Fix issue 11398 by making sure we look at mixin applications

sdk/lib/_internal/compiler/implementation/types/flat_type_mask.dart

Index: sdk/lib/_internal/compiler/implementation/types/flat_type_mask.dart
diff --git a/sdk/lib/_internal/compiler/implementation/types/flat_type_mask.dart b/sdk/lib/_internal/compiler/implementation/types/flat_type_mask.dart
index 33cd88a2b64270805ed1c9a0a5ae3a6943f71ee2..3013586d3fce2c4586e5b05e341aa673fbf705c3 100644
--- a/sdk/lib/_internal/compiler/implementation/types/flat_type_mask.dart
+++ b/sdk/lib/_internal/compiler/implementation/types/flat_type_mask.dart
@@ -429,11 +429,18 @@ class FlatTypeMask implements TypeMask {
           || compiler.world.hasAnySubclassThatMixes(self, other);
     } else {
       assert(isSubtype);
-      return hasElementIn(self, selector, element, compiler)
+      bool result = hasElementIn(self, selector, element, compiler)
           || other.implementsInterface(self)
-          || other.isSubclassOf(self)
-          || compiler.world.hasAnySubclassThatMixes(self, other)
           || compiler.world.hasAnySubclassThatImplements(other, base);
+      if (result) return true;
+      // If the class is used as a mixin, we have to check if the element
+      // can be hit from any of the mixin applications.
+      Iterable<ClassElement> mixinUses = compiler.world.mixinUses[self];
+      if (mixinUses == null) return false;
+      return mixinUses.any((mixinApplication) =>
+           hasElementIn(mixinApplication, selector, element, compiler)
+        || other.isSubclassOf(mixinApplication)

[ngeoffray, 2013/06/24 08:59:06]

indent one more?

+        || compiler.world.hasAnySubclassThatMixes(mixinApplication, other));

[ngeoffray, 2013/06/24 08:59:06]

ditto

     }
   }