Fix parsing of awaitable expressions with nested functions

runtime/vm/parser.cc

 // 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.
 
 #include "vm/parser.h"
 
 #include "lib/invocation_mirror.h"
 #include "platform/utils.h"
 #include "vm/ast_transformer.h"
 #include "vm/bootstrap.h"
@@ skipping 9170 matching lines @@
     }
   }
   return expr;
 }
 
 
 AstNode* Parser::ParseAwaitableExpr(bool require_compiletime_const,
                                     bool consume_cascades,
                                     SequenceNode** await_preamble) {
   TRACE_PARSER("ParseAwaitableExpr");
-  parsed_function()->reset_have_seen_await();
+  BoolScope saved_seen_await(&parsed_function()->have_seen_await_expr_, false);
   AstNode* expr = ParseExpr(require_compiletime_const, consume_cascades);
   if (parsed_function()->have_seen_await()) {
     // Make sure we do not reuse the scope to avoid creating contexts that we
     // are unaware of, i.e, creating contexts that have already been covered.
     // See FlowGraphBuilder::VisitSequenceNode() for details on when contexts
     // are created.
     OpenBlock();
     AwaitTransformer at(current_block_->statements,
                         parsed_function(),
                         async_temp_scope_);
     AstNode* result = at.Transform(expr);
     SequenceNode* preamble = CloseBlock();
     if (await_preamble == NULL) {
       current_block_->statements->Add(preamble);
     } else {
       *await_preamble = preamble;
     }
-    parsed_function()->reset_have_seen_await();
     return result;
   }
   return expr;
 }
 
 
 AstNode* Parser::ParseExpr(bool require_compiletime_const,
                            bool consume_cascades) {
   TRACE_PARSER("ParseExpr");
   String* expr_ident =
@@ skipping 2918 matching lines @@
 void Parser::SkipQualIdent() {
   ASSERT(IsIdentifier());
   ConsumeToken();
   if (CurrentToken() == Token::kPERIOD) {
     ConsumeToken();  // Consume the kPERIOD token.
     ExpectIdentifier("identifier expected after '.'");
   }
 }
 
 }  // namespace dart