From 0e9f80e00b513fd7cb17bf971a970d23f902bde4 Mon Sep 17 00:00:00 2001
From: 2ne1ugly <47616772+2ne1ugly@users.noreply.github.com>
Date: Mon, 9 Jan 2023 21:43:27 +0000
Subject: [PATCH] Implement `SparseSetIndex` for `WorldId` (#7125)

# Objective

- Fixes #7124

## Solution

- Add Hash Derive on `WorldId`
- Add `SparseSetIndex` impl
---
 crates/bevy_ecs/src/world/identifier.rs | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/crates/bevy_ecs/src/world/identifier.rs b/crates/bevy_ecs/src/world/identifier.rs
index 6e2b8efc0f222..c65da1b81a7e1 100644
--- a/crates/bevy_ecs/src/world/identifier.rs
+++ b/crates/bevy_ecs/src/world/identifier.rs
@@ -1,6 +1,7 @@
+use crate::storage::SparseSetIndex;
 use std::sync::atomic::{AtomicUsize, Ordering};
 
-#[derive(Copy, Clone, PartialEq, Eq, Debug)]
+#[derive(Copy, Clone, PartialEq, Eq, Debug, Hash)]
 // We use usize here because that is the largest `Atomic` we want to require
 /// A unique identifier for a [`super::World`].
 // Note that this *is* used by external crates as well as for internal safety checks
@@ -26,6 +27,17 @@ impl WorldId {
     }
 }
 
+impl SparseSetIndex for WorldId {
+    #[inline]
+    fn sparse_set_index(&self) -> usize {
+        self.0
+    }
+
+    fn get_sparse_set_index(value: usize) -> Self {
+        Self(value)
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;