[GHC] #13394: PatternSynonyms/OverloadedStrings regression in GHC HEAD

[GHC]

#13394: PatternSynonyms/OverloadedStrings regression in GHC HEAD
-------------------------------------+-------------------------------------
        Reporter:  RyanGlScott       |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  highest           |            Milestone:  8.2.1
       Component:  Compiler          |              Version:  8.1
      Resolution:                    |             Keywords:
                                     |  PatternSynonyms
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  Compile-time      |            Test Case:
  crash or panic                     |  polykinds/T13394
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Changes (by RyanGlScott):

 * status:  closed => new
 * resolution:  fixed =>


Comment:

 Thanks, Simon. But you didn't include the original program as the test
 case! Rather, you included a slightly tweaked program that doesn't have as
 many list elements in `TypeDataSymbol`. This is crucial, as the original
 program still fails with a GHC panic even after
 8e053700f9357c1b9030c406130062795ae5015c:

 {{{
 $ ~/Software/ghc2/inplace/bin/ghc-stage2 -O1 -fforce-recomp Bug.hs
 [1 of 1] Compiling Bug              ( Bug.hs, Bug.o )
 ghc-stage2: panic! (the 'impossible' happened)
   (GHC version 8.1.20170307 for x86_64-unknown-linux):
         runtimeRepPrimRep
   typePrimRep (r_a28P :: TYPE rep_a28O)
   rep_a28O
   Call stack:
       CallStack (from HasCallStack):
         prettyCurrentCallStack, called at
 compiler/utils/Outputable.hs:1191:58 in ghc:Outputable
         callStackDoc, called at compiler/utils/Outputable.hs:1195:37 in
 ghc:Outputable
         pprPanic, called at compiler/simplStg/RepType.hs:360:5 in
 ghc:RepType
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13394#comment:4>
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