From 1040b9fe8517ca1c6c25ce9534d65464ca42e1eb Mon Sep 17 00:00:00 2001
From: JoJoJet <21144246+JoJoJet@users.noreply.github.com>
Date: Wed, 1 Mar 2023 20:27:57 -0500
Subject: [PATCH 1/7] add marker traits to separate base system sets

---
 crates/bevy_app/src/config.rs          |  6 +++---
 crates/bevy_ecs/macros/src/set.rs      | 22 +++++++++++++++++++++-
 crates/bevy_ecs/src/schedule/config.rs | 10 ++++++----
 crates/bevy_ecs/src/schedule/mod.rs    | 14 --------------
 crates/bevy_ecs/src/schedule/set.rs    | 10 ++++++++++
 5 files changed, 40 insertions(+), 22 deletions(-)

diff --git a/crates/bevy_app/src/config.rs b/crates/bevy_app/src/config.rs
index 81d35f8574445..b2614d8d3be2a 100644
--- a/crates/bevy_app/src/config.rs
+++ b/crates/bevy_app/src/config.rs
@@ -1,8 +1,8 @@
 use bevy_ecs::{
     all_tuples,
     schedule::{
-        BoxedScheduleLabel, Condition, IntoSystemConfig, IntoSystemSet, ScheduleLabel,
-        SystemConfig, SystemConfigs, SystemSet,
+        BaseSystemSet, BoxedScheduleLabel, Condition, IntoSystemConfig, IntoSystemSet,
+        ScheduleLabel, SystemConfig, SystemConfigs, SystemSet,
     },
 };
 
@@ -93,7 +93,7 @@ impl IntoSystemConfig<(), Self> for SystemAppConfig {
     }
 
     #[track_caller]
-    fn in_base_set(self, set: impl SystemSet) -> Self {
+    fn in_base_set(self, set: impl BaseSystemSet) -> Self {
         let Self { system, schedule } = self;
         Self {
             system: system.in_base_set(set),
diff --git a/crates/bevy_ecs/macros/src/set.rs b/crates/bevy_ecs/macros/src/set.rs
index 545de5ef87eb4..cf4134cfc5b7d 100644
--- a/crates/bevy_ecs/macros/src/set.rs
+++ b/crates/bevy_ecs/macros/src/set.rs
@@ -1,5 +1,5 @@
 use proc_macro::TokenStream;
-use quote::{quote, ToTokens};
+use quote::{format_ident, quote, ToTokens};
 use syn::parse::{Parse, ParseStream};
 
 pub static SYSTEM_SET_ATTRIBUTE_NAME: &str = "system_set";
@@ -12,6 +12,14 @@ pub static BASE_ATTRIBUTE_NAME: &str = "base";
 /// - `input`: The [`syn::DeriveInput`] for the struct that we want to derive the set trait for
 /// - `trait_path`: The [`syn::Path`] to the set trait
 pub fn derive_set(input: syn::DeriveInput, trait_path: &syn::Path) -> TokenStream {
+    let mut base_trait_path = trait_path.clone();
+    let x = &mut base_trait_path.segments.last_mut().unwrap().ident;
+    *x = format_ident!("Base{x}");
+
+    let mut free_trait_path = trait_path.clone();
+    let x = &mut free_trait_path.segments.last_mut().unwrap().ident;
+    *x = format_ident!("Free{x}");
+
     let ident = input.ident;
 
     let mut is_base = false;
@@ -65,6 +73,16 @@ pub fn derive_set(input: syn::DeriveInput, trait_path: &syn::Path) -> TokenStrea
         .unwrap(),
     );
 
+    let marker_impl = if is_base {
+        quote! {
+            impl #impl_generics #base_trait_path for #ident #ty_generics #where_clause {}
+        }
+    } else {
+        quote! {
+            impl #impl_generics #free_trait_path for #ident #ty_generics #where_clause {}
+        }
+    };
+
     (quote! {
         impl #impl_generics #trait_path for #ident #ty_generics #where_clause {
             fn is_base(&self) -> bool {
@@ -75,6 +93,8 @@ pub fn derive_set(input: syn::DeriveInput, trait_path: &syn::Path) -> TokenStrea
                 std::boxed::Box::new(std::clone::Clone::clone(self))
             }
         }
+
+        #marker_impl
     })
     .into()
 }
diff --git a/crates/bevy_ecs/src/schedule/config.rs b/crates/bevy_ecs/src/schedule/config.rs
index 15dd3f1f79933..b2252384380d0 100644
--- a/crates/bevy_ecs/src/schedule/config.rs
+++ b/crates/bevy_ecs/src/schedule/config.rs
@@ -9,6 +9,8 @@ use crate::{
     system::{BoxedSystem, IntoSystem, System},
 };
 
+use super::BaseSystemSet;
+
 /// A [`SystemSet`] with scheduling metadata.
 pub struct SystemSetConfig {
     pub(super) set: BoxedSystemSet,
@@ -280,7 +282,7 @@ pub trait IntoSystemConfig<Marker, Config = SystemConfig> {
     fn in_set(self, set: impl SystemSet) -> Config;
     /// Add to the provided "base" `set`. For more information on base sets, see [`SystemSet::is_base`].
     #[track_caller]
-    fn in_base_set(self, set: impl SystemSet) -> Config;
+    fn in_base_set(self, set: impl BaseSystemSet) -> Config;
     /// Don't add this system to the schedules's default set.
     fn no_default_base_set(self) -> Config;
     /// Run before all systems in `set`.
@@ -314,7 +316,7 @@ where
     }
 
     #[track_caller]
-    fn in_base_set(self, set: impl SystemSet) -> SystemConfig {
+    fn in_base_set(self, set: impl BaseSystemSet) -> SystemConfig {
         self.into_config().in_base_set(set)
     }
 
@@ -354,7 +356,7 @@ impl IntoSystemConfig<()> for BoxedSystem<(), ()> {
     }
 
     #[track_caller]
-    fn in_base_set(self, set: impl SystemSet) -> SystemConfig {
+    fn in_base_set(self, set: impl BaseSystemSet) -> SystemConfig {
         self.into_config().in_base_set(set)
     }
 
@@ -477,7 +479,7 @@ where
 
     /// Add these systems to the provided "base" `set`. For more information on base sets, see [`SystemSet::is_base`].
     #[track_caller]
-    fn in_base_set(self, set: impl SystemSet) -> SystemConfigs {
+    fn in_base_set(self, set: impl BaseSystemSet) -> SystemConfigs {
         self.into_configs().in_base_set(set)
     }
 
diff --git a/crates/bevy_ecs/src/schedule/mod.rs b/crates/bevy_ecs/src/schedule/mod.rs
index fa7a2b72844a9..50b01c1345918 100644
--- a/crates/bevy_ecs/src/schedule/mod.rs
+++ b/crates/bevy_ecs/src/schedule/mod.rs
@@ -698,13 +698,6 @@ mod tests {
             schedule.add_system(named_system.in_set(Base::A));
         }
 
-        #[test]
-        #[should_panic]
-        fn disallow_adding_sets_to_system_with_in_base_set() {
-            let mut schedule = Schedule::new();
-            schedule.add_system(named_system.in_base_set(Normal::X));
-        }
-
         #[test]
         #[should_panic]
         fn disallow_adding_base_sets_to_systems_with_in_set() {
@@ -712,13 +705,6 @@ mod tests {
             schedule.add_systems((named_system, named_system).in_set(Base::A));
         }
 
-        #[test]
-        #[should_panic]
-        fn disallow_adding_sets_to_systems_with_in_base_set() {
-            let mut schedule = Schedule::new();
-            schedule.add_systems((named_system, named_system).in_base_set(Normal::X));
-        }
-
         #[test]
         #[should_panic]
         fn disallow_adding_base_sets_to_set_with_in_set() {
diff --git a/crates/bevy_ecs/src/schedule/set.rs b/crates/bevy_ecs/src/schedule/set.rs
index 06a162c7549b9..ad882f11c1897 100644
--- a/crates/bevy_ecs/src/schedule/set.rs
+++ b/crates/bevy_ecs/src/schedule/set.rs
@@ -37,6 +37,16 @@ pub trait SystemSet: DynHash + Debug + Send + Sync + 'static {
     fn dyn_clone(&self) -> Box<dyn SystemSet>;
 }
 
+/// A system set that is never contained in another set.
+/// Systems and other system sets may only belong to one base set.
+///
+/// This should only be implemented for types that return `true` from [`SystemSet::is_base`].
+pub trait BaseSystemSet: SystemSet {}
+
+/// System sets that are *not* base sets. This should not be implemented for
+/// any types that implement [`BaseSystemSet`].
+pub trait FreeSystemSet: SystemSet {}
+
 impl PartialEq for dyn SystemSet {
     fn eq(&self, other: &Self) -> bool {
         self.dyn_eq(other.as_dyn_eq())

From ac4ecd24cadf4bbb373ac1ae80b0043f1068f324 Mon Sep 17 00:00:00 2001
From: JoJoJet <21144246+JoJoJet@users.noreply.github.com>
Date: Wed, 1 Mar 2023 20:41:40 -0500
Subject: [PATCH 2/7] restrict free systems

---
 crates/bevy_app/src/config.rs          |  6 ++---
 crates/bevy_ecs/src/schedule/config.rs | 16 ++++++-------
 crates/bevy_ecs/src/schedule/mod.rs    | 31 --------------------------
 3 files changed, 11 insertions(+), 42 deletions(-)

diff --git a/crates/bevy_app/src/config.rs b/crates/bevy_app/src/config.rs
index b2614d8d3be2a..3a5f30a50453b 100644
--- a/crates/bevy_app/src/config.rs
+++ b/crates/bevy_app/src/config.rs
@@ -1,8 +1,8 @@
 use bevy_ecs::{
     all_tuples,
     schedule::{
-        BaseSystemSet, BoxedScheduleLabel, Condition, IntoSystemConfig, IntoSystemSet,
-        ScheduleLabel, SystemConfig, SystemConfigs, SystemSet,
+        BaseSystemSet, BoxedScheduleLabel, Condition, FreeSystemSet, IntoSystemConfig,
+        IntoSystemSet, ScheduleLabel, SystemConfig, SystemConfigs,
     },
 };
 
@@ -84,7 +84,7 @@ impl IntoSystemConfig<(), Self> for SystemAppConfig {
     }
 
     #[track_caller]
-    fn in_set(self, set: impl SystemSet) -> Self {
+    fn in_set(self, set: impl FreeSystemSet) -> Self {
         let Self { system, schedule } = self;
         Self {
             system: system.in_set(set),
diff --git a/crates/bevy_ecs/src/schedule/config.rs b/crates/bevy_ecs/src/schedule/config.rs
index b2252384380d0..616f4ff0a0c0e 100644
--- a/crates/bevy_ecs/src/schedule/config.rs
+++ b/crates/bevy_ecs/src/schedule/config.rs
@@ -9,7 +9,7 @@ use crate::{
     system::{BoxedSystem, IntoSystem, System},
 };
 
-use super::BaseSystemSet;
+use super::{BaseSystemSet, FreeSystemSet};
 
 /// A [`SystemSet`] with scheduling metadata.
 pub struct SystemSetConfig {
@@ -88,7 +88,7 @@ pub trait IntoSystemSetConfig {
     fn into_config(self) -> SystemSetConfig;
     /// Add to the provided `set`.
     #[track_caller]
-    fn in_set(self, set: impl SystemSet) -> SystemSetConfig;
+    fn in_set(self, set: impl FreeSystemSet) -> SystemSetConfig;
     /// Add to the provided "base" `set`. For more information on base sets, see [`SystemSet::is_base`].
     #[track_caller]
     fn in_base_set(self, set: impl SystemSet) -> SystemSetConfig;
@@ -117,7 +117,7 @@ impl<S: SystemSet> IntoSystemSetConfig for S {
     }
 
     #[track_caller]
-    fn in_set(self, set: impl SystemSet) -> SystemSetConfig {
+    fn in_set(self, set: impl FreeSystemSet) -> SystemSetConfig {
         self.into_config().in_set(set)
     }
 
@@ -157,7 +157,7 @@ impl IntoSystemSetConfig for BoxedSystemSet {
     }
 
     #[track_caller]
-    fn in_set(self, set: impl SystemSet) -> SystemSetConfig {
+    fn in_set(self, set: impl FreeSystemSet) -> SystemSetConfig {
         self.into_config().in_set(set)
     }
 
@@ -279,7 +279,7 @@ pub trait IntoSystemConfig<Marker, Config = SystemConfig> {
     fn into_config(self) -> Config;
     /// Add to `set` membership.
     #[track_caller]
-    fn in_set(self, set: impl SystemSet) -> Config;
+    fn in_set(self, set: impl FreeSystemSet) -> Config;
     /// Add to the provided "base" `set`. For more information on base sets, see [`SystemSet::is_base`].
     #[track_caller]
     fn in_base_set(self, set: impl BaseSystemSet) -> Config;
@@ -311,7 +311,7 @@ where
     }
 
     #[track_caller]
-    fn in_set(self, set: impl SystemSet) -> SystemConfig {
+    fn in_set(self, set: impl FreeSystemSet) -> SystemConfig {
         self.into_config().in_set(set)
     }
 
@@ -351,7 +351,7 @@ impl IntoSystemConfig<()> for BoxedSystem<(), ()> {
     }
 
     #[track_caller]
-    fn in_set(self, set: impl SystemSet) -> SystemConfig {
+    fn in_set(self, set: impl FreeSystemSet) -> SystemConfig {
         self.into_config().in_set(set)
     }
 
@@ -473,7 +473,7 @@ where
 
     /// Add these systems to the provided `set`.
     #[track_caller]
-    fn in_set(self, set: impl SystemSet) -> SystemConfigs {
+    fn in_set(self, set: impl FreeSystemSet) -> SystemConfigs {
         self.into_configs().in_set(set)
     }
 
diff --git a/crates/bevy_ecs/src/schedule/mod.rs b/crates/bevy_ecs/src/schedule/mod.rs
index 50b01c1345918..3bbab7ca5d84f 100644
--- a/crates/bevy_ecs/src/schedule/mod.rs
+++ b/crates/bevy_ecs/src/schedule/mod.rs
@@ -567,16 +567,6 @@ mod tests {
             ));
         }
 
-        #[test]
-        #[should_panic]
-        fn in_system_type_set() {
-            fn foo() {}
-            fn bar() {}
-
-            let mut schedule = Schedule::new();
-            schedule.add_system(foo.in_set(bar.into_system_set()));
-        }
-
         #[test]
         #[should_panic]
         fn configure_system_type_set() {
@@ -691,27 +681,6 @@ mod tests {
             Z,
         }
 
-        #[test]
-        #[should_panic]
-        fn disallow_adding_base_sets_to_system_with_in_set() {
-            let mut schedule = Schedule::new();
-            schedule.add_system(named_system.in_set(Base::A));
-        }
-
-        #[test]
-        #[should_panic]
-        fn disallow_adding_base_sets_to_systems_with_in_set() {
-            let mut schedule = Schedule::new();
-            schedule.add_systems((named_system, named_system).in_set(Base::A));
-        }
-
-        #[test]
-        #[should_panic]
-        fn disallow_adding_base_sets_to_set_with_in_set() {
-            let mut schedule = Schedule::new();
-            schedule.configure_set(Normal::Y.in_set(Base::A));
-        }
-
         #[test]
         #[should_panic]
         fn disallow_adding_sets_to_set_with_in_base_set() {

From a517cd736f336e7e0b9f42fc255453ae99839f69 Mon Sep 17 00:00:00 2001
From: JoJoJet <21144246+JoJoJet@users.noreply.github.com>
Date: Wed, 1 Mar 2023 20:44:12 -0500
Subject: [PATCH 3/7] restrict base sets more

---
 crates/bevy_ecs/src/schedule/config.rs |  8 ++++----
 crates/bevy_ecs/src/schedule/mod.rs    | 15 ---------------
 2 files changed, 4 insertions(+), 19 deletions(-)

diff --git a/crates/bevy_ecs/src/schedule/config.rs b/crates/bevy_ecs/src/schedule/config.rs
index 616f4ff0a0c0e..923848fe6bfec 100644
--- a/crates/bevy_ecs/src/schedule/config.rs
+++ b/crates/bevy_ecs/src/schedule/config.rs
@@ -91,7 +91,7 @@ pub trait IntoSystemSetConfig {
     fn in_set(self, set: impl FreeSystemSet) -> SystemSetConfig;
     /// Add to the provided "base" `set`. For more information on base sets, see [`SystemSet::is_base`].
     #[track_caller]
-    fn in_base_set(self, set: impl SystemSet) -> SystemSetConfig;
+    fn in_base_set(self, set: impl BaseSystemSet) -> SystemSetConfig;
     /// Add this set to the schedules's default base set.
     fn in_default_base_set(self) -> SystemSetConfig;
     /// Run before all systems in `set`.
@@ -122,7 +122,7 @@ impl<S: SystemSet> IntoSystemSetConfig for S {
     }
 
     #[track_caller]
-    fn in_base_set(self, set: impl SystemSet) -> SystemSetConfig {
+    fn in_base_set(self, set: impl BaseSystemSet) -> SystemSetConfig {
         self.into_config().in_base_set(set)
     }
 
@@ -162,7 +162,7 @@ impl IntoSystemSetConfig for BoxedSystemSet {
     }
 
     #[track_caller]
-    fn in_base_set(self, set: impl SystemSet) -> SystemSetConfig {
+    fn in_base_set(self, set: impl BaseSystemSet) -> SystemSetConfig {
         self.into_config().in_base_set(set)
     }
 
@@ -665,7 +665,7 @@ where
 
     /// Add these system sets to the provided "base" `set`. For more information on base sets, see [`SystemSet::is_base`].
     #[track_caller]
-    fn in_base_set(self, set: impl SystemSet) -> SystemSetConfigs {
+    fn in_base_set(self, set: impl BaseSystemSet) -> SystemSetConfigs {
         self.into_configs().in_base_set(set)
     }
 
diff --git a/crates/bevy_ecs/src/schedule/mod.rs b/crates/bevy_ecs/src/schedule/mod.rs
index 3bbab7ca5d84f..448a8d55fe32a 100644
--- a/crates/bevy_ecs/src/schedule/mod.rs
+++ b/crates/bevy_ecs/src/schedule/mod.rs
@@ -678,14 +678,6 @@ mod tests {
         enum Normal {
             X,
             Y,
-            Z,
-        }
-
-        #[test]
-        #[should_panic]
-        fn disallow_adding_sets_to_set_with_in_base_set() {
-            let mut schedule = Schedule::new();
-            schedule.configure_set(Normal::Y.in_base_set(Normal::X));
         }
 
         #[test]
@@ -695,13 +687,6 @@ mod tests {
             schedule.configure_sets((Normal::X, Normal::Y).in_set(Base::A));
         }
 
-        #[test]
-        #[should_panic]
-        fn disallow_adding_sets_to_sets_with_in_base_set() {
-            let mut schedule = Schedule::new();
-            schedule.configure_sets((Normal::X, Normal::Y).in_base_set(Normal::Z));
-        }
-
         #[test]
         #[should_panic]
         fn disallow_adding_base_sets_to_sets() {

From 497b77fcd986a5b535e6e479a2f0a0d769aeee44 Mon Sep 17 00:00:00 2001
From: JoJoJet <21144246+JoJoJet@users.noreply.github.com>
Date: Wed, 1 Mar 2023 20:45:21 -0500
Subject: [PATCH 4/7] restrict free sets more

---
 crates/bevy_ecs/src/schedule/config.rs | 2 +-
 crates/bevy_ecs/src/schedule/mod.rs    | 7 -------
 2 files changed, 1 insertion(+), 8 deletions(-)

diff --git a/crates/bevy_ecs/src/schedule/config.rs b/crates/bevy_ecs/src/schedule/config.rs
index 923848fe6bfec..899985fb22b43 100644
--- a/crates/bevy_ecs/src/schedule/config.rs
+++ b/crates/bevy_ecs/src/schedule/config.rs
@@ -659,7 +659,7 @@ where
 
     /// Add these system sets to the provided `set`.
     #[track_caller]
-    fn in_set(self, set: impl SystemSet) -> SystemSetConfigs {
+    fn in_set(self, set: impl FreeSystemSet) -> SystemSetConfigs {
         self.into_configs().in_set(set)
     }
 
diff --git a/crates/bevy_ecs/src/schedule/mod.rs b/crates/bevy_ecs/src/schedule/mod.rs
index 448a8d55fe32a..f886d815d1d37 100644
--- a/crates/bevy_ecs/src/schedule/mod.rs
+++ b/crates/bevy_ecs/src/schedule/mod.rs
@@ -680,13 +680,6 @@ mod tests {
             Y,
         }
 
-        #[test]
-        #[should_panic]
-        fn disallow_adding_base_sets_to_sets_with_in_set() {
-            let mut schedule = Schedule::new();
-            schedule.configure_sets((Normal::X, Normal::Y).in_set(Base::A));
-        }
-
         #[test]
         #[should_panic]
         fn disallow_adding_base_sets_to_sets() {

From 7c98eb16dde0937b11c232688c038ff19a8b6d97 Mon Sep 17 00:00:00 2001
From: JoJoJet <21144246+JoJoJet@users.noreply.github.com>
Date: Wed, 1 Mar 2023 20:52:33 -0500
Subject: [PATCH 5/7] fix a benchmark

---
 benches/benches/bevy_ecs/scheduling/schedule.rs | 11 +++--------
 1 file changed, 3 insertions(+), 8 deletions(-)

diff --git a/benches/benches/bevy_ecs/scheduling/schedule.rs b/benches/benches/bevy_ecs/scheduling/schedule.rs
index 18a2699becad9..3117c0fff2bc7 100644
--- a/benches/benches/bevy_ecs/scheduling/schedule.rs
+++ b/benches/benches/bevy_ecs/scheduling/schedule.rs
@@ -63,16 +63,11 @@ pub fn build_schedule(criterion: &mut Criterion) {
 
     // Use multiple different kinds of label to ensure that dynamic dispatch
     // doesn't somehow get optimized away.
-    #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+    #[derive(SystemSet, Debug, Clone, Copy, PartialEq, Eq, Hash)]
     struct NumSet(usize);
-    #[derive(Debug, Clone, Copy, SystemSet, PartialEq, Eq, Hash)]
-    struct DummySet;
 
-    impl SystemSet for NumSet {
-        fn dyn_clone(&self) -> Box<dyn SystemSet> {
-            Box::new(self.clone())
-        }
-    }
+    #[derive(SystemSet, Debug, Clone, Copy, PartialEq, Eq, Hash)]
+    struct DummySet;
 
     let mut group = criterion.benchmark_group("build_schedule");
     group.warm_up_time(std::time::Duration::from_millis(500));

From 6c1af1d7a8f9672a84062eefcc4a075f904a0413 Mon Sep 17 00:00:00 2001
From: JoJoJet <21144246+JoJoJet@users.noreply.github.com>
Date: Wed, 1 Mar 2023 21:05:35 -0500
Subject: [PATCH 6/7] use a descriptive variable name

---
 crates/bevy_ecs/macros/src/set.rs | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/crates/bevy_ecs/macros/src/set.rs b/crates/bevy_ecs/macros/src/set.rs
index cf4134cfc5b7d..5db4395ed08a3 100644
--- a/crates/bevy_ecs/macros/src/set.rs
+++ b/crates/bevy_ecs/macros/src/set.rs
@@ -13,12 +13,12 @@ pub static BASE_ATTRIBUTE_NAME: &str = "base";
 /// - `trait_path`: The [`syn::Path`] to the set trait
 pub fn derive_set(input: syn::DeriveInput, trait_path: &syn::Path) -> TokenStream {
     let mut base_trait_path = trait_path.clone();
-    let x = &mut base_trait_path.segments.last_mut().unwrap().ident;
-    *x = format_ident!("Base{x}");
+    let ident = &mut base_trait_path.segments.last_mut().unwrap().ident;
+    *ident = format_ident!("Base{x}");
 
     let mut free_trait_path = trait_path.clone();
-    let x = &mut free_trait_path.segments.last_mut().unwrap().ident;
-    *x = format_ident!("Free{x}");
+    let ident = &mut free_trait_path.segments.last_mut().unwrap().ident;
+    *ident = format_ident!("Free{x}");
 
     let ident = input.ident;
 

From b3a42d031fc2ad84df84bf41d4f40bd7e60319fb Mon Sep 17 00:00:00 2001
From: JoJoJet <21144246+JoJoJet@users.noreply.github.com>
Date: Wed, 1 Mar 2023 21:07:12 -0500
Subject: [PATCH 7/7] f2 betrayed me

---
 crates/bevy_ecs/macros/src/set.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/crates/bevy_ecs/macros/src/set.rs b/crates/bevy_ecs/macros/src/set.rs
index 5db4395ed08a3..054735c858653 100644
--- a/crates/bevy_ecs/macros/src/set.rs
+++ b/crates/bevy_ecs/macros/src/set.rs
@@ -14,11 +14,11 @@ pub static BASE_ATTRIBUTE_NAME: &str = "base";
 pub fn derive_set(input: syn::DeriveInput, trait_path: &syn::Path) -> TokenStream {
     let mut base_trait_path = trait_path.clone();
     let ident = &mut base_trait_path.segments.last_mut().unwrap().ident;
-    *ident = format_ident!("Base{x}");
+    *ident = format_ident!("Base{ident}");
 
     let mut free_trait_path = trait_path.clone();
     let ident = &mut free_trait_path.segments.last_mut().unwrap().ident;
-    *ident = format_ident!("Free{x}");
+    *ident = format_ident!("Free{ident}");
 
     let ident = input.ident;