https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78737
--- Comment #21 from Paul Thomas <pault at gcc dot gnu.org> ---
(In reply to Damian Rouson from comment #19)
> (In reply to Paul Thomas from comment #16)
> > (In reply to Paul Thomas from comment #15)
> > > (In reply to Damian Rouson from comment #14)
> > > > Hi Paul,
> > > >
> > > > Based on comment #12, I assume you no longer believe that type guarding
> > > > is
> > > > required. If I misinterpreted comment #12, please let me know.
>
> FWIW, I now realize I did misread comment #12. I focused in on "assert" and
> didn't notice the type-guarding in write_formatted above it.
>
>
> > >
> > > I have to confess that this "interpretation" is arrived at by the absence
> > > of
> > > any mention of the need for dynamic dispatch and by the implementation by
> > > other vendors.
>
> The Cray and PGI compilers accept the in the original bug report. The Intel
> compiler rejects, but I've noticed a lot of problems with UDDTIO in the
> Intel compiler over the years so I'll submit a bug report to Intel.
>
> >
> > On thinking about it, is the specific instance of write_formatted allowed?
>
> I believe not. Note 7.50 of the 31 August 2016 draft Fortran 2015 standard
> includes the following:
>
> "The dynamic type of an object cannot be abstract; therefore, a deferred
> type-bound procedure cannot be invoked."
>
> I interpret the above quote to mean that write_formatted as written in
> comment #15 cannot be invoked. Presumably that also means it is invalid
> code.
>
> Damian
Dear Damian,
[pault@localhost pr78737]# /irun/bin/gfortran -static-libgfortran c*1.f90 -g
comment1.f90:21:16:
write(*,*) a
1
Error: Data transfer element at (1) cannot be polymorphic unless it is
processed by a defined input/output procedure
[paultt@localhost pr78737]# ifort c*1.f90
comment1.f90(21): error #5513: A polymorphic I/O list item requires a
user-defined derived-type input/output procedure.
write(*,*) a
----^
compilation aborted for comment1.f90 (code 1)
ifort (IFORT) 16.0.3 20160415
This, I happen to think, is correct since there is no UDTIO procedure in sight.
Cheers
Paul
