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

src/parsing/pattern-rewriter.cc

 // Copyright 2015 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 "src/messages.h"
 #include "src/parsing/parameter-initializer-rewriter.h"
 #include "src/parsing/parser.h"
 
 namespace v8 {
@@ skipping 14 matching lines @@
   rewriter.block_ = block;
   rewriter.descriptor_ = declaration_descriptor;
   rewriter.names_ = names;
   rewriter.ok_ = ok;
 
   rewriter.RecurseIntoSubpattern(rewriter.pattern_, declaration->initializer);
 }
 
 
 void Parser::PatternRewriter::RewriteDestructuringAssignment(
-    Parser* parser, RewritableAssignmentExpression* to_rewrite, Scope* scope,
-    bool* ok) {
+    Parser* parser, RewritableAssignmentExpression* to_rewrite, Scope* scope) {
   PatternRewriter rewriter;
 
   DCHECK(!to_rewrite->is_rewritten());
 
+  bool ok = true;
   rewriter.scope_ = scope;
   rewriter.parser_ = parser;
   rewriter.context_ = ASSIGNMENT;
   rewriter.pattern_ = to_rewrite;
   rewriter.block_ = nullptr;
   rewriter.descriptor_ = nullptr;
   rewriter.names_ = nullptr;
-  rewriter.ok_ = ok;
+  rewriter.ok_ = &ok;
 
   rewriter.RecurseIntoSubpattern(rewriter.pattern_, nullptr);
+  DCHECK(ok);
 }
 
 
+Expression* Parser::PatternRewriter::RewriteDestructuringAssignment(
+    Parser* parser, Assignment* assignment, Scope* scope) {
+  DCHECK_NOT_NULL(assignment);
+  DCHECK_EQ(Token::ASSIGN, assignment->op());
+  auto to_rewrite =
+      parser->factory()->NewRewritableAssignmentExpression(assignment);
+  RewriteDestructuringAssignment(parser, to_rewrite, scope);
+  return to_rewrite->expression();
+}
+
+
 bool Parser::PatternRewriter::IsAssignmentContext(PatternContext c) const {
   return c == ASSIGNMENT || c == ASSIGNMENT_INITIALIZER;
 }
 
 
 bool Parser::PatternRewriter::IsBindingContext(PatternContext c) const {
   return c == BINDING || c == INITIALIZER;
 }
 
 
@@ skipping 539 matching lines @@
 NOT_A_PATTERN(TryFinallyStatement)
 NOT_A_PATTERN(UnaryOperation)
 NOT_A_PATTERN(VariableDeclaration)
 NOT_A_PATTERN(WhileStatement)
 NOT_A_PATTERN(WithStatement)
 NOT_A_PATTERN(Yield)
 
 #undef NOT_A_PATTERN
 }  // namespace internal
 }  // namespace v8