But this is not an assumption that can be made by the standard library. There are many reasons why people don’t like java Object.clone. Even the documentation of it states that you can’t make any assumptions about it’s result. Not even simple statements like x.clone() == x or x.clone().getClass == x.getClass() can be assumed to always be true. All that is supposed to be guaranteed is that x.clone() !== x, which means the function is practically useless for any generic usage. Thankfully kotlin didn’t make the same mistake and removed this function form Any.
There might be a point in discussing adding a Cloneable interface to kotlin and deciding on a strict definitions what this interface should mean. Otherwise there is no way to create a deepCopy. The problem I see with this is that the best definition of Cloneable probably depends on the project and therefor can not be made by the standard library.