sets and pipes do not work well together

[olofhagsand]

Example:

a @{
   b;{
      @|mypipe;
   }
   c;{
      @|mypipe;
   }
}

Using TAB/? completion after the first set item, the following alternatives appear:

cli> a b ?
   <cr>
   |

where c should be provided as option.
Actually, without using TAB/? the command a b c is accepted as is a b c | count.
However a b | count c is also accepted which does not make sense.
In summary, there are therefore two issues:
(1) TAB/? completion should show the remaining sets items
(2) An intermediate pipe command should not be accepted