[Hugs-users] Pattern match failure leads to lots of output
ndmitchell at gmail.com
Fri Sep 1 12:41:44 EDT 2006
> It would probably be better to hide the dictionary arguments and the _vNNN
> suffixes altogether in pattern match errors. Can you put a boiled-down
> example in the BTS?
Here is a small failing example, with context and stuff its hard to
know when I get it minimal:
> data Maybe1 a = Just1 a | Nothing1 deriving Eq
> data Maybe2 a = Just2 (Maybe1 a) | Nothing2 deriving Eq
> crash_me = g (Just2 (Just1 1))
> g x = f Nothing2
> where f y | x == y && False = undefined
Run crash_me to see a lot of output.
Ross: I can't test the code you sent me right now, since I'm on a
machine without a C compiler, but should be back by Wednesday.
More information about the Hugs-Users