Hide docs for concrete impls of Fetch, FetchState, and SystemParamState (#4250)

# Objective
 The following pages in the docs are rather noisy, and the types they point to are not particularly useful by themselves:

 - http://dev-docs.bevyengine.org/bevy/ecs/query/index.html
 - http://dev-docs.bevyengine.org/bevy/ecs/system/index.html

## Solution
 
- Replace docs on these types with `#[doc(hidden)]`.
- Hide `InputMarker`  too.

crates/bevy_ecs/src/query/fetch.rs

@@ -413,6 +413,7 @@ impl WorldQuery for Entity {
 }
 
 /// The [`Fetch`] of [`Entity`].
+#[doc(hidden)]
 #[derive(Clone)]
 pub struct EntityFetch {
     entities: *const Entity,
@@ -422,6 +423,7 @@ pub struct EntityFetch {
 unsafe impl ReadOnlyFetch for EntityFetch {}
 
 /// The [`FetchState`] of [`Entity`].
+#[doc(hidden)]
 pub struct EntityState;
 
 // SAFETY: no component or archetype access
@@ -500,6 +502,7 @@ impl<T: Component> WorldQuery for &T {
 }
 
 /// The [`FetchState`] of `&T`.
+#[doc(hidden)]
 pub struct ReadState<T> {
     component_id: ComponentId,
     marker: PhantomData<T>,
@@ -547,6 +550,7 @@ unsafe impl<T: Component> FetchState for ReadState<T> {
 }
 
 /// The [`Fetch`] of `&T`.
+#[doc(hidden)]
 pub struct ReadFetch<T> {
     table_components: NonNull<T>,
     entity_table_rows: *const usize,
@@ -656,6 +660,7 @@ impl<T: Component> WorldQuery for &mut T {
 }
 
 /// The [`Fetch`] of `&mut T`.
+#[doc(hidden)]
 pub struct WriteFetch<T> {
     table_components: NonNull<T>,
     table_ticks: *const UnsafeCell<ComponentTicks>,
@@ -681,6 +686,7 @@ impl<T> Clone for WriteFetch<T> {
 }
 
 /// The [`ReadOnlyFetch`] of `&mut T`.
+#[doc(hidden)]
 pub struct ReadOnlyWriteFetch<T> {
     table_components: NonNull<T>,
     entities: *const Entity,
@@ -703,6 +709,7 @@ impl<T> Clone for ReadOnlyWriteFetch<T> {
 }
 
 /// The [`FetchState`] of `&mut T`.
+#[doc(hidden)]
 pub struct WriteState<T> {
     component_id: ComponentId,
     marker: PhantomData<T>,
@@ -940,6 +947,7 @@ impl<T: WorldQuery> WorldQuery for Option<T> {
 }
 
 /// The [`Fetch`] of `Option<T>`.
+#[doc(hidden)]
 #[derive(Clone)]
 pub struct OptionFetch<T> {
     fetch: T,
@@ -950,6 +958,7 @@ pub struct OptionFetch<T> {
 unsafe impl<T: ReadOnlyFetch> ReadOnlyFetch for OptionFetch<T> {}
 
 /// The [`FetchState`] of `Option<T>`.
+#[doc(hidden)]
 pub struct OptionState<T: FetchState> {
     state: T,
 }
@@ -1116,6 +1125,7 @@ impl<T: Component> WorldQuery for ChangeTrackers<T> {
 }
 
 /// The [`FetchState`] of [`ChangeTrackers`].
+#[doc(hidden)]
 pub struct ChangeTrackersState<T> {
     component_id: ComponentId,
     marker: PhantomData<T>,
@@ -1163,6 +1173,7 @@ unsafe impl<T: Component> FetchState for ChangeTrackersState<T> {
 }
 
 /// The [`Fetch`] of [`ChangeTrackers`].
+#[doc(hidden)]
 pub struct ChangeTrackersFetch<T> {
     table_ticks: *const ComponentTicks,
     entity_table_rows: *const usize,

crates/bevy_ecs/src/query/filter.rs

@@ -79,11 +79,13 @@ impl<T: Component> WorldQuery for With<T> {
 }
 
 /// The [`Fetch`] of [`With`].
+#[doc(hidden)]
 pub struct WithFetch<T> {
     marker: PhantomData<T>,
 }
 
 /// The [`FetchState`] of [`With`].
+#[doc(hidden)]
 pub struct WithState<T> {
     component_id: ComponentId,
     marker: PhantomData<T>,
@@ -202,11 +204,13 @@ impl<T: Component> WorldQuery for Without<T> {
 }
 
 /// The [`Fetch`] of [`Without`].
+#[doc(hidden)]
 pub struct WithoutFetch<T> {
     marker: PhantomData<T>,
 }
 
 /// The [`FetchState`] of [`Without`].
+#[doc(hidden)]
 pub struct WithoutState<T> {
     component_id: ComponentId,
     marker: PhantomData<T>,
@@ -325,6 +329,7 @@ unsafe impl<T> ReadOnlyFetch for WithoutFetch<T> {}
 pub struct Or<T>(pub T);
 
 /// The [`Fetch`] of [`Or`].
+#[doc(hidden)]
 pub struct OrFetch<T: FilterFetch> {
     fetch: T,
     matches: bool,
@@ -458,6 +463,7 @@ macro_rules! impl_tick_filter {
         $(#[$meta])*
         pub struct $name<T>(PhantomData<T>);
 
+        #[doc(hidden)]
         $(#[$fetch_meta])*
         pub struct $fetch_name<T> {
             table_ticks: *const UnsafeCell<ComponentTicks>,
@@ -469,6 +475,7 @@ macro_rules! impl_tick_filter {
             change_tick: u32,
         }
 
+        #[doc(hidden)]
         $(#[$state_meta])*
         pub struct $state_name<T> {
             component_id: ComponentId,

crates/bevy_ecs/src/system/function_system.rs

@@ -308,6 +308,7 @@ impl<In, Out, Sys: System<In = In, Out = Out>> IntoSystem<In, Out, AlreadyWasSys
 /// }
 /// ```
 pub struct In<In>(pub In);
+#[doc(hidden)]
 pub struct InputMarker;
 
 /// The [`System`] counter part of an ordinary function.

crates/bevy_ecs/src/system/system_param.rs

@@ -181,6 +181,7 @@ pub struct QuerySet<'w, 's, T> {
     change_tick: u32,
 }
 
+#[doc(hidden)]
 pub struct QuerySetState<T>(T);
 
 impl_query_set!();
@@ -265,6 +266,7 @@ impl<'w, T: Resource> From<ResMut<'w, T>> for Res<'w, T> {
 }
 
 /// The [`SystemParamState`] of [`Res<T>`].
+#[doc(hidden)]
 pub struct ResState<T> {
     component_id: ComponentId,
     marker: PhantomData<T>,
@@ -332,6 +334,7 @@ impl<'w, 's, T: Resource> SystemParamFetch<'w, 's> for ResState<T> {
 
 /// The [`SystemParamState`] of [`Option<Res<T>>`].
 /// See: [`Res<T>`]
+#[doc(hidden)]
 pub struct OptionResState<T>(ResState<T>);
 
 impl<'a, T: Resource> SystemParam for Option<Res<'a, T>> {
@@ -369,6 +372,7 @@ impl<'w, 's, T: Resource> SystemParamFetch<'w, 's> for OptionResState<T> {
 }
 
 /// The [`SystemParamState`] of [`ResMut<T>`].
+#[doc(hidden)]
 pub struct ResMutState<T> {
     component_id: ComponentId,
     marker: PhantomData<T>,
@@ -441,6 +445,7 @@ impl<'w, 's, T: Resource> SystemParamFetch<'w, 's> for ResMutState<T> {
 
 /// The [`SystemParamState`] of [`Option<ResMut<T>>`].
 /// See: [`ResMut<T>`]
+#[doc(hidden)]
 pub struct OptionResMutState<T>(ResMutState<T>);
 
 impl<'a, T: Resource> SystemParam for Option<ResMut<'a, T>> {
@@ -512,6 +517,7 @@ impl<'w, 's> SystemParamFetch<'w, 's> for CommandQueue {
 unsafe impl ReadOnlySystemParamFetch for WorldState {}
 
 /// The [`SystemParamState`] of [`&World`](crate::world::World).
+#[doc(hidden)]
 pub struct WorldState;
 
 impl<'w, 's> SystemParam for &'w World {
@@ -631,6 +637,7 @@ impl<'a, T: Resource> DerefMut for Local<'a, T> {
 }
 
 /// The [`SystemParamState`] of [`Local<T>`].
+#[doc(hidden)]
 pub struct LocalState<T: Resource>(T);
 
 impl<'a, T: Resource + FromWorld> SystemParam for Local<'a, T> {
@@ -707,6 +714,7 @@ impl<'a, T: Component> RemovedComponents<'a, T> {
 unsafe impl<T: Component> ReadOnlySystemParamFetch for RemovedComponentsState<T> {}
 
 /// The [`SystemParamState`] of [`RemovedComponents<T>`].
+#[doc(hidden)]
 pub struct RemovedComponentsState<T> {
     component_id: ComponentId,
     marker: PhantomData<T>,
@@ -810,6 +818,7 @@ impl<'a, T> From<NonSendMut<'a, T>> for NonSend<'a, T> {
 }
 
 /// The [`SystemParamState`] of [`NonSend<T>`].
+#[doc(hidden)]
 pub struct NonSendState<T> {
     component_id: ComponentId,
     marker: PhantomData<fn() -> T>,
@@ -881,6 +890,7 @@ impl<'w, 's, T: 'static> SystemParamFetch<'w, 's> for NonSendState<T> {
 
 /// The [`SystemParamState`] of [`Option<NonSend<T>>`].
 /// See: [`NonSend<T>`]
+#[doc(hidden)]
 pub struct OptionNonSendState<T>(NonSendState<T>);
 
 impl<'w, T: 'static> SystemParam for Option<NonSend<'w, T>> {
@@ -919,6 +929,7 @@ impl<'w, 's, T: 'static> SystemParamFetch<'w, 's> for OptionNonSendState<T> {
 }
 
 /// The [`SystemParamState`] of [`NonSendMut<T>`].
+#[doc(hidden)]
 pub struct NonSendMutState<T> {
     component_id: ComponentId,
     marker: PhantomData<fn() -> T>,
@@ -994,6 +1005,7 @@ impl<'w, 's, T: 'static> SystemParamFetch<'w, 's> for NonSendMutState<T> {
 
 /// The [`SystemParamState`] of [`Option<NonSendMut<T>>`].
 /// See: [`NonSendMut<T>`]
+#[doc(hidden)]
 pub struct OptionNonSendMutState<T>(NonSendMutState<T>);
 
 impl<'a, T: 'static> SystemParam for Option<NonSendMut<'a, T>> {
@@ -1038,6 +1050,7 @@ impl<'a> SystemParam for &'a Archetypes {
 unsafe impl ReadOnlySystemParamFetch for ArchetypesState {}
 
 /// The [`SystemParamState`] of [`Archetypes`].
+#[doc(hidden)]
 pub struct ArchetypesState;
 
 // SAFE: no component value access
@@ -1069,6 +1082,7 @@ impl<'a> SystemParam for &'a Components {
 unsafe impl ReadOnlySystemParamFetch for ComponentsState {}
 
 /// The [`SystemParamState`] of [`Components`].
+#[doc(hidden)]
 pub struct ComponentsState;
 
 // SAFE: no component value access
@@ -1100,6 +1114,7 @@ impl<'a> SystemParam for &'a Entities {
 unsafe impl ReadOnlySystemParamFetch for EntitiesState {}
 
 /// The [`SystemParamState`] of [`Entities`].
+#[doc(hidden)]
 pub struct EntitiesState;
 
 // SAFE: no component value access
@@ -1131,6 +1146,7 @@ impl<'a> SystemParam for &'a Bundles {
 unsafe impl ReadOnlySystemParamFetch for BundlesState {}
 
 /// The [`SystemParamState`] of [`Bundles`].
+#[doc(hidden)]
 pub struct BundlesState;
 
 // SAFE: no component value access
@@ -1154,6 +1170,7 @@ impl<'w, 's> SystemParamFetch<'w, 's> for BundlesState {
     }
 }
 
+/// The [`SystemParamState`] of [`SystemChangeTick`].
 #[derive(Debug)]
 pub struct SystemChangeTick {
     pub last_change_tick: u32,
@@ -1168,6 +1185,7 @@ impl SystemParam for SystemChangeTick {
 }
 
 /// The [`SystemParamState`] of [`SystemChangeTick`].
+#[doc(hidden)]
 pub struct SystemChangeTickState {}
 
 unsafe impl SystemParamState for SystemChangeTickState {
@@ -1330,7 +1348,8 @@ impl<'w, 's, P: SystemParam> StaticSystemParam<'w, 's, P> {
     }
 }
 
-/// The [`SystemParamState`] of [`SystemChangeTick`].
+/// The [`SystemParamState`] of [`StaticSystemParam`].
+#[doc(hidden)]
 pub struct StaticSystemParamState<S, P>(S, PhantomData<fn() -> P>);
 
 // Safe: This doesn't add any more reads, and the delegated fetch confirms it