Handle missing const constructor.

sdk/lib/_internal/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.
 
 part of dart2js;
 
 /**
  * The [ConstantHandler] keeps track of compile-time constants,
  * initializations of global and static fields, and default values of
  * optional parameters.
@@ skipping 602 matching lines @@
     return compiledArguments;
   }
 
   Constant visitNewExpression(NewExpression node) {
     if (!node.isConst()) {
       return signalNotCompileTimeConstant(node);
     }
 
     Send send = node.send;
     FunctionElement constructor = elements[send];
+    if (Elements.isUnresolved(constructor)) {
+      return signalNotCompileTimeConstant(node);
+    }
     // TODO(ahe): This is nasty: we must eagerly analyze the
     // constructor to ensure the redirectionTarget has been computed
     // correctly.  Find a way to avoid this.
     compiler.analyzeElement(constructor.declaration);
 
     InterfaceType type = elements.getType(node);
     List<Constant> evaluateArguments(FunctionElement constructor) {
       Selector selector = elements.getSelector(send);
       return evaluateArgumentsToConstructor(
           node, selector, send.arguments, constructor);
@@ skipping 245 matching lines @@
           if (fieldValue == null) {
             // Use the default value.
             fieldValue = handler.compileConstant(field);
           }
           jsNewArguments.add(fieldValue);
         },
         includeSuperAndInjectedMembers: true);
     return jsNewArguments;
   }
 }