Fix bugs found in checked mode.

lib/compiler/implementation/unparse_validator.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 ValidatorListener implements DiagnosticListener {
   final SourceFile sourceFile;
 
   ValidatorListener(this.sourceFile);
 
   void cancel([String reason, node, token, instruction, element]) {
@@ skipping 37 matching lines @@
     String name = SourceSpan.withCharacterOffsets(
         originalFunction.beginToken, originalFunction.endToken,
         (beginOffset, endOffset) =>
             'synthesized:${originalScript.name}#$beginOffset:$endOffset');
     SourceFile synthesizedSourceFile = new SourceFile(name, unparsed);
     Script synthesizedScript =
         new Script(originalScript.uri, synthesizedSourceFile);
     LibraryElement lib = new LibraryElement(synthesizedScript);
     lib.canUseNative = originalFunction.getLibrary().canUseNative;
     NodeListener listener =
-        new NodeListener(new ValidatorListener(synthesizedSourceFile), lib);
+        new NodeListener(new ValidatorListener(synthesizedSourceFile),
+                         lib.entryCompilationUnit);
     parser = new Parser(listener);
     parser.parseFunction(newTokens, getOrSet);
     FunctionExpression newNode = listener.popNode();
     // TODO(antonm): add Node comparison.
   }
 
   void check(Element element) {
     if (!validateUnparse) return;
 
     if (element is PartialFunctionElement) {
       checkFunction(element);
     } else if (element.isGenerativeConstructor()) {
       assert(element is FunctionElement);
       // Generative constructors parse to very special function expressions.
       // Handle them when classes are properly handled.
     } else if (element.isField() || element is AbstractFieldElement) {
       assert(element is VariableElement || element is AbstractFieldElement);
       // Fields are just names with possible initialization expressions.
       // Nothing to care about for now.
     } else if (element is VoidElement) {
       // Nothing to do here.
     } else {
       compiler.cancel('Cannot handle $element');
     }
   }
 }