Let's remove the IsDetachedBuffer check in 22.2.4.3, step 18.a

[anba]

I didn't remove the step in #844 to avoid normative changes in that PR, but since this check is only implemented correctly in SpiderMonkey and CloneArrayBuffer will again check for detached buffers, it doesn't seem terrible useful to me to test for detached buffers in this step.

Test case for the current spec.

function detach(ab) {
  if (ArrayBuffer.transfer) {
    ArrayBuffer.transfer(ab);
  } else if (typeof detachArrayBuffer === "function") {
    detachArrayBuffer(ab);
  } else if (typeof transferArrayBuffer === "function") {
    transferArrayBuffer(ab)
  } else if (typeof Worker === "function") {
    try { eval("%ArrayBufferNeuter(ab)") } catch (e) {
      var w = new Worker("");
      w.postMessage(ab, [ab]);
      w.terminate();
    }
  } else {
    throw new TypeError("cannot detach array buffer");
  }
}

function test(from, to) {
    var ta = new from(0);
    ta.buffer.constructor = {
        get [Symbol.species]() {
            print("get @@species");
            detach(ta.buffer);
            return Object.defineProperty(function(){}.bind(), "prototype", {
                get() {
                    print("get prototype");
                    return null;
                }
            });
        }
    };
    try {
        new to(ta);
    } catch (e) {
        print("caught:", e);
        return;
    }
    print("No error");
}

// Expected: Prints "get @@species" and then throws a TypeError
test(Int32Array, Int32Array);

// Expected: Prints "get @@species", "get prototype", and then throws a TypeError
test(Int32Array, Uint32Array);

[bterlson]

@anba want to whip up a needs-consensus PR?

[bterlson]

@anba want to whip up a needs-consensus PR?

[littledan]

This test is valid both in the current spec and after your PR, right?

[littledan]

This test is valid both in the current spec and after your PR, right?

[anba]

This test is valid both in the current spec and after your PR, right?

No. After the update "get prototype" will also be printed for the test(Int32Array, Int32Array) call.

[anba]

This test is valid both in the current spec and after your PR, right?

No. After the update "get prototype" will also be printed for the test(Int32Array, Int32Array) call.