From 6aaa8327f9f47033f4958dbf634413ff0cd98a3e Mon Sep 17 00:00:00 2001
From: Ralf Jung <post@ralfj.de>
Date: Sat, 31 Jul 2021 11:37:48 +0200
Subject: [PATCH] mark a UB doctest as no_run

---
 library/core/src/ptr/non_null.rs | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/library/core/src/ptr/non_null.rs b/library/core/src/ptr/non_null.rs
index 032df7f5a80ad..87c8674af0dc5 100644
--- a/library/core/src/ptr/non_null.rs
+++ b/library/core/src/ptr/non_null.rs
@@ -173,8 +173,14 @@ impl<T: ?Sized> NonNull<T> {
     ///
     /// let mut x = 0u32;
     /// let ptr = unsafe { NonNull::new_unchecked(&mut x as *mut _) };
+    /// ```
+    ///
+    /// *Incorrect* usage of this function:
+    ///
+    /// ```rust,no_run
+    /// use std::ptr::NonNull;
     ///
-    /// // NEVER DO THAT!!!
+    /// // NEVER DO THAT!!! This is undefined behavior. ⚠️
     /// let ptr = unsafe { NonNull::<u32>::new_unchecked(std::ptr::null_mut()) };
     /// ```
     #[stable(feature = "nonnull", since = "1.25.0")]