PR c++/51213 (again)

PR c++/51213 (again)

	PR c++/51213 (again)
	* pt.c (deduction_tsubst_fntype): Remove.
	(fn_type_unification): Check deduction depth and call
	instantiate_template here.  Handle default argument access checks.
	(determine_specialization): Suppress access control.
	(tsubst_decl): Check for excessive deduction depth.
	(recheck_decl_substitution): Make sure access control is on.
	(type_unification_real): Don't mess with access deferring here.
	(get_bindings): Adjust for fn_type_unification return type.
	* call.c (enum rejection_reason_code): Drop rr_template_instantiation.
	(template_instantiation_rejection): Remove.
	(struct rejection_reason): Change targs to num_targs.
	(template_unification_rejection, print_z_candidate): Adjust.
	(add_template_candidate_real): Adjust for fn_type_unification change.
	* class.c (resolve_address_of_overloaded_function): Likewise.
	* cp-tree.h: Adjust declaration.

From-SVN: r190664