PR c++/55542
	* pt.c (make_ith_pack_parameter_name): Return NULL if
	name is NULL.
	(tsubst_decl): Call make_ith_pack_parameter_name even if
	DECL_NAME is NULL.

	* g++.dg/cpp0x/vt-55542.C: New test.

From-SVN: r194010