test262/implementation-contributed/javascriptcore/stress/poly-proto-using-inheritance.js

function assert(b) {
    if (!b)
        throw new Error("Bad");
}

function foo() {
    class C {
        constructor()
        {
            this.y = 22;
        }
        get baz() { return this.x; }
    }
    C.prototype.field = 42;
    new C;
    return C;
}

for (let i = 0; i < 5; ++i)
    foo();

function bar(p) {
    class C extends p {
        constructor() {
            super();
            this.x = 22;
        }
    };
    let result = new C;
    return result;
}

for (let i = 0; i < 5; ++i)
    bar(foo());

let instances = [];
for (let i = 0; i < 40; ++i)
    instances.push(bar(foo()));

function validate(item) {
    assert(item.x === 22);
    assert(item.baz === 22);
    assert(item.field === 42);
}

let start = Date.now();
for (let i = 0; i < 100000; ++i) {
    instances.forEach((x) => validate(x));
}
if (false)
    print(Date.now() - start);