Support for "a is Function".

frog/tests/leg/src/mock_compiler.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.
 
 #library('mock_compiler');
 
 #import("../../../../lib/uri/uri.dart");
 
 #import("../../../leg/elements/elements.dart");
 #import("../../../leg/io/io.dart", prefix: 'io');
@@ skipping 17 matching lines @@
   iae(x) {throw x;} ioore(x) {throw x;}
   guard$array(x) { return x; }
   guard$num(x) { return x; }
   guard$string(x) { return x; }
   guard$stringOrArray(x) { return x; }
   builtin$add$1(receiver, value) {}
   builtin$get$length(var receiver) {}
   builtin$filter$1(receiver, predicate) {}
   builtin$removeLast$0(receiver) {}
   index(a, index) {}
-  indexSet(a, index, value) {}''';
+  indexSet(a, index, value) {}
+  class Closure {} ''';
 
 final String DEFAULT_CORELIB = @'''
   print(var obj) {}
   class int {}
   class double {}
   class bool {}
   class String {}
   class Object {}''';
 
 class MockCompiler extends Compiler {
   List<WarningMessage> warnings;
   List<WarningMessage> errors;
   final Map<String, String> sources;
   Node parsedTree;
   WorkItem lastBailoutWork;
 
   MockCompiler([String coreSource = DEFAULT_CORELIB,
                 String helperSource = DEFAULT_HELPERLIB])
       : warnings = [], errors = [],
         sources = new Map<String, String>(),
         super.withCurrentDirectory(io.getCurrentDirectory()) {
     Uri uri = new Uri(scheme: "source");
     var script = new Script(uri, new MockFile(coreSource));
     coreLibrary = new LibraryElement(script);
     parseScript(coreSource, coreLibrary);
     script = new Script(uri, new MockFile(helperSource));
     jsHelperLibrary = new LibraryElement(script);
     parseScript(helperSource, jsHelperLibrary);
+    scanner.importLibrary(jsHelperLibrary, coreLibrary, null);
     mainApp = mockLibrary(this, "");
+    objectClass = coreLibrary.find(Compiler.OBJECT);
+    closureClass = jsHelperLibrary.find(Compiler.CLOSURE);
   }
 
   void reportWarning(Node node, var message) {
     warnings.add(new WarningMessage(node, message.message));
   }
 
   void reportError(Node node, var message) {
     errors.add(new WarningMessage(node, message.message));
   }
 
@@ skipping 98 matching lines @@
   importLibrary(library, compiler.coreLibrary, compiler);
   return library;
 }
 
 class StringScript extends Script {
   final String code;
   StringScript(this.code) : super(null, null);
   String get text() => code;
   String get name() => "mock script";
 }