[GHC] #10021: Add "Error:" prefix for error-messages

[GHC]

#10021: Add "Error:" prefix for error-messages
-------------------------------------+-------------------------------------
        Reporter:  k-bx              |                   Owner:
            Type:  feature request   |                  Status:  new
        Priority:  normal            |               Milestone:  7.12.1
       Component:  Compiler          |                 Version:  7.8.4
      Resolution:                    |                Keywords:
Operating System:  Unknown/Multiple  |            Architecture:
 Type of failure:  None/Unknown      |  Unknown/Multiple
      Blocked By:                    |               Test Case:
 Related Tickets:                    |                Blocking:
                                     |  Differential Revisions:
-------------------------------------+-------------------------------------

Comment (by hvr):

 I'd like to propose to change the case of `Error` and `Warning` to lower
 case to match the convention as used by the most popular C/C++-compilers
 these days.

 For reference, this is what `gcc` currently does:

 {{{
 $ gcc -Wall  -c foo.c
 foo.c: In function ‘main’:
 foo.c:2:1: warning: control reaches end of non-void function [-Wreturn-
 type]
  int main() { }
  ^
 }}}

 {{{
 $ gcc -Wall -Werror -c foo.c
 foo.c: In function ‘main’:
 foo.c:2:1: error: control reaches end of non-void function [-Werror
 =return-type]
  int main() { }
  ^
 cc1: all warnings being treated as errors
 }}}

 and here's what `clang` does:

 {{{
 $ clang-3.5 -Wall  -c foo.c
 foo.c:2:18: warning: unused variable 'x' [-Wunused-variable]
 int main() { int x = 0; }
                  ^
 1 warning generated.
 }}}

 {{{
 $ clang-3.5 -Wall -Werror -c foo.c
 foo.c:2:18: error: unused variable 'x' [-Werror,-Wunused-variable]
 int main() { int x = 0; }
                  ^
 1 error generated.
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10021#comment:5>
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