Dependent quantification, GHC panic
While exploring Ryan's gist for term-level f :: forall a -> a -> Type
.
{-# Language PolyKinds #-}
{-# Language TypeApplications #-}
{-# Language ImpredicativeTypes #-}
import Data.Kind
data A k :: k -> Type
f :: KindOf A
f a = undefined
type KindOf (a :: k) = k
a = f @Int
gives
$ ~/code/unmodifiedghc/inplace/bin/ghc-stage2 --interactive -ignore-dot-ghci 630_bug.hs
GHCi, version 8.7.20181029: http://www.haskell.org/ghc/ :? for help
[1 of 1] Compiling Main ( 630_bug.hs, interpreted )
ghc-stage2: panic! (the 'impossible' happened)
(GHC version 8.7.20181029 for x86_64-unknown-linux):
ASSERT failed!
KindOf A
forall k -> k -> *
k_a1xQ[sk:0]
k_a1xQ[sk:0] -> *
k_a1xQ[sk:0]
[req]
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/TcExpr.hs:1336:94 in ghc:TcExpr
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 | |
Operating system | |
Architecture |