%Warning-UNOPTFLAT: t/t_dfg_true_cycle_bad.v:10:23: Signal unoptimizable: Circular combinational logic: 't.o'
   10 |     output wire [9:0] o
      |                       ^
                    ... For warning description see https://verilator.org/warn/UNOPTFLAT?v=latest
                    ... Use "/* verilator lint_off UNOPTFLAT */" and lint_on around source to disable this message.
                    t/t_dfg_true_cycle_bad.v:10:23:      Example path: t.o
                    t/t_dfg_true_cycle_bad.v:10:23:      Example path: ASSIGNW
                    t/t_dfg_true_cycle_bad.v:10:23:      Example path: o
                    t/t_dfg_true_cycle_bad.v:10:23:      Example path: ASSIGNW
                    t/t_dfg_true_cycle_bad.v:10:23:      Example path: t.o
%Error: Exiting due to