TcSimplify.lhs:(2093,13)-(2094,38): Non-exhaustive patterns
Dear ghc developers,
instead of giving some kind of 'unresolved overloading'
error message, the following code
% cat Bug.hs
{-# OPTIONS_GHC -fglasgow-exts #-}
module Bug where
class Foo a
instance Foo (a -> b)
foo :: Foo a => a -> ()
foo = undefined
class Bar a r
-- The same happens if we use fundeps:
-- class Bar a r | r -> a
bar :: Bar a r => r -> ()
bar = undefined
test = foo bar
causes ghc to panic:
% ghc Bug.hs
ghc-6.5.20050709: panic! (the `impossible' happened,
GHC version 6.5.20050709):
typecheck/TcSimplify.lhs:(2093,13)-(2094,38):
Non-exhaustive patterns in case
Best regards,
Thomas Jäger
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