Rollup merge of #99198 - RalfJung:alloc-null-ptr, r=JohnTitor

add missing null ptr check in alloc example

`alloc` can return null on OOM, if I understood correctly. So we should never just deref a pointer we get from `alloc`.

1 files changed, 4 insertions, 1 deletions

diff --git a/library/alloc/src/alloc.rs b/library/alloc/src/alloc.rs
index 649aeb0890d..efdc86bf57a 100644
--- a/library/alloc/src/alloc.rs
+++ b/library/alloc/src/alloc.rs
@@ -70,11 +70,14 @@ pub use std::alloc::Global;
 /// # Examples
 ///
 /// ```
-/// use std::alloc::{alloc, dealloc, Layout};
+/// use std::alloc::{alloc, dealloc, handle_alloc_error, Layout};
 ///
 /// unsafe {
 ///     let layout = Layout::new::<u16>();
 ///     let ptr = alloc(layout);
+///     if ptr.is_null() {
+///         handle_alloc_error(layout);
+///     }
 ///
 ///     *(ptr as *mut u16) = 42;
 ///     assert_eq!(*(ptr as *mut u16), 42);