This is yet another deferred character length problem that this time
is caused by a dependency in assignment between lhs and rhs
string_lengths. The comment in the testcase explains all.

Bootstraps and regtests on FC21/x86_64 - OK for trunk and 8-branch?

I cannot commit until next week.

Paul

2018-09-23  Paul Thomas  <pault@gcc.gnu.org>

    PR fortran/65667
    * trans-expr.c (gfc_trans_assignment_1): If there is dependency
    fix the rse stringlength.

2018-09-23  Paul Thomas  <pault@gcc.gnu.org>

    PR fortran/65667
    * gfortran.dg/dependency_52.f90 : New test.