In Clion IDE we have following behavior.
1) User enter following code

vector<int> vi;

vi.p

2) User uses autocomplete for "vi.p" expression and get following autocomplete items(in alphabet order):

pop_back //on first position

push_back // on second position

3) User choose second item (push_back) and get following result:

vi.push_back(1)

4) When user uses autocomplete for "someVectorObject.p" expression next time, autocomplete system provides following autocomplete items:

push_back //on first position

pop_back // on second position

5) "push_back" at first position so user just press enter for this item without pressing arrow down.

I think it is good behavior because developers use some method a lot of times but don't use some other methods in code. So prioritizing frequently used methods in autocomplete list will speed up code writing. It is small but nice feature.

In Qt Creator we have only alphabetic order in autocomplete items list.