[Bug c++/18635] New: use of uninitialised reference accepted in C++ front end

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

The following (presumably invalid) code is compiled successfully:

  int main(void) 
  {
      int &a = a;
  
      printf("a = %d\n", a);
      return 0;
  }

albeit with the following warning (if given -Wall -W):

  foo.cc: In function `int main()':
  foo.cc:5: warning: 'a' might be used uninitialized in this function

The generated assembly is as follows:

main()
        1070c:  9d e3 bf 90        save         %sp, -0x70, %sp
        10710:  11 00 00 41        sethi        %hi(0x10400), %o0
        10714:  90 12 23 c0        or           %o0, 0x3c0, %o0 ! 0x107c0
        10718:  40 00 40 54        call         printf
        1071c:  d2 02 40 00        ld           [%o1], %o1
        10720:  81 c7 e0 08        ret          
        10724:  91 e8 20 00        restore      %g0, 0x0, %o0

Given that the reference above is never bound to any valid object, should this
instead error?

Tested on 3.4.0 and 3.4.3 (both behave identically).

-- 
           Summary: use of uninitialised reference accepted in C++ front end
           Product: gcc
           Version: 3.4.3
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: ajo at acm dot org
                CC: gcc-bugs at gcc dot gnu dot org
 GCC build triplet: sparc-sun-solaris2.9
  GCC host triplet: sparc-sun-solaris2.9
GCC target triplet: sparc-sun-solaris2.9


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18635