Should GHC allow FUN in a GADT declaration?
If I write:
data D a where
MkD :: FUN Many a (D a)
I get a rather confusing error message:
• Data constructor ‘MkD’ returns type ‘a -> D a’
instead of an instance of its parent type ‘D a’
If I write:
data D a where
MkD :: FUN Many a (D a)
I get a rather confusing error message:
• Data constructor ‘MkD’ returns type ‘a -> D a’
instead of an instance of its parent type ‘D a’