[GHC] #10360: GHC ignores command-line options if *.o and *.hi files exist

[GHC]

#10360: GHC ignores command-line options if *.o and *.hi files exist
-------------------------------------+-------------------------------------
              Reporter:  asr         |             Owner:
                  Type:  bug         |            Status:  new
              Priority:  normal      |         Milestone:
             Component:  Compiler    |           Version:  7.10.1
              Keywords:              |  Operating System:  Unknown/Multiple
          Architecture:              |   Type of failure:  None/Unknown
  Unknown/Multiple                   |        Blocked By:
             Test Case:              |   Related Tickets:
              Blocking:              |
Differential Revisions:              |
-------------------------------------+-------------------------------------
 For example, given the module

 {{{#!hs
 module Test where

 foo = putStrLn "Hello World"
 }}}

 if I compile using the command

 {{{
 ghc -c Test.hs
 }}}

 and then I compile adding the `-Wall` flag

 {{{
 ghc -c -Wall Test.hs
 }}}

 I would expect the warning

 {{{
 Test.hs:3:1: Warning:
     Top-level binding with no type signature: foo :: IO ()
 }}}

 but GHC produces the message

 {{{
 compilation IS NOT required
 }}}

 That is, the `-Wall` flag was ignored because the `Test.o` and `Test.hi`
 exist.

 (I couldn't reproduce this behaviour using gcc version 4.6.3.)

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10360>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler