用于进行gcc测试

				// { dg-do compile }								// Copyright (C) 2003 Free Software Foundation, Inc.				// Contributed by Nathan Sidwell 11 Sep 2003 				// Origin: Wolfgang Bangerth  				// PR c++/12184. ICE								class C; 				class D;				bool mm(D); 				 				void g(C& f) { 				  mm(f); // { dg-error "parameter" "" }				}