[GHC] #13803: Panic while forcing the thunk for TyThing IsFile (regression)

[GHC]

#13803: Panic while forcing the thunk for TyThing IsFile (regression)
-------------------------------------+-------------------------------------
        Reporter:  inaki             |                Owner:  (none)
            Type:  bug               |               Status:  closed
        Priority:  normal            |            Milestone:  8.2.1
       Component:  Compiler          |              Version:  8.2.1-rc2
      Resolution:  fixed             |             Keywords:  hs-boot
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  crash or panic                     |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):  Phab:D3742
       Wiki Page:                    |
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Comment (by inaki):

 Thanks for the fix, I just gave it a try. Unfortunately the original issue
 still seems to be present (perhaps I am hitting #13981?). The error
 message I am getting is basically the same as before:
 {{{
 <no location info>: error:
     ghc-stage2: panic! (the 'impossible' happened)
   (GHC version 8.2.0.20170720 for x86_64-unknown-linux):
         tcIfaceGlobal (local): not found
   You are in a maze of twisty little passages, all alike.
   While forcing the thunk for TyThing IsFile
   which was lazily initialized by initIfaceCheck typecheckLoop,
   I tried to tie the knot, but I couldn't find IsFile
   in the current type environment.
   If you are developing GHC, please read Note [Tying the knot]
   and Note [Type-checking inside the knot].
   Consider rebuilding GHC with profiling for a better stack trace.
   Contents of current type environment: []
   Call stack:
       CallStack (from HasCallStack):
         prettyCurrentCallStack, called at
 compiler/utils/Outputable.hs:1133:58 in ghc:Outputable
         callStackDoc, called at compiler/utils/Outputable.hs:1137:37 in
 ghc:Outputable
         pprPanic, called at compiler/iface/TcIface.hs:1696:23 in
 ghc:TcIface

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

 This is when trying to compile `gi-gio`, following the same steps as in
 the original report, but using GHC 8.2 from git.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13803#comment:20>
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