Improve equivalence testing of unnamed mixin applications.

pkg/compiler/lib/src/serialization/equivalence.dart

 // Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 /// Functions for asserting equivalence across serialization.
 
 library dart2js.serialization.equivalence;
 
 import '../closure.dart';
 import '../common.dart';
@@ skipping 365 matching lines @@
       CompilationUnitElement element1, CompilationUnitElement element2) {
     return strategy.test(
             element1, element2, 'name', element1.name, element2.name) &&
         strategy.test(element1, element2, 'script.resourceUri',
             element1.script.resourceUri, element2.script.resourceUri) &&
         visit(element1.library, element2.library);
   }
 
   @override
   bool visitClassElement(ClassElement element1, ClassElement element2) {
-    return strategy.test(
-            element1, element2, 'name', element1.name, element2.name) &&
-        visit(element1.library, element2.library);
+    if (!strategy.test(element1, element2, 'isUnnamedMixinApplication',
+        element1.isUnnamedMixinApplication,
+        element2.isUnnamedMixinApplication)) {
+      return false;
+    }
+    if (element1.isUnnamedMixinApplication) {
+      MixinApplicationElement mixin1 = element1;
+      MixinApplicationElement mixin2 = element2;
+      return strategy.testElements(mixin1, mixin2, 'subclass',
+          mixin1.subclass, mixin2.subclass) &&
+          // Using the [mixinType] is more precise but requires the test to
+          // handle self references: The identity of a type variable is based on
+          // its type declaration and if [mixin1] is generic the [mixinType]
+          // will contain the type variables declared by [mixin1], i.e.
+          // `abstract class Mixin<T> implements MixinType<T> {}`
+          strategy.testElements(mixin1, mixin2, 'mixin',
+              mixin1.mixin, mixin2.mixin);
+    } else {
+      return strategy.test(
+          element1, element2, 'name', element1.name, element2.name) &&
+          visit(element1.library, element2.library);
+    }
   }
 
   bool checkMembers(Element element1, Element element2) {
     if (!strategy.test(
         element1, element2, 'name', element1.name, element2.name)) {
       return false;
     }
     if (element1.enclosingClass != null || element2.enclosingClass != null) {
       return visit(element1.enclosingClass, element2.enclosingClass);
     } else {
@@ skipping 1401 matching lines @@
   @override
   bool visitStatement(Statement node1, Statement node2) {
     throw new UnsupportedError('Unexpected nodes: $node1 <> $node2');
   }
 
   @override
   bool visitStringNode(StringNode node1, StringNode node2) {
     throw new UnsupportedError('Unexpected nodes: $node1 <> $node2');
   }
 }