diff --git a/library/alloc/src/vec/spec_from_elem.rs b/library/alloc/src/vec/spec_from_elem.rs
index 4e4150d9435..63225b41cbd 100644
--- a/library/alloc/src/vec/spec_from_elem.rs
+++ b/library/alloc/src/vec/spec_from_elem.rs
@@ -64,7 +64,7 @@ fn from_elem<A: Allocator>(elem: u8, n: usize, alloc: A) -> Vec<u8, A> {
 // but this cannot be implemented currently
 impl SpecFromElem for () {
     #[inline]
-    fn from_elem<A: Allocator>(elem: (), n: usize, alloc: A) -> Vec<(), A> {
+    fn from_elem<A: Allocator>(_elem: (), n: usize, alloc: A) -> Vec<(), A> {
         let mut v = Vec::with_capacity_in(n, alloc);
         // SAFETY: the capacity has just been set to `n` and `()`
         // is a ZST with trivial `Clone` implementation