GHC panic from PolyKinds + DataKinds
Playing around with GhcKinds/KindInference/Examples gives me a GHC panic
-- https://ghc.haskell.org/trac/ghc/wiki/GhcKinds/KindInference/Examples?version=4
{-# Language PolyKinds #-}
{-# Language KindSignatures #-}
{-# Language DataKinds #-}
import Data.Kind
import Data.Proxy
import GHC.TypeLits
class C6 (k :: Type) (a :: k) (b :: Proxy (a :: k)) where
type T6 (proxy :: Proxy '(k, b))
on an out of date version of HEAD I get
$ ghci -ignore-dot-ghci 519.hs
GHCi, version 8.7.20180828: http://www.haskell.org/ghc/ :? for help
[1 of 1] Compiling Main ( 519.hs, interpreted )
ghc-stage2: panic! (the 'impossible' happened)
(GHC version 8.7.20180828 for x86_64-unknown-linux):
ASSERT failed!
1
0
k_a1FD[tau:0]
Proxy a_a1EN[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:768:54 in ghc:TcMType
Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug
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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 | |
Operating system | |
Architecture |