diff options
| -rw-r--r-- | src/libcore/cmp.rs | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/src/libcore/cmp.rs b/src/libcore/cmp.rs index 9336b130d1b..f420d0d00a4 100644 --- a/src/libcore/cmp.rs +++ b/src/libcore/cmp.rs @@ -472,9 +472,11 @@ impl<T: Ord> Ord for Reverse<T> { /// Then you must define an implementation for `cmp()`. You may find it useful to use /// `cmp()` on your type's fields. /// -/// Implementations of `PartialEq`, `PartialOrd`, and `Ord` *must* agree with each other. It's -/// easy to accidentally make them disagree by deriving some of the traits and manually -/// implementing others. +/// Implementations of `PartialEq`, `PartialOrd`, and `Ord` *must* +/// agree with each other. That is, `a.cmp(b) == Ordering::Equal` if +/// and only if `a == b` and `Some(a.cmp(b)) == a.partial_cmp(b)` for +/// all `a` and `b`. It's easy to accidentally make them disagree by +/// deriving some of the traits and manually implementing others. /// /// Here's an example where you want to sort people by height only, disregarding `id` /// and `name`: |