support unparsing of "new Object()":

lib/compiler/implementation/dart_backend/backend.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 BailoutException {
   final String reason;
 
   const BailoutException(this.reason);
 }
 
@@ skipping 24 matching lines @@
   void assembleProgram() {
     resolvedElements.forEach((element, treeElements) {
       unparseValidator.check(element);
     });
 
     // TODO(antonm): Eventually bailouts will be proper errors.
     void bailout(String reason) {
       throw new BailoutException(reason);
     }
 
+    /**
+     * Tells whether we should output given element. Corelib classes like
+     * Object should not be in the resulting code.
+     */
+    bool shouldOutput(Element element) {
+      var compilationUnitUri = element.getCompilationUnit().script.uri;
+      if (compilationUnitUri !== null && compilationUnitUri.path !== null &&

[Anton Muhin, 2012/07/09 18:31:26]

I believe (but not 100% sure) that we have a references to core lib and some
other standard libs, cannot you just do === check on it?

[Roman, 2012/07/10 03:20:29]

Done.
Thanks! Indeed we have reference in compiler. I just grepped for corelib and
found some hacks like mine in tests, that confused me.

+          // TODO(smok): URI hacks, should we have a special 'core' flag for
+          // elements from corelib?
+          (compilationUnitUri.path.endsWith('/core.dart')
+              || compilationUnitUri.path.contains('/corelib/src/'))) {
+        return false;
+      }
+      return element.kind !== ElementKind.VOID;
+    }
+
     try {
       StringBuffer sb = new StringBuffer();
       resolvedElements.forEach((element, treeElements) {
+        if (!shouldOutput(element)) {

[Anton Muhin, 2012/07/09 18:31:26]

nit: single line.

[Roman, 2012/07/10 03:20:29]

Done.

+          return;
+        }
         if (!element.isTopLevel()) {
           bailout('Cannot process non top-level $element');
         }
 
         if (element.isField()) {
           // Add modifiers first.
           sb.add(element.modifiers.toString());
           sb.add(' ');
           // Figure out type.
           if (element is VariableElement) {
@@ skipping 16 matching lines @@
       compiler.assembledCode = '''
 main() {
   final bailout_reason = "${e.reason}";
 }
 ''';
     }
   }
 
   log(String message) => compiler.log('[DartBackend] $message');
 }