#3421: Iface Lint failure panic with HEAD ghc-stage1
---------------------------+------------------------------------------------
Reporter: Ashley Yakeley | Owner:
Type: bug | Status: new
Priority: normal | Component: Compiler
Version: 6.11 | Severity: normal
Keywords: | Testcase:
Os: Linux | Architecture: x86_64 (amd64)
---------------------------+------------------------------------------------
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
}}}
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/3421>
GHC <http://www.haskell.org/ghc/>
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