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Jacob Pratt
221dab89b4
`impl Default for RepeatN` This creates an empty iterator, like `repeat_n(value, 0)` but without needing any such value at hand. There's precedent in many other iterators that the `Default` is empty, like `slice::Iter`. I found myself wanting this for rayon's `RepeatN` as it lowers to a sequential iterator [here][1]. Since rayon is also optimizing to avoid extra clones, it may end up with parallel splits that have count 0 and no item value. Calling `std::iter::repeat_n(x, 0)` just drops that value, but there's no way to construct the same result without a value yet. This would be straightforward with an empty `Default`. [1]: https://github.com/rayon-rs/rayon/blob/ae07384e3e0b238cea89f0c14891f351c65a5cee/src/iter/repeat.rs#L201-L202 r? libs-api (insta-stable)