Improve equivalence testing of unnamed mixin applications.

pkg/compiler/lib/src/resolution/class_hierarchy.dart

Index: pkg/compiler/lib/src/resolution/class_hierarchy.dart
diff --git a/pkg/compiler/lib/src/resolution/class_hierarchy.dart b/pkg/compiler/lib/src/resolution/class_hierarchy.dart
index e136a149b1abff7e55284fab75b19d2f47d04cc8..6ca1695a55fb299a8545f32d617c55d2582b6cd2 100644
--- a/pkg/compiler/lib/src/resolution/class_hierarchy.dart
+++ b/pkg/compiler/lib/src/resolution/class_hierarchy.dart
@@ -305,7 +305,7 @@ class ClassResolverVisitor extends TypeDefinitionVisitor {
     MixinApplicationElementX mixinApplication =
         new UnnamedMixinApplicationElementX(
             "${superName}+${mixinName}",
-            element.compilationUnit,

[Siggi Cherem (dart-lang), 2016/05/31 21:37:11]

oh wow, and it used to work?

[Johnni Winther, 2016/06/02 08:19:39]

We only use this for the enclosingElement.

+            element,
             compiler.idGenerator.getNextFreeId(),
             node);
     // Create synthetic type variables for the mixin application.