Iface Lint failure panic with HEAD ghc-stage1
A.hs:
module A where
class C1 a where
c1 :: p a -> Maybe a
class C2 a where
c2 :: a
instance (C1 a) => C2 (Maybe a) where
c2 = c1 undefined
B.hs:
module B where
import A
c2' :: (C1 a) => Maybe a
c2' = c2
Compiling them with "ghc-stage1 -dcore-lint -O2" gives this:
inplace/bin/ghc-stage1 -c A.hs -dcore-lint -O2 && inplace/bin/ghc-stage1 -c B.hs -dcore-lint -O2
ghc-stage1: panic! (the 'impossible' happened)
(GHC version 6.11.20090806 for x86_64-unknown-linux):
Iface Lint failure
Unfolding of main:A.$fC2Maybe_c2{v r33}
<no location info>:
In the expression: ($dC1{v aed} [lid]
`cast` (main:A.NTCo:T:C1{tc r31} a{tv aec} [tv]
:: <pred>main:A.T:C1{tc r36} a{tv aec} [tv]
~
forall (p{tv ael} [tv] :: ghc-prim:GHC.Prim.*{(w) tc 34d}
-> ghc-prim:GHC.Prim.*{(w) tc 34d}).
p{tv ael} [tv] a{tv aec} [tv]
-> base:Data.Maybe.Maybe{tc rm} a{tv aec} [tv]))
@ ghc-prim:GHC.Prim.Any{(w) tc 31N}
Kinds don't match in type application:
Type variable:
p{tv ael} [tv] :: ghc-prim:GHC.Prim.*{(w) tc 34d}
-> ghc-prim:GHC.Prim.*{(w) tc 34d}
Arg type:
ghc-prim:GHC.Prim.Any{(w) tc 31N} :: ghc-prim:GHC.Prim.*{(w) tc 34d}
Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug
Trac metadata
Trac field | Value |
---|---|
Version | 6.11 |
Type | Bug |
TypeOfFailure | OtherFailure |
Priority | normal |
Resolution | Unresolved |
Component | Compiler |
Test case | |
Differential revisions | |
BlockedBy | |
Related | |
Blocking | |
CC | |
Operating system | |
Architecture |