Fix incorrect desugaring of cascades.

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 "vm/bigint_operations.h"
 #include "vm/class_finalizer.h"
 #include "vm/compiler.h"
 #include "vm/compiler_stats.h"
@@ skipping 6894 matching lines @@
     EnsureExpressionTemp();
   }
   return result;
 }
 
 
 AstNode* Parser::ParseCascades(AstNode* expr) {
   intptr_t cascade_pos = TokenPos();
   LocalVariable* cascade_receiver_var =
       CreateTempConstVariable(cascade_pos, "casc");
+  SequenceNode* cascade = new SequenceNode(cascade_pos, NULL);

[Ivan Posva, 2013/01/04 17:31:56]

Can you please explain why this is not a hack? You make it sound as if the
LoadLocal can overtake the StoreLocal here in general, which makes me nervous.

Adding a comment to the creation of the SequenceNode would help, thanks.

[Kevin Millikin (Google), 2013/01/07 09:14:14]

I think it is a hack.  I'll add a comment here, at the other use, and in the
LoadLocal AST class explaining it.

   StoreLocalNode* save_cascade =
       new StoreLocalNode(cascade_pos, cascade_receiver_var, expr);
-  current_block_->statements->Add(save_cascade);
+  cascade->Add(save_cascade);
   while (CurrentToken() == Token::kCASCADE) {
     cascade_pos = TokenPos();
     LoadLocalNode* load_cascade_receiver =
         new LoadLocalNode(cascade_pos, cascade_receiver_var);
     if (Token::IsIdentifier(LookaheadToken(1))) {
       // Replace .. with . for ParseSelectors().
       token_kind_ = Token::kPERIOD;
     } else if (LookaheadToken(1) == Token::kLBRACK) {
       ConsumeToken();
     } else {
@@ skipping 17 matching lines @@
       right_expr =
           ExpandAssignableOp(assignment_pos, assignment_op, expr, right_expr);
       AstNode* assign_expr = CreateAssignmentNode(left_expr, right_expr);
       if (assign_expr == NULL) {
         ErrorMsg(assignment_pos,
                  "left hand side of '%s' is not assignable",
                  Token::Str(assignment_op));
       }
       expr = assign_expr;
     }
-    current_block_->statements->Add(expr);
+    cascade->Add(expr);
   }
   // Result of the cascade is the receiver.
-  return new LoadLocalNode(cascade_pos, cascade_receiver_var);
+  return new LoadLocalNode(cascade_pos, cascade_receiver_var, cascade);
 }
 
 
 AstNode* Parser::ParseExpr(bool require_compiletime_const,
                            bool consume_cascades) {
   TRACE_PARSER("ParseExpr");
   const intptr_t expr_pos = TokenPos();
 
   if (CurrentToken() == Token::kTHROW) {
     ConsumeToken();
@@ skipping 2729 matching lines @@
 void Parser::SkipQualIdent() {
   ASSERT(IsIdentifier());
   ConsumeToken();
   if (CurrentToken() == Token::kPERIOD) {
     ConsumeToken();  // Consume the kPERIOD token.
     ExpectIdentifier("identifier expected after '.'");
   }
 }
 
 }  // namespace dart