diff --git a/core/src/ptr/mod.rs b/core/src/ptr/mod.rs
index acc9ca29d..5f094ac4e 100644
--- a/core/src/ptr/mod.rs
+++ b/core/src/ptr/mod.rs
@@ -710,6 +710,7 @@ pub const fn from_ref<T: ?Sized>(r: &T) -> *const T {
 #[inline(always)]
 #[must_use]
 #[unstable(feature = "ptr_from_ref", issue = "106116")]
+#[rustc_diagnostic_item = "ptr_from_mut"]
 pub const fn from_mut<T: ?Sized>(r: &mut T) -> *mut T {
     r
 }
diff --git a/core/src/ptr/mut_ptr.rs b/core/src/ptr/mut_ptr.rs
index e7f274395..e3a3f69af 100644
--- a/core/src/ptr/mut_ptr.rs
+++ b/core/src/ptr/mut_ptr.rs
@@ -54,6 +54,7 @@ impl<T: ?Sized> *mut T {
     /// Casts to a pointer of another type.
     #[stable(feature = "ptr_cast", since = "1.38.0")]
     #[rustc_const_stable(feature = "const_ptr_cast", since = "1.38.0")]
+    #[rustc_diagnostic_item = "ptr_cast"]
     #[inline(always)]
     pub const fn cast<U>(self) -> *mut U {
         self as _