Prepare for computation of NewStructure in Resolution.

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

Index: pkg/compiler/lib/src/resolution/class_members.dart
diff --git a/pkg/compiler/lib/src/resolution/class_members.dart b/pkg/compiler/lib/src/resolution/class_members.dart
index 449173373f7fc9884d5d3f0024b21a44a29d57bd..95e31939562d0292351015a67f92101650c8049b 100644
--- a/pkg/compiler/lib/src/resolution/class_members.dart
+++ b/pkg/compiler/lib/src/resolution/class_members.dart
@@ -378,7 +378,9 @@ abstract class MembersCreator {
           // superMember.declarations. Investigate why.
         } else if (cls == inherited.declarer.element) {
           // An error should already have been reported.
-          assert(invariant(declared.element, compiler.compilationFailed));
+          assert(invariant(declared.element, compiler.compilationFailed,
+              message: "Member $inherited inherited from its "
+                       "declaring class: ${cls}."));

[Siggi Cherem (dart-lang), 2015/09/01 20:13:40]

Not sure I follow the message, does this indicate a circular type hierarchy
issue? Maybe call that out explicitly in the message?

           continue;
         }