From de72cd33be9988df5902b32c66a585d0c85d4985 Mon Sep 17 00:00:00 2001
From: Godfrey Chan <godfreykfc@gmail.com>
Date: Tue, 3 Sep 2024 11:27:34 -0700
Subject: [PATCH] Elaborate on deriving vs implementing `Copy`

---
 core/src/marker.rs | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/core/src/marker.rs b/core/src/marker.rs
index 5654f5aa4b8d2..91ec046eeabdd 100644
--- a/core/src/marker.rs
+++ b/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`?
 ///