The impossible happened (no skolem info) - untouchable kind variable
{-# LANGUAGE RankNTypes, PolyKinds, DataKinds, TypeFamilies #-}
module GHCBug where
data Proxy p = Proxy
data KProxy (a :: *) = KProxy
h :: forall r . (Proxy ('KProxy :: KProxy k) ~ Proxy ('KProxy :: KProxy *) => r) -> r
h = undefined
GHC reports
GHCBug.hs:8:6:
Couldn't match kind ‘k’ with ‘*’
‘k’ is untouchable
inside the constraints (Proxy 'KProxy ~ Proxy 'KProxy)
bound by the type signature for
h :: (Proxy 'KProxy ~ Proxy 'KProxy) => r
at GHCBug.hs:8:6-87ghc: panic! (the 'impossible' happened)
(GHC version 7.10.1 for x86_64-unknown-linux):
No skolem info: k_amc[sk]
Trac metadata
Trac field | Value |
---|---|
Version | 7.10.1 |
Type | Bug |
TypeOfFailure | OtherFailure |
Priority | normal |
Resolution | Unresolved |
Component | Compiler |
Test case | |
Differential revisions | |
BlockedBy | |
Related | |
Blocking | |
CC | |
Operating system | |
Architecture |