%Warning-PINNOCONNECT: t/t_inst_missing_bad.v:9:22: Cell pin is not connected: '__pinNumber2'
    9 |    sub sub (.ok(ok), , .nc());
      |                      ^
                       ... For warning description see https://verilator.org/warn/PINNOCONNECT?v=latest
                       ... Use "/* verilator lint_off PINNOCONNECT */" and lint_on around source to disable this message.
%Warning-PINCONNECTEMPTY: t/t_inst_missing_bad.v:9:25: Cell pin connected by name with empty reference: 'nc'
    9 |    sub sub (.ok(ok), , .nc());
      |                         ^~
%Warning-PINMISSING: t/t_inst_missing_bad.v:9:8: Cell has missing pin: 'missing'
    9 |    sub sub (.ok(ok), , .nc());
      |        ^~~
%Error: Exiting due to
