http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58114
--- Comment #5 from Jonathan Wakely <redi at gcc dot gnu.org> --- That change would force compilers to reject currently valid programs that have well-defined behaviour. Changes that like are not popular. It is valid in C to pass a pointer to an incomplete type to free(), and this C++ rule is compatible. You can delete incomplete types if they have trivial destructors (like C structs).
