[GHC] #14756: `ghc -M` doesn't emit dependencies for header files included either via CPP or CApiFFI

[GHC]

#14756: `ghc -M` doesn't emit dependencies for header files included either via CPP
or CApiFFI
-------------------------------------+-------------------------------------
        Reporter:  hvr               |                Owner:  (none)
            Type:  feature request   |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.2.2
      Resolution:                    |             Keywords:  capi capiffi
                                     |  cpp
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
-------------------------------------+-------------------------------------
Description changed by hvr:

Old description:

> Given the following simple module
>
> {{{#!hs
> {-# LANGUAGE CApiFFI #-}
>
> #include "Bar.hs.inc"
>
> module Foo where
>
> foreign import capi unsafe "cbits.h foo" c_foo :: Int -> IO ()
> }}}
>
> The dependency information produced by `ghc -dep-suffix '' -M  Foo.hs` is
>
> {{{
> # DO NOT DELETE: Beginning of Haskell dependencies
> Foo.o : Foo.hs
> # DO NOT DELETE: End of Haskell dependencies
> }}}
>
> And neither mention the include header dependency `cbits.h` nor
> `Bar.hs.inc`.
>

>
> See also
> https://downloads.haskell.org/~ghc/latest/docs/html/users_guide/separate_compilation.html
> #makefile-dependencies

New description:

 Given the following simple module

 {{{#!hs
 {-# LANGUAGE CPP, CApiFFI #-}

 #include "Bar.hs.inc"

 module Foo where

 foreign import capi unsafe "cbits.h foo" c_foo :: Int -> IO ()
 }}}

 The dependency information produced by `ghc -dep-suffix '' -M  Foo.hs` is

 {{{
 # DO NOT DELETE: Beginning of Haskell dependencies
 Foo.o : Foo.hs
 # DO NOT DELETE: End of Haskell dependencies
 }}}

 And neither mention the include header dependency `cbits.h` nor
 `Bar.hs.inc`.



 See also
 https://downloads.haskell.org/~ghc/latest/docs/html/users_guide/separate_compilation.html
 #makefile-dependencies

--

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14756#comment:1>
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