a === b -> identical(a, b)

tests/compiler/dart2js/compiler_test.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.
 
 import "../../../sdk/lib/_internal/compiler/implementation/dart2jslib.dart";
 import "../../../sdk/lib/_internal/compiler/implementation/elements/elements.dart";
 import "../../../sdk/lib/_internal/compiler/implementation/resolution/resolution.dart";
 import "../../../sdk/lib/_internal/compiler/implementation/tree/tree.dart";
 import "../../../sdk/lib/_internal/compiler/implementation/util/util.dart";
 import "mock_compiler.dart";
 import "parser_helper.dart";
 
 class CallbackMockCompiler extends MockCompiler {
   CallbackMockCompiler();
 
   var onError;
   var onWarning;
 
   setOnError(var f) => onError = f;
   setOnWarning(var f) => onWarning = f;
 
   void reportWarning(Node node, var message) {
-    if (onWarning !== null) onWarning(this, node, message);
+    if (onWarning != null) onWarning(this, node, message);
     super.reportWarning(node, message);
   }
 
   void reportError(Node node, var message) {
-    if (onError !== null) onError(this, node, message);
+    if (onError != null) onError(this, node, message);
     super.reportError(node, message);
   }
 }
 
 testErrorHandling() {
   // Test that compiler.currentElement is set correctly when
   // reporting errors/warnings.
   CallbackMockCompiler compiler = new CallbackMockCompiler();
   ResolverVisitor visitor = compiler.resolverVisitor();
   compiler.parseScript('NoSuchPrefix.NoSuchType foo() {}');
   FunctionElement foo = compiler.mainApp.find(buildSourceString('foo'));
   compiler.setOnWarning((c, n, m) => Expect.equals(foo, compiler.currentElement));
   foo.computeType(compiler);
   Expect.equals(1, compiler.warnings.length);
 }
 
 main() {
   testErrorHandling();
 }