re PR c++/71450 (ICE on invalid C++11 code on x86_64-linux-gnu: in tree check: expected record_type or union_type or qual_union_type, have template_type_parm in lookup_base, at cp/search.c:203)

	PR c++/71450
	* pt.c (tsubst_copy): Return error_mark_node when mark_used
	fails, even when complain & tf_error.

	* g++.dg/cpp0x/pr71450-1.C: New test.
	* g++.dg/cpp0x/pr71450-2.C: New test.

From-SVN: r242767