C2: TypeAryPtr::cast_to_autobox_cache does not use ptr_type

CLion reports "ptr_type" is unused here:

const TypeAryPtr* TypeAryPtr::cast_to_autobox_cache(bool cache) const {
  ...
  // The pointers in the autobox arrays are always non-null.
  TypePtr::PTR ptr_type = cache ? TypePtr::NotNull : TypePtr::AnyNull;
  etype = etype->cast_to_ptr_type(TypePtr::NotNull)->is_oopptr();
  ...
}

I wonder if cast_to_ptr_type on the next line was supposed to use ptr_type? If not, then ptr_type definition can be just pruned (and this might be just the Enhancement, not bug).

Assigning to Vladimir, because that code is from JDK-8078629.