[GHC] #12630: Assertion failed with BuildFlavour = devel2

[GHC]

#12630: Assertion failed with  BuildFlavour = devel2
-------------------------------------+-------------------------------------
        Reporter:  pacak             |                Owner:
            Type:  bug               |               Status:  merge
        Priority:  normal            |            Milestone:  8.0.2
       Component:  Compiler          |              Version:  8.0.1
      Resolution:                    |             Keywords:
Operating System:  Linux             |         Architecture:  x86_64
 Type of failure:  Compile-time      |  (amd64)
  crash                              |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
-------------------------------------+-------------------------------------

Comment (by pacak):

 Simon: That other failure is not fixed in HEAD, but panic looks a bit
 different:

 {{{
   (GHC version 8.1.20161024 for x86_64-unknown-linux):
         ASSERT failed!
   in_scope InScope {wild_00 wild_Xw wild1_XH t'_a2XC pos'_a2XD
                     more'_a2XE a1_a2XF dt_d2iY dt1_d2iZ dt2_d2j0 dt3_d2j1
 dt4_d2j2
                     dt5_d2j3 decodeOTCLine $trModule nt1_s3K7 ipv1_s3K9
 $trModule_sc1H
                     $trModule_sc1I lvl_sc1T $wsucc_sc5K
 $wdecodeOTCLine_sc5T lvl_sc6y
                     lvl_sc6z lvl_sc6A lvl_sc6B lvl_sc6C lvl_sc6D lvl_sc6F
 lvl_sc6G
                     lvl_sc6H lvl_sc6I fail_sc6K lvl_sc6L lvl_sc6M lvl_sc6N
 lvl_sc6O
                     lvl_sc6P sc_sc7y sc_sc7z sc_sc7A sc_sc7B sc_sc7F
 $s$wsucc_sc7I}
   tenv []
   tenvFVs []
   cenv [sc7E :-> sg_sc7E]
   cenvFVs [sc7E :-> sg_sc7E]
   tys [ByteString]
   cos []
   Call stack:
       CallStack (from HasCallStack):
         prettyCurrentCallStack, called at
 compiler/utils/Outputable.hs:1076:58 in ghc:Outputable
         callStackDoc, called at compiler/utils/Outputable.hs:1125:22 in
 ghc:Outputable
         assertPprPanic, called at compiler/types/TyCoRep.hs:2070:56 in
 ghc:TyCoRep
         checkValidSubst, called at compiler/types/TyCoRep.hs:2103:17 in
 ghc:TyCoRep
         substTy, called at compiler/simplCore/SimplEnv.hs:701:18 in
 ghc:SimplEnv
   Call stack:
       CallStack (from HasCallStack):
         prettyCurrentCallStack, called at
 compiler/utils/Outputable.hs:1076:58 in ghc:Outputable
         callStackDoc, called at compiler/utils/Outputable.hs:1080:37 in
 ghc:Outputable
         pprPanic, called at compiler/utils/Outputable.hs:1123:5 in
 ghc:Outputable
         assertPprPanic, called at compiler/types/TyCoRep.hs:2070:56 in
 ghc:TyCoRep
         checkValidSubst, called at compiler/types/TyCoRep.hs:2103:17 in
 ghc:TyCoRep
         substTy, called at compiler/simplCore/SimplEnv.hs:701:18 in
 ghc:SimplEnv

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

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12630#comment:12>
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