[GHC] #12595: Linker failure: multiple definition of

[GHC]

#12595: Linker failure: multiple definition of
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        Reporter:  MikolajKonarski   |                Owner:
            Type:  bug               |               Status:  new
        Priority:  high              |            Milestone:  8.0.2
       Component:  Compiler          |              Version:  8.0.1
      Resolution:                    |             Keywords:
Operating System:  Linux             |         Architecture:  x86_64
 Type of failure:  GHC rejects       |  (amd64)
  valid program                      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #10531            |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by rwbarton):

 I managed to reproduce this. It has something to do with BangPatterns
 apparently. Here is a reproducer with just two modules:
 {{{
 -- U.hs
 module U where
 u :: Int
 u = 1

 -- Main.hs
 {-# LANGUAGE BangPatterns #-}
 import U
 main = print $ let !x = u in x
 }}}
 `ghc-8.0.1 -O Main` fails with the same sort of linker error.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12595#comment:2>
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