Handle generic local functions without a return type (issue 27965)

pkg/analyzer/lib/src/generated/parser.dart

 // Copyright (c) 2014, 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 analyzer.src.generated.parser;
 
 import 'dart:collection';
 import "dart:math" as math;
 
 import 'package:analyzer/dart/ast/ast.dart';
@@ skipping 6858 matching lines @@
     if (keyword == Keyword.VOID) {
       return astFactory.typeName(
           astFactory.simpleIdentifier(getAndAdvance()), null);
     } else if (_matchesIdentifier()) {
       Token next = _peek();
       if (keyword != Keyword.GET &&
           keyword != Keyword.SET &&
           keyword != Keyword.OPERATOR &&
           (_tokenMatchesIdentifier(next) ||
               _tokenMatches(next, TokenType.LT))) {
+        Token afterTypeParameters = _skipTypeParameterList(next);
+        if (afterTypeParameters != null &&
+            _tokenMatches(afterTypeParameters, TokenType.OPEN_PAREN)) {
+          // If the identifier is followed by type parameters and a parenthesis,
+          // then the identifier is the name of a generic method, not a return
+          // type.
+          return null;
+        }
         return parseReturnType();
       }
       Token next2 = next.next;
       Token next3 = next2.next;
       if (_tokenMatches(next, TokenType.PERIOD) &&
           _tokenMatchesIdentifier(next2) &&
           (_tokenMatchesIdentifier(next3) ||
               _tokenMatches(next3, TokenType.LT))) {
         return parseReturnType();
       }
@@ skipping 1292 matching lines @@
    */
   Parser_SyntheticKeywordToken(Keyword keyword, int offset)
       : super(keyword, offset);
 
   @override
   int get length => 0;
 
   @override
   Token copy() => new Parser_SyntheticKeywordToken(keyword, offset);
 }