[preproc]
  #  define  KEY  pass
KEY

[preproc]
#if 0
#error
#endif
pass

[preproc]
#define pass fail
"pass"

[preproc]
#define pass fail
" escape \" pass "

[preproc]
#define fail pass
" escape \\" fail

[preproc]
"multiline
string"
pass

[preproc]
"multiline
pass"

[preproc]
"pass
string"

[preproc]
/*
#error
fail
 * / fail*/pass

[preproc]
pass/*
#error
fail
 */

[preproc]
pass//fail

[preproc]
// multiline comment \
fail
pass

[preproc]
fa/* */il
pass

[preproc]
#define KEY //
KEY pass

[preproc]
#define KEY /* fail */ pass
KEY

[preproc]
#define KEY(a, b) /* multiline

comment */ a
KEY(pass, fail)

[preproc]
pass /* fail

[preproc]
/* The backslash must be the last character in the line. */
#define KEY \ 
pass