[GHC] #15475: Plugin recompilation check still panics

[GHC]

#15475: Plugin recompilation check still panics
-------------------------------------+-------------------------------------
           Reporter:  mpickering     |             Owner:  (none)
               Type:  bug            |            Status:  new
           Priority:  highest        |         Milestone:  8.6.1
          Component:  Compiler       |           Version:  8.4.3
           Keywords:                 |  Operating System:  Unknown/Multiple
       Architecture:                 |   Type of failure:  None/Unknown
  Unknown/Multiple                   |
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
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 I get a panic as follows when trying to use a plugin with the latest
 commit on the 8.6 branch.

 {{{
 <no location info>: error:
     ghc: panic! (the 'impossible' happened)
   (GHC version 8.6.1.20180803 for x86_64-unknown-linux):
         mkPluginUsage: file not found
   LiftPlugin /nix/store/q8rg4mca5zqv98arpxd7164pqa72hf1n-ncurses-6.1/lib
 /libHSlift-plugin-0.1.0.0-LpWZumtLigSEjndVxGCyUH-ghc8.6.1.20180803.so
   Call stack:
       CallStack (from HasCallStack):
         callStackDoc, called at compiler/utils/Outputable.hs:1164:37 in
 ghc:Outputable
         pprPanic, called at compiler/deSugar/DsUsage.hs:215:15 in
 ghc:DsUsage

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

 My example is nixified and not very minimal but I can provide it tomorrow
 if that would help.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15475>
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