%Error: t/t_interface_array_bad.v:23:16: Expecting expression to be constant, but variable isn't const: 'bar'
                                       : ... In instance t
   assign foos[bar].a = 1'b1;
               ^~~
%Error: t/t_interface_array_bad.v:23:15: Could not expand constant selection inside dotted reference: 'bar'
                                       : ... In instance t
   assign foos[bar].a = 1'b1;
              ^
%Error: Exiting due to