id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc	os	architecture	failure	difficulty	testcase	blockedby	blocking	related
7193	darcs 2.8 fails to compile with ghc 7.6	pcapriotti		"Ganesh Sittampalam reports the following failure when building darcs 2.8 with ghc 7.6 RC1:

{{{
ghc.exe: panic! (the 'impossible' happened)
  (GHC version 7.6.0.20120822 for i386-unknown-mingw32):
        ds_ev_term
    cobox{v a6Aho} [lid] `cast`
(<main:Darcs.Test.Patch.WithState.WithState{tc r1oms}
                                    model{tv t4H} [tv]
                                    (main:Darcs.Witnesses.Ordered.FL{tc
r1iNn} prim{tv t4D} [tv]
                                     main:Darcs.Witnesses.Ordered.:>{tc
r1iNy} main:Darcs.Witnesses.Ordered.FL{tc r1iNn}

prim{tv t4D} [tv])>
                                 ghc-prim:GHC.Types.~{(w) tc 31Q}
main:Darcs.Test.Patch.WithState.WithState{tc r1oms}
                                                                    (Sym
cobox{v a6AgE} [lid])

<main:Darcs.Witnesses.Ordered.FL{tc r1iNn}

prim{tv t4D} [tv]

main:Darcs.Witnesses.Ordered.:>{tc r1iNy}
main:Darcs.Witnesses.Ordered.FL{tc r1iNn}

prim{tv t4D} [tv]>)
    (let {EvBinds{cobox{v a6zY5} [lid]
                    = cobox{v a6Aho} [lid] `cast`
(<main:Darcs.Test.Patch.WithState.WithState{tc r1oms}
                                                      model{tv t4H} [tv]

(main:Darcs.Witnesses.Ordered.FL{tc r1iNn}
                                                         prim{tv t4D} [tv]

main:Darcs.Witnesses.Ordered.:>{tc r1iNy}
main:Darcs.Witnesses.Ordered.FL{tc r1iNn}

prim{tv t4D} [tv])>

ghc-prim:GHC.Types.~{(w) tc 31Q}
main:Darcs.Test.Patch.WithState.WithState{tc r1oms}

(Sym

cobox{v a6AgE} [lid])

<main:Darcs.Witnesses.Ordered.FL{tc r1iNn}

prim{tv t4D} [tv]

main:Darcs.Witnesses.Ordered.:>{tc r1iNy}
main:Darcs.Witnesses.Ordered.FL{tc r1iNn}

prim{tv t4D} [tv]>)
                  cobox{v a6zY6} [lid] = CO <t{tv a6zY1} [tv]>}}
     cobox{v a6zY5} [lid] <xx{tv a6zY3} [sk]> <yy{tv a6zY4} [sk]>
     -> <t{tv a6zY1} [tv]>)
}}}


Project + dependencies can be found at http://urchin.earth.li/~ganesh/temp/tcproblem.tar.bz2 (run build.sh).

"	bug	closed	highest	7.6.1	Compiler	7.6.1-rc1	fixed		ganesh	Unknown/Multiple	Unknown/Multiple	Compile-time crash	Unknown