N3582
	* cp-tree.h (AUTO_IS_DECLTYPE): New.
	* parser.c (cp_parser_decltype): Handle decltype(auto).
	(cp_parser_type_id_1): Allow auto without a late-specified
	return in C++1y.
	(cp_parser_primary_expression): Use the return value of
	finish_parenthesized_expr.
	(cp_parser_transaction_expression): Likewise.
	* semantics.c (force_paren_expr): New.
	(finish_parenthesized_expr): Use it.
	* call.c (build_conditional_expr_1): Likewise.
	* pt.c (do_auto_deduction): Handle decltype(auto).
	(tsubst_copy): Handle PAREN_EXPR.
	(tsubst_copy_and_build): Likewise.
	* error.c (dump_expr): Handle PAREN_EXPR.
	* cxx-pretty-print.c (pp_cxx_expression): Likewise.
	* mangle.c (write_expression): Ignore PAREN_EXPR.

	* parser.c (cp_parser_decltype_expr): Split out...
	(cp_parser_decltype): ...from here.

From-SVN: r197248