// { dg-do compile }// Origin:// PR c++/6716// ICE in complex class structure when components are incompletetemplate <class T> struct X {  T t;				// { dg-error "incomplete" }};template <class T> struct Y {  X<T> x;			// { dg-error "instantiated" }};template <class T> struct Z {	// { dg-error "declaration" }  Y<Z<T> > y;			// { dg-error "instantiated" }};struct ZZ : Z<int>		// { dg-error "instantiated" }{};