%Error: t/t_past_bad.v:16:20: Expecting expression to be constant, but variable isn't const: 'num'
                            : ... In instance t
   16 |       if ($past(d, num)) $stop;   
      |                    ^~~
%Error: t/t_past_bad.v:16:11: $past tick value must be constant (IEEE 1800-2017 16.9.3)
                            : ... In instance t
   16 |       if ($past(d, num)) $stop;   
      |           ^~~~~
%Error: t/t_past_bad.v:17:20: $past tick value must be >= 1 (IEEE 1800-2017 16.9.3)
                            : ... In instance t
   17 |       if ($past(d, 0)) $stop;   
      |                    ^
%Warning-TICKCOUNT: t/t_past_bad.v:18:20: $past tick value of 10000 may have a large performance cost
                                        : ... In instance t
   18 |       if ($past(d, 10000)) $stop;   
      |                    ^~~~~
                    ... For warning description see https://verilator.org/warn/TICKCOUNT?v=4.201
                    ... Use "/* verilator lint_off TICKCOUNT */" and lint_on around source to disable this message.
%Error: Exiting due to