update AsSystemLabel trait

* Updated it to return a `LabelId` directly.
* yeeted the associated type.

Author: joseph-gio

crates/bevy_ecs/src/system/function_system.rs

@@ -12,7 +12,7 @@ use crate::{
     world::{World, WorldId},
 };
 use bevy_ecs_macros::all_tuples;
-use std::{borrow::Cow, fmt::Debug, hash::Hash, marker::PhantomData};
+use std::{borrow::Cow, fmt::Debug, marker::PhantomData};
 
 /// The metadata of a [`System`].
 #[derive(Clone)]
@@ -452,41 +452,28 @@ where
 /// A [`SystemLabel`] that was automatically generated for a system on the basis of its `TypeId`.
 pub struct SystemTypeIdLabel<T: 'static>(PhantomData<fn() -> T>);
 
+impl<T: 'static> SystemLabel for SystemTypeIdLabel<T> {
+    #[inline]
+    fn as_str(&self) -> &'static str {
+        std::any::type_name::<T>()
+    }
+}
+
 impl<T> Debug for SystemTypeIdLabel<T> {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         f.debug_tuple("SystemTypeIdLabel")
             .field(&std::any::type_name::<T>())
             .finish()
     }
 }
-impl<T> Hash for SystemTypeIdLabel<T> {
-    fn hash<H: std::hash::Hasher>(&self, _state: &mut H) {
-        // All SystemTypeIds of a given type are the same.
-    }
-}
+
 impl<T> Clone for SystemTypeIdLabel<T> {
     fn clone(&self) -> Self {
-        Self(PhantomData)
+        *self
     }
 }
-
 impl<T> Copy for SystemTypeIdLabel<T> {}
 
-impl<T> PartialEq for SystemTypeIdLabel<T> {
-    #[inline]
-    fn eq(&self, _other: &Self) -> bool {
-        // All labels of a given type are equal, as they will all have the same type id
-        true
-    }
-}
-impl<T> Eq for SystemTypeIdLabel<T> {}
-
-impl<T> SystemLabel for SystemTypeIdLabel<T> {
-    fn as_str(&self) -> &'static str {
-        std::any::type_name::<T>()
-    }
-}
-
 /// A trait implemented for all functions that can be used as [`System`]s.
 ///
 /// This trait can be useful for making your own systems which accept other systems,
@@ -612,24 +599,21 @@ all_tuples!(impl_system_function, 0, 16, F);
 /// Used to implicitly convert systems to their default labels. For example, it will convert
 /// "system functions" to their [`SystemTypeIdLabel`].
 pub trait AsSystemLabel<Marker> {
-    type SystemLabel: SystemLabel;
-    fn as_system_label(&self) -> Self::SystemLabel;
+    fn as_system_label(&self) -> SystemLabelId;
 }
 
 impl<In, Out, Param: SystemParam, Marker, T: SystemParamFunction<In, Out, Param, Marker>>
     AsSystemLabel<(In, Out, Param, Marker)> for T
 {
-    type SystemLabel = SystemTypeIdLabel<Self>;
-
-    fn as_system_label(&self) -> Self::SystemLabel {
-        SystemTypeIdLabel(PhantomData::<fn() -> Self>)
+    #[inline]
+    fn as_system_label(&self) -> SystemLabelId {
+        SystemTypeIdLabel::<T>(PhantomData).as_label()
     }
 }
 
-impl<T: SystemLabel + Clone> AsSystemLabel<()> for T {
-    type SystemLabel = T;
-
-    fn as_system_label(&self) -> Self::SystemLabel {
-        self.clone()
+impl<T: SystemLabel> AsSystemLabel<()> for T {
+    #[inline]
+    fn as_system_label(&self) -> SystemLabelId {
+        self.as_label()
     }
 }