c++: parenthesized -> resolving to static data member [PR98283]

c++: parenthesized -> resolving to static data member [PR98283]

Here we're neglecting to propagate parenthesized-ness when the
member access (this->m) resolves to a static data member (and
thus finish_class_member_access_expr yields a VAR_DECL instead
of a COMPONENT_REF).

	PR c++/98283

gcc/cp/ChangeLog:

	* pt.cc (tsubst_copy_and_build) <case COMPONENT_REF>: Propagate
	REF_PARENTHESIZED_P more generally via force_paren_expr.
	* semantics.cc (force_paren_expr): Document default argument.

gcc/testsuite/ChangeLog:

	* g++.dg/cpp1y/paren6.C: New test.