assign x = condition_a ? foo :
           condition_b ? bar :
           condition_c ? baz :
           condition_d ? qux :
                         quux;

conds_onehot: assert property ($onehot0({condition_a, condition_b, condition_c, condition_d, condition_e}));

assign x = ({8{condition_a}} & foo)
         | ({8{condition_b}} & bar)
         | ({8{condition_c}} & baz)
         | ({8{condition_d}} & qux)
         | ({8{condition_e}} & quux);