Support 'implements' clause on typedef mixin applications.

sdk/lib/_internal/compiler/implementation/tree/unparser.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.
 
 part of tree;
 
 String unparse(Node node) {
   Unparser unparser = new Unparser();
   unparser.unparse(node);
   return unparser.result;
@@ skipping 64 matching lines @@
       visit(member);
     }
     sb.add('}');
   }
 
   visitClassNode(ClassNode node) {
     unparseClassWithBody(node, node.body.nodes);
   }
 
   visitMixinApplication(MixinApplication node) {
-    if (!node.modifiers.nodes.isEmpty) {
-      visit(node.modifiers);
-      sb.add(' ');
-    }
     visit(node.superclass);
     sb.add(' with ');
     visit(node.mixins);
   }
 
   visitNamedMixinApplication(NamedMixinApplication node) {
     sb.add('typedef ');
     visit(node.name);
     if (node.typeParameters != null) {
       visit(node.typeParameters);
     }
     sb.add(' = ');
+    if (!node.modifiers.nodes.isEmpty) {
+      visit(node.modifiers);
+      sb.add(' ');
+    }
     visit(node.mixinApplication);
+    if (node.interfaces != null) {
+      sb.add(' implements ');
+      visit(node.interfaces);
+    }
     sb.add(';');
   }
 
   visitConditional(Conditional node) {
     visit(node.condition);
     add(node.questionToken.value);
     visit(node.thenExpression);
     add(node.colonToken.value);
     visit(node.elseExpression);
   }
@@ skipping 505 matching lines @@
   }
 
   visitStatement(Statement node) {
     throw 'internal error'; // Should not be called.
   }
 
   visitStringNode(StringNode node) {
     throw 'internal error'; // Should not be called.
   }
 }