For the mangled code in the new testcase, gfortran issues
a somewhat obtuse error message.  The problem is the matcher
for a complex entity runs prior to the matcher for an implied
do-loop.  Errors are queued in that order so an error messagei
for a mangled complex constant is emitted.

Regression tested on x86_64-*-freebsd.

2018-03-07  Steven G. Kargl  <kargl@gcc.gnu.org>

	PR fortran/56667
	* primary.c (match_sym_complex_part): Give the matcher for an implied
	do-loop a chance to run.

2018-03-07  Steven G. Kargl  <kargl@gcc.gnu.org>

	PR fortran/56667
	* gfortran.dg/implied_do_2.f90: New test.
	* gfortran.dg/coarray_8.f90: Update for new error message.

-- 
Steve