https://gcc.gnu.org/ml/gcc-patches/2018-01/msg01954.html
	PR c++/83988
	* pt.c (tsubst_baselink): Remove optype assert.
	* ptree.c (cxx_print_xnode): <case BASELINK> Print BASELINK_OPTYPE.

	PR c++/83988
	* g++.dg/template/pr83988.C: New.

From-SVN: r256986