diff options
| -rw-r--r-- | library/core/src/marker.rs | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/library/core/src/marker.rs b/library/core/src/marker.rs index 5654f5aa4b8..91ec046eeab 100644 --- a/library/core/src/marker.rs +++ b/library/core/src/marker.rs @@ -288,8 +288,18 @@ marker_impls! { /// } /// ``` /// -/// There is a small difference between the two: the `derive` strategy will also place a `Copy` -/// bound on type parameters, which isn't always desired. +/// There is a small difference between the two. The `derive` strategy will also place a `Copy` +/// bound on type parameters: +/// +/// ``` +/// struct MyStruct<T>; +/// +/// impl<T: Copy> Copy for MyStruct<T> { } +/// ``` +/// +/// This isn't always desired. For example, shared references (`&T`) can be copied regardless of +/// whether `T` is `Copy`. Likewise, a generic struct containing markers such as [`PhantomData`] +/// could potentially be duplicated with a bit-wise copy. /// /// ## What's the difference between `Copy` and `Clone`? /// |