diff --git a/library/core/src/slice/mod.rs b/library/core/src/slice/mod.rs
index 376ab41248d..78fad46e793 100644
--- a/library/core/src/slice/mod.rs
+++ b/library/core/src/slice/mod.rs
@@ -852,7 +852,7 @@ impl<T> [T] {
     #[stable(feature = "rust1", since = "1.0.0")]
     #[inline]
     pub fn chunks_mut(&mut self, chunk_size: usize) -> ChunksMut<'_, T> {
-        assert_ne!(chunk_size, 0, "Chunks cannot have a size of zero!");
+        assert_ne!(chunk_size, 0, "chunks cannot have a size of zero");
         ChunksMut::new(self, chunk_size)
     }