reduce constant index

src/future_moves.rs

@@ -101,7 +101,10 @@ impl FutureMoves {
     pub fn extend_layers(&mut self) {
         let mut next_nodes: Vec<usize> = (0..self.arena.len())
             // we want to select all nodes that don't have children, or are lazy (need to maybe be regenerated)
-            .filter(|&idx| self.arena[idx].children.is_empty() || self.arena[idx].lazy_children)
+            .filter(|&idx| {
+                let got = &self.arena[idx];
+                got.lazy_children || got.children.is_empty()
+            })
             .filter(|&idx| self.is_connected_to_root(idx)) // put here so this will not extend needlessly before prunes
             .collect();