Document TrustedLen guarantees more explicitly

This commit is contained in:
oberien 2018-02-04 16:04:06 +01:00
parent 75474ff132
commit 6caec2c049

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@ -970,9 +970,11 @@ impl<'a, I: FusedIterator + ?Sized> FusedIterator for &'a mut I {}
/// The iterator reports a size hint where it is either exact
/// (lower bound is equal to upper bound), or the upper bound is [`None`].
/// The upper bound must only be [`None`] if the actual iterator length is
/// larger than [`usize::MAX`].
/// larger than [`usize::MAX`]. In that case, the lower bound must be
/// [`usize::MAX`], resulting in a [`.size_hint`] of `(usize::MAX, None)`.
///
/// The iterator must produce exactly the number of elements it reported.
/// The iterator must produce exactly the number of elements it reported
/// or diverge before reaching the end.
///
/// # Safety
///