c++: non-dependent immediate member fn call [PR99895]

c++: non-dependent immediate member fn call [PR99895]

Here we're emitting a bogus error during ahead of time evaluation of a
non-dependent immediate member function call such as a.f(args) because
the defacto templated form for such a call is (a.f)(args) but we're
trying to evaluate it using the intermediate CALL_EXPR built by
build_over_call, which has the non-member form f(a, args).  The defacto
member form is built in build_new_method_call, so it seems we should
handle the immediate call there instead, or perhaps make build_over_call
build the correct form in the first place.

Giiven that there are many spots other than build_new_method_call that
call build_over_call for member functions, e.g. build_op_call, this
patch takes the latter approach.

In passing, this patch makes us avoid wrapping PARM_DECL in
NON_DEPENDENT_EXPR for benefit of the third testcase below.

	PR c++/99895

gcc/cp/ChangeLog:

	* call.cc (build_over_call): For a non-dependent member call,
	build up a CALL_EXPR using a COMPONENT_REF callee, as in
	build_new_method_call.
	* pt.cc (build_non_dependent_expr): Don't wrap PARM_DECL either.
	* tree.cc (build_min_non_dep_op_overload): Adjust accordingly
	after the build_over_call change.

gcc/ChangeLog:

	* tree.cc (build_call_vec): Add const to second parameter.
	* tree.h (build_call_vec): Likewise.

gcc/testsuite/ChangeLog:

	* g++.dg/cpp2a/consteval-memfn1.C: New test.
	* g++.dg/cpp2a/consteval-memfn2.C: New test.
	* g++.dg/cpp2a/consteval28.C: New test.