enum E { A; B; } class Main { static var n:Int = 3; static var e:Null = A; static function main() { switch (e) { case A: // commenting this trace makes it work... trace("hi"); for (i in 0...n) { trace(i); } case B: for (i in 0...n) { trace(i); } // commenting this default removes the nullcheck for `e` // and makes it work... default: } } }