Comment by wrs

You still had to tell the compiler ahead of time about the property. The actual test is more like

    NSObject obj = [NSObject init];
    giveObjectAProperty(obj, @"progressView");
    obj.progressView = [NSNumber 42];

Writing giveObjectAProperty may not be "nearly impossible" but it sure isn't easy.

And of course the parent is talking about methods, not properties, but...same argument.