[Bug preprocessor/34695] New: Preprocessor warning->error conversion from -Werror is silent

["ed at catmur dot co dot uk" <gcc-bugzilla at gcc dot gnu dot org>]

When -Werror is passed in, libcpp silently converts warnings to errors:
$ gcc foo.c -Wall -Werror
foo.c:3:1: error: "FOO" redefined
foo.c:2:1: error: this is the location of the previous definition

This is potentially confusing, and inconsistent with cc, which displays:
$ gcc foo.c -Wall -Werror
cc1: warnings being treated as errors
foo.c:1: warning: return type defaults to ‘int’
foo.c: In function ‘main’:
foo.c:1: warning: control reaches end of non-void function


-- 
           Summary: Preprocessor warning->error conversion from -Werror is
                    silent
           Product: gcc
           Version: 4.2.2
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: preprocessor
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: ed at catmur dot co dot uk


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34695