Ensure supertypes are loaded safely.

dart/lib/compiler/implementation/compile_time_constants.dart

 // Copyright (c) 2012, 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.
 
 class Constant implements Hashable {
   const Constant();
 
   bool isNull() => false;
   bool isBool() => false;
   bool isTrue() => false;
@@ skipping 1112 matching lines @@
       }
     }
 
     if (!foundSuperOrRedirect) {
       // No super initializer found. Try to find the default constructor if
       // the class is not Object.
       ClassElement enclosingClass = constructor.getEnclosingClass();
       ClassElement superClass = enclosingClass.superclass;
       if (enclosingClass != compiler.objectClass) {
         assert(superClass !== null);
-        assert(superClass.isResolved);
+        assert(superClass.resolutionState == ClassElement.STATE_DONE);
         FunctionElement targetConstructor =
             superClass.lookupConstructor(superClass.name);
         if (targetConstructor === null) {
           compiler.internalError("no default constructor available",
                                  node: functionNode);
         }
 
         evaluateSuperOrRedirectSend(Selector.INVOCATION_0,
                                     const EmptyLink<Node>(),
                                     targetConstructor);
@@ skipping 22 matching lines @@
       Constant fieldValue = fieldValues[field];
       if (fieldValue === null) {
         // Use the default value.
         fieldValue = compiler.compileVariable(field);
       }
       jsNewArguments.add(fieldValue);
     });
     return jsNewArguments;
   }
 }