GHC panic with visible kind applications
Using the https://phabricator.haskell.org/D5229 diff
This is fine
{-# Language RankNTypes #-}
{-# Language TypeApplications #-}
{-# Language PolyKinds #-}
{-# Language GADTs #-}
import Data.Kind
data
App :: forall (f :: Type -> Type). Type -> Type
where
MkApp :: f a -> App @f a
Kind polymorphic is fine
{-# Language RankNTypes #-}
{-# Language TypeApplications #-}
{-# Language PolyKinds #-}
{-# Language GADTs #-}
import Data.Kind
data
App :: forall k (f :: k -> Type). k -> Type
where
MkApp :: f a -> App @k @(f :: k -> Type) (a :: k)
But offing the visibility of k
fails
{-# Language RankNTypes #-}
{-# Language TypeApplications #-}
{-# Language PolyKinds #-}
{-# Language GADTs #-}
import Data.Kind
data
App :: forall (f :: k -> Type). k -> Type
where
MkApp :: f a -> App @(f :: k -> Type) (a :: k)
{-# Language RankNTypes #-}
{-# Language TypeApplications #-}
{-# Language PolyKinds #-}
{-# Language GADTs #-}
import Data.Kind
data
App :: forall (f :: k -> Type). k -> Type
where
MkApp :: f a -> App @f a
$ ghci -ignore-dot-ghci 581_bug.hs
GHCi, version 8.7.20181017: http://www.haskell.org/ghc/ :? for help
[1 of 1] Compiling Main ( 581_bug.hs, interpreted )
ghc-stage2: panic! (the 'impossible' happened)
(GHC version 8.7.20181017 for x86_64-unknown-linux):
ASSERT failed!
2
1
f_a1yB[tau:1]
f_a1yx[sk:1]
Call stack:
CallStack (from HasCallStack):
callStackDoc, called at compiler/utils/Outputable.hs:1160:37 in ghc:Outputable
pprPanic, called at compiler/utils/Outputable.hs:1219:5 in ghc:Outputable
assertPprPanic, called at compiler/typecheck/TcMType.hs:778:54 in ghc:TcMType
Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug
>
Trac metadata
Trac field | Value |
---|---|
Version | 8.6.1 |
Type | Bug |
TypeOfFailure | OtherFailure |
Priority | normal |
Resolution | Unresolved |
Component | Compiler |
Test case | |
Differential revisions | |
BlockedBy | |
Related | |
Blocking | |
CC | mnguyen |
Operating system | |
Architecture |