[ast] AstTraversalVisitor should visit the Declarations of Block scopes

R=marja@chromium.org

Bug: v8:6509
Change-Id: If8be12e2ce6c00de0bdee38ab721ef5b7b47efe5
Reviewed-on: https://chromium-review.googlesource.com/556239Reviewed-by: Marja Hölttä <marja@chromium.org>
Commit-Queue: Adam Klein <adamk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46331}

src/ast/ast-traversal-visitor.h

@@ -136,6 +136,9 @@ void AstTraversalVisitor<Subclass>::VisitFunctionDeclaration(
 template <class Subclass>
 void AstTraversalVisitor<Subclass>::VisitBlock(Block* stmt) {
   PROCESS_NODE(stmt);
+  if (stmt->scope() != nullptr) {
+    RECURSE_EXPRESSION(VisitDeclarations(stmt->scope()->declarations()));
+  }
   RECURSE(VisitStatements(stmt->statements()));
 }
 

test/mjsunit/regress/regress-6509.js

+// Copyright 2017 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.
+
+(function testSloppy() {
+  var arrow = (sth = (function f() {
+    {
+      function f2() { }
+    }
+  })()) => 0;
+
+  assertEquals(0, arrow());
+})();
+
+(function testStrict() {
+  "use strict";
+  var arrow = (sth = (function f() {
+    {
+      function f2() { }
+    }
+  })()) => 0;
+
+  assertEquals(0, arrow());
+})();