From 75a14185437c0cd8fd71349ed4f4b4a6a2e24207 Mon Sep 17 00:00:00 2001
From: dianne <diannes.gm@gmail.com>
Date: Mon, 16 Sep 2024 20:20:46 -0700
Subject: [PATCH] Document `#[rustc_default_body_unstable]`

---
 src/stability.md | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/src/stability.md b/src/stability.md
index ac77ad3f1..444bef7af 100644
--- a/src/stability.md
+++ b/src/stability.md
@@ -68,6 +68,16 @@ even on an `unstable` function, if that function is called from another
 Furthermore this attribute is needed to mark an intrinsic as callable from
 `rustc_const_stable` functions.
 
+## rustc_default_body_unstable
+
+The `#[rustc_default_body_unstable(feature = "foo", issue = "1234", reason =
+"lorem ipsum")]` attribute has the same interface as the `unstable` attribute.
+It is used to mark the default implementation for an item within a trait as
+unstable.
+A trait with a default-body-unstable item can be implemented stably by providing
+an explicit body for any such item, or the default body can be used by enabling
+its corresponding `#![feature]`.
+
 ## Stabilizing a library feature
 
 To stabilize a feature, follow these steps: