@steffo
Something about a dentist,

Idk why, but YouTube's had a weird habit of repeatedly recommending me an old trailer for Payday 2, despite never showing interest in Payday related content and the fact Payday 3 is already a thing...??

(she made another one)

@steffo Bruh- ok, apparently looking at where Vec::from_iterator ends up, it does end up running into the same bug as vec! eventually, just in a different method... Iterator handling with Vec is so frustratingly indirected...

It does still pre-allocate with Iterator::size_hint though.

@steffo vec! ends up expanding out into a function that uses Vec::extend_with, which explicitly notes it has to compensate for compiler bugs, but otherwise has quite similar implementation...

@steffo This file:
https://doc.rust-lang.org/src/alloc/vec/spec_from_iter_nested.rs.html

@steffo std::iter::repeat_n has a guaranteed size, because it has a set number of iterators, and is cloning the item until the last iteration, so it's also ExactLenIterator.

Depending on the provider, Vec::from_iterator can take advantage of Iterator::size_hint.

@steffo Tbh, reading the methods vec! ends up expanding out to, they seem like a bit of a mess... repeat_n may be the better option from a technical standpoint...

@steffo Also of note: std::iter::repeat_n, and Iterator::take and Iterator::collect...

@steffo "Slowly... gently... this is how a life is taken..."