[Bug c++/23418] New: old-style cast uses reinterpret+const instead of static+const

["stephan dot bergmann at sun dot com" <gcc-bugzilla at gcc dot gnu dot org>]

In the program

  #include <stdio.h>
  struct Base1 { int x1; };
  struct Base2 { int x2; };
  struct Derived: public Base1, public Base2 {};
  int main() {
    Derived const * d = new Derived;
    printf("%p %p %p\n", d, (Base2 *) d, (Base2 const *) d);
  }

the cast "(Base2 *) d" effectively does a

  const_cast< Base2 * >(reinterpret_cast< Base2 const * >(d))

instead of a

  const_cast< Base2 * >(static_cast< Base2 const * >(d))

(with the effect that of the three printed pointer values, errouneously the
first two are identical instead of the last two).  This is in violation of 5.4/5
of the C++ Standard.

This happens with both 4.0.0 and 4.0.1, but not with 3.4.3.  This error affects
the OpenOffice.org code base.

-- 
           Summary: old-style cast uses reinterpret+const instead of
                    static+const
           Product: gcc
           Version: 4.0.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: stephan dot bergmann at sun dot com
                CC: gcc-bugs at gcc dot gnu dot org
 GCC build triplet: i686-pc-linux-gnu
  GCC host triplet: i686-pc-linux-gnu
GCC target triplet: i686-pc-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23418