* is not an indexed type family
I can't seem to create an indexed data family using the kind *
with -XTypeInType
enabled. I have to work around it by using Type
:
$ /opt/ghc/head/bin/ghci
GHCi, version 8.1.20160108: http://www.haskell.org/ghc/ :? for help
λ> :set -XTypeInType -XTypeFamilies
λ> import Data.Kind
λ> data family IdxProxy k (a :: k)
λ> data instance IdxProxy * a
<interactive>:5:1: error:
• Illegal family instance for ‘*’
(* is not an indexed type family)
• In the data instance declaration for ‘*’
λ> data instance IdxProxy Type a
λ> :kind! IdxProxy *
IdxProxy * :: * -> *
= IdxProxy *
λ> :kind! IdxProxy Type
IdxProxy Type :: Type -> *
= IdxProxy Type
Trac metadata
Trac field | Value |
---|---|
Version | 8.1 |
Type | Bug |
TypeOfFailure | OtherFailure |
Priority | normal |
Resolution | Unresolved |
Component | Compiler (Type checker) |
Test case | |
Differential revisions | |
BlockedBy | |
Related | |
Blocking | |
CC | goldfire |
Operating system | |
Architecture |