[icholy]

I'm commenting on the proposed implementation of using an array to keep track of insertion order.

[lifthrasiir]

An array can be used to efficiently simulate a linked list and other data structure, however. (Or an intrusive linked list may be embedded into the bucket structure like PHP, but this is less efficient with open addressing scheme which is nowadays better for cache locality.)

[icholy]

> An array can be used to efficiently simulate a linked list

That's obviously not what the OP meant. Also, I don't think there's an efficient way of implementing deletes with an array backed linked list.