PR78494 add missing returns to propagate_const

PR78494 add missing returns to propagate_const

2016-11-23  Felix Morgner  <felix.morgner@gmail.com>
	    Jonathan Wakely  <jwakely@redhat.com>

	PR libstdc++/78494
	* include/experimental/propagate_const (propagate_const::operator=):
	Add missing return statements.
	* testsuite/experimental/propagate_const/assignment/move_neg.cc:
	Adjust dg-error line numbers.
	* testsuite/experimental/propagate_const/requirements2.cc: Likewise.

Co-Authored-By: Jonathan Wakely <jwakely@redhat.com>
From-SVN: r242760