[GHC] #15002: Panic: collectNBinders

[GHC]

#15002: Panic: collectNBinders
-------------------------------------+-------------------------------------
           Reporter:  crockeea       |             Owner:  (none)
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:  8.4.2
          Component:  Compiler       |           Version:  8.4.2-rc1
           Keywords:                 |  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):                 |         Wiki Page:
-------------------------------------+-------------------------------------
 Steps to reproduce:

 Download concurrent-extra-0.7.0.12 and add the following stack.yaml file:
 resolver: nightly-2018-04-04
 system-ghc: true
 compiler-check: newer-minor

 {{{
 > ghc --version
 The Glorious Glasgow Haskell Compilation System, version 8.4.1.20180329

 > stack build --library-profiling
 concurrent-extra-0.7.0.12: build (lib)
 Preprocessing library for concurrent-extra-0.7.0.12..
 Building library for concurrent-extra-0.7.0.12..
 [7 of 8] Compiling Control.Concurrent.Broadcast (
 Control/Concurrent/Broadcast.hs, .stack-
 work/dist/x86_64-linux/Cabal-2.2.0.1/build/Control/Concurrent/Broadcast.p_o
 )
 ghc: panic! (the 'impossible' happened)
   (GHC version 8.4.1.20180329 for x86_64-unknown-linux):
         collectNBinders
   1
   Call stack:
       CallStack (from HasCallStack):
         callStackDoc, called at compiler/utils/Outputable.hs:1150:37 in
 ghc:Outputable
         pprPanic, called at compiler/coreSyn/CoreSyn.hs:2189:39 in
 ghc:CoreSyn

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


 --  While building custom Setup.hs for package concurrent-extra-0.7.0.12
 using:
       /home/local/ANT/ericcro/.stack/setup-exe-cache/x86_64-linux/Cabal-
 simple_mPHDZzAJ_2.2.0.1_ghc-8.4.1.20180329 --builddir=.stack-
 work/dist/x86_64-linux/Cabal-2.2.0.1 build lib:concurrent-extra --ghc-
 options " -ddump-hi -ddump-to-file -fdiagnostics-color=always"
     Process exited with code: ExitFailure 1
 }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15002>
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