diff --git a/compiler/rustc_span/src/symbol.rs b/compiler/rustc_span/src/symbol.rs
index 1fb15fe98000b..6f1d3a74a8165 100644
--- a/compiler/rustc_span/src/symbol.rs
+++ b/compiler/rustc_span/src/symbol.rs
@@ -2184,8 +2184,10 @@ symbols! {
         vec_macro,
         vec_new,
         vec_pop,
+        vec_reserve,
         vec_with_capacity,
         vecdeque_iter,
+        vecdeque_reserve,
         vector,
         version,
         vfp2,
diff --git a/library/alloc/src/collections/vec_deque/mod.rs b/library/alloc/src/collections/vec_deque/mod.rs
index 1c33f8f60d824..299c8b8679e3d 100644
--- a/library/alloc/src/collections/vec_deque/mod.rs
+++ b/library/alloc/src/collections/vec_deque/mod.rs
@@ -823,6 +823,7 @@ impl<T, A: Allocator> VecDeque<T, A> {
     /// assert!(buf.capacity() >= 11);
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[cfg_attr(not(test), rustc_diagnostic_item = "vecdeque_reserve")]
     #[track_caller]
     pub fn reserve(&mut self, additional: usize) {
         let new_cap = self.len.checked_add(additional).expect("capacity overflow");
diff --git a/library/alloc/src/vec/mod.rs b/library/alloc/src/vec/mod.rs
index 54673ceb1da81..48afcf6e0645b 100644
--- a/library/alloc/src/vec/mod.rs
+++ b/library/alloc/src/vec/mod.rs
@@ -1267,6 +1267,7 @@ impl<T, A: Allocator> Vec<T, A> {
     #[cfg(not(no_global_oom_handling))]
     #[stable(feature = "rust1", since = "1.0.0")]
     #[track_caller]
+    #[cfg_attr(not(test), rustc_diagnostic_item = "vec_reserve")]
     pub fn reserve(&mut self, additional: usize) {
         self.buf.reserve(self.len, additional);
     }