GHC Panic with TypeInType / levity polymorphism
This code is rightfully rejected.
-- {-# Language TypeInType #-}
{-# Language RankNTypes, KindSignatures, PolyKinds #-}
import GHC.Types (TYPE)
import Data.Kind
data Lan (g::TYPE rep -> TYPE rep') (h::TYPE rep -> TYPE rep'') a where Lan :: forall xx (g::TYPE rep -> TYPE rep') (h::TYPE rep -> Type) a. (g xx -> a) -> h xx -> Lan g h a
But uncomment first line and it panics
$ ghci2 ~/hs/132-bug.hs
GHCi, version 8.3.20171122: http://www.haskell.org/ghc/ :? for help
[1 of 1] Compiling Main ( /home/baldur/hs/132-bug.hs, interpreted )
ghc-stage2: panic! (the 'impossible' happened)
(GHC version 8.3.20171122 for x86_64-unknown-linux):
zonkTcTyVarToVar
'LiftedRep
Call stack:
CallStack (from HasCallStack):
callStackDoc, called at compiler/utils/Outputable.hs:1147:37 in ghc:Outputable
pprPanic, called at compiler/typecheck/TcType.hs:1640:17 in ghc:TcType
Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug
>
Maybe the same as #14555 (closed).
Trac metadata
Trac field | Value |
---|---|
Version | 8.2.1 |
Type | Bug |
TypeOfFailure | OtherFailure |
Priority | normal |
Resolution | Unresolved |
Component | Compiler |
Test case | |
Differential revisions | |
BlockedBy | |
Related | |
Blocking | |
CC | |
Operating system | |
Architecture |