Support parameter metadata.

sdk/lib/_internal/compiler/implementation/dart_backend/utils.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 dart_backend;
 
 class CloningVisitor implements Visitor<Node> {
   final TreeElements originalTreeElements;
   final TreeElementMapping cloneTreeElements;
 
@@ skipping 99 matching lines @@
       visit(node.typeArguments), visit(node.entries), node.constKeyword);
 
   visitLiteralMapEntry(LiteralMapEntry node) => new LiteralMapEntry(
       visit(node.key), node.colonToken, visit(node.value));
 
   visitLiteralNull(LiteralNull node) => new LiteralNull(node.token);
 
   visitLiteralString(LiteralString node) => new LiteralString(
       node.token, node.dartString);
 
+  visitMetadata(Metadata node) => new Metadata(
+      node.token, visit(node.expression));
+
   visitMixinApplication(MixinApplication node) => new MixinApplication(
       visit(node.superclass), visit(node.mixins));
 
   visitNamedMixinApplication(NamedMixinApplication node) =>
       new NamedMixinApplication(visit(node.name),
                                 visit(node.typeParameters),
                                 visit(node.modifiers),
                                 visit(node.mixinApplication),
                                 visit(node.interfaces),
                                 node.classKeyword,
@@ skipping 76 matching lines @@
   visitTypeAnnotation(TypeAnnotation node) => new TypeAnnotation(
       visit(node.typeName), visit(node.typeArguments));
 
   visitTypedef(Typedef node) => new Typedef(
       visit(node.returnType), visit(node.name), visit(node.typeParameters),
       visit(node.formals), node.typedefKeyword, node.endToken);
 
   visitTypeVariable(TypeVariable node) => new TypeVariable(
       visit(node.name), visit(node.bound));
 
-  visitVariableDefinitions(VariableDefinitions node) => new VariableDefinitions(
-      visit(node.type), visit(node.modifiers), visit(node.definitions));
+  visitVariableDefinitions(VariableDefinitions node) =>
+      new VariableDefinitions.forParameter(
+          visit(node.metadata), visit(node.type),
+          visit(node.modifiers), visit(node.definitions));
 
   visitWhile(While node) => new While(
       visit(node.condition), visit(node.body), node.whileKeyword);
 
   Node visitNode(Node node) {
     unimplemented('visitNode', node: node);
   }
 
   Node visitCombinator(Combinator node) {
     unimplemented('visitNode', node: node);
@@ skipping 56 matching lines @@
   }
 
   Node visitStringNode(StringNode node) {
     unimplemented('visitNode', node: node);
   }
 
   unimplemented(String message, {Node node}) {
     throw message;
   }
 }