https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85542
--- Comment #2 from kargl at gcc dot gnu.org --- (In reply to G. Steinmetz from comment #0) > gfortran-8 changed between 20180304 and 20180311. > gfortran-7 changed between 20180215 and 20180308. > gfortran-6 changed between 20180307 and 20180314. > > > $ cat z1.f90 > function f(x) > character(*), intent(in) :: x > character((len((x)))) :: f > f = x > end > Workaround: remove superfluous parentheses.