[GHC] #10531: modules that can be linked successfully when compiled with optimizations, fail to link with: multiple definition of `__stginit_ZCMain'

[GHC]

#10531: modules that can be linked successfully when compiled with optimizations,
fail to link with: multiple definition of `__stginit_ZCMain'
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        Reporter:  imz               |                   Owner:
            Type:  bug               |                  Status:  new
        Priority:  normal            |               Milestone:
       Component:  Compiler          |                 Version:  7.6.1
      Resolution:                    |                Keywords:
Operating System:  Linux             |            Architecture:  x86_64
 Type of failure:  GHC rejects       |  (amd64)
  valid program                      |               Test Case:  attached
      Blocked By:                    |                Blocking:
 Related Tickets:  437               |  Differential Revisions:
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Comment (by imz):

 Strangely, this happens only on the second pass, after removing `A.o`.
 Although the sequence of actions is the same in the first pass, there are
 no errors in the first pass.

 (I've noticed a field named "Test Case" in the description. Should I write
 it according to
 https://ghc.haskell.org/trac/ghc/wiki/Building/RunningTests/Adding and
 request a pull? Or what am I supposed to submit a test-case? I'm not sure
 that the repeating the compilation commands can be described easily in
 that format...)

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10531#comment:5>
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