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

function test(f, n = 1000) {
    for (let i = 0; i < n; ++i)
        f();
}

let o1 = {
    get foo() {
        "use strict";
        return this;
    }
};

let o2 = {
    __proto__: o1,
    a() {
        return super.foo;
    },

    aa() {
        let arr = () => super.foo;
        return arr();
    },

    b() {
        "use strict";
        return super.foo;
    },

    bb() {
        "use strict";
        let arr = () => super.foo;
        return arr();
    }
};

var A = o2.a;
var AA = o2.aa;
var B = o2.b;
var BB = o2.b;

let globalObj = this;

test(function() {
    let num = o2.a.call(25);
    assert(typeof num === "object");
    assert(num instanceof Number);

    let str = o2.a.call("foo bar");
    assert(typeof str === "object");
    assert(str instanceof String);
    assert(str == "foo bar");

    let o = {};
    assert(o2.a.call(o) === o);

    assert(A() === globalObj);
});

test(function() {
    let num = o2.aa.call(25);
    assert(typeof num === "object");
    assert(num instanceof Number);

    let str = o2.aa.call("foo bar");
    assert(typeof str === "object");
    assert(str instanceof String);
    assert(str == "foo bar");

    let o = {};
    assert(o2.aa.call(o) === o);

    assert(AA() === globalObj);
});

test(function() {
    let num = o2.b.call(25);
    assert(typeof num === "number");
    assert(num === 25);

    let str = o2.b.call("foo bar");
    assert(typeof str === "string");
    assert(str === "foo bar");

    let o = {};
    assert(o2.b.call(o) === o);

    assert(B() === undefined);
});

test(function() {
    let num = o2.bb.call(25);
    assert(typeof num === "number");
    assert(num === 25);

    let str = o2.bb.call("foo bar");
    assert(typeof str === "string");
    assert(str === "foo bar");

    let o = {};
    assert(o2.bb.call(o) === o);

    assert(BB() === undefined);
});