re PR c++/21592 (ICE in resolve_overloaded_unification/arg_assoc)

re PR c++/21592 (ICE in resolve_overloaded_unification/arg_assoc)

cp:
	PR c++/21592
	* pt.c (build_non_dependent_expr): Don't wrap a COMPONENT_REF
	with already looked up member functions.  Assert we're not
	returning a NON_DEPENDENT_EXPR with unknown type.
	* typeck.c (finish_class_member_access_expr):  We can get
	non-template-id-expr baselinks.  If the lookup finds a baselink,
	remember it even inside templates.
testsuite:
	PR c++/21592
	* g++.dg/template/dependent-expr1.C: Add new expected error.
	* g++.dg/template/dependent-expr2.C: Adjust error text.
	* g++.dg/template/overload6.C: New.

From-SVN: r105313