Fix various parser bugs related to modifiers of top-level and class members.

dart/sdk/lib/_internal/compiler/implementation/scanner/partial_parser.dart

 // Copyright (c) 2011, 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 PartialParser extends Parser {
   PartialParser(Listener listener) : super(listener);
 
   Token parseClassBody(Token token) => skipClassBody(token);
@@ skipping 77 matching lines @@
     BeginGroupToken beginGroupToken = token;
     Token endGroup = beginGroupToken.endGroup;
     if (endGroup == null) {
       return listener.unmatched(beginGroupToken);
     } else if (!identical(endGroup.kind, $CLOSE_CURLY_BRACKET)) {
       return listener.unmatched(beginGroupToken);
     }
     return endGroup;
   }
 
-  Token parseFunctionBody(Token token, bool isExpression) {
+  Token parseFunctionBody(Token token, bool isExpression, bool allowAbstract) {
     assert(!isExpression);
     String value = token.stringValue;
     if (identical(value, ';')) {
+      if (!allowAbstract) {
+        listener.reportError(token, MessageKind.BODY_EXPECTED);
+      }
       // No body.
     } else if (identical(value, '=>')) {
       token = parseExpression(token.next);
       expectSemicolon(token);
     } else if (value == '=') {
       token = parseRedirectingFactoryBody(token);
       expectSemicolon(token);
     } else {
       token = skipBlock(token);
     }
@@ skipping 13 matching lines @@
         return token;
       }
       return listener.unexpected(token);
     }
     BeginGroupToken beginGroupToken = token;
     Token endToken = beginGroupToken.endGroup;
     listener.endFormalParameters(0, token, endToken);
     return endToken.next;
   }
 }