Switch to using MultiDecorator

serde_codegen/src/de.rs

@@ -1,6 +1,9 @@
 use std::collections::HashSet;
 
+use aster;
+
 use syntax::ast::{
+    self,
     Ident,
     MetaItem,
     Item,
@@ -8,25 +11,32 @@ use syntax::ast::{
     StructDef,
     EnumDef,
 };
-use syntax::ast;
 use syntax::codemap::Span;
-use syntax::ext::base::ExtCtxt;
+use syntax::ext::base::{Annotatable, ExtCtxt};
 use syntax::ext::build::AstBuilder;
 use syntax::owned_slice::OwnedSlice;
 use syntax::ptr::P;
 
-use aster;
-
 use attr;
 use field;
 
 pub fn expand_derive_deserialize(
     cx: &mut ExtCtxt,
     span: Span,
-    _mitem: &MetaItem,
+    meta_item: &MetaItem,
-    item: &Item,
+    annotatable: Annotatable,
-    push: &mut FnMut(P<ast::Item>)
+    push: &mut FnMut(Annotatable)
 ) {
+    let item = match annotatable {
+        Annotatable::Item(item) => item,
+        _ => {
+            cx.span_err(
+                meta_item.span,
+                "`derive` may only be applied to structs and enums");
+            return;
+        }
+    };
+
     let builder = aster::AstBuilder::new().span(span);
 
     let generics = match item.node {
@@ -48,7 +58,7 @@ pub fn expand_derive_deserialize(
     let body = deserialize_body(
         cx,
         &builder,
-        item,
+        &item,
         &impl_generics,
         ty.clone(),
     );
@@ -66,7 +76,7 @@ pub fn expand_derive_deserialize(
         }
     ).unwrap();
 
-    push(impl_item)
+    push(Annotatable::Item(impl_item))
 }
 
 fn deserialize_body(
@@ -661,10 +671,7 @@ fn deserialize_field_visitor(
                     })
     };
 
-    vec![
+    let impl_item = quote_item!(cx,
-        field_enum,
-
-        quote_item!(cx,
         impl ::serde::de::Deserialize for __Field {
             #[inline]
             fn deserialize<D>(deserializer: &mut D) -> ::std::result::Result<__Field, D::Error>
@@ -702,8 +709,9 @@ fn deserialize_field_visitor(
                     __FieldVisitor::<D>{ phantom: PhantomData })
             }
         }
-        ).unwrap(),
+    ).unwrap();
-    ]
+
+    vec![field_enum, impl_item]
 }
 
 fn deserialize_struct_visitor(

serde_codegen/src/lib.rs

@@ -14,11 +14,11 @@ mod ser;
 pub fn register(reg: &mut rustc::plugin::Registry) {
     reg.register_syntax_extension(
         syntax::parse::token::intern("derive_Serialize"),
-        syntax::ext::base::Decorator(
+        syntax::ext::base::MultiDecorator(
             Box::new(ser::expand_derive_serialize)));
 
     reg.register_syntax_extension(
         syntax::parse::token::intern("derive_Deserialize"),
-        syntax::ext::base::Decorator(
+        syntax::ext::base::MultiDecorator(
             Box::new(de::expand_derive_deserialize)));
 }

serde_codegen/src/ser.rs

@@ -1,3 +1,5 @@
+use aster;
+
 use syntax::ast::{
     Ident,
     MetaItem,
@@ -7,21 +9,29 @@ use syntax::ast::{
 };
 use syntax::ast;
 use syntax::codemap::Span;
-use syntax::ext::base::ExtCtxt;
+use syntax::ext::base::{Annotatable, ExtCtxt};
 use syntax::ext::build::AstBuilder;
 use syntax::ptr::P;
 
-use aster;
-
 use field::struct_field_attrs;
 
 pub fn expand_derive_serialize(
     cx: &mut ExtCtxt,
     span: Span,
-    _mitem: &MetaItem,
+    meta_item: &MetaItem,
-    item: &Item,
+    annotatable: Annotatable,
-    push: &mut FnMut(P<ast::Item>)
+    push: &mut FnMut(Annotatable)
 ) {
+    let item = match annotatable {
+        Annotatable::Item(item) => item,
+        _ => {
+            cx.span_err(
+                meta_item.span,
+                "`derive` may only be applied to structs and enums");
+            return;
+        }
+    };
+
     let builder = aster::AstBuilder::new().span(span);
 
     let generics = match item.node {
@@ -43,7 +53,7 @@ pub fn expand_derive_serialize(
     let body = serialize_body(
         cx,
         &builder,
-        item,
+        &item,
         &impl_generics,
         ty.clone(),
     );
@@ -61,7 +71,7 @@ pub fn expand_derive_serialize(
         }
     ).unwrap();
 
-    push(impl_item)
+    push(Annotatable::Item(impl_item))
 }
 
 fn serialize_body(