Core lint error when compiling hindent-6.0.0 with GHC 9.4
This reproduces as far back as GHC 9.4.3 at least.
I was unable to quickly test other GHC versions because hindent-6.0.0 only builds with GHC 9.4
[27 of 34] Compiling HIndent.ModulePreprocessing.CommentRelocation ( src/HIndent/ModulePreprocessing/CommentRelocation.hs, dist/build/HIndent/ModulePreprocessing/CommentRelocation.o, dist/build/HIndent/ModulePreprocessing/CommentRelocation.dyn_o )
WARNING:
Simplifier bailing out
HIndent.ModulePreprocessing.CommentRelocation, after 4 iterations [2935, 256, 147, 18]
Size = {terms: 2,032, types: 4,376, coercions: 1,971, joins: 2/66}
Call stack:
CallStack (from HasCallStack):
warnPprTrace, called at compiler/GHC/Core/Opt/Pipeline.hs:700:9 in ghc:GHC.Core.Opt.Pipeline
WARNING:
Missed specialisation opportunity
return
[m_aiez, v_B1] [~]
Call stack:
CallStack (from HasCallStack):
warnPprTrace, called at compiler/GHC/Core/Opt/Specialise.hs:1464:5 in ghc:GHC.Core.Opt.Specialise
*** Core Lint errors : in result of CorePrep ***
<no location info>: warning:
The coercion variable co1_a121C
:: (f2_a11D3 :~~: EpAnn) ~# (Any :~~: Any)
[LclId[CoVarId]]
is out of scope
In the RHS of $wgo1_r15Om :: forall {a1}.
Typeable a1 =>
(forall (m :: * -> *).
Monad m =>
(forall d. Data d => d -> m d) -> a1 -> m a1)
-> a1 -> StateT [LEpaComment] Identity a1
In the body of lambda with binder a1_s15CI :: *
In the body of lambda with binder ww_s15Zl :: Typeable a1_s15CI
In the body of lambda with binder ww1_s15Zm :: forall (m :: *
-> *).
Monad m =>
(forall d. Data d => d -> m d)
-> a1_s15CI -> m a1_s15CI
In the body of lambda with binder x_s15Zn :: a1_s15CI
In the body of letrec with binders lvl24_s15Zo :: AppOrCon a1_s15CI
In the body of letrec with binders m1_s15Zp :: StateT
[LEpaComment] Identity a1_s15CI
In the body of lambda with binder s1_s15Zq :: [LEpaComment]
In the body of letrec with binders ds_s15Zr :: Identity
(a1_s15CI, [LEpaComment])
In a case alternative: (IsApp k'_a11D2 :: *,
f2_a11D3 :: k'_a11D2 -> *,
x1_a11D4 :: k'_a11D2,
co_a11D5 :: a1_s15CI ~# f2_a11D3 x1_a11D4,
f3_s15Zt :: TypeRep f2_a11D3,
x2_s15Zu :: TypeRep x1_a11D4)
In a case alternative: (True)
In a case alternative: ((,) a2_s15ZF :: a1_s15CI,
s'_s15ZG :: [LEpaComment])
In a case alternative: (EpAnn ds1_s15ZI :: Anchor,
ds2_s15ZJ :: (x1_a11D4 |> Sym (Nth:3
(Kind
(Sym (Nth:3
(Sub (Sym Univ(nominal CorePrep
:: f2_a11D3
:~~: EpAnn, Any
:~~: Any))))
; Nth:2
(Sub (Sym Univ(nominal CorePrep
:: f2_a11D3
:~~: EpAnn, Any
:~~: Any))))))),
ds3_s15ZK :: EpAnnComments)
In a case alternative: (Anchor ds4_s15ZM :: RealSrcSpan,
ds5_s15ZN :: AnchorOperation)
In the body of letrec with binders ds6_s15ZO :: ([LEpaComment],
[LEpaComment])
In the body of letrec with binders sat_s162b :: [LEpaComment]
In the result-type of a case with scrutinee: ds3_s15ZK
In the type ‘EpAnn
(x1_a11D4 |> Sym (Nth:3
(Kind
(Sym (Nth:3 (Sub (Sym co1_a121C)))
; Nth:2 (Sub (Sym co1_a121C))))))’
Substitution: [TCvSubst
In scope: InScope {k'_a11D2 f2_a11D3 x1_a11D4 co_a11D5 a1_s15CI}
Type env: [a11D2 :-> k'_a11D2, a11D3 :-> f2_a11D3,
a11D4 :-> x1_a11D4, s15CI :-> a1_s15CI]
Co env: [a11D5 :-> co_a11D5]]