; Iter 18g.tidy.fu2 RED-test fixture 1/3: dynamic-tag partial-drop
; carve-out at fn-return (Iter B / lib.rs:1093).
;
; Shape:
;   - `Pair` carries two `Cell` fields (both pointer-typed).
;   - `Cell` carries two `Wrap` fields (both pointer-typed).
;   - `use_first` takes `(own Pair)` and pattern-binds the first
;     slot only, wildcarding the second.
;   - The bound slot's `Cell` is dec'd via `drop_<m>_Cell` at the
;     outer arm-close (moves[a] empty → field_drop_call routes
;     correctly).
;   - At fn return, `p`'s `consume_count == 0`, mode = Own, and
;     `moved_slots[p] = {0}`. Iter B's drop (lib.rs:1093) hits the
;     dynamic-tag carve-out: moves non-empty → shallow
;     `ailang_rc_dec(p)`. p's outer cell is freed; slot 1 (the
;     wildcarded second Cell + its two MkWrap children = 3 cells)
;     leaks.
;
; Pre-fix:  live = 3 (one Cell + two MkWrap children).
; Post-fix: live = 0.
;
; This fixture is the cleanest of the three because no inner match
; is involved: the leak surfaces from Iter B alone.

(module rc_own_param_partial_drop_leak

  (data Wrap
    (ctor MkWrap (con Int)))

  (data Cell
    (ctor MkCell (con Wrap) (con Wrap)))

  (data Pair
    (ctor MkPair (con Cell) (con Cell)))

  (fn build_pair
    (type
      (fn-type
        (params (con Int))
        (ret (own (con Pair)))))
    (params n)
    (body
      (term-ctor Pair MkPair
        (term-ctor Cell MkCell
          (term-ctor Wrap MkWrap n)
          (term-ctor Wrap MkWrap 2))
        (term-ctor Cell MkCell
          (term-ctor Wrap MkWrap 3)
          (term-ctor Wrap MkWrap 4)))))

  (fn use_first
    (type
      (fn-type
        (params (own (con Pair)))
        (ret (con Int))))
    (params p)
    (body
      (match p
        (case (pat-ctor MkPair a _) 1))))

  (fn main
    (type (fn-type (params) (ret (con Unit)) (effects IO)))
    (params)
    (body
      (do io/print_int (app use_first (app build_pair 1))))))