diff --git a/lib/std/hash_map.zig b/lib/std/hash_map.zig
index 274d2d0404c8..f56e457f2006 100644
--- a/lib/std/hash_map.zig
+++ b/lib/std/hash_map.zig
@@ -1236,7 +1236,7 @@ pub fn HashMapUnmanaged(
             metadata[0].fill(fingerprint);
             const new_key = &self.keys()[idx];
             const new_value = &self.values()[idx];
-            new_key.* = key;
+            new_key.* = undefined;
             new_value.* = undefined;
             self.size += 1;