anchor.diff:  
   (5am:test build-30
     (signals varjo-conditions:cross-scope-mutate
  -    (varjo.tests::compile-vert () :450
  +    (compile-vert () :450
         (let* ((y 10)
                (fn (labels ((test ((x :int))
                               (setf y 2)
  
positive.code: 
  (5am:test build-29
    (signals varjo-conditions:closures-not-supported
      (varjo.tests::compile-vert () :450
        (let* ((y 10)
               (fn (labels ((test ((x :int)) (* y x)))
                     #'test)))
  
negative.code: 
  (5am:test build-32
    (signals varjo-conditions:symbol-unidentified
      (compile-vert () :450
        (labels ((foo ((ffn (function (:int) :int)))
                   (funcall ffn y)))
          (let ((y 10))
  