/NODIAGNOSTICS (D)

  Creates a diagnostic file for use by some Digital layered products,
  including  the  Language-Sensitive  Editor.   The  diagnostic  file
  (which is  not  human  readable)  contains  compiler  messages  and
  diagnostic  information.  If you omit the qualifier, /NODIAGNOSTICS
  is the default.  The file type is .DIA by default.