[GHC] #8650: Unexpected behaviour of import ccall "header.h function"

[GHC]

#8650: Unexpected behaviour of import ccall "header.h function"
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              Reporter:  nh2         |            Owner:
                  Type:  bug         |           Status:  new
              Priority:  normal      |        Milestone:
             Component:  Compiler    |          Version:  7.6.3
            Resolution:              |         Keywords:
      Operating System:              |     Architecture:  Unknown/Multiple
  Unknown/Multiple                   |       Difficulty:  Unknown
       Type of failure:              |       Blocked By:
  Documentation bug                  |  Related Tickets:
             Test Case:              |
              Blocking:              |
Differential Revisions:              |
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Comment (by thomie):

 From Section 8.5.1 of the report (emphasis mine):
 >The ''optional'' filename `chname` specifies a C header file, where the
 intended meaning is that the header file declares the C entity identified
 by `cid`.

 From the GHC [https://www.haskell.org/ghc/docs/7.8.3/html/users_guide/ffi-
 ghc.html#glasgow-foreign-headers user's guide]:
 > C functions are normally declared using prototypes in a C header file.
 Earlier versions of GHC (6.8.3 and earlier) #included the header file in
 the C source file generated from the Haskell code, and the C compiler
 could therefore check that the C function being called via the FFI was
 being called at the right type.

 > GHC no longer includes external header files when compiling via C, so
 this checking is not performed.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8650#comment:2>
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