read_rtlil <<EOT

module \a
  wire width 1 \w
  process $p
    switch 3'001
      case 3'--1
        assign \w 3'001
      case 3'-1-
        assign \w 3'010
      case 3'1--
        assign \w 3'100
    end
  end
end

module \b
  wire width 1 \w
  process $p
    switch 3'--1
      case 3'001
        assign \w 3'001
      case 3'010
        assign \w 3'010
      case 3'100
        assign \w 3'100
    end
  end
end

EOT

proc_clean  # Bug: removes the cases.
proc_clean  # Removes the now-empty switch and its containing process.

select -assert-count 1 a/p:*
select -assert-count 1 b/p:*
