqDeserializer::new(seq);
+        let value = try!(visitor.visit_seq(&mut seq_visitor));
+        try!(seq_visitor.end());
+        Ok(value)
+    }
+
+    fn visit_content_map_ref<'a, 'de, V, E>(
+        content: &'a [(Content<'de>, Content<'de>)],
+        visitor: V,
+    ) -> Result<V::Value, E>
+    where
+        V: Visitor<'de>,
+        E: de::Error,
+    {
+        let map = content.into_iter().map(|&(ref k, ref v)| {
+            (
+                ContentRefDeserializer::new(k),
+                ContentRefDeserializer::new(v),
+            )
+        });
+        let mut map_visitor = de::value::MapDeserializer::new(map);
+        let value = try!(visitor.visit_map(&mut map_visitor));
+        try!(map_visitor.end());
+        Ok(value)
+    }
+
     /// Used when deserializing an untagged enum because the content may need to be
     /// used more than once.
     impl<'de, 'a, E> Deserializer<'de> for ContentRefDeserializer<'a, 'de, E>
@@ -1487,28 +1815,155 @@ mod content {
                 Content::Newtype(ref v) => {
                     visitor.visit_newtype_struct(ContentRefDeserializer::new(v))
                 }
-                Content::Seq(ref v) => {
-                    let seq = v.into_iter().map(ContentRefDeserializer::new);
-                    let mut seq_visitor = de::value::SeqDeserializer::new(seq);
-                    let value = try!(visitor.visit_seq(&mut seq_visitor));
-                    try!(seq_visitor.end());
-                    Ok(value)
-                }
-                Content::Map(ref v) => {
-                    let map = v.into_iter().map(|&(ref k, ref v)| {
-                        (
-                            ContentRefDeserializer::new(k),
-                            ContentRefDeserializer::new(v),
-                        )
-                    });
-                    let mut map_visitor = de::value::MapDeserializer::new(map);
-                    let value = try!(visitor.visit_map(&mut map_visitor));
-                    try!(map_visitor.end());
-                    Ok(value)
-                }
+                Content::Seq(ref v) => visit_content_seq_ref(v, visitor),
+                Content::Map(ref v) => visit_content_map_ref(v, visitor),
             }
         }
 
+        fn deserialize_bool<V>(self, visitor: V) -> Result<V::Value, Self::Error>
+        where
+            V: Visitor<'de>,
+        {
+            match *self.content {
+                Content::Bool(v) => visitor.visit_bool(v),
+                _ => Err(self.invalid_type(&visitor)),
+            }
+        }
+
+        fn deserialize_i8<V>(self, visitor: V) -> Result<V::Value, Self::Error>
+        where
+            V: Visitor<'de>,
+        {
+            self.deserialize_integer(visitor)
+        }
+
+        fn deserialize_i16<V>(self, visitor: V) -> Result<V::Value, Self::Error>
+        where
+            V: Visitor<'de>,
+        {
+            self.deserialize_integer(visitor)
+        }
+
+        fn deserialize_i32<V>(self, visitor: V) -> Result<V::Value, Self::Error>
+        where
+            V: Visitor<'de>,
+        {
+            self.deserialize_integer(visitor)
+        }
+
+        fn deserialize_i64<V>(self, visitor: V) -> Result<V::Value, Self::Error>
+        where
+            V: Visitor<'de>,
+        {
+            self.deserialize_integer(visitor)
+        }
+
+        fn deserialize_u8<V>(self, visitor: V) -> Result<V::Value, Self::Error>
+        where
+            V: Visitor<'de>,
+        {
+            self.deserialize_integer(visitor)
+        }
+
+        fn deserialize_u16<V>(self, visitor: V) -> Result<V::Value, Self::Error>
+        where
+            V: Visitor<'de>,
+        {
+            self.deserialize_integer(visitor)
+        }
+
+        fn deserialize_u32<V>(self, visitor: V) -> Result<V::Value, Self::Error>
+        where
+            V: Visitor<'de>,
+        {
+            self.deserialize_integer(visitor)
+        }
+
+        fn deserialize_u64<V>(self, visitor: V) -> Result<V::Value, Self::Error>
+        where
+            V: Visitor<'de>,
+        {
+            self.deserialize_integer(visitor)
+        }
+
+        fn deserialize_f32<V>(self, visitor: V) -> Result<V::Value, Self::Error>
+        where
+            V: Visitor<'de>,
+        {
+            match *self.content {
+                Content::F32(v) => visitor.visit_f32(v),
+                Content::F64(v) => visitor.visit_f64(v),
+                Content::U64(v) => visitor.visit_u64(v),
+                Content::I64(v) => visitor.visit_i64(v),
+                _ => Err(self.invalid_type(&visitor)),
+            }
+        }
+
+        fn deserialize_f64<V>(self, visitor: V) -> Result<V::Value, Self::Error>
+        where
+            V: Visitor<'de>,
+        {
+            match *self.content {
+                Content::F64(v) => visitor.visit_f64(v),
+                Content::U64(v) => visitor.visit_u64(v),
+                Content::I64(v) => visitor.visit_i64(v),
+                _ => Err(self.invalid_type(&visitor)),
+            }
+        }
+
+        fn deserialize_char<V>(self, visitor: V) -> Result<V::Value, Self::Error>
+        where
+            V: Visitor<'de>,
+        {
+            match *self.content {
+                Content::Char(v) => visitor.visit_char(v),
+                Content::String(ref v) => visitor.visit_str(v),
+                Content::Str(v) => visitor.visit_borrowed_str(v),
+                _ => Err(self.invalid_type(&visitor)),
+            }
+        }
+
+        fn deserialize_str<V>(self, visitor: V) -> Result<V::Value, Self::Error>
+        where
+            V: Visitor<'de>,
+        {
+            match *self.content {
+                Content::String(ref v) => visitor.visit_str(v),
+                Content::Str(v) => visitor.visit_borrowed_str(v),
+                Content::ByteBuf(ref v) => visitor.visit_bytes(v),
+                Content::Bytes(v) => visitor.visit_borrowed_bytes(v),
+                _ => Err(self.invalid_type(&visitor)),
+            }
+        }
+
+        fn deserialize_string<V>(self, visitor: V) -> Result<V::Value, Self::Error>
+        where
+            V: Visitor<'de>,
+        {
+            self.deserialize_str(visitor)
+        }
+
+        fn deserialize_bytes<V>(self, visitor: V) -> Result<V::Value, Self::Error>
+        where
+            V: Visitor<'de>,
+        {
+            match *self.content {
+                Content::String(ref v) => visitor.visit_str(v),
+                Content::Str(v) => visitor.visit_borrowed_str(v),
+                Content::ByteBuf(ref v) => visitor.visit_bytes(v),
+                Content::Bytes(v) => visitor.visit_borrowed_bytes(v),
+                Content::Seq(ref v) => visit_content_seq_ref(v, visitor),
+                _ => Err(self.invalid_type(&visitor)),
+            }
+        }
+
+        fn deserialize_byte_buf<V>(self, visitor: V) -> Result<V::Value, Self::Error>
+        where
+            V: Visitor<'de>,
+        {
+            self.deserialize_bytes(visitor)
+        }
+
         fn deserialize_option<V>(self, visitor: V) -> Result<V::Value, E>
         where
             V: Visitor<'de>,
@@ -1521,6 +1976,27 @@ mod content {
             }
         }
 
+        fn deserialize_unit<V>(self, visitor: V) -> Result<V::Value, Self::Error>
+        where
+            V: Visitor<'de>,
+        {
+            match *self.content {
+                Content::Unit => visitor.visit_unit(),
+                _ => Err(self.invalid_type(&visitor)),
+            }
+        }
+
+        fn deserialize_unit_struct<V>(
+            self,
+            _name: &'static str,
+            visitor: V,
+        ) -> Result<V::Value, Self::Error>
+        where
+            V: Visitor<'de>,
+        {
+            self.deserialize_unit(visitor)
+        }
+
         fn deserialize_newtype_struct<V>(self, _name: &str, visitor: V) -> Result<V::Value, E>
         where
             V: Visitor<'de>,
@@ -1528,6 +2004,61 @@ mod content {
             visitor.visit_newtype_struct(self)
         }
 
+        fn deserialize_seq<V>(self, visitor: V) -> Result<V::Value, Self::Error>
+        where
+            V: Visitor<'de>,
+        {
+            match *self.content {
+                Content::Seq(ref v) => visit_content_seq_ref(v, visitor),
+                _ => Err(self.invalid_type(&visitor)),
+            }
+        }
+
+        fn deserialize_tuple<V>(self, _len: usize, visitor: V) -> Result<V::Value, Self::Error>
+        where
+            V: Visitor<'de>,
+        {
+            self.deserialize_seq(visitor)
+        }
+
+        fn deserialize_tuple_struct<V>(
+            self,
+            _name: &'static str,
+            _len: usize,
+            visitor: V,
+        ) -> Result<V::Value, Self::Error>
+        where
+            V: Visitor<'de>,
+        {
+            self.deserialize_seq(visitor)
+        }
+
+        fn deserialize_map<V>(self, visitor: V) -> Result<V::Value, Self::Error>
+        where
+            V: Visitor<'de>,
+        {
+            match *self.content {
+                Content::Map(ref v) => visit_content_map_ref(v, visitor),
+                _ => Err(self.invalid_type(&visitor)),
+            }
+        }
+
+        fn deserialize_struct<V>(
+            self,
+            _name: &'static str,
+            _fields: &'static [&'static str],
+            visitor: V,
+        ) -> Result<V::Value, Self::Error>
+        where
+            V: Visitor<'de>,
+        {
+            match *self.content {
+                Content::Seq(ref v) => visit_content_seq_ref(v, visitor),
+                Content::Map(ref v) => visit_content_map_ref(v, visitor),
+                _ => Err(self.invalid_type(&visitor)),
+            }
+        }
+
         fn deserialize_enum<V>(
             self,
             _name: &str,
@@ -1574,10 +2105,22 @@ mod content {
             })
         }
 
-        forward_to_deserialize_any! {
-            bool i8 i16 i32 i64 u8 u16 u32 u64 f32 f64 char str string bytes
-            byte_buf unit unit_struct seq tuple tuple_struct map struct
-            identifier ignored_any
+        fn deserialize_identifier<V>(self, visitor: V) -> Result<V::Value, Self::Error>
+        where
+            V: Visitor<'de>,
+        {
+            match *self.content {
+                Content::String(ref v) => visitor.visit_str(v),
+                Content::Str(v) => visitor.visit_borrowed_str(v),
+                _ => Err(self.invalid_type(&visitor)),
+            }
+        }
+
+        fn deserialize_ignored_any<V>(self, visitor: V) -> Result<V::Value, Self::Error>
+        where
+            V: Visitor<'de>,
+        {
+            visitor.visit_unit()
         }
     }
 

serde_derive/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "serde_derive"
-version = "1.0.38" # remember to update html_root_url
+version = "1.0.42" # remember to update html_root_url
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>", "David Tolnay <dtolnay@gmail.com>"]
 license = "MIT/Apache-2.0"
 description = "Macros 1.1 implementation of #[derive(Serialize, Deserialize)]"

serde_derive/src/de.rs

@@ -16,6 +16,7 @@ use bound;
 use fragment::{Expr, Fragment, Match, Stmts};
 use internals::ast::{Container, Data, Field, Style, Variant};
 use internals::{self, attr};
+use try;
 
 use std::collections::BTreeSet;
 
@@ -36,10 +37,9 @@ pub fn expand_derive_deserialize(input: &syn::DeriveInput) -> Result<Tokens, Str
 
     let impl_block = if let Some(remote) = cont.attrs.remote() {
         let vis = &input.vis;
-        let fun = quote_spanned!(Span::call_site()=> deserialize);
         quote! {
             impl #de_impl_generics #ident #ty_generics #where_clause {
-                #vis fn #fun<__D>(__deserializer: __D) -> _serde::export::Result<#remote #ty_generics, __D::Error>
+                #vis fn deserialize<__D>(__deserializer: __D) -> _serde::export::Result<#remote #ty_generics, __D::Error>
                     where __D: _serde::Deserializer<#delife>
                 {
                     #body
@@ -63,10 +63,12 @@ pub fn expand_derive_deserialize(input: &syn::DeriveInput) -> Result<Tokens, Str
         }
     };
 
+    let try_replacement = try::replacement();
     let generated = quote! {
         #[allow(non_upper_case_globals, unused_attributes, unused_qualifications)]
         const #dummy_const: () = {
             extern crate serde as _serde;
+            #try_replacement
             #impl_block
         };
     };
@@ -583,11 +585,11 @@ fn deserialize_seq(
 
     let mut result = if is_struct {
         let names = fields.iter().map(|f| &f.ident);
-        quote_spanned! {Span::call_site()=>
+        quote! {
             #type_path { #( #names: #vars ),* }
         }
     } else {
-        quote_spanned! {Span::call_site()=>
+        quote! {
             #type_path ( #(#vars),* )
         }
     };
@@ -649,11 +651,10 @@ fn deserialize_seq_in_place(
                 })
             });
 
-            let dot = quote_spanned!(Span::call_site()=> .);
             if field.attrs.skip_deserializing() {
                 let default = Expr(expr_is_missing(field, cattrs));
                 quote! {
-                    self.place #dot #field_name = #default;
+                    self.place.#field_name = #default;
                 }
             } else {
                 let return_invalid_length = quote! {
@@ -663,7 +664,7 @@ fn deserialize_seq_in_place(
                     None => {
                         quote! {
                             if let _serde::export::None = try!(_serde::de::SeqAccess::next_element_seed(&mut __seq,
-                                _serde::private::de::InPlaceSeed(&mut self.place #dot #field_name)))
+                                _serde::private::de::InPlaceSeed(&mut self.place.#field_name)))
                             {
                                 #return_invalid_length
                             }
@@ -676,7 +677,7 @@ fn deserialize_seq_in_place(
                             #wrapper
                             match try!(_serde::de::SeqAccess::next_element::<#wrapper_ty>(&mut __seq)) {
                                 _serde::export::Some(__wrap) => {
-                                    self.place #dot #field_name = __wrap.value;
+                                    self.place.#field_name = __wrap.value;
                                 }
                                 _serde::export::None => {
                                     #return_invalid_length
@@ -732,7 +733,7 @@ fn deserialize_newtype_struct(type_path: &Tokens, params: &Parameters, field: &F
         }
     };
 
-    let mut result = quote_spanned!(Span::call_site()=> #type_path(#value));
+    let mut result = quote!(#type_path(__field0));
     if params.has_getter {
         let this = &params.this;
         result = quote! {
@@ -745,6 +746,7 @@ fn deserialize_newtype_struct(type_path: &Tokens, params: &Parameters, field: &F
         fn visit_newtype_struct<__E>(self, __e: __E) -> _serde::export::Result<Self::Value, __E::Error>
             where __E: _serde::Deserializer<#delife>
         {
+            let __field0 = #value;
             _serde::export::Ok(#result)
         }
     }
@@ -757,13 +759,12 @@ fn deserialize_newtype_struct_in_place(params: &Parameters, field: &Field) -> To
 
     let delife = params.borrowed.de_lifetime();
 
-    let elem = quote_spanned!(Span::call_site()=> .0);
     quote! {
         #[inline]
         fn visit_newtype_struct<__E>(self, __e: __E) -> _serde::export::Result<Self::Value, __E::Error>
             where __E: _serde::Deserializer<#delife>
         {
-            _serde::Deserialize::deserialize_in_place(__e, &mut self.place #elem)
+            _serde::Deserialize::deserialize_in_place(__e, &mut self.place.0)
         }
     }
 }
@@ -1625,12 +1626,13 @@ fn deserialize_untagged_variant(
             let type_name = params.type_name();
             let variant_name = variant.ident.as_ref();
             quote_expr! {
-                _serde::export::Result::map(
-                    _serde::Deserializer::deserialize_any(
-                        #deserializer,
-                        _serde::private::de::UntaggedUnitVisitor::new(#type_name, #variant_name)
-                    ),
-                    |()| #this::#variant_ident)
+                match _serde::Deserializer::deserialize_any(
+                    #deserializer,
+                    _serde::private::de::UntaggedUnitVisitor::new(#type_name, #variant_name)
+                ) {
+                    _serde::export::Ok(()) => _serde::export::Ok(#this::#variant_ident),
+                    _serde::export::Err(__err) => _serde::export::Err(__err),
+                }
             }
         }
         Style::Newtype => deserialize_untagged_newtype_variant(
@@ -2305,9 +2307,9 @@ fn deserialize_map(
         let ident = field.ident.expect("struct contains unnamed fields");
         if field.attrs.skip_deserializing() {
             let value = Expr(expr_is_missing(field, cattrs));
-            quote_spanned!(Span::call_site()=> #ident: #value)
+            quote!(#ident: #value)
         } else {
-            quote_spanned!(Span::call_site()=> #ident: #name)
+            quote!(#ident: #name)
         }
     });
 
@@ -2325,7 +2327,7 @@ fn deserialize_map(
         }
     };
 
-    let mut result = quote_spanned!(Span::call_site()=> #struct_path { #(#result),* });
+    let mut result = quote!(#struct_path { #(#result),* });
     if params.has_getter {
         let this = &params.this;
         result = quote! {

serde_derive/src/lib.rs

@@ -22,7 +22,7 @@
 //!
 //! [https://serde.rs/derive.html]: https://serde.rs/derive.html
 
-#![doc(html_root_url = "https://docs.rs/serde_derive/1.0.38")]
+#![doc(html_root_url = "https://docs.rs/serde_derive/1.0.42")]
 #![cfg_attr(
     feature = "cargo-clippy",
     allow(enum_variant_names, redundant_field_names, too_many_arguments, used_underscore_binding)
@@ -43,14 +43,6 @@ extern crate proc_macro2;
 use proc_macro::TokenStream;
 use syn::DeriveInput;
 
-// Quote's default is def_site but it appears call_site is likely to stabilize
-// before def_site. Thus we try to use only call_site.
-macro_rules! quote {
-    ($($tt:tt)*) => {
-        quote_spanned!($crate::proc_macro2::Span::call_site()=> $($tt)*)
-    }
-}
-
 #[macro_use]
 mod bound;
 #[macro_use]
@@ -58,6 +50,7 @@ mod fragment;
 
 mod de;
 mod ser;
+mod try;
 
 #[proc_macro_derive(Serialize, attributes(serde))]
 pub fn derive_serialize(input: TokenStream) -> TokenStream {

serde_derive/src/ser.rs

@@ -15,6 +15,7 @@ use bound;
 use fragment::{Fragment, Match, Stmts};
 use internals::ast::{Container, Data, Field, Style, Variant};
 use internals::{attr, Ctxt};
+use try;
 
 use std::u32;
 
@@ -32,10 +33,9 @@ pub fn expand_derive_serialize(input: &syn::DeriveInput) -> Result<Tokens, Strin
 
     let impl_block = if let Some(remote) = cont.attrs.remote() {
         let vis = &input.vis;
-        let fun = quote_spanned!(Span::call_site()=> serialize);
         quote! {
             impl #impl_generics #ident #ty_generics #where_clause {
-                #vis fn #fun<__S>(__self: &#remote #ty_generics, __serializer: __S) -> _serde::export::Result<__S::Ok, __S::Error>
+                #vis fn serialize<__S>(__self: &#remote #ty_generics, __serializer: __S) -> _serde::export::Result<__S::Ok, __S::Error>
                     where __S: _serde::Serializer
                 {
                     #body
@@ -55,10 +55,12 @@ pub fn expand_derive_serialize(input: &syn::DeriveInput) -> Result<Tokens, Strin
         }
     };
 
+    let try_replacement = try::replacement();
     let generated = quote! {
         #[allow(non_upper_case_globals, unused_attributes, unused_qualifications)]
         const #dummy_const: () = {
             extern crate serde as _serde;
+            #try_replacement
             #impl_block
         };
     };
@@ -594,9 +596,15 @@ fn serialize_adjacently_tagged_variant(
                     field_expr = wrap_serialize_field_with(params, field.ty, path, &field_expr);
                 }
 
-                quote_expr! {
-                    _serde::Serialize::serialize(#field_expr, __serializer)
-                }
+                return quote_block! {
+                    let mut __struct = try!(_serde::Serializer::serialize_struct(
+                        __serializer, #type_name, 2));
+                    try!(_serde::ser::SerializeStruct::serialize_field(
+                        &mut __struct, #tag, #variant_name));
+                    try!(_serde::ser::SerializeStruct::serialize_field(
+                        &mut __struct, #content, #field_expr));
+                    _serde::ser::SerializeStruct::end(__struct)
+                };
             }
             Style::Tuple => {
                 serialize_tuple_variant(TupleVariant::Untagged, params, &variant.fields)
@@ -1056,9 +1064,9 @@ fn mut_if(is_mut: bool) -> Option<Tokens> {
 fn get_member(params: &Parameters, field: &Field, member: &Member) -> Tokens {
     let self_var = &params.self_var;
     match (params.is_remote, field.attrs.getter()) {
-        (false, None) => quote_spanned!(Span::call_site()=> &#self_var.#member),
+        (false, None) => quote!(&#self_var.#member),
         (true, None) => {
-            let inner = quote_spanned!(Span::call_site()=> &#self_var.#member);
+            let inner = quote!(&#self_var.#member);
             let ty = field.ty;
             quote!(_serde::private::ser::constrain::<#ty>(#inner))
         }

serde_derive/src/try.rs

@@ -0,0 +1,25 @@
+use quote::Tokens;
+use proc_macro2::{Op, Spacing};
+
+// None of our generated code requires the `From::from` error conversion
+// performed by the standard library's `try!` macro. With this simplified macro
+// we see a significant improvement in type checking and borrow checking time of
+// the generated code and a slight improvement in binary size.
+pub fn replacement() -> Tokens {
+    // Cannot pass `$expr` to `quote!` prior to Rust 1.17.0 so interpolate it.
+    let dollar = Op::new('$', Spacing::Alone);
+
+    quote! {
+        #[allow(unused_macros)]
+        macro_rules! try {
+            (#dollar __expr:expr) => {
+                match #dollar __expr {
+                    _serde::export::Ok(__val) => __val,
+                    _serde::export::Err(__err) => {
+                        return _serde::export::Err(__err);
+                    }
+                }
+            }
+        }
+    }
+}

serde_test/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "serde_test"
-version = "1.0.38" # remember to update html_root_url
+version = "1.0.42" # remember to update html_root_url
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>", "David Tolnay <dtolnay@gmail.com>"]
 license = "MIT/Apache-2.0"
 description = "Token De/Serializer for testing De/Serialize implementations"

serde_test/src/lib.rs

@@ -155,7 +155,7 @@
 //! # }
 //! ```
 
-#![doc(html_root_url = "https://docs.rs/serde_test/1.0.38")]
+#![doc(html_root_url = "https://docs.rs/serde_test/1.0.42")]
 #![cfg_attr(feature = "cargo-clippy", deny(clippy, clippy_pedantic))]
 // Whitelisted clippy lints
 #![cfg_attr(feature = "cargo-clippy", allow(float_cmp))]

serde_test/src/ser.rs

@@ -45,7 +45,7 @@ macro_rules! assert_next_token {
     ($ser:expr, $expected:ident($v:expr)) => {
         assert_next_token!(
             $ser,
-            format_args!("{}({:?})", stringify!($expected), $v),
+            format_args!(concat!(stringify!($expected), "({:?})"), $v),
             Token::$expected(v),
             v == $v
         );
@@ -56,13 +56,13 @@ macro_rules! assert_next_token {
             use std::fmt::Write;
             let mut buffer = String::new();
             $(
-                write!(&mut buffer, "{}: {:?}, ", stringify!($k), $k).unwrap();
+                write!(&mut buffer, concat!(stringify!($k), ": {:?}, "), $k).unwrap();
             )*
             buffer
         };
         assert_next_token!(
             $ser,
-            format_args!("{} {{ {}}}", stringify!($expected), field_format()),
+            format_args!(concat!(stringify!($expected), " {{ {}}}"), field_format()),
             Token::$expected { $($k),* },
             ($($k,)*) == compare
         );

test_suite/tests/bytes/mod.rs

@@ -0,0 +1,52 @@
+use serde::de::{Deserializer, Visitor, SeqAccess, Error};
+use std::fmt;
+
+pub fn deserialize<'de, D>(deserializer: D) -> Result<Vec<u8>, D::Error>
+    where D: Deserializer<'de>
+{
+    deserializer.deserialize_byte_buf(ByteBufVisitor)
+}
+
+struct ByteBufVisitor;
+
+impl<'de> Visitor<'de> for ByteBufVisitor {
+    type Value = Vec<u8>;
+
+    fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+        formatter.write_str("byte array")
+    }
+
+    fn visit_seq<V>(self, mut visitor: V) -> Result<Self::Value, V::Error>
+        where V: SeqAccess<'de>
+    {
+        let mut values = Vec::new();
+        while let Some(value) = try!(visitor.next_element()) {
+            values.push(value);
+        }
+        Ok(values)
+    }
+
+    fn visit_bytes<E>(self, v: &[u8]) -> Result<Self::Value, E>
+        where E: Error
+    {
+        Ok(v.to_vec())
+    }
+
+    fn visit_byte_buf<E>(self, v: Vec<u8>) -> Result<Self::Value, E>
+        where E: Error
+    {
+        Ok(v)
+    }
+
+    fn visit_str<E>(self, v: &str) -> Result<Self::Value, E>
+        where E: Error
+    {
+        Ok(v.as_bytes().to_vec())
+    }
+
+    fn visit_string<E>(self, v: String) -> Result<Self::Value, E>
+        where E: Error
+    {
+        Ok(v.into_bytes())
+    }
+}

test_suite/tests/test_macros.rs

@@ -13,7 +13,11 @@
 #[macro_use]
 extern crate serde_derive;
 
+extern crate serde;
 extern crate serde_test;
+
+mod bytes;
+
 use self::serde_test::{assert_de_tokens, assert_de_tokens_error, assert_ser_tokens, assert_tokens,
                        Token};
 
@@ -779,6 +783,158 @@ fn test_internally_tagged_enum() {
     );
 }
 
+#[test]
+fn test_internally_tagged_bytes() {
+    #[derive(Debug, PartialEq, Deserialize)]
+    #[serde(tag = "type")]
+    enum InternallyTagged {
+        String {
+            string: String,
+        },
+        Bytes {
+            #[serde(with = "bytes")]
+            bytes: Vec<u8>,
+        },
+    }
+
+    assert_de_tokens(
+        &InternallyTagged::String { string: "\0".to_owned() },
+        &[
+            Token::Struct {
+                name: "String",
+                len: 2,
+            },
+            Token::Str("type"),
+            Token::Str("String"),
+            Token::Str("string"),
+            Token::Str("\0"),
+            Token::StructEnd,
+        ],
+    );
+
+    assert_de_tokens(
+        &InternallyTagged::String { string: "\0".to_owned() },
+        &[
+            Token::Struct {
+                name: "String",
+                len: 2,
+            },
+            Token::Str("type"),
+            Token::Str("String"),
+            Token::Str("string"),
+            Token::String("\0"),
+            Token::StructEnd,
+        ],
+    );
+
+    assert_de_tokens(
+        &InternallyTagged::String { string: "\0".to_owned() },
+        &[
+            Token::Struct {
+                name: "String",
+                len: 2,
+            },
+            Token::Str("type"),
+            Token::Str("String"),
+            Token::Str("string"),
+            Token::Bytes(b"\0"),
+            Token::StructEnd,
+        ],
+    );
+
+    assert_de_tokens(
+        &InternallyTagged::String { string: "\0".to_owned() },
+        &[
+            Token::Struct {
+                name: "String",
+                len: 2,
+            },
+            Token::Str("type"),
+            Token::Str("String"),
+            Token::Str("string"),
+            Token::ByteBuf(b"\0"),
+            Token::StructEnd,
+        ],
+    );
+
+    assert_de_tokens(
+        &InternallyTagged::Bytes { bytes: vec![0] },
+        &[
+            Token::Struct {
+                name: "Bytes",
+                len: 2,
+            },
+            Token::Str("type"),
+            Token::Str("Bytes"),
+            Token::Str("bytes"),
+            Token::Str("\0"),
+            Token::StructEnd,
+        ],
+    );
+
+    assert_de_tokens(
+        &InternallyTagged::Bytes { bytes: vec![0] },
+        &[
+            Token::Struct {
+                name: "Bytes",
+                len: 2,
+            },
+            Token::Str("type"),
+            Token::Str("Bytes"),
+            Token::Str("bytes"),
+            Token::String("\0"),
+            Token::StructEnd,
+        ],
+    );
+
+    assert_de_tokens(
+        &InternallyTagged::Bytes { bytes: vec![0] },
+        &[
+            Token::Struct {
+                name: "Bytes",
+                len: 2,
+            },
+            Token::Str("type"),
+            Token::Str("Bytes"),
+            Token::Str("bytes"),
+            Token::Bytes(b"\0"),
+            Token::StructEnd,
+        ],
+    );
+
+    assert_de_tokens(
+        &InternallyTagged::Bytes { bytes: vec![0] },
+        &[
+            Token::Struct {
+                name: "Bytes",
+                len: 2,
+            },
+            Token::Str("type"),
+            Token::Str("Bytes"),
+            Token::Str("bytes"),
+            Token::ByteBuf(b"\0"),
+            Token::StructEnd,
+        ],
+    );
+
+    assert_de_tokens(
+        &InternallyTagged::Bytes { bytes: vec![0] },
+        &[
+            Token::Struct {
+                name: "Bytes",
+                len: 2,
+            },
+            Token::Str("type"),
+            Token::Str("Bytes"),
+            Token::Str("bytes"),
+            Token::Seq { len: Some(1) },
+            Token::U8(0),
+            Token::SeqEnd,
+            Token::StructEnd,
+        ],
+    );
+}
+
 #[test]
 fn test_internally_tagged_struct_variant_containing_unit_variant() {
     #[derive(Debug, PartialEq, Serialize, Deserialize)]
@@ -1246,6 +1402,140 @@ fn test_enum_in_untagged_enum() {
     );
 }
 
+#[test]
+fn test_untagged_bytes() {
+    #[derive(Debug, PartialEq, Deserialize)]
+    #[serde(untagged)]
+    enum Untagged {
+        String {
+            string: String,
+        },
+        Bytes {
+            #[serde(with = "bytes")]
+            bytes: Vec<u8>,
+        },
+    }
+
+    assert_de_tokens(
+        &Untagged::String { string: "\0".to_owned() },
+        &[
+            Token::Struct {
+                name: "Untagged",
+                len: 1,
+            },
+            Token::Str("string"),
+            Token::Str("\0"),
+            Token::StructEnd,
+        ],
+    );
+
+    assert_de_tokens(
+        &Untagged::String { string: "\0".to_owned() },
+        &[
+            Token::Struct {
+                name: "Untagged",
+                len: 1,
+            },
+            Token::Str("string"),
+            Token::String("\0"),
+            Token::StructEnd,
+        ],
+    );
+
+    assert_de_tokens(
+        &Untagged::String { string: "\0".to_owned() },
+        &[
+            Token::Struct {
+                name: "Untagged",
+                len: 1,
+            },
+            Token::Str("string"),
+            Token::Bytes(b"\0"),
+            Token::StructEnd,
+        ],
+    );
+
+    assert_de_tokens(
+        &Untagged::String { string: "\0".to_owned() },
+        &[
+            Token::Struct {
+                name: "Untagged",
+                len: 1,
+            },
+            Token::Str("string"),
+            Token::ByteBuf(b"\0"),
+            Token::StructEnd,
+        ],
+    );
+
+    assert_de_tokens(
+        &Untagged::Bytes { bytes: vec![0] },
+        &[
+            Token::Struct {
+                name: "Untagged",
+                len: 1,
+            },
+            Token::Str("bytes"),
+            Token::Str("\0"),
+            Token::StructEnd,
+        ],
+    );
+
+    assert_de_tokens(
+        &Untagged::Bytes { bytes: vec![0] },
+        &[
+            Token::Struct {
+                name: "Untagged",
+                len: 1,
+            },
+            Token::Str("bytes"),
+            Token::String("\0"),
+            Token::StructEnd,
+        ],
+    );
+
+    assert_de_tokens(
+        &Untagged::Bytes { bytes: vec![0] },
+        &[
+            Token::Struct {
+                name: "Untagged",
+                len: 1,
+            },
+            Token::Str("bytes"),
+            Token::Bytes(b"\0"),
+            Token::StructEnd,
+        ],
+    );
+
+    assert_de_tokens(
+        &Untagged::Bytes { bytes: vec![0] },
+        &[
+            Token::Struct {
+                name: "Untagged",
+                len: 1,
+            },
+            Token::Str("bytes"),
+            Token::ByteBuf(b"\0"),
+            Token::StructEnd,
+        ],
+    );
+
+    assert_de_tokens(
+        &Untagged::Bytes { bytes: vec![0] },
+        &[
+            Token::Struct {
+                name: "Untagged",
+                len: 1,
+            },
+            Token::Str("bytes"),
+            Token::Seq { len: Some(1) },
+            Token::U8(0),
+            Token::SeqEnd,
+            Token::StructEnd,
+        ],
+    );
+}
+
 #[test]
 fn test_rename_all() {
     #[derive(Serialize, Deserialize, Debug, PartialEq)]