ftd.list.length function

[amitu]

/-- rejected:
-- ftd.integer: $list.length

/-- most likely:
-- ftd.integer: ftd.list.length: $list, x=10, z=hello
> y: 20

/-- other option:
-- ftd.integer: ftd.list.length: $list, x: 10, z: hello
> y: 20