Support parameter metadata.

sdk/lib/_internal/compiler/implementation/scanner/parser.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 scanner;
 
 class FormalParameterType {
   final String type;
   const FormalParameterType(this.type);
   bool get isRequired => this == REQUIRED;
@@ skipping 197 matching lines @@
     assert(optional('part', token));
     assert(optional('of', token.next));
     Token partKeyword = token;
     token = parseQualified(token.next.next);
     Token semicolon = token;
     token = expect(';', token);
     listener.endPartOf(partKeyword, semicolon);
     return token;
   }
 
-  Token parseMetadataStar(Token token) {
+  Token parseMetadataStar(Token token, {bool forParameter: false}) {
+    listener.beginMetadataStar(token);
+    int count = 0;
     while (optional('@', token)) {
       token = parseMetadata(token);
+      count++;
     }
+    listener.endMetadataStar(count, forParameter);
     return token;
   }
 
   /**
    * Parse
    * [: '@' qualified (‘.’ identifier)? (arguments)? :]
    */
   Token parseMetadata(Token token) {
     listener.beginMetadata(token);
     Token atToken = token;
@@ skipping 87 matching lines @@
         token = parseOptionalFormalParameters(token, true);
         break;
       }
       token = parseFormalParameter(token, FormalParameterType.REQUIRED);
     } while (optional(',', token));
     listener.endFormalParameters(parameterCount, begin, token);
     return expect(')', token);
   }
 
   Token parseFormalParameter(Token token, FormalParameterType type) {
+    token = parseMetadataStar(token, forParameter: true);
     listener.beginFormalParameter(token);
     token = parseModifiers(token);
     // TODO(ahe): Validate that there are formal parameters if void.
     token = parseReturnTypeOpt(token);
     Token thisKeyword = null;
     if (optional('this', token)) {
       thisKeyword = token;
       // TODO(ahe): Validate field initializers are only used in
       // constructors, and not for function-typed arguments.
       token = expect('.', token.next);
@@ skipping 2087 matching lines @@
     }
     listener.handleContinueStatement(hasTarget, continueKeyword, token);
     return expectSemicolon(token);
   }
 
   Token parseEmptyStatement(Token token) {
     listener.handleEmptyStatement(token);
     return expectSemicolon(token);
   }
 }