test/Modules/Inputs/submodule-visibility/cycle2.h - third_party/swift-clang - Git at Google

 #ifndef CYCLE2
 #define CYCLE2

 #include "cycle1.h"

 struct C2 {};

 #endif
	#ifndef CYCLE2
	#define CYCLE2

	#include "cycle1.h"

	struct C2 {};

	#endif