t5352.scala:11: error: type mismatch;
 found   : boop.Bar
 required: boop.BarF
    (which expands to)  AnyRef{def f(): Int}
  x = xs.head
         ^
t5352.scala:14: error: method f in class Bar1 cannot be accessed in boop.Bar1
 Access to protected method f not permitted because
 enclosing object boop is not a subclass of
 class Bar1 in object boop where target is defined
  (new Bar1).f
             ^
two errors found