Kind variables not allowed in data declaration kind annotation
GHC won't accept kind variables stated directly in a data declaration. For example, the following does not compile:
data SMaybe :: (k -> *) -> Maybe k -> * where
SNothing :: SMaybe s 'Nothing
SJust :: s a -> SMaybe s ('Just a)However, the following does compile:
data SMaybe' (s :: k -> *) (m :: Maybe k) where
SNothing' :: SMaybe' s 'Nothing
SJust' :: s a -> SMaybe' s ('Just a)Trac metadata
| Trac field | Value |
|---|---|
| Version | 7.5 |
| Type | Bug |
| TypeOfFailure | OtherFailure |
| Priority | normal |
| Resolution | Unresolved |
| Component | Compiler (Type checker) |
| Test case | |
| Differential revisions | |
| BlockedBy | |
| Related | |
| Blocking | |
| CC | |
| Operating system | |
| Architecture |