message: replaced as with static_cast in mixin
diff: @@ -819,10 +819,10 @@ public:
  {
  GKO_ASSERT_IS_SCALAR(a);
  GKO_ASSERT_IS_SCALAR(b);
  - auto ae =
  - make_temporary_clone(as<ConcreteType>(this)->get_executor(), a);
  - auto be =
  - make_temporary_clone(as<ConcreteType>(this)->get_executor(), b);
  + auto ae = make_temporary_clone(
  + static_cast<ConcreteType*>(this)->get_executor(), a);
  + auto be = make_temporary_clone(
  + static_cast<ConcreteType*>(this)->get_executor(), b);
  add_scaled_identity_impl(ae.get(), be.get());
  }
  