linux下编程用 编译软件

				// { dg-do compile }								// Copyright (C) 2003 Free Software Foundation, Inc.				// Contributed by Nathan Sidwell 20 Apr 2003 								// PR 10337, unneeded warning								class A {				  public:				  A() {}				};								class B : public A {				  public:				  B() {}				  void operator=(const A& b) {}				  void operator=(const B& b) {}				};								class C {				  public:				  C() {}				  operator B &() { return _b; }				  operator const B &() const { return _b; }				  				  B _b;				};								int main() {				  B b;				  C c;				  b = c;				}