Issue 3268. Support for replacing 'assert' statement with 'assert' function

compiler/java/com/google/dart/compiler/resolver/TopLevelElementBuilder.java

 // 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.
 
 package com.google.dart.compiler.resolver;
 
 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.collect.Maps;
 import com.google.dart.compiler.DartCompilationError;
 import com.google.dart.compiler.DartCompilerContext;
@@ skipping 105 matching lines @@
   private void compilationError(DartCompilerListener listener, SourceInfo node, ErrorCode errorCode,
                         Object... args) {
     DartCompilationError error = new DartCompilationError(node, errorCode, args);
     listener.onError(error);
   }
 
   private void declare(Element newElement, DartCompilerListener listener, Scope scope) {
     Element oldElement = scope.declareElement(newElement.getName(), newElement);
     // We had already node with such name, report duplicate.
     if (oldElement != null) {
+      // ignore "assert"
+      if (Elements.isArtificialAssertMethod(oldElement)) {
+        return;
+      }
       // Getter/setter can shared same name, but not setter/setter and getter/getter.
       if (newElement.getModifiers().isAbstractField()
           && oldElement.getModifiers().isAbstractField()) {
         if (newElement.getModifiers().isGetter() && !oldElement.getModifiers().isGetter()) {
           return;
         }
         if (newElement.getModifiers().isSetter() && !oldElement.getModifiers().isSetter()) {
           return;
         }
       }
@@ skipping 58 matching lines @@
       Modifiers modifiers = node.getModifiers();
       if (modifiers.isFinal()) {
         // final toplevel fields are implicitly compile-time constants.
         modifiers = modifiers.makeConstant();
       }
       node.setElement(Elements.fieldFromNode(node, library, modifiers));
       return null;
     }
   }
 }