import typeinfo type CustomAny* = object value: pointer rawType: pointer proc customToAny*[T](x: var T): CustomAny {.inline.} = result = cast[CustomAny](toAny(x)) proc compareRuntimeTypes[A, B](a: var A, b: var B): bool = result = customToAny(a).rawType == customToAny(b).rawType type Parent = ref object {.inheritable.} Derived = ref object of Parent var a: Parent = Parent() var b: Parent = Derived() echo "a == b? " & $(compareRuntimeTypes(a, b)) # ==> true, expected false