gcc/cp/ChangeLog:

	PR c++/68948
	* pt.c (tsubst_baselink): Diagnose an invalid constructor call
	if lookup_fnfields returns NULL_TREE and the name being looked
	up has the form A::A.

gcc/testsuite/ChangeLog:

	PR c++/68948
	* g++.dg/template/pr68948.C: New test.

From-SVN: r233176