Regression on borrowchecker + match-ref + lambda

[TimDeve]

Using a match-ref within a lambda can confuse the borrow checker.

Example:

(deftype WorldState (Intro [Int]) (Outro [Int]))

(deftype World [state WorldState])

(defn main []
 (let [world (World (WorldState.Intro 13))
       f     (fn [wrld]
              (match-ref (World.state &wrld)
                 (WorldState.Intro tikin) (+ @tikin 13)
                 (WorldState.Outro tikout) (+ @tikout 13)
                 _                      0))]
   (f world)))

Outputs this error:

The reference 'tikout' (depending on the variable 'tikin') isn't alive at line 11, column 48 in '/.../main.carp'. at /.../main.carp:6:2.

Traceback:
  (defn main [] (let [world (World (WorldState.Intro 13)) f (f...) at /.../main.carp:6:1.

This seems to be a regression as this line used to compile.