%Warning-PINNOCONNECT: t/t_inst_missing_bad.v:8: Cell pin is not connected: '__pinNumber2'
   sub sub (.ok(ok), , .nc());
                     ^
                       ... Use "/* verilator lint_off PINNOCONNECT */" and lint_on around source to disable this message.
%Warning-PINCONNECTEMPTY: t/t_inst_missing_bad.v:8: Cell pin connected by name with empty reference: 'nc'
   sub sub (.ok(ok), , .nc());
                        ^~
%Warning-PINMISSING: t/t_inst_missing_bad.v:8: Cell has missing pin: 'missing'
   sub sub (.ok(ok), , .nc());
       ^~~
%Error: Exiting due to