I personally wouldn't expect someone to implement one (end cases easy to mess up if they are stressed), but writing a function to reverse one (foreach, pop front, push front) is enough to catch the liars. You can argue about how often a std::list vs std::vector is a performance win, but I'd run a mile from any developer who wasn't highly familiar with the basic data structures provided by any language they are claiming to be fluent in.

> or even use a linked list.

You must work in a super specialized industry, then

The only real requirements to "never use a linked list" are a) use a language where some kind of contiguous-storage-based sequence (array, vector, whatever you want to call it; Python calls it a list, even) is built in (or in the standard library); plus b) not ever need to remove O(1) values from the middle of a sequence in O(1) time while preserving order.

But arguably, a candidate who hasn't ever had to contemplate the concept of "linked list" but can derive the necessary ideas on the spot given the basic design, has some useful talents.