rustc: Check self types in method lookup; allow required trait methods to have self types; write self types into metadata

src/libsyntax/ast.rs

@@ -503,7 +503,8 @@ type ty_field = spanned<ty_field_>;
 
 #[auto_serialize]
 type ty_method = {ident: ident, attrs: ~[attribute],
-                  decl: fn_decl, tps: ~[ty_param], span: span};
+                  decl: fn_decl, tps: ~[ty_param], self_ty: self_ty,
+                  span: span};
 
 #[auto_serialize]
 // A trait method is either required (meaning it doesn't have an