%Warning-UNOPTFLAT: t/t_unoptflat_simple_2.v:16:15: Signal unoptimizable: Circular combinational logic: 't.x'
   16 |    wire [2:0] x;
      |               ^
                    ... 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_unoptflat_simple_2.v:16:15:      Example path: t.x
                    t/t_unoptflat_simple_2.v:13:10:      Example path: ASSIGNW
                    t/t_unoptflat_simple_2.v:16:15:      Example path: t.x
                    ... Widest variables candidate to splitting:
                        t/t_unoptflat_simple_2.v:16:15:  t.x, width 3, circular fanout 1, can split_var
                    ... Candidates with the highest fanout:
                        t/t_unoptflat_simple_2.v:16:15:  t.x, width 3, circular fanout 1, can split_var
                    ... Suggest add /*verilator split_var*/ to appropriate variables above.
%Error: Exiting due to