v8/test/mjsunit/regress/regress-crbug-664942.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.

// Flags: --allow-natives-syntax

function foo() {
  return 'x'[0];
};
%PrepareFunctionForOptimization(foo);
foo();
%OptimizeFunctionOnNextCall(foo);
assertEquals("x", foo());