[preproc]
#define KEY
#ifdef KEY
pass
#endif

[preproc]
#define KEY
#if defined(KEY)
pass
#endif

[preproc]
#define KEY
#if defined KEY
pass
#endif

[preproc]
#ifndef KEY
pass
#endif

[preproc]
#if !defined(KEY)
pass
#endif

[preproc]
#define KEY
#ifndef KEY
fail
#else
pass
#endif

[preproc]
#ifdef KEY
fail
#else
pass
#endif

[preproc]
#define KEY(a, b)
#ifdef KEY
pass
#endif

[preproc]
#ifdef KEY
fail
#endif
#define KEY
pass

[preproc]
#define KEY 0
#ifdef KEY
pass
#endif

[preproc]
#define KEY
#undef KEY
#ifndef KEY
pass
#endif

[preproc]
#if KEY
fail
#else
pass
#endif

[preproc]
#if KEY == 0
pass
#else
fail
#endif

[preproc]
#if KEY == 1
fail
#else
pass
#endif