https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65144
--- Comment #7 from Zaak <zbeekman at gmail dot com> ---
(In reply to Dominique d'Humieres from comment #1)
> AFAICT the substring problem occurs for PARAMETER only:
>
> program test3
> INTEGER,PARAMETER :: ucs4 = selected_char_kind("ISO_10646")
> CHARACTER(3,UCS4),PARAMETER ::
> unip=CHAR(INT(Z'5e74'),UCS4)//CHAR(INT(Z'6708'),ucs4)//CHAR(INT(Z'65e5'),
> ucs4)
> character(3,UCS4) :: uni
> uni = unip
> open(6, encoding="utf-8")
> print *, uni
> print *, uni(2:2)
> print *, unip
> print *, "'",unip(1:1),"'"
> end program test3
>
> gives at run time
>
> 年月日
> 月
> 年月日
> 't'
As Dominique noted a problem does exist with ISO 10646 characters with the
parameter attribute. Pleas see PR 65151
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65141 for more details
