Dear type wizards,
what's wrong with the following program?
> module Test where
> data Empty q = Empty (Ord a => q a)
> q :: (Ord a) => [a]
> q = []
> e0, e1, e2 :: Empty []
> e0 = Empty []
> e1 = Empty ([] :: (Ord a) => [a])
> e2 = Empty q
ghc-2.08 tells me ...
> ghc -c -fglasgow-exts Test.lhs
Test.lhs:11: Context `{Ord taDr}'
required by inferred type, but missing on a type signature
`Ord taDr' arising from use of `q' at Test.lhs:11
In a polymorphic function argument `q'
In the first argument of `Empty', namely `q'
In a pattern binding: `e2 = Empty q'
Compilation had errors
If I remove the definition of `e2' everything works fine. But look:
`q' is just a name for `[]'. Maybe it's a bug ssssssszzzzzzzzzzzzd?
Ralf
