Chayim Refael Friedman 54556f49d3 Specialize TrustedLen for Iterator::unzip() ... Don't check the capacity every time (and also for `Extend` for tuples, as this is how `unzip()` is implemented). I did this with an unsafe method on `Extend` that doesn't check for growth (`extend_one_unchecked()`). I've marked it as perma-unstable currently, although we may want to expose it in the future so collections outside of std can benefit from it. Then specialize `Extend for (A, B)` for `TrustedLen` to call it. It may seem that an alternative way of implementing this is to have a semi-public trait (`#[doc(hidden)]` public, so collections outside of core can implement it) for `extend()` inside tuples, and specialize it from collections. However, it is impossible due to limitations of `min_specialization`. A concern that may arise with the current approach is that implementing `extend_one_unchecked()` correctly must also incur implementing `extend_reserve()`, otherwise you can have UB. This is a somewhat non-local safety invariant. However, I believe this is fine, since to have actual UB you must have unsafe code inside your `extend_one_unchecked()` that makes incorrect assumption, *and* not implement `extend_reserve()`. I've also documented this requirement.		2024-07-07 06:58:52 +03:00
..
benches	disable benches in Miri	2024-04-07 09:58:10 +02:00
src	Specialize TrustedLen for Iterator::unzip()	2024-07-07 06:58:52 +03:00
tests	Generalize {Rc,Arc}::make_mut() to unsized types.	2024-06-22 08:08:00 -07:00
Cargo.toml	Cleanup bootstrap check-cfg	2024-06-27 11:30:03 +02:00