[GHC] #12906: GHC fails to typecheck Main module without main

[GHC]

#12906: GHC fails to typecheck Main module without main
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        Reporter:  dfeuer            |                Owner:
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.0.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  Other             |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by osa1):

 I tried this module using 8.0, 7.10 and 7.8 and they all failed with the
 same error message:

 {{{#!haskell
 module Main where

 x :: String -> String
 x s = print (reverse s + 1)
 }}}

 {{{
 > t12906 /home/omer/ghc_bins/ghc-8.0.1/bin/ghc test
 [1 of 1] Compiling Main             ( test.hs, test.o )

 test.hs:1:1: error:
     The IO action ‘main’ is not defined in module ‘Main’

 > t12906 /home/omer/ghc_bins/ghc-7.10.1/bin/ghc test
 [1 of 1] Compiling Main             ( test.hs, test.o )

 test.hs:1:1: The IO action ‘main’ is not defined in module ‘Main’

 > t12906 /home/omer/ghc_bins/ghc-7.8.1/bin/ghc test
 [1 of 1] Compiling Main             ( test.hs, test.o )

 test.hs:1:1: The IO action ‘main’ is not defined in module ‘Main’
 }}}

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12906#comment:1>
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