[Bug c++/32121] New: [4.1/4.2/4.3 Regression] C++ front-end accepts invalid __label__ declarations

["pinskia at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>]

According to our documentation, __label__ declarations have to come first but
the C++ accepts code where they don't which can be shown to be a bit weird with
two labels with the same name.
Here is a testcase which shows that the C++ front-end can accept a case where
we have two labels with the same name:
int f(void)
{
  a:;
  __label__ a;
  int b;
  __label__ c;
  a:;
  c:;
}

This should be rejected, the C front-end rejects this code with the following
errors:
t56.c: In function 'f':
t56.c:4: error: expected expression before '__label__'
t56.c:6: error: expected expression before '__label__'
t56.c:7: error: duplicate label 'a'
t56.c:3: error: previous definition of 'a' was here


This bug was originally found by Chris Lattner.


-- 
           Summary: [4.1/4.2/4.3 Regression] C++ front-end accepts invalid
                    __label__ declarations
           Product: gcc
           Version: 4.3.0
            Status: UNCONFIRMED
          Keywords: accepts-invalid
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: pinskia at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32121