%Warning-UNDRIVEN: t/t_lint_unused_iface_bad.v:8:10: Signal is not driven: 'sig_udrv'
                                                   : ... In instance t.sub
    8 |    logic sig_udrv;
      |          ^~~~~~~~
                   ... For warning description see https://verilator.org/warn/UNDRIVEN?v=latest
                   ... Use "/* verilator lint_off UNDRIVEN */" and lint_on around source to disable this message.
%Warning-UNUSEDSIGNAL: t/t_lint_unused_iface_bad.v:9:10: Signal is not used: 'sig_uusd'
                                                       : ... In instance t.sub
    9 |    logic sig_uusd;
      |          ^~~~~~~~
%Error: Exiting due to
