dart2dart Collect type placeholder for default class.

lib/compiler/implementation/dart_backend/placeholder_collector.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 LocalPlaceholder implements Hashable {
   final String identifier;
   final Set<Node> nodes;
   LocalPlaceholder(this.identifier) : nodes = new Set<Node>();
   int hashCode() => identifier.hashCode();
   String toString() =>
@@ skipping 396 matching lines @@
         }
       }
     }
     node.visitChildren(this);
   }
 
   visitClassNode(ClassNode node) {
     assert(currentElement is ClassElement);
     makeElementPlaceholder(node.name, currentElement);
     node.visitChildren(this);
+    if (node.defaultClause !== null) {
+      // Can't just visit class node's default clause because of the bug in the
+      // resolver, it just crashes when it meets type variable.
+      Type defaultType = (currentElement as ClassElement).defaultClass;
+      assert(defaultType !== null);
+      makeTypePlaceholder(node.defaultClause.typeName, defaultType);
+      visit(node.defaultClause.typeArguments);
+    }
   }
 
   visitTypedef(Typedef node) {
     assert(currentElement is TypedefElement);
     makeElementPlaceholder(node.name, currentElement);
     node.visitChildren(this);
   }
 }