[Bug c/58154] New: if declaration and definition of a function differ in scope, emit a warning

[alexander.huemer at xx dot vu]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58154

            Bug ID: 58154
           Summary: if declaration and definition of a function differ in
                    scope, emit a warning
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: enhancement
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: alexander.huemer at xx dot vu

Hi,

i just stumbled upon a piece of code like this:

static int foo(void);

int foo(void)
{
        volatile int a = 3;

        return a;
}

According to http://std.dkuug.dk/JTC1/SC22/open/n2620/n2620.txt --> 6.1.2.2 #7
the behavior in this situation is undefined.

       If, within a  translation  unit,  the  same  identifier
       appears   with  both  internal  and  external  linkage,  the
       behavior is undefined.

Steps to Reproduce:
the code above goes into foo.c
$ gcc -Wall -Wextra -c foo.c

Actual Results:
gcc does not emit a warning when compiling with -Wall -Wextra.

Expected Results:
gcc should emit a warning when compiling such code.