From 2305a8065fd86333058b66900a2c38484cdde40a Mon Sep 17 00:00:00 2001
From: Simon Gardling <titaniumtown@proton.me>
Date: Sat, 22 Feb 2025 14:08:39 -0500
Subject: [PATCH] nits

---
 src/logic/future_moves.rs | 36 +++++++++++++++++++-----------------
 1 file changed, 19 insertions(+), 17 deletions(-)

diff --git a/src/logic/future_moves.rs b/src/logic/future_moves.rs
index ad880e8..3178d0e 100644
--- a/src/logic/future_moves.rs
+++ b/src/logic/future_moves.rs
@@ -314,21 +314,23 @@ impl FutureMoves {
 
         let mut index_map = vec![None; self.arena.len()];
 
-        let new_start: Vec<(usize, (usize, Move))> = retain
+        let new_start: Vec<(usize, usize, Move)> = retain
             .into_iter()
             .enumerate() // old_idx
             .zip(self.arena.drain(..))
-            .flat_map(|((old_idx, keep), node)| keep.then_some((old_idx, node))) // filter out unrelated nodes
+            .filter(|&((_, keep), _)| keep) // filter out un-related nodes
+            .map(|((old_idx, _), node)| (old_idx, node))
             .enumerate() // new_idx
+            .map(|(a, (b, c))| (a, b, c))
             .collect();
 
-        for &(new_idx, (old_idx, _)) in &new_start {
+        for &(new_idx, old_idx, _) in &new_start {
             index_map[old_idx] = Some(new_idx);
         }
 
         self.arena = new_start
             .into_iter()
-            .map(|(_, (_, mut node))| {
+            .map(|(_, _, mut node)| {
                 if let Some(parent) = node.parent.as_mut() {
                     if let Some(new_parent) = index_map[*parent] {
                         *parent = new_parent;
@@ -339,7 +341,10 @@ impl FutureMoves {
                 }
 
                 for c in node.children.as_mut_slice() {
-                    debug_assert!(index_map.get(*c).unwrap().is_some());
+                    debug_assert!(
+                        index_map.get(*c).unwrap().is_some(),
+                        "index_map should contain the child's index"
+                    );
                     *c = unsafe { index_map.get_unchecked(*c).unwrap_unchecked() };
                 }
 
@@ -426,18 +431,15 @@ mod tests {
     #[test]
     fn expand_layer_test() {
         let mut futm = FutureMoves::new(Piece::Black, 1, 1);
-        futm.arena.push(Move {
-            i: 0,
-            j: 0,
-            board: Board::new().starting_pos(),
-            winner: Winner::None,
-            parent: None,
-            children: Vec::new(),
-            value: 0,
-            self_value: 0,
-            color: Piece::Black,
-            lazy_children: false,
-        });
+        futm.arena.push(Move::new(
+            0,
+            0,
+            Board::new().starting_pos(),
+            Piece::Black,
+            false,
+            Piece::Black,
+            None,
+        ));
 
         futm.update_root_idx_raw(0);