From bf164a593635ba2ed269902d1abd0d4f371df103 Mon Sep 17 00:00:00 2001
From: Carter Anderson <mcanders1@gmail.com>
Date: Sat, 18 Jul 2020 01:14:16 -0700
Subject: [PATCH] ecs: fix tuple query item skipping

---
 crates/bevy_ecs/hecs/src/query.rs      | 4 +++-
 crates/bevy_ecs/src/world/component.rs | 7 +++++++
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/crates/bevy_ecs/hecs/src/query.rs b/crates/bevy_ecs/hecs/src/query.rs
index 83cee2ef81..b6beedd783 100644
--- a/crates/bevy_ecs/hecs/src/query.rs
+++ b/crates/bevy_ecs/hecs/src/query.rs
@@ -650,7 +650,9 @@ macro_rules! tuple_impl {
             }
             
             unsafe fn should_skip(&self) -> bool {
-                false
+                #[allow(non_snake_case)]
+                let ($($name,)*) = self;
+                $($name.should_skip()||)* false
             }
         }
 
diff --git a/crates/bevy_ecs/src/world/component.rs b/crates/bevy_ecs/src/world/component.rs
index 3d8a38c507..7baddbf4b4 100644
--- a/crates/bevy_ecs/src/world/component.rs
+++ b/crates/bevy_ecs/src/world/component.rs
@@ -213,5 +213,12 @@ mod tests {
             .iter()
             .collect::<Vec<Entity>>();
         assert_eq!(a_b_changed, vec![e2]);
+
+        let a_b_changed_tuple = world
+            .query::<(Changed<A, Entity>, Changed<B, &B>)>()
+            .iter()
+            .map(|(e, _b)| e)
+            .collect::<Vec<Entity>>();
+        assert_eq!(a_b_changed_tuple, vec![e2]);
     }
 }