:kind! doesn't reduce type families with poly-kinded return kinds
Originally discovered here, here is a simplified example:
$ ghci
GHCi, version 7.10.3: http://www.haskell.org/ghc/ :? for help
λ> :set -XPolyKinds -XTypeFamilies
λ> type family Hm :: k where Hm = Int
λ> :kind! Hm
Hm :: k
= Hm
Giving Hm
a monomorphic return kind of *
makes it work with :kind!
:
$ ghci
GHCi, version 7.10.3: http://www.haskell.org/ghc/ :? for help
λ> :set -XTypeFamilies
λ> type family Hm :: * where Hm = Int
λ> :kind! Hm
Hm :: *
= Int
Trac metadata
Trac field | Value |
---|---|
Version | 7.10.3 |
Type | Bug |
TypeOfFailure | OtherFailure |
Priority | normal |
Resolution | Unresolved |
Component | GHCi |
Test case | |
Differential revisions | |
BlockedBy | |
Related | |
Blocking | |
CC | |
Operating system | |
Architecture |