[GHC] #13704: -main-is flag should change exports in default module header

[GHC]

#13704: -main-is flag should change exports in default module header
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           Reporter:  cdsmith        |             Owner:  (none)
               Type:  feature        |            Status:  new
  request                            |
           Priority:  normal         |         Milestone:
          Component:  Compiler       |           Version:  8.0.1
           Keywords:                 |  Operating System:  Unknown/Multiple
       Architecture:                 |   Type of failure:  None/Unknown
  Unknown/Multiple                   |
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
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 The -main-is option to GHC should probably change the export list for the
 default module header.  It doesn't.

 {{{
 $ cat Main.hs
 program = return ()
 $ ghc -main-is Main.program Main.hs
 [1 of 1] Compiling Main             ( Main.hs, Main.o )

 Main.hs:1:1: error:
     Not in scope: ‘main’
     Perhaps you meant ‘min’ (imported from Prelude)

 Main.hs:1:1: error:
     The main IO action ‘program’ is not exported by module ‘Main’
 }}}

 I cannot imagine any possible use case for a feature that changes the
 entry point name to something else, and then deliberately fails to export
 the symbol by that name.  This seems like an obvious thing to fix.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13704>
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