gcc/cp/ChangeLog:

	PR c++/78774
	* pt.c (convert_template_argument): Avoid assuming operand type
	is non-null since that of SCOPE_REF is not.

gcc/testsuite/ChangeLog:

	PR c++/78774
	* g++.dg/cpp1y/pr78774.C: New test.

From-SVN: r243683