[Bug fortran/78737] [OOP] linking error with deferred, undefined user-defined derived-type I/O

[pault at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78737

--- Comment #13 from Paul Thomas <pault at gcc dot gnu.org> ---
(In reply to Paul Thomas from comment #12)
> Created attachment 40305 [details]
> Patch for the PR
> 
> That attachment appears to fix the testcases of comments #6 and #9. This
> check of comment #6 runs OK:
> 
> module object_interface
>   type, abstract :: object
>   contains
>     procedure(write_formatted_interface), deferred :: write_formatted
>     generic :: write(formatted) => write_formatted
>   end type
>   abstract interface
>     subroutine write_formatted_interface(this,unit,iotype,vlist,iostat,iomsg)
>       import object
>       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
>   end interface
>   type, extends(object) :: non_abstract_child
>     integer :: i
>   contains
>     procedure :: write_formatted
>   end type
> contains
>   subroutine write_formatted(this,unit,iotype,vlist,iostat,iomsg)
>     class(non_abstract_child), 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
>     select type (this)
>       class is (non_abstract_child)
>         print *, this%i
>       class default
>         print *, "Error"
>     end select
>   end subroutine
>   subroutine assert(a)
>     class(object):: a
>     write(*,*) a
>   end subroutine
> end module
> 
>   use object_interface
>   class (object), allocatable :: z
>   allocate (z, source = non_abstract_child (99))
>   call assert (z)
> end
> 
> The patch bootstraps and regtests OK. Will submit tomorrow.
> 
> Paul

Sorry, should have had:
...snip...
  subroutine write_formatted(this,unit,iotype,vlist,iostat,iomsg)
    class(object), intent(in) :: this
...snip...

Both versions work fine.

Paul