[ignition] Fix hole check for dynamic local variables

The fast-path for dynamic local variables was previously checking the
lookup variable rather than the shadowed variable when deciding whether
to add a hole check.

BUG=669540

Review-Url: https://codereview.chromium.org/2551023004
Cr-Commit-Position: refs/heads/master@{#41677}

src/ast/scopes.cc

@@ -1690,6 +1690,15 @@ void Scope::ResolveVariable(ParseInfo* info, VariableProxy* proxy) {
 namespace {
 
 bool AccessNeedsHoleCheck(Variable* var, VariableProxy* proxy, Scope* scope) {
+  if (var->mode() == DYNAMIC_LOCAL) {
+    // Dynamically introduced variables never need a hole check (since they're
+    // VAR bindings, either from var or function declarations), but the variable
+    // they shadow might need a hole check, which we want to do if we decide
+    // that no shadowing variable was dynamically introoduced.
+    DCHECK(!var->binding_needs_init());
+    return AccessNeedsHoleCheck(var->local_if_not_shadowed(), proxy, scope);
+  }
+
   if (!var->binding_needs_init()) {
     return false;
   }

test/mjsunit/regress/regress-crbug-669540.js

+// Copyright 2016 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 f({
+    [
+        (function g() {
+            assertThrows(function(){
+                print(eval("p"));
+            }, ReferenceError);
+        })()
+    ]: p
+}) {};
+
+f({});