usage.scala:3: warning: inheritance from class Foo in package t6126 is deprecated (since 2.10.0): `Foo` will be made final in a future version.
class SubFoo extends Foo
                     ^
usage.scala:5: warning: inheritance from trait T in package t6126 is deprecated
object SubT extends T
                    ^
usage.scala:8: warning: inheritance from trait S in package t6126 is deprecated
  new S {
      ^
error: No warnings can be incurred under -Xfatal-warnings.
three warnings found
one error found