feat(cargo): Rustup to latest nightly

Update serde_codegen for rustc 1.8.0-nightly (ce4b75f25 2016-02-12)

.travis.yml

@@ -22,9 +22,11 @@ script:
 - |
     (cd serde && travis-cargo build) &&
     (cd serde && travis-cargo test) &&
+    (cd serde && travis-cargo --only nightly test -- --features nightly-testing) &&
     (cd serde_tests && travis-cargo test) &&
-    (cd serde_macros && travis-cargo --only nightly test) &&
-    (cd serde_macros && travis-cargo --only nightly bench) &&
+    (cd serde_tests && travis-cargo --only nightly test -- --features nightly-testing) &&
+    (cd serde_macros && travis-cargo --only nightly test -- --features nightly-testing) &&
+    (cd serde_macros && travis-cargo --only nightly bench -- --features nightly-testing) &&
     (cd serde && travis-cargo --only stable doc) &&
     (cd serde_codegen && travis-cargo --only stable doc)
 

README.md

@@ -129,6 +129,28 @@ fn main() {
 }
 ```
 
+`build.rs`
+
+```rust
+extern crate syntex;
+extern crate serde_codegen;
+
+use std::env;
+use std::path::Path;
+
+pub fn main() {
+    let out_dir = env::var_os("OUT_DIR").unwrap();
+
+    let src = Path::new("src/main.rs.in");
+    let dst = Path::new(&out_dir).join("main.rs");
+
+    let mut registry = syntex::Registry::new();
+
+    serde_codegen::register(&mut registry);
+    registry.expand("", &src, &dst).unwrap();
+}
+```
+
 This also produces:
 
 ```
@@ -579,6 +601,69 @@ impl serde::de::Visitor for PointVisitor {
 }
 ```
 
+Design Considerations and tradeoffs for Serializers and Deserializers
+=====================================================================
+
+Serde serialization and deserialization implementations are written in such a
+way that they err on being able to represent more values, and also provide
+better error messages when they are passed an incorrect type to deserialize
+from. For example, by default, it is a syntax error to deserialize a `String`
+into an `Option<String>`. This is implemented such that it is possible to
+distinguish between the values `None` and `Some(())`, if the serialization
+format supports option types.
+
+However, many formats do not have option types, and represents optional values
+as either a `null`, or some other value. Serde `Serializer`s and
+`Deserializer`s can opt-in support for this. For serialization, this is pretty
+easy. Simply implement these methods:
+
+```rust
+...
+
+    fn visit_none(&mut self) -> Result<(), Self::Error> {
+        self.visit_unit()
+    }
+
+    fn visit_some<T>(&mut self, value: T) -> Result<(), Self::Error> {
+        value.serialize(self)
+    }
+...
+```
+
+For deserialization, this can be implemented by way of the
+`Deserializer::visit_option` hook, which presumes that there is some ability to peek at what is the
+next value in the serialized token stream. This following example is from
+[serde_tests::TokenDeserializer](https://github.com/serde-rs/serde/blob/master/serde_tests/tests/token.rs#L435-L454),
+where it checks to see if the next value is an `Option`, a `()`, or some other
+value:
+
+```rust
+...
+
+    fn visit_option<V>(&mut self, mut visitor: V) -> Result<V::Value, Error>
+        where V: de::Visitor,
+    {
+        match self.tokens.peek() {
+            Some(&Token::Option(false)) => {
+                self.tokens.next();
+                visitor.visit_none()
+            }
+            Some(&Token::Option(true)) => {
+                self.tokens.next();
+                visitor.visit_some(self)
+            }
+            Some(&Token::Unit) => {
+                self.tokens.next();
+                visitor.visit_none()
+            }
+            Some(_) => visitor.visit_some(self),
+            None => Err(Error::EndOfStreamError),
+        }
+    }
+
+...
+```
+
 Annotations
 ===========
 

serde/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "serde"
-version = "0.6.6"
+version = "0.6.14"
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>"]
 license = "MIT/Apache-2.0"
 description = "A generic serialization/deserialization framework"
@@ -9,12 +9,13 @@ documentation = "https://serde-rs.github.io/serde/serde/serde/index.html"
 readme = "../README.md"
 keywords = ["serde", "serialization"]
 
-[dependencies]
-num = "^0.1.27"
-
 [features]
-nightly = []
-num-impls = ["num-bigint", "num-complex", "num-rational"]
+nightly-testing = ["clippy"]
 num-bigint = ["num/bigint"]
 num-complex = ["num/complex"]
+num-impls = ["num-bigint", "num-complex", "num-rational"]
 num-rational = ["num/rational"]
+
+[dependencies]
+clippy = { version = "^0.*", optional = true }
+num = { version = "^0.1.27", default-features = false }

serde/src/de/impls.rs

@@ -154,7 +154,9 @@ impl<
     fn visit_str<E>(&mut self, v: &str) -> Result<T, E>
         where E: Error,
     {
-        str::FromStr::from_str(v.trim()).or(Err(Error::type_mismatch(Type::Str)))
+        str::FromStr::from_str(v.trim()).or_else(|_| {
+            Err(Error::type_mismatch(Type::Str))
+        })
     }
 }
 
@@ -234,7 +236,7 @@ impl Visitor for StringVisitor {
     fn visit_str<E>(&mut self, v: &str) -> Result<String, E>
         where E: Error,
     {
-        Ok(v.to_string())
+        Ok(v.to_owned())
     }
 
     fn visit_string<E>(&mut self, v: String) -> Result<String, E>
@@ -247,12 +249,12 @@ impl Visitor for StringVisitor {
         where E: Error,
     {
         match str::from_utf8(v) {
-            Ok(s) => Ok(s.to_string()),
+            Ok(s) => Ok(s.to_owned()),
             Err(_) => Err(Error::type_mismatch(Type::String)),
         }
     }
 
-    fn visit_byte_buf<'a, E>(&mut self, v: Vec<u8>) -> Result<String, E>
+    fn visit_byte_buf<E>(&mut self, v: Vec<u8>) -> Result<String, E>
         where E: Error,
     {
         match String::from_utf8(v) {
@@ -281,6 +283,13 @@ impl<
 > Visitor for OptionVisitor<T> {
     type Value = Option<T>;
 
+    #[inline]
+    fn visit_unit<E>(&mut self) -> Result<Option<T>, E>
+        where E: Error,
+    {
+        Ok(None)
+    }
+
     #[inline]
     fn visit_none<E>(&mut self) -> Result<Option<T>, E>
         where E: Error,
@@ -753,7 +762,7 @@ impl Deserialize for path::PathBuf {
     fn deserialize<D>(deserializer: &mut D) -> Result<path::PathBuf, D::Error>
         where D: Deserializer,
     {
-        deserializer.visit(PathBufVisitor)
+        deserializer.visit_string(PathBufVisitor)
     }
 }
 

serde/src/de/mod.rs

@@ -403,6 +403,16 @@ pub trait Deserializer {
         self.visit_seq(visitor)
     }
 
+    /// This method hints that the `Deserialize` type is expecting some sort of struct key mapping.
+    /// This allows deserializers to choose between &str, usize, or &[u8] to properly deserialize a
+    /// struct key.
+    #[inline]
+    fn visit_struct_field<V>(&mut self, visitor: V) -> Result<V::Value, Self::Error>
+        where V: Visitor,
+    {
+        self.visit(visitor)
+    }
+
     /// Specify a format string for the deserializer.
     ///
     /// The deserializer format is used to determine which format

serde/src/lib.rs

@@ -10,7 +10,10 @@
 //! [github repository](https://github.com/serde-rs/serde)
 
 #![doc(html_root_url="https://serde-rs.github.io/serde/serde")]
-#![cfg_attr(feature = "nightly", feature(collections, core, enumset, nonzero, step_trait, zero_one))]
+#![cfg_attr(feature = "nightly", feature(collections, enumset, nonzero, plugin, step_trait,
+                                         zero_one))]
+#![cfg_attr(feature = "nightly", plugin(clippy))]
+#![cfg_attr(feature = "nightly", allow(linkedlist))]
 
 #![deny(missing_docs)]
 

serde/src/ser/impls.rs

@@ -566,8 +566,8 @@ impl<K, V, I> MapVisitor for MapIteratorVisitor<I>
     {
         match self.iter.next() {
             Some((key, value)) => {
-                let value = try!(serializer.visit_map_elt(key, value));
-                Ok(Some(value))
+                try!(serializer.visit_map_elt(key, value));
+                Ok(Some(()))
             }
             None => Ok(None)
         }

serde/src/ser/mod.rs

@@ -322,6 +322,7 @@ pub trait Serializer {
 }
 
 /// A trait that is used by a `Serialize` to iterate through a sequence.
+#[cfg_attr(feature = "nightly", allow(len_without_is_empty))]
 pub trait SeqVisitor {
     /// Serializes a sequence item in the serializer.
     ///
@@ -338,6 +339,7 @@ pub trait SeqVisitor {
 }
 
 /// A trait that is used by a `Serialize` to iterate through a map.
+#[cfg_attr(feature = "nightly", allow(len_without_is_empty))]
 pub trait MapVisitor {
     /// Serializes a map item in the serializer.
     ///

serde_codegen/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "serde_codegen"
-version = "0.6.6"
+version = "0.6.14"
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>"]
 license = "MIT/Apache-2.0"
 description = "Macros to auto-generate implementations for the serde framework"
@@ -12,15 +12,17 @@ keywords = ["serde", "serialization"]
 [features]
 default = ["with-syntex"]
 nightly = ["quasi_macros"]
+nightly-testing = ["clippy"]
 with-syntex = ["quasi/with-syntex", "quasi_codegen", "quasi_codegen/with-syntex", "syntex", "syntex_syntax"]
 
 [build-dependencies]
-quasi_codegen = { verision = "^0.3.9", optional = true }
-syntex = { version = "^0.22.0", optional = true }
+quasi_codegen = { version = "^0.7.0", optional = true }
+syntex = { version = "^0.29.0", optional = true }
 
 [dependencies]
-aster = { version = "^0.9.0", default-features = false }
-quasi = { verision = "^0.3.9", default-features = false }
-quasi_macros = { version = "^0.3.9", optional = true }
-syntex = { version = "^0.22.0", optional = true }
-syntex_syntax = { version = "^0.23.0", optional = true }
+aster = { version = "^0.13.1", default-features = false }
+clippy = { version = "^0.*", optional = true }
+quasi = { version = "^0.7.0", default-features = false }
+quasi_macros = { version = "^0.7.0", optional = true }
+syntex = { version = "^0.29.0", optional = true }
+syntex_syntax = { version = "^0.29.0", optional = true }

serde_codegen/src/attr.rs

@@ -4,6 +4,7 @@ use std::collections::HashSet;
 use syntax::ast;
 use syntax::attr;
 use syntax::ext::base::ExtCtxt;
+use syntax::print::pprust::meta_item_to_string;
 use syntax::ptr::P;
 
 use aster;
@@ -32,7 +33,7 @@ impl FieldAttrs {
     /// Return a set of formats that the field has attributes for.
     pub fn formats(&self) -> HashSet<P<ast::Expr>> {
         match self.names {
-            FieldNames::Format{ref formats, default: _} => {
+            FieldNames::Format { ref formats, .. } => {
                 let mut set = HashSet::new();
                 for (fmt, _) in formats.iter() {
                     set.insert(fmt.clone());
@@ -70,7 +71,7 @@ impl FieldAttrs {
     pub fn default_key_expr(&self) -> &P<ast::Expr> {
         match self.names {
             FieldNames::Global(ref expr) => expr,
-            FieldNames::Format{formats: _, ref default} => default,
+            FieldNames::Format { ref default, .. } => default,
         }
     }
 
@@ -104,6 +105,7 @@ impl FieldAttrs {
 }
 
 pub struct FieldAttrsBuilder<'a> {
+    cx: &'a ExtCtxt<'a>,
     builder: &'a aster::AstBuilder,
     skip_serializing_field: bool,
     skip_serializing_field_if_empty: bool,
@@ -114,8 +116,10 @@ pub struct FieldAttrsBuilder<'a> {
 }
 
 impl<'a> FieldAttrsBuilder<'a> {
-    pub fn new(builder: &'a aster::AstBuilder) -> FieldAttrsBuilder<'a> {
+    pub fn new(cx: &'a ExtCtxt<'a>,
+               builder: &'a aster::AstBuilder) -> FieldAttrsBuilder<'a> {
         FieldAttrsBuilder {
+            cx: cx,
             builder: builder,
             skip_serializing_field: false,
             skip_serializing_field_if_empty: false,
@@ -126,7 +130,7 @@ impl<'a> FieldAttrsBuilder<'a> {
         }
     }
 
-    pub fn field(mut self, field: &ast::StructField) -> FieldAttrsBuilder<'a> {
+    pub fn field(mut self, field: &ast::StructField) -> Result<FieldAttrsBuilder<'a>, ()> {
         match field.node.kind {
             ast::NamedField(name, _) => {
                 self.name = Some(self.builder.expr().str(name));
@@ -137,33 +141,41 @@ impl<'a> FieldAttrsBuilder<'a> {
         self.attrs(&field.node.attrs)
     }
 
-    pub fn attrs(self, attrs: &[ast::Attribute]) -> FieldAttrsBuilder<'a> {
-        attrs.iter().fold(self, FieldAttrsBuilder::attr)
+    pub fn attrs(mut self, attrs: &[ast::Attribute]) -> Result<FieldAttrsBuilder<'a>, ()> {
+        for attr in attrs {
+            self = try!(self.attr(attr));
+        }
+
+        Ok(self)
     }
 
-    pub fn attr(self, attr: &ast::Attribute) -> FieldAttrsBuilder<'a> {
+    pub fn attr(mut self, attr: &ast::Attribute) -> Result<FieldAttrsBuilder<'a>, ()> {
         match attr.node.value.node {
-            ast::MetaList(ref name, ref items) if name == &"serde" => {
+            ast::MetaItemKind::List(ref name, ref items) if name == &"serde" => {
                 attr::mark_used(&attr);
-                items.iter().fold(self, FieldAttrsBuilder::meta_item)
+                for item in items {
+                    self = try!(self.meta_item(item));
+                }
+
+                Ok(self)
             }
             _ => {
-                self
+                Ok(self)
             }
         }
     }
 
-    pub fn meta_item(mut self, meta_item: &P<ast::MetaItem>) -> FieldAttrsBuilder<'a> {
+    pub fn meta_item(mut self, meta_item: &P<ast::MetaItem>) -> Result<FieldAttrsBuilder<'a>, ()> {
         match meta_item.node {
-            ast::MetaNameValue(ref name, ref lit) if name == &"rename" => {
+            ast::MetaItemKind::NameValue(ref name, ref lit) if name == &"rename" => {
                 let expr = self.builder.expr().build_lit(P(lit.clone()));
 
-                self.name(expr)
+                Ok(self.name(expr))
             }
-            ast::MetaList(ref name, ref items) if name == &"rename" => {
+            ast::MetaItemKind::List(ref name, ref items) if name == &"rename" => {
                 for item in items {
                     match item.node {
-                        ast::MetaNameValue(ref name, ref lit) => {
+                        ast::MetaItemKind::NameValue(ref name, ref lit) => {
                             let name = self.builder.expr().str(name);
                             let expr = self.builder.expr().build_lit(P(lit.clone()));
 
@@ -172,23 +184,27 @@ impl<'a> FieldAttrsBuilder<'a> {
                         _ => { }
                     }
                 }
-                self
+
+                Ok(self)
             }
-            ast::MetaWord(ref name) if name == &"default" => {
-                self.default()
+            ast::MetaItemKind::Word(ref name) if name == &"default" => {
+                Ok(self.default())
             }
-            ast::MetaWord(ref name) if name == &"skip_serializing" => {
-                self.skip_serializing_field()
+            ast::MetaItemKind::Word(ref name) if name == &"skip_serializing" => {
+                Ok(self.skip_serializing_field())
             }
-            ast::MetaWord(ref name) if name == &"skip_serializing_if_empty" => {
-                self.skip_serializing_field_if_empty()
+            ast::MetaItemKind::Word(ref name) if name == &"skip_serializing_if_empty" => {
+                Ok(self.skip_serializing_field_if_empty())
             }
-            ast::MetaWord(ref name) if name == &"skip_serializing_if_none" => {
-                self.skip_serializing_field_if_none()
+            ast::MetaItemKind::Word(ref name) if name == &"skip_serializing_if_none" => {
+                Ok(self.skip_serializing_field_if_none())
             }
             _ => {
-                // Ignore unknown meta variables for now.
-                self
+                self.cx.span_err(
+                    meta_item.span,
+                    &format!("unknown serde field attribute `{}`",
+                             meta_item_to_string(meta_item)));
+                Err(())
             }
         }
     }
@@ -243,3 +259,59 @@ impl<'a> FieldAttrsBuilder<'a> {
         }
     }
 }
+
+/// Represents container (e.g. struct) attribute information
+#[derive(Debug)]
+pub struct ContainerAttrs;
+
+pub struct ContainerAttrsBuilder<'a> {
+    cx: &'a ExtCtxt<'a>,
+}
+
+impl<'a> ContainerAttrsBuilder<'a> {
+    pub fn new(cx: &'a ExtCtxt) -> Self {
+        ContainerAttrsBuilder {
+            cx: cx,
+        }
+    }
+
+    pub fn attrs(mut self, attrs: &[ast::Attribute]) -> Result<Self, ()> {
+        for attr in attrs {
+            self = try!(self.attr(attr));
+        }
+
+        Ok(self)
+    }
+
+    pub fn attr(mut self, attr: &ast::Attribute) -> Result<Self, ()> {
+        match attr.node.value.node {
+            ast::MetaItemKind::List(ref name, ref items) if name == &"serde" => {
+                attr::mark_used(&attr);
+                for item in items {
+                    self = try!(self.meta_item(item));
+                }
+
+                Ok(self)
+            }
+            _ => {
+                Ok(self)
+            }
+        }
+    }
+
+    pub fn meta_item(self, meta_item: &P<ast::MetaItem>) -> Result<Self, ()> {
+        match meta_item.node {
+            _ => {
+                self.cx.span_err(
+                    meta_item.span,
+                    &format!("unknown serde container attribute `{}`",
+                             meta_item_to_string(meta_item)));
+                Err(())
+            }
+        }
+    }
+
+    pub fn build(self) -> ContainerAttrs {
+        ContainerAttrs
+    }
+}

serde_codegen/src/de.rs

@@ -5,7 +5,6 @@ use aster;
 use syntax::ast::{
     self,
     EnumDef,
-    Expr,
     Ident,
     Item,
     MetaItem,
@@ -13,7 +12,6 @@ use syntax::ast::{
 use syntax::codemap::Span;
 use syntax::ext::base::{Annotatable, ExtCtxt};
 use syntax::ext::build::AstBuilder;
-use syntax::owned_slice::OwnedSlice;
 use syntax::ptr::P;
 
 use attr;
@@ -31,7 +29,7 @@ pub fn expand_derive_deserialize(
         _ => {
             cx.span_err(
                 meta_item.span,
-                "`derive` may only be applied to structs and enums");
+                "`#[derive(Deserialize)]` may only be applied to structs and enums");
             return;
         }
     };
@@ -39,9 +37,14 @@ pub fn expand_derive_deserialize(
     let builder = aster::AstBuilder::new().span(span);
 
     let generics = match item.node {
-        ast::ItemStruct(_, ref generics) => generics,
-        ast::ItemEnum(_, ref generics) => generics,
-        _ => cx.bug("expected ItemStruct or ItemEnum in #[derive(Deserialize)]")
+        ast::ItemKind::Struct(_, ref generics) => generics,
+        ast::ItemKind::Enum(_, ref generics) => generics,
+        _ => {
+            cx.span_err(
+                meta_item.span,
+                "`#[derive(Deserialize)]` may only be applied to structs and enums");
+            return;
+        }
     };
 
     let impl_generics = builder.from_generics(generics.clone())
@@ -54,13 +57,13 @@ pub fn expand_derive_deserialize(
         .segment(item.ident).with_generics(impl_generics.clone()).build()
         .build();
 
-    let body = deserialize_body(
-        cx,
-        &builder,
-        &item,
-        &impl_generics,
-        ty.clone(),
-    );
+    let body = match deserialize_body(cx, &builder, &item, &impl_generics, ty.clone()) {
+        Ok(body) => body,
+        Err(()) => {
+            // An error occured, but it should have been reported already.
+            return;
+        }
+    };
 
     let where_clause = &impl_generics.where_clause;
 
@@ -83,19 +86,24 @@ fn deserialize_body(
     item: &Item,
     impl_generics: &ast::Generics,
     ty: P<ast::Ty>,
-) -> P<ast::Expr> {
+) -> Result<P<ast::Expr>, ()> {
+    // Note: While we don't have any container attributes, we still want to try to
+    // parse them so we can report a proper error if we get passed an unknown attribute.
+    let _ = try!(field::container_attrs(cx, item));
+
     match item.node {
-        ast::ItemStruct(ref variant_data, _) => {
+        ast::ItemKind::Struct(ref variant_data, _) => {
             deserialize_item_struct(
                 cx,
                 builder,
                 item,
                 impl_generics,
                 ty,
+                item.span,
                 variant_data,
             )
         }
-        ast::ItemEnum(ref enum_def, _) => {
+        ast::ItemKind::Enum(ref enum_def, _) => {
             deserialize_item_enum(
                 cx,
                 builder,
@@ -105,7 +113,10 @@ fn deserialize_body(
                 enum_def,
             )
         }
-        _ => cx.bug("expected ItemStruct or ItemEnum in #[derive(Deserialize)]")
+        _ => {
+            cx.span_bug(item.span,
+                        "expected ItemStruct or ItemEnum in #[derive(Deserialize)]")
+        }
     }
 }
 
@@ -115,8 +126,9 @@ fn deserialize_item_struct(
     item: &Item,
     impl_generics: &ast::Generics,
     ty: P<ast::Ty>,
+    span: Span,
     variant_data: &ast::VariantData,
-) -> P<ast::Expr> {
+) -> Result<P<ast::Expr>, ()> {
     match *variant_data {
         ast::VariantData::Unit(_) => {
             deserialize_unit_struct(
@@ -136,7 +148,7 @@ fn deserialize_item_struct(
         }
         ast::VariantData::Tuple(ref fields, _) => {
             if fields.iter().any(|field| !field.node.kind.is_unnamed()) {
-                cx.bug("tuple struct has named fields")
+                cx.span_bug(span, "tuple struct has named fields")
             }
 
             deserialize_tuple_struct(
@@ -150,7 +162,7 @@ fn deserialize_item_struct(
         }
         ast::VariantData::Struct(ref fields, _) => {
             if fields.iter().any(|field| field.node.kind.is_unnamed()) {
-                cx.bug("struct has unnamed fields")
+                cx.span_bug(span, "struct has unnamed fields")
             }
 
             deserialize_struct(
@@ -172,14 +184,14 @@ fn deserialize_visitor(
     trait_generics: &ast::Generics,
     forward_ty_params: Vec<ast::TyParam>,
     forward_tys: Vec<P<ast::Ty>>
-) -> (P<ast::Item>, P<ast::Ty>, P<ast::Expr>, ast::Generics) {
+) -> Result<(P<ast::Item>, P<ast::Ty>, P<ast::Expr>, ast::Generics), ()> {
     if trait_generics.ty_params.is_empty() && forward_tys.is_empty() {
-        (
+        Ok((
             builder.item().tuple_struct("__Visitor").build(),
             builder.ty().id("__Visitor"),
             builder.expr().id("__Visitor"),
             trait_generics.clone(),
-        )
+        ))
     } else {
         let placeholders : Vec<_> = trait_generics.ty_params.iter()
             .map(|t| builder.ty().id(t.ident))
@@ -187,9 +199,9 @@ fn deserialize_visitor(
         let mut trait_generics = trait_generics.clone();
         let mut ty_params = forward_ty_params.clone();
         ty_params.extend(trait_generics.ty_params.into_vec());
-        trait_generics.ty_params = OwnedSlice::from_vec(ty_params);
+        trait_generics.ty_params = P::from_vec(ty_params);
 
-        (
+        Ok((
             builder.item().tuple_struct("__Visitor")
                 .generics().with(trait_generics.clone()).build()
                 .with_tys({
@@ -227,7 +239,7 @@ fn deserialize_visitor(
                 })
                 .build(),
             trait_generics,
-        )
+        ))
     }
 }
 
@@ -251,10 +263,10 @@ fn deserialize_unit_struct(
     cx: &ExtCtxt,
     builder: &aster::AstBuilder,
     type_ident: Ident,
-) -> P<ast::Expr> {
+) -> Result<P<ast::Expr>, ()> {
     let type_name = builder.expr().str(type_ident);
 
-    quote_expr!(cx, {
+    Ok(quote_expr!(cx, {
         struct __Visitor;
 
         impl ::serde::de::Visitor for __Visitor {
@@ -277,7 +289,7 @@ fn deserialize_unit_struct(
         }
 
         deserializer.visit_unit_struct($type_name, __Visitor)
-    })
+    }))
 }
 
 fn deserialize_newtype_struct(
@@ -286,16 +298,15 @@ fn deserialize_newtype_struct(
     type_ident: Ident,
     impl_generics: &ast::Generics,
     ty: P<ast::Ty>,
-) -> P<ast::Expr> {
+) -> Result<P<ast::Expr>, ()> {
     let where_clause = &impl_generics.where_clause;
 
-    let (visitor_item, visitor_ty, visitor_expr, visitor_generics) =
-        deserialize_visitor(
-            builder,
-            impl_generics,
-            vec![deserializer_ty_param(builder)],
-            vec![deserializer_ty_arg(builder)],
-        );
+    let (visitor_item, visitor_ty, visitor_expr, visitor_generics) = try!(deserialize_visitor(
+        builder,
+        impl_generics,
+        vec![deserializer_ty_param(builder)],
+        vec![deserializer_ty_arg(builder)],
+    ));
 
     let visit_seq_expr = deserialize_seq(
         cx,
@@ -306,7 +317,7 @@ fn deserialize_newtype_struct(
 
     let type_name = builder.expr().str(type_ident);
 
-    quote_expr!(cx, {
+    Ok(quote_expr!(cx, {
         $visitor_item
 
         impl $visitor_generics ::serde::de::Visitor for $visitor_ty $where_clause {
@@ -329,7 +340,7 @@ fn deserialize_newtype_struct(
         }
 
         deserializer.visit_newtype_struct($type_name, $visitor_expr)
-    })
+    }))
 }
 
 fn deserialize_tuple_struct(
@@ -339,16 +350,15 @@ fn deserialize_tuple_struct(
     impl_generics: &ast::Generics,
     ty: P<ast::Ty>,
     fields: usize,
-) -> P<ast::Expr> {
+) -> Result<P<ast::Expr>, ()> {
     let where_clause = &impl_generics.where_clause;
 
-    let (visitor_item, visitor_ty, visitor_expr, visitor_generics) =
-        deserialize_visitor(
-            builder,
-            impl_generics,
-            vec![deserializer_ty_param(builder)],
-            vec![deserializer_ty_arg(builder)],
-        );
+    let (visitor_item, visitor_ty, visitor_expr, visitor_generics) = try!(deserialize_visitor(
+        builder,
+        impl_generics,
+        vec![deserializer_ty_param(builder)],
+        vec![deserializer_ty_arg(builder)],
+    ));
 
     let visit_seq_expr = deserialize_seq(
         cx,
@@ -359,7 +369,7 @@ fn deserialize_tuple_struct(
 
     let type_name = builder.expr().str(type_ident);
 
-    quote_expr!(cx, {
+    Ok(quote_expr!(cx, {
         $visitor_item
 
         impl $visitor_generics ::serde::de::Visitor for $visitor_ty $where_clause {
@@ -374,7 +384,7 @@ fn deserialize_tuple_struct(
         }
 
         deserializer.visit_tuple_struct($type_name, $fields, $visitor_expr)
-    })
+    }))
 }
 
 fn deserialize_seq(
@@ -383,7 +393,7 @@ fn deserialize_seq(
     struct_path: ast::Path,
     fields: usize,
 ) -> P<ast::Expr> {
-    let let_values: Vec<P<ast::Stmt>> = (0 .. fields)
+    let let_values: Vec<ast::Stmt> = (0 .. fields)
         .map(|i| {
             let name = builder.id(format!("__field{}", i));
             quote_stmt!(cx,
@@ -416,8 +426,8 @@ fn deserialize_struct_as_seq(
     builder: &aster::AstBuilder,
     struct_path: ast::Path,
     fields: &[ast::StructField],
-) -> P<ast::Expr> {
-    let let_values: Vec<P<ast::Stmt>> = (0 .. fields.len())
+) -> Result<P<ast::Expr>, ()> {
+    let let_values: Vec<ast::Stmt> = (0 .. fields.len())
         .map(|i| {
             let name = builder.id(format!("__field{}", i));
             quote_stmt!(cx,
@@ -439,7 +449,9 @@ fn deserialize_struct_as_seq(
                     (
                         match field.node.kind {
                             ast::NamedField(name, _) => name.clone(),
-                            ast::UnnamedField(_) => cx.bug("struct contains unnamed fields"),
+                            ast::UnnamedField(_) => {
+                                cx.span_bug(field.span, "struct contains unnamed fields")
+                            }
                         },
                         builder.expr().id(format!("__field{}", i)),
                     )
@@ -447,13 +459,13 @@ fn deserialize_struct_as_seq(
         )
         .build();
 
-    quote_expr!(cx, {
+    Ok(quote_expr!(cx, {
         $let_values
 
         try!(visitor.end());
 
         Ok($result)
-    })
+    }))
 }
 
 fn deserialize_struct(
@@ -463,35 +475,35 @@ fn deserialize_struct(
     impl_generics: &ast::Generics,
     ty: P<ast::Ty>,
     fields: &[ast::StructField],
-) -> P<ast::Expr> {
+) -> Result<P<ast::Expr>, ()> {
     let where_clause = &impl_generics.where_clause;
 
-    let (visitor_item, visitor_ty, visitor_expr, visitor_generics) = deserialize_visitor(
+    let (visitor_item, visitor_ty, visitor_expr, visitor_generics) = try!(deserialize_visitor(
         builder,
         &impl_generics,
         vec![deserializer_ty_param(builder)],
         vec![deserializer_ty_arg(builder)],
-    );
+    ));
 
     let type_path = builder.path().id(type_ident).build();
 
-    let visit_seq_expr = deserialize_struct_as_seq(
+    let visit_seq_expr = try!(deserialize_struct_as_seq(
         cx,
         builder,
         type_path.clone(),
         fields,
-    );
+    ));
 
-    let (field_visitor, fields_stmt, visit_map_expr) = deserialize_struct_visitor(
+    let (field_visitor, fields_stmt, visit_map_expr) = try!(deserialize_struct_visitor(
         cx,
         builder,
         type_path.clone(),
         fields,
-    );
+    ));
 
     let type_name = builder.expr().str(type_ident);
 
-    quote_expr!(cx, {
+    Ok(quote_expr!(cx, {
         $field_visitor
 
         $visitor_item
@@ -517,7 +529,7 @@ fn deserialize_struct(
         $fields_stmt
 
         deserializer.visit_struct($type_name, FIELDS, $visitor_expr)
-    })
+    }))
 }
 
 fn deserialize_item_enum(
@@ -527,7 +539,7 @@ fn deserialize_item_enum(
     impl_generics: &ast::Generics,
     ty: P<ast::Ty>,
     enum_def: &EnumDef,
-) -> P<ast::Expr> {
+) -> Result<P<ast::Expr>, ()> {
     let where_clause = &impl_generics.where_clause;
 
     let type_name = builder.expr().str(type_ident);
@@ -538,7 +550,7 @@ fn deserialize_item_enum(
         enum_def.variants.iter()
             .map(|variant| {
                 let expr = builder.expr().str(variant.node.name);
-                 attr::FieldAttrsBuilder::new(builder)
+                 attr::FieldAttrsBuilder::new(cx, builder)
                     .name(expr)
                     .default()
                     .build()
@@ -546,7 +558,7 @@ fn deserialize_item_enum(
             .collect()
     );
 
-    let variants_expr = builder.expr().addr_of().slice()
+    let variants_expr = builder.expr().ref_().slice()
         .with_exprs(
             enum_def.variants.iter()
                 .map(|variant| {
@@ -560,35 +572,33 @@ fn deserialize_item_enum(
     ).unwrap();
 
     // Match arms to extract a variant from a string
-    let variant_arms: Vec<_> = enum_def.variants.iter()
-        .enumerate()
-        .map(|(i, variant)| {
-            let variant_name = builder.pat().enum_()
-                .id("__Field").id(format!("__field{}", i)).build()
-                .build();
+    let mut variant_arms = vec![];
+    for (i, variant) in enum_def.variants.iter().enumerate() {
+        let variant_name = builder.pat().path()
+            .id("__Field").id(format!("__field{}", i))
+            .build();
 
-            let expr = deserialize_variant(
-                cx,
-                builder,
-                type_ident,
-                impl_generics,
-                ty.clone(),
-                variant,
-            );
-
-            quote_arm!(cx, $variant_name => { $expr })
-        })
-        .collect();
-
-    let (visitor_item, visitor_ty, visitor_expr, visitor_generics) =
-        deserialize_visitor(
+        let expr = try!(deserialize_variant(
+            cx,
             builder,
+            type_ident,
             impl_generics,
-            vec![deserializer_ty_param(builder)],
-            vec![deserializer_ty_arg(builder)],
-        );
+            ty.clone(),
+            variant,
+        ));
 
-    quote_expr!(cx, {
+        let arm = quote_arm!(cx, $variant_name => { $expr });
+        variant_arms.push(arm);
+    }
+
+    let (visitor_item, visitor_ty, visitor_expr, visitor_generics) = try!(deserialize_visitor(
+        builder,
+        impl_generics,
+        vec![deserializer_ty_param(builder)],
+        vec![deserializer_ty_arg(builder)],
+    ));
+
+    Ok(quote_expr!(cx, {
         $variant_visitor
 
         $visitor_item
@@ -608,7 +618,7 @@ fn deserialize_item_enum(
         $variants_stmt
 
         deserializer.visit_enum($type_name, VARIANTS, $visitor_expr)
-    })
+    }))
 }
 
 fn deserialize_variant(
@@ -618,21 +628,21 @@ fn deserialize_variant(
     generics: &ast::Generics,
     ty: P<ast::Ty>,
     variant: &ast::Variant,
-) -> P<ast::Expr> {
+) -> Result<P<ast::Expr>, ()> {
     let variant_ident = variant.node.name;
 
     match variant.node.data {
         ast::VariantData::Unit(_) => {
-            quote_expr!(cx, {
+            Ok(quote_expr!(cx, {
                 try!(visitor.visit_unit());
                 Ok($type_ident::$variant_ident)
-            })
+            }))
         }
         ast::VariantData::Tuple(ref args, _) if args.len() == 1 => {
-            quote_expr!(cx, {
+            Ok(quote_expr!(cx, {
                 let val = try!(visitor.visit_newtype());
                 Ok($type_ident::$variant_ident(val))
-            })
+            }))
         }
         ast::VariantData::Tuple(ref fields, _) => {
             deserialize_tuple_variant(
@@ -667,16 +677,15 @@ fn deserialize_tuple_variant(
     generics: &ast::Generics,
     ty: P<ast::Ty>,
     fields: usize,
-) -> P<ast::Expr> {
+) -> Result<P<ast::Expr>, ()> {
     let where_clause = &generics.where_clause;
 
-    let (visitor_item, visitor_ty, visitor_expr, visitor_generics) =
-        deserialize_visitor(
-            builder,
-            generics,
-            vec![deserializer_ty_param(builder)],
-            vec![deserializer_ty_arg(builder)],
-        );
+    let (visitor_item, visitor_ty, visitor_expr, visitor_generics) = try!(deserialize_visitor(
+        builder,
+        generics,
+        vec![deserializer_ty_param(builder)],
+        vec![deserializer_ty_arg(builder)],
+    ));
 
     let visit_seq_expr = deserialize_seq(
         cx,
@@ -685,7 +694,7 @@ fn deserialize_tuple_variant(
         fields,
     );
 
-    quote_expr!(cx, {
+    Ok(quote_expr!(cx, {
         $visitor_item
 
         impl $visitor_generics ::serde::de::Visitor for $visitor_ty $where_clause {
@@ -699,7 +708,7 @@ fn deserialize_tuple_variant(
         }
 
         visitor.visit_tuple($fields, $visitor_expr)
-    })
+    }))
 }
 
 fn deserialize_struct_variant(
@@ -710,7 +719,7 @@ fn deserialize_struct_variant(
     generics: &ast::Generics,
     ty: P<ast::Ty>,
     fields: &[ast::StructField],
-) -> P<ast::Expr> {
+) -> Result<P<ast::Expr>, ()> {
     let where_clause = &generics.where_clause;
 
     let type_path = builder.path()
@@ -718,29 +727,28 @@ fn deserialize_struct_variant(
         .id(variant_ident)
         .build();
 
-    let visit_seq_expr = deserialize_struct_as_seq(
+    let visit_seq_expr = try!(deserialize_struct_as_seq(
         cx,
         builder,
         type_path.clone(),
         fields,
-    );
+    ));
 
-    let (field_visitor, fields_stmt, field_expr) = deserialize_struct_visitor(
+    let (field_visitor, fields_stmt, field_expr) = try!(deserialize_struct_visitor(
         cx,
         builder,
         type_path,
         fields,
-    );
+    ));
 
-    let (visitor_item, visitor_ty, visitor_expr, visitor_generics) =
-        deserialize_visitor(
-            builder,
-            generics,
-            vec![deserializer_ty_param(builder)],
-            vec![deserializer_ty_arg(builder)],
-        );
+    let (visitor_item, visitor_ty, visitor_expr, visitor_generics) = try!(deserialize_visitor(
+        builder,
+        generics,
+        vec![deserializer_ty_param(builder)],
+        vec![deserializer_ty_arg(builder)],
+    ));
 
-    quote_expr!(cx, {
+    Ok(quote_expr!(cx, {
         $field_visitor
 
         $visitor_item
@@ -766,7 +774,7 @@ fn deserialize_struct_variant(
         $fields_stmt
 
         visitor.visit_struct(FIELDS, $visitor_expr)
-    })
+    }))
 }
 
 fn deserialize_field_visitor(
@@ -909,7 +917,7 @@ fn deserialize_field_visitor(
                     }
                 }
 
-                deserializer.visit(__FieldVisitor::<D>{ phantom: PhantomData })
+                deserializer.visit_struct_field(__FieldVisitor::<D>{ phantom: PhantomData })
             }
         }
     ).unwrap();
@@ -922,27 +930,29 @@ fn deserialize_struct_visitor(
     builder: &aster::AstBuilder,
     struct_path: ast::Path,
     fields: &[ast::StructField],
-) -> (Vec<P<ast::Item>>, P<ast::Stmt>, P<ast::Expr>) {
+) -> Result<(Vec<P<ast::Item>>, ast::Stmt, P<ast::Expr>), ()> {
     let field_visitor = deserialize_field_visitor(
         cx,
         builder,
-        field::struct_field_attrs(cx, builder, fields),
+        try!(field::struct_field_attrs(cx, builder, fields)),
     );
 
-    let visit_map_expr = deserialize_map(
+    let visit_map_expr = try!(deserialize_map(
         cx,
         builder,
         struct_path,
         fields,
-    );
+    ));
 
-    let fields_expr = builder.expr().addr_of().slice()
+    let fields_expr = builder.expr().ref_().slice()
         .with_exprs(
             fields.iter()
                 .map(|field| {
                     match field.node.kind {
                         ast::NamedField(name, _) => builder.expr().str(name),
-                        ast::UnnamedField(_) => panic!("struct contains unnamed fields"),
+                        ast::UnnamedField(_) => {
+                            cx.span_bug(field.span, "struct contains unnamed fields")
+                        }
                     }
                 })
         )
@@ -952,7 +962,7 @@ fn deserialize_struct_visitor(
         const FIELDS: &'static [&'static str] = $fields_expr;
     ).unwrap();
 
-    (field_visitor, fields_stmt, visit_map_expr)
+    Ok((field_visitor, fields_stmt, visit_map_expr))
 }
 
 fn deserialize_map(
@@ -960,14 +970,14 @@ fn deserialize_map(
     builder: &aster::AstBuilder,
     struct_path: ast::Path,
     fields: &[ast::StructField],
-) -> P<ast::Expr> {
+) -> Result<P<ast::Expr>, ()> {
     // Create the field names for the fields.
     let field_names: Vec<ast::Ident> = (0 .. fields.len())
         .map(|i| builder.id(format!("__field{}", i)))
         .collect();
 
     // Declare each field.
-    let let_values: Vec<P<ast::Stmt>> = field_names.iter()
+    let let_values: Vec<ast::Stmt> = field_names.iter()
         .map(|field_name| quote_stmt!(cx, let mut $field_name = None;).unwrap())
         .collect();
 
@@ -982,8 +992,10 @@ fn deserialize_map(
         })
         .collect();
 
-    let extract_values: Vec<P<ast::Stmt>> = field_names.iter()
-        .zip(field::struct_field_attrs(cx, builder, fields).iter())
+    let field_attrs = try!(field::struct_field_attrs(cx, builder, fields));
+
+    let extract_values: Vec<ast::Stmt> = field_names.iter()
+        .zip(field_attrs.iter())
         .map(|(field_name, field_attr)| {
             let missing_expr = if field_attr.use_default() {
                 quote_expr!(cx, ::std::default::Default::default())
@@ -1026,7 +1038,9 @@ fn deserialize_map(
                     (
                         match field.node.kind {
                             ast::NamedField(name, _) => name.clone(),
-                            ast::UnnamedField(_) => panic!("struct contains unnamed fields"),
+                            ast::UnnamedField(_) => {
+                                cx.span_bug(field.span, "struct contains unnamed fields")
+                            }
                         },
                         builder.expr().id(field_name),
                     )
@@ -1034,7 +1048,7 @@ fn deserialize_map(
         )
         .build();
 
-    quote_expr!(cx, {
+    Ok(quote_expr!(cx, {
         $let_values
 
         while let Some(key) = try!(visitor.visit_key()) {
@@ -1048,5 +1062,5 @@ fn deserialize_map(
         try!(visitor.end());
 
         Ok($result)
-    })
+    }))
 }

serde_codegen/src/field.rs

@@ -2,16 +2,29 @@ use syntax::ast;
 use syntax::ext::base::ExtCtxt;
 
 use aster;
-use attr::{FieldAttrs, FieldAttrsBuilder};
+use attr;
 
 pub fn struct_field_attrs(
-    _cx: &ExtCtxt,
+    cx: &ExtCtxt,
     builder: &aster::AstBuilder,
     fields: &[ast::StructField],
-) -> Vec<FieldAttrs> {
-    fields.iter()
-        .map(|field| {
-            FieldAttrsBuilder::new(builder).field(field).build()
-        })
-        .collect()
+) -> Result<Vec<attr::FieldAttrs>, ()> {
+    let mut attrs = vec![];
+    for field in fields {
+        let builder = attr::FieldAttrsBuilder::new(cx, builder);
+        let builder = try!(builder.field(field));
+        let attr = builder.build();
+        attrs.push(attr);
+    }
+
+    Ok(attrs)
+}
+
+pub fn container_attrs(
+    cx: &ExtCtxt,
+    container: &ast::Item,
+) -> Result<attr::ContainerAttrs, ()> {
+    let builder = attr::ContainerAttrsBuilder::new(cx);
+    let builder = try!(builder.attrs(container.attrs()));
+    Ok(builder.build())
 }

serde_codegen/src/lib.rs

@@ -1,3 +1,6 @@
+#![cfg_attr(feature = "nightly-testing", plugin(clippy))]
+#![cfg_attr(feature = "nightly-testing", feature(plugin))]
+#![cfg_attr(feature = "nightly-testing", allow(used_underscore_binding))]
 #![cfg_attr(not(feature = "with-syntex"), feature(rustc_private, plugin))]
 #![cfg_attr(not(feature = "with-syntex"), plugin(quasi_macros))]
 
@@ -16,6 +19,9 @@ extern crate syntax;
 #[cfg(not(feature = "with-syntex"))]
 extern crate rustc_plugin;
 
+#[cfg(not(feature = "with-syntex"))]
+use syntax::feature_gate::AttributeType;
+
 #[cfg(feature = "with-syntex")]
 include!(concat!(env!("OUT_DIR"), "/lib.rs"));
 
@@ -26,14 +32,6 @@ include!("lib.rs.in");
 pub fn register(reg: &mut syntex::Registry) {
     use syntax::{ast, fold};
 
-    reg.add_attr("feature(custom_derive)");
-    reg.add_attr("feature(custom_attribute)");
-
-    reg.add_decorator("derive_Serialize", ser::expand_derive_serialize);
-    reg.add_decorator("derive_Deserialize", de::expand_derive_deserialize);
-
-    reg.add_post_expansion_pass(strip_attributes);
-
     /// Strip the serde attributes from the crate.
     #[cfg(feature = "with-syntex")]
     fn strip_attributes(krate: ast::Crate) -> ast::Crate {
@@ -43,7 +41,7 @@ pub fn register(reg: &mut syntex::Registry) {
         impl fold::Folder for StripAttributeFolder {
             fn fold_attribute(&mut self, attr: ast::Attribute) -> Option<ast::Attribute> {
                 match attr.node.value.node {
-                    ast::MetaList(ref n, _) if n == &"serde" => { return None; }
+                    ast::MetaItemKind::List(ref n, _) if n == &"serde" => { return None; }
                     _ => {}
                 }
 
@@ -57,6 +55,14 @@ pub fn register(reg: &mut syntex::Registry) {
 
         fold::Folder::fold_crate(&mut StripAttributeFolder, krate)
     }
+
+    reg.add_attr("feature(custom_derive)");
+    reg.add_attr("feature(custom_attribute)");
+
+    reg.add_decorator("derive_Serialize", ser::expand_derive_serialize);
+    reg.add_decorator("derive_Deserialize", de::expand_derive_deserialize);
+
+    reg.add_post_expansion_pass(strip_attributes);
 }
 
 #[cfg(not(feature = "with-syntex"))]
@@ -70,4 +76,6 @@ pub fn register(reg: &mut rustc_plugin::Registry) {
         syntax::parse::token::intern("derive_Deserialize"),
         syntax::ext::base::MultiDecorator(
             Box::new(de::expand_derive_deserialize)));
+
+    reg.register_attribute("serde".to_owned(), AttributeType::Normal);
 }

serde_codegen/src/ser.rs

@@ -4,7 +4,6 @@ use syntax::ast::{
     Ident,
     MetaItem,
     Item,
-    Expr,
 };
 use syntax::ast;
 use syntax::codemap::Span;
@@ -12,7 +11,7 @@ use syntax::ext::base::{Annotatable, ExtCtxt};
 use syntax::ext::build::AstBuilder;
 use syntax::ptr::P;
 
-use field::struct_field_attrs;
+use field;
 
 pub fn expand_derive_serialize(
     cx: &mut ExtCtxt,
@@ -26,7 +25,7 @@ pub fn expand_derive_serialize(
         _ => {
             cx.span_err(
                 meta_item.span,
-                "`derive` may only be applied to structs and enums");
+                "`#[derive(Serialize)]` may only be applied to structs and enums");
             return;
         }
     };
@@ -34,9 +33,14 @@ pub fn expand_derive_serialize(
     let builder = aster::AstBuilder::new().span(span);
 
     let generics = match item.node {
-        ast::ItemStruct(_, ref generics) => generics,
-        ast::ItemEnum(_, ref generics) => generics,
-        _ => cx.bug("expected ItemStruct or ItemEnum in #[derive(Serialize)]")
+        ast::ItemKind::Struct(_, ref generics) => generics,
+        ast::ItemKind::Enum(_, ref generics) => generics,
+        _ => {
+            cx.span_err(
+                meta_item.span,
+                "`#[derive(Serialize)]` may only be applied to structs and enums");
+            return;
+        }
     };
 
     let impl_generics = builder.from_generics(generics.clone())
@@ -49,13 +53,13 @@ pub fn expand_derive_serialize(
         .segment(item.ident).with_generics(impl_generics.clone()).build()
         .build();
 
-    let body = serialize_body(
-        cx,
-        &builder,
-        &item,
-        &impl_generics,
-        ty.clone(),
-    );
+    let body = match serialize_body(cx, &builder, &item, &impl_generics, ty.clone()) {
+        Ok(body) => body,
+        Err(()) => {
+            // An error occured, but it should have been reported already.
+            return;
+        }
+    };
 
     let where_clause = &impl_generics.where_clause;
 
@@ -78,19 +82,24 @@ fn serialize_body(
     item: &Item,
     impl_generics: &ast::Generics,
     ty: P<ast::Ty>,
-) -> P<ast::Expr> {
+) -> Result<P<ast::Expr>, ()> {
+    // Note: While we don't have any container attributes, we still want to try to
+    // parse them so we can report a proper error if we get passed an unknown attribute.
+    let _ = try!(field::container_attrs(cx, item));
+
     match item.node {
-        ast::ItemStruct(ref variant_data, _) => {
+        ast::ItemKind::Struct(ref variant_data, _) => {
             serialize_item_struct(
                 cx,
                 builder,
                 item,
                 impl_generics,
                 ty,
+                item.span,
                 variant_data,
             )
         }
-        ast::ItemEnum(ref enum_def, _) => {
+        ast::ItemKind::Enum(ref enum_def, _) => {
             serialize_item_enum(
                 cx,
                 builder,
@@ -100,7 +109,10 @@ fn serialize_body(
                 enum_def,
             )
         }
-        _ => cx.bug("expected ItemStruct or ItemEnum in #[derive(Serialize)]")
+        _ => {
+            cx.span_bug(item.span,
+                        "expected ItemStruct or ItemEnum in #[derive(Serialize)]");
+        }
     }
 }
 
@@ -110,8 +122,9 @@ fn serialize_item_struct(
     item: &Item,
     impl_generics: &ast::Generics,
     ty: P<ast::Ty>,
+    span: Span,
     variant_data: &ast::VariantData,
-) -> P<ast::Expr> {
+) -> Result<P<ast::Expr>, ()> {
     match *variant_data {
         ast::VariantData::Unit(_) => {
             serialize_unit_struct(
@@ -129,7 +142,7 @@ fn serialize_item_struct(
         }
         ast::VariantData::Tuple(ref fields, _) => {
             if fields.iter().any(|field| !field.node.kind.is_unnamed()) {
-                cx.bug("tuple struct has named fields")
+                cx.span_bug(span, "tuple struct has named fields")
             }
 
             serialize_tuple_struct(
@@ -143,7 +156,7 @@ fn serialize_item_struct(
         }
         ast::VariantData::Struct(ref fields, _) => {
             if fields.iter().any(|field| field.node.kind.is_unnamed()) {
-                cx.bug("struct has unnamed fields")
+                cx.span_bug(span, "struct has unnamed fields")
             }
 
             serialize_struct(
@@ -162,20 +175,24 @@ fn serialize_unit_struct(
     cx: &ExtCtxt,
     builder: &aster::AstBuilder,
     type_ident: Ident
-) -> P<ast::Expr> {
+) -> Result<P<ast::Expr>, ()> {
     let type_name = builder.expr().str(type_ident);
 
-    quote_expr!(cx, serializer.visit_unit_struct($type_name))
+    Ok(quote_expr!(cx,
+        serializer.visit_unit_struct($type_name)
+    ))
 }
 
 fn serialize_newtype_struct(
     cx: &ExtCtxt,
     builder: &aster::AstBuilder,
     type_ident: Ident
-) -> P<ast::Expr> {
+) -> Result<P<ast::Expr>, ()> {
     let type_name = builder.expr().str(type_ident);
 
-    quote_expr!(cx, serializer.visit_newtype_struct($type_name, &self.0))
+    Ok(quote_expr!(cx,
+        serializer.visit_newtype_struct($type_name, &self.0)
+    ))
 }
 
 fn serialize_tuple_struct(
@@ -185,7 +202,7 @@ fn serialize_tuple_struct(
     impl_generics: &ast::Generics,
     ty: P<ast::Ty>,
     fields: usize,
-) -> P<ast::Expr> {
+) -> Result<P<ast::Expr>, ()> {
     let (visitor_struct, visitor_impl) = serialize_tuple_struct_visitor(
         cx,
         builder,
@@ -200,7 +217,7 @@ fn serialize_tuple_struct(
 
     let type_name = builder.expr().str(type_ident);
 
-    quote_expr!(cx, {
+    Ok(quote_expr!(cx, {
         $visitor_struct
         $visitor_impl
         serializer.visit_tuple_struct($type_name, Visitor {
@@ -208,7 +225,7 @@ fn serialize_tuple_struct(
             state: 0,
             _structure_ty: ::std::marker::PhantomData::<&$ty>,
         })
-    })
+    }))
 }
 
 fn serialize_struct(
@@ -218,8 +235,13 @@ fn serialize_struct(
     impl_generics: &ast::Generics,
     ty: P<ast::Ty>,
     fields: &[ast::StructField],
-) -> P<ast::Expr> {
-    let (visitor_struct, visitor_impl) = serialize_struct_visitor(
+) -> Result<P<ast::Expr>, ()> {
+    let value_exprs = fields.iter().map(|field| {
+        let name = field.node.ident().expect("struct has unnamed field");
+        quote_expr!(cx, &self.value.$name)
+    });
+
+    let (visitor_struct, visitor_impl) = try!(serialize_struct_visitor(
         cx,
         builder,
         ty.clone(),
@@ -229,15 +251,12 @@ fn serialize_struct(
             .build_ty(ty.clone()),
         fields,
         impl_generics,
-        fields.iter().map(|field| {
-            let name = field.node.ident().expect("struct has unnamed field");
-            quote_expr!(cx, &self.value.$name)
-        })
-    );
+        value_exprs,
+    ));
 
     let type_name = builder.expr().str(type_ident);
 
-    quote_expr!(cx, {
+    Ok(quote_expr!(cx, {
         $visitor_struct
         $visitor_impl
         serializer.visit_struct($type_name, Visitor {
@@ -245,7 +264,7 @@ fn serialize_struct(
             state: 0,
             _structure_ty: ::std::marker::PhantomData::<&$ty>,
         })
-    })
+    }))
 }
 
 fn serialize_item_enum(
@@ -255,27 +274,28 @@ fn serialize_item_enum(
     impl_generics: &ast::Generics,
     ty: P<ast::Ty>,
     enum_def: &ast::EnumDef,
-) -> P<ast::Expr> {
-    let arms: Vec<ast::Arm> = enum_def.variants.iter()
-        .enumerate()
-        .map(|(variant_index, variant)| {
-            serialize_variant(
-                cx,
-                builder,
-                type_ident,
-                impl_generics,
-                ty.clone(),
-                variant,
-                variant_index,
-            )
-        })
-        .collect();
+) -> Result<P<ast::Expr>, ()> {
+    let mut arms = vec![];
 
-    quote_expr!(cx,
+    for (variant_index, variant) in enum_def.variants.iter().enumerate() {
+        let arm = try!(serialize_variant(
+            cx,
+            builder,
+            type_ident,
+            impl_generics,
+            ty.clone(),
+            variant,
+            variant_index,
+        ));
+
+        arms.push(arm);
+    }
+
+    Ok(quote_expr!(cx,
         match *self {
             $arms
         }
-    )
+    ))
 }
 
 fn serialize_variant(
@@ -286,18 +306,18 @@ fn serialize_variant(
     ty: P<ast::Ty>,
     variant: &ast::Variant,
     variant_index: usize,
-) -> ast::Arm {
+) -> Result<ast::Arm, ()> {
     let type_name = builder.expr().str(type_ident);
     let variant_ident = variant.node.name;
     let variant_name = builder.expr().str(variant_ident);
 
     match variant.node.data {
         ast::VariantData::Unit(_) => {
-            let pat = builder.pat().enum_()
-                .id(type_ident).id(variant_ident).build()
+            let pat = builder.pat().path()
+                .id(type_ident).id(variant_ident)
                 .build();
 
-            quote_arm!(cx,
+            Ok(quote_arm!(cx,
                 $pat => {
                     ::serde::ser::Serializer::visit_unit_variant(
                         serializer,
@@ -306,7 +326,7 @@ fn serialize_variant(
                         $variant_name,
                     )
                 }
-            )
+            ))
         },
         ast::VariantData::Tuple(ref fields, _) if fields.len() == 1 => {
             let field = builder.id("__simple_value");
@@ -315,7 +335,8 @@ fn serialize_variant(
                 .id(type_ident).id(variant_ident).build()
                 .with_pats(Some(field).into_iter())
                 .build();
-            quote_arm!(cx,
+
+            Ok(quote_arm!(cx,
                 $pat => {
                     ::serde::ser::Serializer::visit_newtype_variant(
                         serializer,
@@ -325,7 +346,7 @@ fn serialize_variant(
                         __simple_value,
                     )
                 }
-            )
+            ))
         },
         ast::VariantData::Tuple(ref fields, _) => {
             let field_names: Vec<ast::Ident> = (0 .. fields.len())
@@ -352,7 +373,9 @@ fn serialize_variant(
                 field_names,
             );
 
-            quote_arm!(cx, $pat => { $expr })
+            Ok(quote_arm!(cx,
+                $pat => { $expr }
+            ))
         }
         ast::VariantData::Struct(ref fields, _) => {
             let field_names: Vec<_> = (0 .. fields.len())
@@ -368,7 +391,7 @@ fn serialize_variant(
                             let name = match field.node.kind {
                                 ast::NamedField(name, _) => name,
                                 ast::UnnamedField(_) => {
-                                    cx.bug("struct variant has unnamed fields")
+                                    cx.span_bug(field.span, "struct variant has unnamed fields")
                                 }
                             };
 
@@ -377,7 +400,7 @@ fn serialize_variant(
                 )
                 .build();
 
-            let expr = serialize_struct_variant(
+            let expr = try!(serialize_struct_variant(
                 cx,
                 builder,
                 type_name,
@@ -387,9 +410,11 @@ fn serialize_variant(
                 ty,
                 fields,
                 field_names,
-            );
+            ));
 
-            quote_arm!(cx, $pat => { $expr })
+            Ok(quote_arm!(cx,
+                $pat => { $expr }
+            ))
         }
     }
 }
@@ -454,7 +479,7 @@ fn serialize_struct_variant(
     structure_ty: P<ast::Ty>,
     fields: &[ast::StructField],
     field_names: Vec<Ident>,
-) -> P<ast::Expr> {
+) -> Result<P<ast::Expr>, ()> {
     let value_ty = builder.ty().tuple()
         .with_tys(
             fields.iter().map(|field| {
@@ -474,7 +499,7 @@ fn serialize_struct_variant(
         )
         .build();
 
-    let (visitor_struct, visitor_impl) = serialize_struct_visitor(
+    let (visitor_struct, visitor_impl) = try!(serialize_struct_visitor(
         cx,
         builder,
         structure_ty.clone(),
@@ -486,9 +511,9 @@ fn serialize_struct_variant(
                 .tup_field(i)
                 .field("value").self_()
         })
-    );
+    ));
 
-    quote_expr!(cx, {
+    Ok(quote_expr!(cx, {
         $visitor_struct
         $visitor_impl
         serializer.visit_struct_variant($type_name, $variant_index, $variant_name, Visitor {
@@ -496,7 +521,7 @@ fn serialize_struct_variant(
             state: 0,
             _structure_ty: ::std::marker::PhantomData::<&$structure_ty>,
         })
-    })
+    }))
 }
 
 fn serialize_tuple_struct_visitor(
@@ -574,12 +599,12 @@ fn serialize_struct_visitor<I>(
     fields: &[ast::StructField],
     generics: &ast::Generics,
     value_exprs: I,
-) -> (P<ast::Item>, P<ast::Item>)
+) -> Result<(P<ast::Item>, P<ast::Item>), ()>
     where I: Iterator<Item=P<ast::Expr>>,
 {
     let value_exprs = value_exprs.collect::<Vec<_>>();
 
-    let field_attrs = struct_field_attrs(cx, builder, fields);
+    let field_attrs = try!(field::struct_field_attrs(cx, builder, fields));
 
     let arms: Vec<ast::Arm> = field_attrs.iter()
         .zip(value_exprs.iter())
@@ -642,7 +667,7 @@ fn serialize_struct_visitor<I>(
         })
         .fold(quote_expr!(cx, 0), |sum, expr| quote_expr!(cx, $sum + $expr));
 
-    (
+    Ok((
         quote_item!(cx,
             struct Visitor $visitor_impl_generics $where_clause {
                 state: usize,
@@ -674,5 +699,5 @@ fn serialize_struct_visitor<I>(
                 }
             }
         ).unwrap(),
-    )
+    ))
 }

serde_macros/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "serde_macros"
-version = "0.6.6"
+version = "0.6.14"
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>"]
 license = "MIT/Apache-2.0"
 description = "Macros to auto-generate implementations for the serde framework"
@@ -12,10 +12,23 @@ keywords = ["serde", "serialization"]
 name = "serde_macros"
 plugin = true
 
+[features]
+nightly-testing = ["clippy", "serde/nightly-testing", "serde_codegen/nightly-testing"]
+
 [dependencies]
-serde_codegen = { version = "*", path = "../serde_codegen", default-features = false, features = ["nightly"] }
+clippy = { version = "^0.*", optional = true }
+serde_codegen = { version = "^0.6.14", path = "../serde_codegen", default-features = false, features = ["nightly"] }
 
 [dev-dependencies]
+compiletest_rs = "^0.0.11"
 num = "^0.1.27"
 rustc-serialize = "^0.3.16"
-serde = { version = "*", path = "../serde", features = ["nightly", "num-impls"] }
+serde = { version = "^0.6.14", path = "../serde", features = ["num-impls"] }
+
+[[test]]
+name = "test"
+path = "tests/test.rs"
+
+[[bench]]
+name = "bench"
+path = "benches/bench.rs"

serde_macros/benches/bench.rs

@@ -1,4 +1,5 @@
 #![feature(custom_attribute, custom_derive, plugin, test)]
+#![cfg_attr(feature = "clippy", plugin(clippy))]
 #![plugin(serde_macros)]
 
 extern crate num;

serde_macros/src/lib.rs

@@ -1,4 +1,6 @@
 #![feature(plugin_registrar, rustc_private)]
+#![cfg_attr(feature = "clippy", feature(plugin))]
+#![cfg_attr(feature = "clippy", plugin(clippy))]
 
 extern crate serde_codegen;
 extern crate rustc_plugin;

serde_macros/tests/compile-fail/reject-unknown-attributes.rs

@@ -0,0 +1,30 @@
+#![feature(custom_attribute, custom_derive, plugin)]
+#![plugin(serde_macros)]
+
+extern crate serde;
+
+#[derive(Serialize)]
+#[serde(abc="xyz")] //~ unknown serde container attribute `abc = "xyz"`
+struct Foo {
+    x: u32,
+}
+
+#[derive(Deserialize)]
+#[serde(abc="xyz")] //~ unknown serde container attribute `abc = "xyz"`
+struct Foo {
+    x: u32,
+}
+
+#[derive(Serialize)]
+struct Foo {
+    #[serde(abc="xyz")] //~ unknown serde field attribute `abc = "xyz"`
+    x: u32,
+}
+
+#[derive(Deserialize)]
+struct Foo {
+    #[serde(abc="xyz")] //~ unknown serde field attribute `abc = "xyz"`
+    x: u32,
+}
+
+fn main() { }

serde_macros/tests/compile_tests.rs

@@ -0,0 +1,25 @@
+extern crate compiletest_rs as compiletest;
+
+use std::path::PathBuf;
+use std::env::var;
+
+fn run_mode(mode: &'static str) {
+    let mut config = compiletest::default_config();
+
+    let cfg_mode = mode.parse().ok().expect("Invalid mode");
+
+    config.target_rustcflags = Some("-L target/debug/ -L target/debug/deps/".to_owned());
+    if let Ok(name) = var::<&str>("TESTNAME") {
+        let s : String = name.to_owned();
+        config.filter = Some(s)
+    }
+    config.mode = cfg_mode;
+    config.src_base = PathBuf::from(format!("tests/{}", mode));
+
+    compiletest::run_tests(&config);
+}
+
+#[test]
+fn compile_test() {
+    run_mode("compile-fail");
+}

serde_macros/tests/test.rs

@@ -6,3 +6,5 @@ extern crate serde;
 extern crate test;
 
 include!("../../serde_tests/tests/test.rs.in");
+
+mod compile_tests;

serde_tests/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "serde_tests"
-version = "0.6.2"
+version = "0.6.3"
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>"]
 license = "MIT/Apache-2.0"
 description = "A generic serialization/deserialization framework"
@@ -10,16 +10,22 @@ readme = "README.md"
 keywords = ["serialization"]
 build = "build.rs"
 
+[features]
+nightly-testing = ["clippy", "serde/nightly-testing", "serde_codegen/nightly-testing"]
+
 [build-dependencies]
-syntex = { version = "^0.22.0" }
-syntex_syntax = { version = "^0.23.0" }
-serde_codegen = { version = "*", path = "../serde_codegen", features = ["with-syntex"] }
+syntex = { version = "^0.29.0" }
+syntex_syntax = { version = "^0.29.0" }
+serde_codegen = { version = "^0.6.14", path = "../serde_codegen", features = ["with-syntex"] }
 
 [dev-dependencies]
-num = "^0.1.27"
+num = "^0.1.26"
 rustc-serialize = "^0.3.16"
 serde = { version = "*", path = "../serde", features = ["num-impls"] }
-syntex = "^0.22.0"
+syntex = "^0.29.0"
+
+[dependencies]
+clippy = { version = "^0.*", optional = true }
 
 [[test]]
 name = "test"

serde_tests/benches/bench.rs

@@ -1,4 +1,6 @@
 #![feature(test)]
+#![cfg_attr(feature = "nightly", feature(plugin))]
+#![cfg_attr(feature = "nightly", plugin(clippy))]
 
 extern crate num;
 extern crate rustc_serialize;

serde_tests/benches/bench_enum.rs

@@ -415,7 +415,7 @@ fn bench_decoder_dog(b: &mut Bencher) {
 #[bench]
 fn bench_decoder_frog(b: &mut Bencher) {
     b.iter(|| {
-        let animal = Animal::Frog("Henry".to_string(), 349);
+        let animal = Animal::Frog("Henry".to_owned(), 349);
 
         let mut d = decoder::AnimalDecoder::new(animal.clone());
         let value: Animal = Decodable::decode(&mut d).unwrap();
@@ -439,7 +439,7 @@ fn bench_deserializer_dog(b: &mut Bencher) {
 #[bench]
 fn bench_deserializer_frog(b: &mut Bencher) {
     b.iter(|| {
-        let animal = Animal::Frog("Henry".to_string(), 349);
+        let animal = Animal::Frog("Henry".to_owned(), 349);
 
         let mut d = deserializer::AnimalDeserializer::new(animal.clone());
         let value: Animal = Deserialize::deserialize(&mut d).unwrap();

serde_tests/benches/bench_map.rs

@@ -399,7 +399,7 @@ fn bench_decoder_000(b: &mut Bencher) {
 fn bench_decoder_003(b: &mut Bencher) {
     b.iter(|| {
         let mut m: HashMap<String, isize> = HashMap::new();
-        for i in (0 .. 3) {
+        for i in 0 .. 3 {
             m.insert(i.to_string(), i);
         }
         run_decoder(decoder::IsizeDecoder::new(m.clone()), m)
@@ -410,7 +410,7 @@ fn bench_decoder_003(b: &mut Bencher) {
 fn bench_decoder_100(b: &mut Bencher) {
     b.iter(|| {
         let mut m: HashMap<String, isize> = HashMap::new();
-        for i in (0 .. 100) {
+        for i in 0 .. 100 {
             m.insert(i.to_string(), i);
         }
         run_decoder(decoder::IsizeDecoder::new(m.clone()), m)
@@ -439,7 +439,7 @@ fn bench_deserializer_000(b: &mut Bencher) {
 fn bench_deserializer_003(b: &mut Bencher) {
     b.iter(|| {
         let mut m: HashMap<String, isize> = HashMap::new();
-        for i in (0 .. 3) {
+        for i in 0 .. 3 {
             m.insert(i.to_string(), i);
         }
         run_deserializer(deserializer::IsizeDeserializer::new(m.clone()), m)
@@ -450,7 +450,7 @@ fn bench_deserializer_003(b: &mut Bencher) {
 fn bench_deserializer_100(b: &mut Bencher) {
     b.iter(|| {
         let mut m: HashMap<String, isize> = HashMap::new();
-        for i in (0 .. 100) {
+        for i in 0 .. 100 {
             m.insert(i.to_string(), i);
         }
         run_deserializer(deserializer::IsizeDeserializer::new(m.clone()), m)

serde_tests/benches/bench_struct.rs

@@ -614,7 +614,7 @@ mod deserializer {
 fn bench_decoder_0_0(b: &mut Bencher) {
     b.iter(|| {
         let mut map = HashMap::new();
-        map.insert("abc".to_string(), Some('c'));
+        map.insert("abc".to_owned(), Some('c'));
 
         let outer = Outer {
             inner: vec!(),
@@ -653,11 +653,11 @@ fn bench_decoder_1_0(b: &mut Bencher) {
 fn bench_decoder_1_5(b: &mut Bencher) {
     b.iter(|| {
         let mut map = HashMap::new();
-        map.insert("1".to_string(), Some('a'));
-        map.insert("2".to_string(), None);
-        map.insert("3".to_string(), Some('b'));
-        map.insert("4".to_string(), None);
-        map.insert("5".to_string(), Some('c'));
+        map.insert("1".to_owned(), Some('a'));
+        map.insert("2".to_owned(), None);
+        map.insert("3".to_owned(), Some('b'));
+        map.insert("4".to_owned(), None);
+        map.insert("5".to_owned(), Some('c'));
 
         let outer = Outer {
             inner: vec!(
@@ -716,11 +716,11 @@ fn bench_deserializer_1_0(b: &mut Bencher) {
 fn bench_deserializer_1_5(b: &mut Bencher) {
     b.iter(|| {
         let mut map = HashMap::new();
-        map.insert("1".to_string(), Some('a'));
-        map.insert("2".to_string(), None);
-        map.insert("3".to_string(), Some('b'));
-        map.insert("4".to_string(), None);
-        map.insert("5".to_string(), Some('c'));
+        map.insert("1".to_owned(), Some('a'));
+        map.insert("2".to_owned(), None);
+        map.insert("3".to_owned(), Some('b'));
+        map.insert("4".to_owned(), None);
+        map.insert("5".to_owned(), Some('c'));
 
         let outer = Outer {
             inner: vec!(

serde_tests/tests/test.rs

@@ -1,3 +1,6 @@
+#![cfg_attr(feature = "nightly", feature(plugin))]
+#![cfg_attr(feature = "nightly", plugin(clippy))]
+
 extern crate num;
 extern crate serde;
 

serde_tests/tests/test_de.rs

@@ -1,4 +1,5 @@
 use std::collections::{BTreeMap, BTreeSet, HashMap, HashSet};
+use std::path::PathBuf;
 
 use num::FromPrimitive;
 use num::bigint::{BigInt, BigUint};
@@ -95,12 +96,12 @@ declare_tests! {
     test_char {
         'a' => vec![Token::Char('a')],
         'a' => vec![Token::Str("a")],
-        'a' => vec![Token::String("a".to_string())],
+        'a' => vec![Token::String("a".to_owned())],
     }
     test_string {
-        "abc".to_string() => vec![Token::Str("abc")],
-        "abc".to_string() => vec![Token::String("abc".to_string())],
-        "a".to_string() => vec![Token::Char('a')],
+        "abc".to_owned() => vec![Token::Str("abc")],
+        "abc".to_owned() => vec![Token::String("abc".to_owned())],
+        "a".to_owned() => vec![Token::Char('a')],
     }
     test_option {
         None::<i32> => vec![Token::Unit],
@@ -589,4 +590,9 @@ declare_tests! {
             Token::SeqEnd,
         ],
     }
+    test_path_buf {
+        PathBuf::from("/usr/local/lib") => vec![
+            Token::String("/usr/local/lib".to_owned()),
+        ],
+    }
 }

serde_tests/tests/test_ser.rs

@@ -1,4 +1,5 @@
 use std::collections::BTreeMap;
+use std::path::{Path, PathBuf};
 
 use num::FromPrimitive;
 use num::bigint::{BigInt, BigUint};
@@ -63,7 +64,7 @@ declare_ser_tests! {
     }
     test_str {
         "abc" => &[Token::Str("abc")],
-        "abc".to_string() => &[Token::Str("abc")],
+        "abc".to_owned() => &[Token::Str("abc")],
     }
     test_option {
         None::<i32> => &[Token::Option(false)],
@@ -293,4 +294,14 @@ declare_ser_tests! {
             Token::SeqEnd,
         ],
     }
+    test_path {
+        Path::new("/usr/local/lib") => &[
+            Token::Str("/usr/local/lib"),
+        ],
+    }
+    test_path_buf {
+        PathBuf::from("/usr/local/lib") => &[
+            Token::Str("/usr/local/lib"),
+        ],
+    }
 }

serde_tests/tests/token.rs

@@ -325,7 +325,7 @@ impl de::Error for Error {
     fn end_of_stream() -> Error { Error::EndOfStreamError }
 
     fn unknown_field(field: &str) -> Error {
-        Error::UnknownFieldError(field.to_string())
+        Error::UnknownFieldError(field.to_owned())
     }
 
     fn missing_field(field: &'static str) -> Error {
@@ -379,7 +379,6 @@ impl<I> de::Deserializer for Deserializer<I>
     fn visit<V>(&mut self, mut visitor: V) -> Result<V::Value, Error>
         where V: de::Visitor,
     {
-        println!("visit {:?}", self.tokens.peek());
         match self.tokens.next() {
             Some(Token::Bool(v)) => visitor.visit_bool(v),
             Some(Token::Isize(v)) => visitor.visit_isize(v),