past the end of the argument list.  This check is supressed if the
#define advance(f) do { ++pos; if (f && pos >= argc) beyond (); } while (0)
  if (pos >= argc)
  if (pos >= argc)
      else if (argv[pos][0] != ')' || argv[pos][1]) /* ( */
  if ((pos + 3 <= argc) && test_binop (argv[pos + 1]))
      if (test_unop (argv[pos]))
      if (pos < argc)
	  if (legal_number (argv[pos], &r))
      if (sh_stat (arg, &stat_buf) < 0)
      if (test_unop (argv[pos]))
  if (test_binop (argv[pos+1]))
  else if (ANDOR (argv[pos+1]))
      if (margv[margc] && (margv[margc][0] != ']' || margv[margc][1]))
      if (margc < 2)
  if (pos >= argc)
  if (pos != argc)