[VM parser] Insert missing result type check in async functions using arrow

runtime/vm/parser.h

 // 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.
 
 #ifndef RUNTIME_VM_PARSER_H_
 #define RUNTIME_VM_PARSER_H_
 
 #include "include/dart_api.h"
 
 #include "lib/invocation_mirror.h"
@@ skipping 926 matching lines @@
                                 bool is_compound = false);
 
   ConstructorCallNode* CreateConstructorCallNode(
       TokenPosition token_pos,
       const TypeArguments& type_arguments,
       const Function& constructor,
       ArgumentListNode* arguments);
 
   void AddEqualityNullCheck();
 
+  AstNode* AddAsyncResultTypeCheck(TokenPosition expr_pos, AstNode* expr);
+
   AstNode* BuildClosureCall(TokenPosition token_pos,
                             AstNode* closure,
                             ArgumentListNode* arguments);
 
   RawInstance* TryCanonicalize(const Instance& instance,
                                TokenPosition token_pos);
   void CacheConstantValue(TokenPosition token_pos, const Instance& value);
   bool GetCachedConstant(TokenPosition token_pos, Instance* value);
 
   Thread* thread() const { return thread_; }
@@ skipping 69 matching lines @@
 
   intptr_t recursion_counter_;
   friend class RecursionChecker;
 
   DISALLOW_COPY_AND_ASSIGN(Parser);
 };
 
 }  // namespace dart
 
 #endif  // RUNTIME_VM_PARSER_H_