class AnyVals { def f1 = (5: Any).getClass def f2 = (5: AnyVal).getClass def f3 = 5.getClass def f4 = (5: java.lang.Integer).getClass def f5 = (5.asInstanceOf[AnyRef]).getClass // scalap says: // // def f1 : java.lang.Class[?0] forSome {type ?0} = { /* compiled code */ } // def f2 : java.lang.Class[?0] forSome {type ?0} = { /* compiled code */ } // def f3 : java.lang.Class[scala.Int] = { /* compiled code */ } // def f4 : java.lang.Class[?0] forSome {type ?0 <: java.lang.Integer} = { /* compiled code */ } // def f5 : java.lang.Class[?0] forSome {type ?0 <: scala.AnyRef} = { /* compiled code */ } // // java generic signature says: // // f1: java.lang.Class // f2: java.lang.Class // f3: java.lang.Class // f4: java.lang.Class // f5: java.lang.Class } class AnyRefs { class A class B extends A def f1 = (new B: Any).getClass().newInstance() def f2 = (new B: AnyRef).getClass().newInstance() def f3 = (new B: A).getClass().newInstance() def f4 = (new B: B).getClass().newInstance() def f0[T >: B] = (new B: T).getClass().newInstance() def f5 = f0[Any] def f6 = f0[AnyRef] def f7 = f0[A] def f8 = f0[B] } class MoreAnyRefs { trait A trait B // don't leak anon/refinements def f1 = (new A with B { }).getClass() def f2 = (new B with A { }).getClass() def f3 = (new { def bippy() = 5 }).getClass() def f4 = (new A { def bippy() = 5 }).getClass() } @deprecated("Suppress warnings", since="2.11") object Test { def returnTypes[T: Manifest] = ( manifest[T].runtimeClass.getMethods.toList filter (_.getName startsWith "f") sortBy (_.getName) map (m => m.getName + ": " + m.getGenericReturnType.toString) ) def main(args: Array[String]): Unit = { returnTypes[AnyVals] foreach println returnTypes[AnyRefs] foreach println returnTypes[MoreAnyRefs] foreach println } }