t7872.scala:6: error: contravariant type a occurs in covariant position in type [-a]Cov[a] of type l
  type x = {type l[-a] = Cov[a]}
                 ^
t7872.scala:8: error: covariant type a occurs in contravariant position in type [+a]Inv[a] of type l
  foo[({type l[+a] = Inv[a]})#l]
             ^
t7872.scala:5: error: contravariant type a occurs in covariant position in type [-a]Cov[a] of type l
  type l[-a] = Cov[a]
       ^
three errors found