2 files changed, 1 insertions, 3 deletions
diff --git a/src/libsyntax/ext/auto_serialize.rs b/src/libsyntax/ext/auto_serialize.rs
index a42a51fd302..7a1b973c3a1 100644
--- a/src/libsyntax/ext/auto_serialize.rs
+++ b/src/libsyntax/ext/auto_serialize.rs
@@ -393,7 +393,6 @@ fn mk_impl(
     let opt_trait = Some(@{
         path: path,
         ref_id: cx.next_id(),
-        impl_id: cx.next_id(),
     });
 
     let ty = cx.ty_path(
diff --git a/src/libsyntax/ext/deriving.rs b/src/libsyntax/ext/deriving.rs
index b8bb9c20dc0..2aca54446d7 100644
--- a/src/libsyntax/ext/deriving.rs
+++ b/src/libsyntax/ext/deriving.rs
@@ -220,8 +220,7 @@ fn create_derived_impl(cx: ext_ctxt,
     let trait_path = @move trait_path;
     let trait_ref = {
         path: trait_path,
-        ref_id: cx.next_id(),
-        impl_id: cx.next_id(),
+        ref_id: cx.next_id()
     };
     let trait_ref = @move trait_ref;