I think a widely used library that does this transparently will make life better for everyone. I hope the implementation I mentioned earlier can save you some time :) I don't think you need to worry about this, if the coercion changes the semantic value, not just the representation or the precision, the sender is in error. Sending '10.1' to a slot that is semantically an integer should be undefined, though in practice you get '10'. Receivers need to run domain checks in any case... Regards, Rohan