id,summary,reporter,owner,description,type,status,priority,milestone,component,version,resolution,keywords,cc,os,architecture,failure,difficulty,testcase,blockedby,blocking,related
5668,panic: updInertSet,simonmar,dimitris,"Building `parsec-3.1.2` with HEAD panics with a complaint about `updInertSet`.

{{{
Building parsec-3.1.2...
[ 1 of 25] Compiling Text.Parsec.Pos  ( Text/Parsec/Pos.hs, dist/build/Text/Parsec/Pos.o )
[ 2 of 25] Compiling Text.Parsec.Error ( Text/Parsec/Error.hs, dist/build/Text/Parsec/Error.o )
[ 3 of 25] Compiling Text.ParserCombinators.Parsec.Error ( Text/ParserCombinators/Parsec/Error.hs, dist/build/Text/ParserCombinators/Parsec/Error.o )
[ 4 of 25] Compiling Text.ParserCombinators.Parsec.Pos ( Text/ParserCombinators/Parsec/Pos.hs, dist/build/Text/ParserCombinators/Parsec/Pos.o )
[ 5 of 25] Compiling Text.Parsec.Prim ( Text/Parsec/Prim.hs, dist/build/Text/Parsec/Prim.o )
ghc-stage2: panic! (the 'impossible' happened)
  (GHC version 7.3.20111129 for x86_64-unknown-linux):
        updInertSet
    Multiple inert equalities:
    Old (already inert): ([W]{0} ( cobox{v a5FZ} [lid] :: ( m_ta4{tv} [tau] :: ghc-prim:GHC.Prim.*{(w) tc 34d}
                                                                               -> ghc-prim:GHC.Prim.*{(w) tc 34d} )
                                                          ghc-prim:GHC.Types.~{(w) tc 31Q} ( m{tv a5Fj} [sk] :: ghc-prim:GHC.Prim.*{(w) tc 34d}
                                                                                                                -> ghc-prim:GHC.Prim.*{(w) tc 34d} ) ) :: ( m_ta4{tv} [tau] :: ghc-prim:GHC.Prim.*{(w) tc 34d}
                                                                                                                                                                               -> ghc-prim:GHC.Prim.*{(w) tc 34d} )
                                                                                                                                                          ghc-prim:GHC.Types.~{(w) tc 31Q} ( m{tv a5Fj} [sk] :: ghc-prim:GHC.Prim.*{(w) tc 34d}
                                                                                                                                                                                                                -> ghc-prim:GHC.Prim.*{(w) tc 34d} ) (CTyEqCan),
                          ( cobox{v a5FZ} [lid] :: ( m_ta4{tv} [tau] :: ghc-prim:GHC.Prim.*{(w) tc 34d}
                                                                        -> ghc-prim:GHC.Prim.*{(w) tc 34d} )
                                                   ghc-prim:GHC.Types.~{(w) tc 31Q} ( m{tv a5Fj} [sk] :: ghc-prim:GHC.Prim.*{(w) tc 34d}
                                                                                                         -> ghc-prim:GHC.Prim.*{(w) tc 34d} ) ))
    Trying to insert   : ([W]{0} ( cobox{v a5FZ} [lid] :: ( m_ta4{tv} [tau] :: ghc-prim:GHC.Prim.*{(w) tc 34d}
                                                                               -> ghc-prim:GHC.Prim.*{(w) tc 34d} )
                                                          ghc-prim:GHC.Types.~{(w) tc 31Q} ( m{tv a5Fj} [sk] :: ghc-prim:GHC.Prim.*{(w) tc 34d}
                                                                                                                -> ghc-prim:GHC.Prim.*{(w) tc 34d} ) ) :: ( m_ta4{tv} [tau] :: ghc-prim:GHC.Prim.*{(w) tc 34d}
                                                                                                                                                                               -> ghc-prim:GHC.Prim.*{(w) tc 34d} )
                                                                                                                                                          ghc-prim:GHC.Types.~{(w) tc 31Q} ( m{tv a5Fj} [sk] :: ghc-prim:GHC.Prim.*{(w) tc 34d}
                                                                                                                                                                                                                -> ghc-prim:GHC.Prim.*{(w) tc 34d} ) (CTyEqCan),
                          ( cobox{v a5FZ} [lid] :: ( m_ta4{tv} [tau] :: ghc-prim:GHC.Prim.*{(w) tc 34d}
                                                                        -> ghc-prim:GHC.Prim.*{(w) tc 34d} )
                                                   ghc-prim:GHC.Types.~{(w) tc 31Q} ( m{tv a5Fj} [sk] :: ghc-prim:GHC.Prim.*{(w) tc 34d}
                                                                                                         -> ghc-prim:GHC.Prim.*{(w) tc 34d} ) ))

Please report this as a GHC bug:  http://www.haskell.org/ghc/reportabug
}}}


To repeat:

{{{
$ cabal install --with-ghc=$ghcval parsec
}}}

where `$ghcval` is your GHC.  In this case it was a GHC I had just built with `validate`, I wanted to install `parsec` so I could test something else.
",bug,closed,highest,7.4.1,Compiler,7.2.1,fixed,,dimitris@…,Unknown/Multiple,Unknown/Multiple,Compile-time crash,Unknown,,,,