https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78737
Paul Thomas <pault at gcc dot gnu.org> changed:
What |Removed |Added
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CC| |pault at gcc dot gnu.org
--- Comment #8 from Paul Thomas <pault at gcc dot gnu.org> ---
(In reply to janus from comment #5)
> (In reply to janus from comment #4)
> > Looking at the dump, one probably needs a polymorphic reference to
> > 'a->_vptr->write_formatted' instead of using the interface?
>
> Btw, such wrong-code behavior is also seen in the non-abstract version:
>
>
> module object_interface
> type :: object
> contains
> procedure :: write_formatted
> generic :: write(formatted) => write_formatted
> end type
> contains
> subroutine write_formatted(this,unit,iotype,vlist,iostat,iomsg)
> class(object), intent(in) :: this
> integer, intent(in) :: unit
> character (len=*), intent(in) :: iotype
> integer, intent(in) :: vlist(:)
> integer, intent(out) :: iostat
> character (len=*), intent(inout) :: iomsg
> end subroutine
>
> subroutine assert(a)
> class(object):: a
> write(*,*) a
> end subroutine
> end module
>
> end
>
>
> If the write procedure is overwritten in an extended type, then the write
> statement still calls the one from the base class, which is wrong.
Janus,
We interpreted the standard to imply that a SELECT TYPE is required in
write_formatted to obtain the correct dtio io procedure.
I did think about adding pointers to the procedures in the vtable but decided
that the standard did not require it.
Cheers
Paul
