[GHC] #8150: Foreign export requires redundant type signature

[GHC]

#8150: Foreign export requires redundant type signature
-------------------------+-------------------------------------------------
       Reporter:         |             Owner:
  evincarofautumn        |            Status:  new
           Type:  bug    |         Milestone:
       Priority:         |           Version:  7.6.3
  normal                 |  Operating System:  Unknown/Multiple
      Component:         |   Type of failure:  Incorrect warning at
  Compiler               |  compile-time
       Keywords:         |         Test Case:
   Architecture:         |          Blocking:
  Unknown/Multiple       |
     Difficulty:         |
  Unknown                |
     Blocked By:         |
Related Tickets:         |
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 With a source file such as:

 {{{
 module FFITest where

 foreign export ccall "function"
   function :: IO ()
 function :: IO ()
 function = putStrLn "Hello, world!"
 }}}

 The second `function :: IO ()` signature is required to satisfy `-fwarn-
 missing-signatures`, even though a signature is already present in the
 `foreign export` declaration, and the types are required to be the same.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8150>
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