c++: fix ICE when comparing targs [PR119580]

c++: fix ICE when comparing targs [PR119580]

In r10-7816, cp_tree_equal/TEMPLATE_ID_EXPR was changed to use
comp_template_args to compare the targs.  This makes sense, but
comp_template_args won't deal with an error_mark_node.  We created
a BASELINK for S::foo<T::value_type>, but since value_type couldn't
be looked up, we ended up with an error_mark_node instead of a TREE_VEC
of arguments for the TEMPLATE_ID_EXPR in the BASELINK.

It seems reasonable not to create such a TEMPLATE_ID_EXPR by checking
the result of tsubst_template_args like we do in so many other places.
This changes the diagnostic in three tests, but it's only the followup
error message after complaining about the type/value mismatch.

	PR c++/119580

gcc/cp/ChangeLog:

	* pt.cc (tsubst_baselink): Return error_mark_node if
	tsubst_template_args returned error_mark_node.

gcc/testsuite/ChangeLog:

	* g++.dg/template/crash106.C: Adjust expected diagnostics.
	* g++.dg/template/crash112.C: Likewise.
	* g++.dg/template/dependent-args1.C: Likewise.
	* g++.dg/cpp0x/pr119580.C: New test.

Reviewed-by: Jason Merrill <jason@redhat.com>