| I think I've worked out what's going on now. But I don't like it.
| When I use -fallow-undecidable-instances and -fallow-overlapping-instances
| (as I did) I was assuming (like Keith Wansbrough did) that
| GHC would do a Prolog-style backtracking search when it was time to
resolve
| an
Thu, 26 Oct 2000 01:29:38 -0700, Simon Peyton-Jones [EMAIL PROTECTED] pisze:
a') when trying to solve a constraint, search for all solutions,
and check that in the end there is only one.
b') never comlain of overlap when declaring instance declarations;
instead only complain when solving
Marcin 'Qrczak' Kowalczyk wrote:
[snip]
I am worried if the following scenario is possible: There are
two modules. Everything is OK. Now one of them adds an innocent
instance. It is perfectly correct in its context, but it happens that
it triggers an ambiguity in the second module. Still
