Improve List implementation.

dart/frog/leg/emitter.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.
 
 /**
  * Generates the code for all used classes in the program. Static fields (even
  * in classes) are ignored, since they can be treated as non-class elements.
  *
  * The code for the containing (used) methods must exist in the [:universe:].
  */
@@ skipping 482 matching lines @@
     // }
 
     // TODO(floitsch): share the closure classes with other classes
     // if they share methods with the same signature.
 
     // The closure class.
     SourceString name = const SourceString("BoundClosure");
     CompilationUnitElement compilationUnit = member.getCompilationUnit();
     ClassElement closureClassElement = new ClassElement(name, compilationUnit);
     String isolateAccess = namer.isolatePropertyAccess(closureClassElement);
-    buffer.add("$isolateAccess = function(self) { this.self = self; };\n");
+
+    // Define the constructor with a name so that Object.toString can
+    // find the class name of the closure class.
+    buffer.add("$isolateAccess = function $name(self) ");
+    buffer.add("{ this.self = self; };\n");
+
+    // Make the closure class extend Object.
+    addInheritFunctionIfNecessary(buffer);
+    ClassElement objectClass =
+        compiler.coreLibrary.find(const SourceString('Object'));
+    String superName = namer.isolatePropertyAccess(objectClass);
+    buffer.add('${inheritsName}($isolateAccess, $superName);\n');
+
     String prototype = "$isolateAccess.prototype";
 
     // Now add the methods on the closure class. The instance method does not
     // have the correct name. Since [addParameterStubs] use the name to create
     // its stubs we simply create a fake element with the correct name.
     // Note: the callElement will not have the correct modifiers (in case
     // of static functions) and will not have any enclosingElement.
     FunctionElement callElement =
         new FunctionElement.from(Namer.CLOSURE_INVOCATION_NAME, member, null);
 
@@ skipping 186 matching lines @@
       emitCallStubForGetters(buffer);
       emitStaticFinalFieldInitializations(buffer);
       buffer.add('var ${namer.CURRENT_ISOLATE} = new ${namer.ISOLATE}();\n');
       Element main = compiler.mainApp.find(Compiler.MAIN);
       buffer.add('${namer.isolateAccess(main)}();\n');
       compiler.assembledCode = buffer.toString();
     });
     return compiler.assembledCode;
   }
 }