[es6] support AssignmentPattern as LHS in for-in/of loops

src/ast/ast.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/ast/ast.h"
 
 #include <cmath>  // For isfinite.
 #include "src/ast/scopes.h"
 #include "src/builtins.h"
 #include "src/code-stubs.h"
@@ skipping 119 matching lines @@
                                       ? FeedbackVectorSlotKind::KEYED_STORE_IC
                                       : FeedbackVectorSlotKind::STORE_IC;
     *out_slot = spec->AddSlot(kind);
   }
 }
 
 
 void ForEachStatement::AssignFeedbackVectorSlots(
     Isolate* isolate, FeedbackVectorSpec* spec,
     FeedbackVectorSlotCache* cache) {
+  // TODO(caitp): for-of statements do not make use of this feedback slot.
+  // The each_slot_ should be specific to ForInStatement, and this work moved
+  // there.
+  if (IsForOfStatement()) return;
   AssignVectorSlots(each(), spec, &each_slot_);
 }
 
 
 Assignment::Assignment(Zone* zone, Token::Value op, Expression* target,
                        Expression* value, int pos)
     : Expression(zone, pos),
       bit_field_(
           IsUninitializedField::encode(false) | KeyTypeField::encode(ELEMENT) |
           StoreModeField::encode(STANDARD_STORE) | TokenField::encode(op)),
@@ skipping 993 matching lines @@
 bool Literal::Match(void* literal1, void* literal2) {
   const AstValue* x = static_cast<Literal*>(literal1)->raw_value();
   const AstValue* y = static_cast<Literal*>(literal2)->raw_value();
   return (x->IsString() && y->IsString() && x->AsString() == y->AsString()) ||
          (x->IsNumber() && y->IsNumber() && x->AsNumber() == y->AsNumber());
 }
 
 
 }  // namespace internal
 }  // namespace v8