What one IDE does that seems to work for autocomplete (its goto is precise AFAICT so no list needed for that) is to display the list of unique names only and then for the selected one a fixed width multiline subwindow shows one of the the overloads with full file, line, and signature and an up/down arrow to cycle them.
I expect it does not simply use a second level menu showing al the overloads is that for the example I tried `get` has 24 overloads and most of the ones I cycled to were multiple lines, so the submenu would be HUUUUUGE.
Maybe a calltip can be used for the second level to simplify implementation?