https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78661
--- Comment #5 from janus at gcc dot gnu.org ---
Btw, this variant is wrongly rejected:
MODULE m
IMPLICIT NONE
TYPE :: t
CHARACTER :: c
CONTAINS
PROCEDURE :: write_formatted
GENERIC :: WRITE(FORMATTED) => write_formatted
END TYPE
CONTAINS
SUBROUTINE write_formatted(dtv, unit, iotype, v_list, iostat, iomsg)
CLASS(t), INTENT(IN) :: dtv
INTEGER, INTENT(IN) :: unit
CHARACTER(*), INTENT(IN) :: iotype
INTEGER, INTENT(IN) :: v_list(:)
INTEGER, INTENT(OUT) :: iostat
CHARACTER(*), INTENT(INOUT) :: iomsg
WRITE (unit, "(A)", IOSTAT=iostat, IOMSG=iomsg) dtv%c
END SUBROUTINE
END MODULE
PROGRAM p
USE m
IMPLICIT NONE
Class(t), allocatable :: x
NAMELIST /nml/ x
x = t('a')
WRITE (*, nml)
END
NAMELIST /nml/ x
1
Error: NAMELIST object ‘x’ in namelist ‘nml’ at (1) is polymorphic and requires
a defined input/output procedure
