GHC 9.6 panics about kindPrimRep
Summary
GHC 9.6.0.20230111 (alpha 1) fails with kindPrimRep
panic.
Steps to reproduce
Save this as Foo.hs
:
{-# LANGUAGE GADTs #-}
{-# OPTIONS_GHC -O #-}
module Lib where
data Foo a where
Foo :: Foo Int
data Bar a = Bar a (Foo a)
data Some t = forall ix. Some (t ix)
instance Show (Some Bar) where
show (Some (Bar v t)) = case t of
Foo -> show v
Run
$ ghc-9.4 Foo.hs
[1 of 1] Compiling Lib ( Foo.hs, Foo.o )
$ ghc-9.6 Foo.hs
[1 of 1] Compiling Lib ( Foo.hs, Foo.o )
<no location info>: error:
panic! (the 'impossible' happened)
GHC version 9.6.0.20230111:
kindPrimRep
k_aDP
typePrimRep (ix_aDW :: k_aDP)
Call stack:
CallStack (from HasCallStack):
callStackDoc, called at compiler/GHC/Utils/Panic.hs:189:37 in ghc:GHC.Utils.Panic
pprPanic, called at compiler/GHC/Types/RepType.hs:588:5 in ghc:GHC.Types.RepType
CallStack (from HasCallStack):
panic, called at compiler/GHC/Utils/Error.hs:454:29 in ghc:GHC.Utils.Error
Expected behavior
I'd expect GHC 9.6 to succeed, similar to GHC 9.4.
Environment
- GHC version used: GHC 9.6.0.20230111 (alpha 1)