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

src/ast/ast.cc

Index: src/ast/ast.cc
diff --git a/src/ast/ast.cc b/src/ast/ast.cc
index b8ed4a287fab5121951e7adfc49f1ad2f85190d1..eb5f2864696a475b911b722c8bb7b59dfd91723b 100644
--- a/src/ast/ast.cc
+++ b/src/ast/ast.cc
@@ -137,6 +137,10 @@ static void AssignVectorSlots(Expression* expr, FeedbackVectorSpec* spec,
 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_);
 }