diff --git a/lib/std/rb.zig b/lib/std/rb.zig
index d7840b75b0246664b4a21910bbd661414a7b79ff..a39b815e749144f446a1d8a4e6325d2324c6652a 100644
--- a/lib/std/rb.zig
+++ b/lib/std/rb.zig
@@ -123,7 +123,8 @@ pub const Node = struct {
         return node;
     }
 
-    fn getLast(node: *Node) *Node {
+    fn getLast(nodeconst: *Node) *Node {
+        var node = nodeconst;
         while (node.right) |right| {
             node = right;
         }