https://gcc.gnu.org/ml/gcc-patches/2017-10/msg00249.html
	gcc/cp/
	Warn on MVP declarations
	* cp-tree.h (struct cp_declarator): Add parenthesized field.
	* decl.c (grokdeclarator): Warn about unnecessary parens.
	* parser.c (make_declarator): Init parenthesized field.
	(cp_parser_direct_declarator): Set parenthesized field.

	gcc/
	* doc/invoke.texi (Wparentheses): Document C++ MVP behaviour.

	gcc/testsuite/
	* g++.dg/warn/mvp.C: New.

From-SVN: r253446