[GHC] #16063: ghc-8.6.3 + Mac OSX + FFI dependency causes 'impossible happened' compiler failure

[GHC]

#16063: ghc-8.6.3 + Mac OSX +  FFI dependency causes 'impossible happened' compiler
failure
-------------------------------------+-------------------------------------
           Reporter:  benselfridge   |             Owner:  (none)
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:
          Component:  Compiler       |           Version:  8.6.3
           Keywords:                 |  Operating System:  MacOS X
       Architecture:  x86_64         |   Type of failure:  Compile-time
  (amd64)                            |  crash or panic
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
-------------------------------------+-------------------------------------
 I am trying to build this library: https://github.com/GaloisInc/grift

 The build works perfectly on my Mac OS X system under ghc-8.4.4 via the
 README instructions. However, if I update to ghc-8.6.3, I get the
 following error:

 {{{
 Building library for bv-sized-float-0.1.0..
 [1 of 2] Compiling Data.BitVector.Sized.Float (
 src/Data/BitVector/Sized/Float.hs, /Users/benselfridge/grift/dist-
 newstyle/build/x86_64-osx/ghc-8.6.3/bv-sized-
 float-0.1.0/build/Data/BitVector/Sized/Float.o )
 [2 of 2] Compiling Data.BitVector.Sized.Float.App (
 src/Data/BitVector/Sized/Float/App.hs, /Users/benselfridge/grift/dist-
 newstyle/build/x86_64-osx/ghc-8.6.3/bv-sized-
 float-0.1.0/build/Data/BitVector/Sized/Float/App.o )
 ghc: loadArchive: Failed reading header from `/Users/benselfridge/grift
 /dist-newstyle/build/x86_64-osx/ghc-8.6.3/softfloat-
 hs-0.1.0/build/SoftFloat'
 ghc: panic! (the 'impossible' happened)
   (GHC version 8.6.3 for x86_64-apple-darwin):
         loadArchive "/Users/benselfridge/grift/dist-
 newstyle/build/x86_64-osx/ghc-8.6.3/softfloat-hs-0.1.0/build/SoftFloat":
 failed

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

 The library "softfloat-hs" is a Haskell library that calls C functions
 that are dynamically linked. If I try to run it within this project via
 "cabal new-repl softfloat-hs", the dependency works fine. It's only when I
 try to build "bv-sized-float", which depends on softfloat-hs, that I get
 the above error.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/16063>
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