Support enabling type checker.

pkg/compiler/lib/src/dart_types.dart

Index: pkg/compiler/lib/src/dart_types.dart
diff --git a/pkg/compiler/lib/src/dart_types.dart b/pkg/compiler/lib/src/dart_types.dart
index 41ce1e548b7ad659bd26a6e11651d39323e56bae..098b5603e074510952f04ede62300df2812ce69c 100644
--- a/pkg/compiler/lib/src/dart_types.dart
+++ b/pkg/compiler/lib/src/dart_types.dart
@@ -233,6 +233,10 @@ class TypeVariableType extends DartType {
   }
 
   String toString() => name;
+
+  // TODO(ahe): Remove this method. It's a hack to work around problems when
+  // copying down methods in mixin applications.
+  bool get treatAsDynamic => element.enclosingElement.isMixinApplication;
 }
 
 /// Internal type representing the result of analyzing a statement.
@@ -511,6 +515,10 @@ class InterfaceType extends GenericType {
     FunctionType type = element.callType;
     return type != null && isGeneric ? type.substByContext(this) : type;
   }
+
+  // TODO(ahe): Remove this method. It's a hack to work around problems when
+  // copying down methods in mixin applications.
+  bool get treatAsDynamic => element.isMixinApplication;
 }
 
 /**