Pattern match failure in do expression at TypeCheckCommon.hs:144:15-21

[mpickering]

The following program triggers an error due to an incomplete pattern match. I haven't
dug into why yet. The crucial part is that Card is a datatype which contains a computation.

--- start of standard stuff ---
on : {X -> {X -> Y} -> Y}
on x f = f x

data S = S (List Card)  

data Card = Card { Unit }

interface State = get : S | put : S -> Unit

drawCardDeck : [State]Card
drawCardDeck! =
	on get! { (S (cons top deck)) -> put (S deck); top }

main : { [Console]Unit }
main! = unit

[lucques]

Hi Matthew, having made some changes to the compiler (not related to this issue), the problem still occured in my working state 93f2559. I noticed that there was a bug in assigning (implicit, explicit) [£]'s to the definitions of S and Card, fixing this removed the issue: 4101e28
The same error came up again though, due to a bug in the unification algorithm, now fixed in 376bcf5 (I hope I did not overlook anything fixing it).
We'll probably pull in my branch soon to the master branch so the issue (at least this particular instance) can be seen as closed.
Cheers, Lukas