src/v8/test/mjsunit/compiler/escape-analysis-typeguard.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.

// Flags: --allow-natives-syntax --turbo-escape

class C { constructor(x) { this.a = x; } };
class D { constructor(x) { this.a = x; } };

function foo(){
  var x = new C(7);
  var y = new D(x);
  var z = y.a;
  %DeoptimizeNow();
  assertEquals(7, z.a);
}

foo();
foo();
foo();
foo();
%OptimizeFunctionOnNextCall(foo)
foo();