Merge branch 'v0.6.x' into master

# Conflicts:
#	serde/Cargo.toml
#	serde/src/ser/impls.rs
#	serde_codegen/src/attr.rs
#	serde_codegen/src/de.rs
#	serde_codegen/src/field.rs
#	serde_codegen/src/ser.rs

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));
@@ -137,28 +141,36 @@ 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" => {
                 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" => {
                 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" => {
                 for item in items {
@@ -172,23 +184,27 @@ impl<'a> FieldAttrsBuilder<'a> {
                         _ => { }
                     }
                 }
-                self
+
+                Ok(self)
             }
             ast::MetaWord(ref name) if name == &"default" => {
-                self.default()
+                Ok(self.default())
             }
             ast::MetaWord(ref name) if name == &"skip_serializing" => {
-                self.skip_serializing_field()
+                Ok(self.skip_serializing_field())
             }
             ast::MetaWord(ref name) if name == &"skip_serializing_if_empty" => {
-                self.skip_serializing_field_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()
+                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(())
             }
         }
     }
@@ -256,46 +272,59 @@ impl ContainerAttrs {
     }
 }
 
-pub struct ContainerAttrsBuilder {
+pub struct ContainerAttrsBuilder<'a> {
+    cx: &'a ExtCtxt<'a>,
     deny_unknown_fields: bool,
 }
 
-impl ContainerAttrsBuilder {
-    pub fn new() -> ContainerAttrsBuilder {
+impl<'a> ContainerAttrsBuilder<'a> {
+    pub fn new(cx: &'a ExtCtxt) -> Self {
         ContainerAttrsBuilder {
+            cx: cx,
             deny_unknown_fields: false,
         }
     }
 
-    pub fn attrs(self, attrs: &[ast::Attribute]) -> ContainerAttrsBuilder {
-        attrs.iter().fold(self, ContainerAttrsBuilder::attr)
+    pub fn attrs(mut self, attrs: &[ast::Attribute]) -> Result<Self, ()> {
+        for attr in attrs {
+            self = try!(self.attr(attr));
+        }
+
+        Ok(self)
     }
 
-    pub fn attr(self, attr: &ast::Attribute) -> ContainerAttrsBuilder {
+    pub fn attr(mut self, attr: &ast::Attribute) -> Result<Self, ()> {
         match attr.node.value.node {
             ast::MetaList(ref name, ref items) if name == &"serde" => {
                 attr::mark_used(&attr);
-                items.iter().fold(self, ContainerAttrsBuilder::meta_item)
+                for item in items {
+                    self = try!(self.meta_item(item));
+                }
+
+                Ok(self)
             }
             _ => {
-                self
+                Ok(self)
             }
         }
     }
 
-    pub fn meta_item(self, meta_item: &P<ast::MetaItem>) -> ContainerAttrsBuilder {
+    pub fn meta_item(self, meta_item: &P<ast::MetaItem>) -> Result<Self, ()> {
         match meta_item.node {
             ast::MetaWord(ref name) if name == &"deny_unknown_fields" => {
-                self.deny_unknown_fields()
+                Ok(self.deny_unknown_fields())
             }
             _ => {
-                // Ignore unknown meta variables for now.
-                self
+                self.cx.span_err(
+                    meta_item.span,
+                    &format!("unknown serde container attribute `{}`",
+                             meta_item_to_string(meta_item)));
+                Err(())
             }
         }
     }
 
-    pub fn deny_unknown_fields(mut self) -> ContainerAttrsBuilder {
+    pub fn deny_unknown_fields(mut self) -> Self {
         self.deny_unknown_fields = true;
         self
     }

serde_codegen/src/de.rs

@@ -57,13 +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;
 
@@ -86,8 +86,8 @@ fn deserialize_body(
     item: &Item,
     impl_generics: &ast::Generics,
     ty: P<ast::Ty>,
-) -> P<ast::Expr> {
-    let container_attrs = field::container_attrs(cx, item);
+) -> Result<P<ast::Expr>, ()> {
+    let container_attrs = try!(field::container_attrs(cx, item));
 
     match item.node {
         ast::ItemStruct(ref variant_data, _) => {
@@ -129,7 +129,7 @@ fn deserialize_item_struct(
     span: Span,
     variant_data: &ast::VariantData,
     container_attrs: &ContainerAttrs,
-) -> P<ast::Expr> {
+) -> Result<P<ast::Expr>, ()> {
     match *variant_data {
         ast::VariantData::Unit(_) => {
             deserialize_unit_struct(
@@ -186,14 +186,14 @@ 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))
@@ -203,7 +203,7 @@ fn deserialize_visitor(
         ty_params.extend(trait_generics.ty_params.into_vec());
         trait_generics.ty_params = P::from_vec(ty_params);
 
-        (
+        Ok((
             builder.item().tuple_struct("__Visitor")
                 .generics().with(trait_generics.clone()).build()
                 .with_tys({
@@ -241,7 +241,7 @@ fn deserialize_visitor(
                 })
                 .build(),
             trait_generics,
-        )
+        ))
     }
 }
 
@@ -265,10 +265,10 @@ 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 {
@@ -291,7 +291,7 @@ fn deserialize_unit_struct(
         }
 
         deserializer.deserialize_unit_struct($type_name, __Visitor)
-    })
+    }))
 }
 
 fn deserialize_newtype_struct(
@@ -300,16 +300,15 @@ 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,
@@ -320,7 +319,7 @@ 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 {
@@ -343,7 +342,7 @@ fn deserialize_newtype_struct(
         }
 
         deserializer.deserialize_newtype_struct($type_name, $visitor_expr)
-    })
+    }))
 }
 
 fn deserialize_tuple_struct(
@@ -353,16 +352,15 @@ 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,
@@ -373,7 +371,7 @@ 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 {
@@ -388,7 +386,7 @@ fn deserialize_tuple_struct(
         }
 
         deserializer.deserialize_tuple_struct($type_name, $fields, $visitor_expr)
-    })
+    }))
 }
 
 fn deserialize_seq(
@@ -430,7 +428,7 @@ fn deserialize_struct_as_seq(
     builder: &aster::AstBuilder,
     struct_path: ast::Path,
     fields: &[ast::StructField],
-) -> P<ast::Expr> {
+) -> Result<P<ast::Expr>, ()> {
     let let_values: Vec<P<ast::Stmt>> = (0 .. fields.len())
         .map(|i| {
             let name = builder.id(format!("__field{}", i));
@@ -463,13 +461,13 @@ fn deserialize_struct_as_seq(
         )
         .build();
 
-    quote_expr!(cx, {
+    Ok(quote_expr!(cx, {
         $let_values
 
         try!(visitor.end());
 
         Ok($result)
-    })
+    }))
 }
 
 fn deserialize_struct(
@@ -480,36 +478,36 @@ fn deserialize_struct(
     ty: P<ast::Ty>,
     fields: &[ast::StructField],
     container_attrs: &ContainerAttrs,
-) -> 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,
         container_attrs
-    );
+    ));
 
     let type_name = builder.expr().str(type_ident);
 
-    quote_expr!(cx, {
+    Ok(quote_expr!(cx, {
         $field_visitor
 
         $visitor_item
@@ -535,7 +533,7 @@ fn deserialize_struct(
         $fields_stmt
 
         deserializer.deserialize_struct($type_name, FIELDS, $visitor_expr)
-    })
+    }))
 }
 
 fn deserialize_item_enum(
@@ -546,7 +544,7 @@ fn deserialize_item_enum(
     ty: P<ast::Ty>,
     enum_def: &EnumDef,
     container_attrs: &ContainerAttrs
-) -> P<ast::Expr> {
+) -> Result<P<ast::Expr>, ()> {
     let where_clause = &impl_generics.where_clause;
 
     let type_name = builder.expr().str(type_ident);
@@ -557,7 +555,7 @@ 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)
                     .build()
             })
@@ -585,37 +583,35 @@ fn deserialize_item_enum(
     };
 
     // 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().enum_()
+            .id("__Field").id(format!("__field{}", i)).build()
+            .build();
 
-            let expr = deserialize_variant(
-                cx,
-                builder,
-                type_ident,
-                impl_generics,
-                ty.clone(),
-                variant,
-                container_attrs,
-            );
-
-            quote_arm!(cx, $variant_name => { $expr })
-        })
-        .chain(ignored_arm.into_iter())
-        .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,
+            container_attrs,
+        ));
 
-    quote_expr!(cx, {
+        let arm = quote_arm!(cx, $variant_name => { $expr });
+        variant_arms.push(arm);
+    }
+    variant_arms.extend(ignored_arm.into_iter());
+
+    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
@@ -635,7 +631,7 @@ fn deserialize_item_enum(
         $variants_stmt
 
         deserializer.deserialize_enum($type_name, VARIANTS, $visitor_expr)
-    })
+    }))
 }
 
 fn deserialize_variant(
@@ -646,21 +642,21 @@ fn deserialize_variant(
     ty: P<ast::Ty>,
     variant: &ast::Variant,
     container_attrs: &ContainerAttrs,
-) -> 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(
@@ -696,16 +692,15 @@ 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,
@@ -714,7 +709,7 @@ 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 {
@@ -728,7 +723,7 @@ fn deserialize_tuple_variant(
         }
 
         visitor.visit_tuple($fields, $visitor_expr)
-    })
+    }))
 }
 
 fn deserialize_struct_variant(
@@ -740,7 +735,7 @@ fn deserialize_struct_variant(
     ty: P<ast::Ty>,
     fields: &[ast::StructField],
     container_attrs: &ContainerAttrs,
-) -> P<ast::Expr> {
+) -> Result<P<ast::Expr>, ()> {
     let where_clause = &generics.where_clause;
 
     let type_path = builder.path()
@@ -748,30 +743,29 @@ 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,
         container_attrs,
-    );
+    ));
 
-    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
@@ -797,7 +791,7 @@ fn deserialize_struct_variant(
         $fields_stmt
 
         visitor.visit_struct(FIELDS, $visitor_expr)
-    })
+    }))
 }
 
 fn deserialize_field_visitor(
@@ -969,21 +963,21 @@ fn deserialize_struct_visitor(
     struct_path: ast::Path,
     fields: &[ast::StructField],
     container_attrs: &ContainerAttrs,
-) -> (Vec<P<ast::Item>>, P<ast::Stmt>, P<ast::Expr>) {
+) -> Result<(Vec<P<ast::Item>>, P<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)),
         container_attrs
     );
 
-    let visit_map_expr = deserialize_map(
+    let visit_map_expr = try!(deserialize_map(
         cx,
         builder,
         struct_path,
         fields,
         container_attrs,
-    );
+    ));
 
     let fields_expr = builder.expr().addr_of().slice()
         .with_exprs(
@@ -1003,7 +997,7 @@ 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(
@@ -1012,7 +1006,7 @@ fn deserialize_map(
     struct_path: ast::Path,
     fields: &[ast::StructField],
     container_attrs: &ContainerAttrs,
-) -> 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)))
@@ -1045,8 +1039,10 @@ fn deserialize_map(
         .chain(ignored_arm.into_iter())
         .collect();
 
+    let field_attrs = try!(field::struct_field_attrs(cx, builder, fields));
+
     let extract_values: Vec<P<ast::Stmt>> = field_names.iter()
-        .zip(field::struct_field_attrs(cx, builder, fields).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())
@@ -1099,7 +1095,7 @@ fn deserialize_map(
         )
         .build();
 
-    quote_expr!(cx, {
+    Ok(quote_expr!(cx, {
         $let_values
 
         while let Some(key) = try!(visitor.visit_key()) {
@@ -1113,5 +1109,5 @@ fn deserialize_map(
         try!(visitor.end());
 
         Ok($result)
-    })
+    }))
 }

serde_codegen/src/field.rs

@@ -2,23 +2,29 @@ use syntax::ast;
 use syntax::ext::base::ExtCtxt;
 
 use aster;
-use attr::{ContainerAttrs, ContainerAttrsBuilder, 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,
+    cx: &ExtCtxt,
     container: &ast::Item,
-) -> ContainerAttrs {
-    ContainerAttrsBuilder::new().attrs(container.attrs()).build()
-}
+) -> 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 +1,5 @@
+#![cfg_attr(feature = "nightly", plugin(clippy))]
+#![cfg_attr(feature = "nightly", 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 +18,9 @@ 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"));
 
@@ -70,4 +75,6 @@ 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

@@ -11,7 +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,
@@ -53,13 +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;
 
@@ -82,7 +82,11 @@ 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, _) => {
             serialize_item_struct(
@@ -107,7 +111,7 @@ fn serialize_body(
         }
         _ => {
             cx.span_bug(item.span,
-                        "expected ItemStruct or ItemEnum in #[derive(Serialize)]")
+                        "expected ItemStruct or ItemEnum in #[derive(Serialize)]");
         }
     }
 }
@@ -120,7 +124,7 @@ fn serialize_item_struct(
     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(
@@ -171,20 +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.serialize_unit_struct($type_name))
+    Ok(quote_expr!(cx,
+        serializer.serialize_unit_struct($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.serialize_newtype_struct($type_name, &self.0))
+    Ok(quote_expr!(cx,
+        serializer.serialize_newtype_struct($type_name, &self.0)
+    ))
 }
 
 fn serialize_tuple_struct(
@@ -194,7 +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,
@@ -209,7 +217,7 @@ fn serialize_tuple_struct(
 
     let type_name = builder.expr().str(type_ident);
 
-    quote_expr!(cx, {
+    Ok(quote_expr!(cx, {
         $visitor_struct
         $visitor_impl
         serializer.serialize_tuple_struct($type_name, Visitor {
@@ -217,7 +225,7 @@ fn serialize_tuple_struct(
             state: 0,
             _structure_ty: ::std::marker::PhantomData::<&$ty>,
         })
-    })
+    }))
 }
 
 fn serialize_struct(
@@ -227,8 +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.$name)
+    });
+
+    let (visitor_struct, visitor_impl) = try!(serialize_struct_visitor(
         cx,
         builder,
         ty.clone(),
@@ -238,15 +251,12 @@ fn serialize_struct(
             .build_ty(ty.clone()),
         fields,
         impl_generics,
-        fields.iter().map(|field| {
-            let name = field.node.ident().expect("struct has unnamed field");
-            quote_expr!(cx, &self.value.$name)
-        })
-    );
+        value_exprs,
+    ));
 
     let type_name = builder.expr().str(type_ident);
 
-    quote_expr!(cx, {
+    Ok(quote_expr!(cx, {
         $visitor_struct
         $visitor_impl
         serializer.serialize_struct($type_name, Visitor {
@@ -254,7 +264,7 @@ fn serialize_struct(
             state: 0,
             _structure_ty: ::std::marker::PhantomData::<&$ty>,
         })
-    })
+    }))
 }
 
 fn serialize_item_enum(
@@ -264,27 +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(
@@ -295,7 +306,7 @@ 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);
@@ -306,7 +317,7 @@ fn serialize_variant(
                 .id(type_ident).id(variant_ident).build()
                 .build();
 
-            quote_arm!(cx,
+            Ok(quote_arm!(cx,
                 $pat => {
                     ::serde::ser::Serializer::serialize_unit_variant(
                         serializer,
@@ -315,7 +326,7 @@ fn serialize_variant(
                         $variant_name,
                     )
                 }
-            )
+            ))
         },
         ast::VariantData::Tuple(ref fields, _) if fields.len() == 1 => {
             let field = builder.id("__simple_value");
@@ -324,7 +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::serialize_newtype_variant(
                         serializer,
@@ -334,7 +346,7 @@ fn serialize_variant(
                         __simple_value,
                     )
                 }
-            )
+            ))
         },
         ast::VariantData::Tuple(ref fields, _) => {
             let field_names: Vec<ast::Ident> = (0 .. fields.len())
@@ -361,7 +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())
@@ -386,7 +400,7 @@ fn serialize_variant(
                 )
                 .build();
 
-            let expr = serialize_struct_variant(
+            let expr = try!(serialize_struct_variant(
                 cx,
                 builder,
                 type_name,
@@ -396,9 +410,11 @@ fn serialize_variant(
                 ty,
                 fields,
                 field_names,
-            );
+            ));
 
-            quote_arm!(cx, $pat => { $expr })
+            Ok(quote_arm!(cx,
+                $pat => { $expr }
+            ))
         }
     }
 }
@@ -463,7 +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| {
@@ -483,7 +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(),
@@ -495,9 +511,9 @@ fn serialize_struct_variant(
                 .tup_field(i)
                 .field("value").self_()
         })
-    );
+    ));
 
-    quote_expr!(cx, {
+    Ok(quote_expr!(cx, {
         $visitor_struct
         $visitor_impl
         serializer.serialize_struct_variant($type_name, $variant_index, $variant_name, Visitor {
@@ -505,7 +521,7 @@ fn serialize_struct_variant(
             state: 0,
             _structure_ty: ::std::marker::PhantomData::<&$structure_ty>,
         })
-    })
+    }))
 }
 
 fn serialize_tuple_struct_visitor(
@@ -583,12 +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())
@@ -651,7 +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,
@@ -683,5 +699,5 @@ fn serialize_struct_visitor<I>(
                 }
             }
         ).unwrap(),
-    )
+    ))
 }