[GHC] #15122: Compiling a library problem with a local 8.5 build

[GHC]

#15122: Compiling a library problem with a local 8.5 build
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           Reporter:  fmixing        |             Owner:  (none)
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:  8.6.1
          Component:  Compiler       |           Version:  8.5
           Keywords:                 |  Operating System:  MacOS X
       Architecture:  x86_64         |   Type of failure:  GHC rejects
  (amd64)                            |  valid program
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
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 I’ve discovered that one library throws type checking exception when I try
 to compile it with my version of ghc compiler (I build it using `cabal
 new-build --with-compiler=/usr/local/bin/ghc-8.5.20180504`, the compiler
 was built from the master with 56974323ed427988059b5153bb43c694358cbb9b as
 the last commit), but it builds with 8.4.2 compiler (cabal new-build
 --with-compiler=/usr/local/bin/ghc-8.4.2). It’s really strange, so I tried
 to `make` the local version of 8.4.2 in the branch ghc-8.4.2-release, and
 found out that it cannot be built because there are missing some files
 that are necessary for build.  So maybe I’m doing something wrong? And can
 it be that this library doesn’t type check with 8.5 because it’s built
 from source files?

 The exception can be seen here:
 https://gist.github.com/fmixing/93d140dc7dbe25199af28616c6a143da

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15122>
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