Auto merge of #85528 - the8472:iter-markers, r=dtolnay

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Implement iterator specialization traits on more adapters

This adds

* `TrustedLen` to `Skip` and `StepBy`
* `TrustedRandomAccess` to `Skip`
* `InPlaceIterable` and `SourceIter` to  `Copied` and `Cloned`

The first two might improve performance in the compiler itself since `skip` is used in several places. Constellations that would exercise the last point are probably rare since it would require an owning iterator that has references as Items somewhere in its iterator pipeline.

Improvements for `Skip`:

```
# old
test iter::bench_skip_trusted_random_access                     ... bench:       8,335 ns/iter (+/- 90)

# new
test iter::bench_skip_trusted_random_access                     ... bench:       2,753 ns/iter (+/- 27)
```

...

This commit is contained in:

bors 2024-01-21 11:17:46 +00:00

parent b5ced3120b b41a1a4e98

commit e8d09bff13

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