Implement metadata on methods and fields.

pkg/front_end/lib/src/fasta/parser/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.
 
 library fasta.parser.parser;
 
 import '../fasta_codes.dart'
     show
         FastaCode,
         FastaMessage,
@@ skipping 26 matching lines @@
         codeExtraneousModifier,
         codeFactoryNotSync,
         codeFinalFieldWithoutInitializer,
         codeFunctionTypeDefaultValue,
         codeGeneratorReturnsValue,
         codeGetterWithFormals,
         codeInvalidAwaitFor,
         codeInvalidInlineFunctionType,
         codeInvalidSyncModifier,
         codeInvalidVoid,
+        codeMetadataTypeArguments,
         codeNoFormals,
         codeNonAsciiIdentifier,
         codeNonAsciiWhitespace,
         codeOnlyTry,
         codePositionalParameterWithEquals,
         codePrivateNamedParameter,
         codeRequiredParameterWithDefault,
         codeSetterNotSync,
         codeStackOverflow,
         codeSuperNullAware,
@@ skipping 526 matching lines @@
   }
 
   /// Parse `'@' qualified (‘.’ identifier)? (arguments)?`
   Token parseMetadata(Token token) {
     listener.beginMetadata(token);
     Token atToken = token;
     assert(optional('@', token));
     token = parseIdentifier(token.next, IdentifierContext.metadataReference);
     token =
         parseQualifiedRestOpt(token, IdentifierContext.metadataContinuation);
+    if (optional("<", token)) {
+      reportRecoverableErrorCode(token, codeMetadataTypeArguments);
+    }
     token = parseTypeArgumentsOpt(token);
     Token period = null;
     if (optional('.', token)) {
       period = token;
       token = parseIdentifier(
           token.next, IdentifierContext.metadataContinuationAfterTypeArguments);
     }
     token = parseArgumentsOpt(token);
     listener.endMetadata(atToken, period, token);
     return token;
@@ skipping 3423 matching lines @@
     return reportUnrecoverableError(
         token, () => code.format(uri, token.charOffset, string));
   }
 }
 
 typedef FastaMessage NoArgument(Uri uri, int charOffset);
 
 typedef FastaMessage TokenArgument(Uri uri, int charOffset, Token token);
 
 typedef FastaMessage StringArgument(Uri uri, int charOffset, String string);