From 0367716ff343910972b49b931a87f9e12700a2d2 Mon Sep 17 00:00:00 2001
From: Carter Anderson <mcanders1@gmail.com>
Date: Thu, 22 Oct 2020 12:14:43 -0700
Subject: [PATCH] ecs: ergonomic query.iter(), remove locks, add QuerySets

---
 crates/bevy_core/src/label.rs                 |   4 +-
 crates/bevy_core/src/time/timer.rs            |   2 +-
 crates/bevy_ecs/hecs/macros/src/lib.rs        |  75 ++-
 crates/bevy_ecs/hecs/src/access.rs            | 364 +++++++++++++
 crates/bevy_ecs/hecs/src/archetype.rs         |   7 +-
 crates/bevy_ecs/hecs/src/lib.rs               |  11 +-
 crates/bevy_ecs/hecs/src/query.rs             | 508 ++++++------------
 crates/bevy_ecs/hecs/src/query_one.rs         | 144 -----
 crates/bevy_ecs/hecs/src/world.rs             | 121 ++---
 crates/bevy_ecs/hecs/tests/tests.rs           |  96 ++--
 crates/bevy_ecs/src/lib.rs                    |   4 +-
 .../bevy_ecs/src/resource/resource_query.rs   |  34 +-
 .../src/schedule/parallel_executor.rs         |  56 +-
 crates/bevy_ecs/src/schedule/schedule.rs      |   2 +-
 crates/bevy_ecs/src/system/commands.rs        |   4 +-
 crates/bevy_ecs/src/system/into_system.rs     | 276 +++++++---
 crates/bevy_ecs/src/system/query.rs           | 451 ----------------
 crates/bevy_ecs/src/system/query/mod.rs       | 203 +++++++
 crates/bevy_ecs/src/system/query/query_set.rs |  25 +
 crates/bevy_ecs/src/system/system.rs          | 129 +----
 .../bevy_pbr/src/render_graph/lights_node.rs  |   5 +-
 .../bevy_render/src/camera/active_cameras.rs  |   4 +-
 crates/bevy_render/src/camera/camera.rs       |  12 +-
 .../src/camera/visible_entities.rs            |   6 +-
 crates/bevy_render/src/draw.rs                |  22 +-
 crates/bevy_render/src/mesh/mesh.rs           |   2 +-
 .../src/pipeline/render_pipelines.rs          |   2 +-
 .../src/render_graph/nodes/pass_node.rs       |   8 +-
 .../nodes/render_resources_node.rs            |  10 +-
 crates/bevy_render/src/shader/shader_defs.rs  |   6 +-
 crates/bevy_sprite/src/sprite.rs              |   2 +-
 .../bevy_transform/src/hierarchy/hierarchy.rs |  13 +-
 .../hierarchy/hierarchy_maintenance_system.rs |  12 +-
 .../src/transform_propagate_system.rs         |  20 +-
 crates/bevy_ui/src/flex/mod.rs                |  18 +-
 crates/bevy_ui/src/focus.rs                   |   8 +-
 crates/bevy_ui/src/update.rs                  |  14 +-
 crates/bevy_ui/src/widget/image.rs            |   2 +-
 crates/bevy_ui/src/widget/text.rs             |  52 +-
 examples/2d/sprite_sheet.rs                   |   2 +-
 examples/3d/parenting.rs                      |   2 +-
 examples/3d/spawner.rs                        |   2 +-
 examples/3d/z_sort_debug.rs                   |   6 +-
 examples/ecs/ecs_guide.rs                     |  10 +-
 examples/ecs/hierarchy.rs                     |  16 +-
 examples/ecs/parallel_query.rs                |   6 +-
 examples/game/breakout.rs                     |  12 +-
 examples/scene/scene.rs                       |   4 +-
 examples/ui/button.rs                         |   4 +-
 examples/ui/font_atlas_debug.rs               |   2 +-
 examples/ui/text.rs                           |   2 +-
 51 files changed, 1313 insertions(+), 1489 deletions(-)
 create mode 100644 crates/bevy_ecs/hecs/src/access.rs
 delete mode 100644 crates/bevy_ecs/hecs/src/query_one.rs
 delete mode 100644 crates/bevy_ecs/src/system/query.rs
 create mode 100644 crates/bevy_ecs/src/system/query/mod.rs
 create mode 100644 crates/bevy_ecs/src/system/query/query_set.rs

diff --git a/crates/bevy_core/src/label.rs b/crates/bevy_core/src/label.rs
index 16de6edd39744..e01aa170a536d 100644
--- a/crates/bevy_core/src/label.rs
+++ b/crates/bevy_core/src/label.rs
@@ -70,10 +70,10 @@ pub(crate) fn entity_labels_system(
     mut entity_labels: ResMut<EntityLabels>,
     // TODO: use change tracking when add/remove events are added
     // mut query: Query<(Entity, Changed<Labels>)>,
-    mut query: Query<(Entity, &Labels)>,
+    query: Query<(Entity, &Labels)>,
 ) {
     let entity_labels = entity_labels.deref_mut();
-    for (entity, labels) in &mut query.iter() {
+    for (entity, labels) in query.iter() {
         let current_labels = entity_labels
             .entity_labels
             .entry(entity)
diff --git a/crates/bevy_core/src/time/timer.rs b/crates/bevy_core/src/time/timer.rs
index 7ba5d5c61daf3..4a9df0da96662 100644
--- a/crates/bevy_core/src/time/timer.rs
+++ b/crates/bevy_core/src/time/timer.rs
@@ -57,7 +57,7 @@ impl Timer {
 }
 
 pub(crate) fn timer_system(time: Res<Time>, mut query: Query<&mut Timer>) {
-    for mut timer in &mut query.iter() {
+    for mut timer in query.iter_mut() {
         timer.tick(time.delta_seconds);
     }
 }
diff --git a/crates/bevy_ecs/hecs/macros/src/lib.rs b/crates/bevy_ecs/hecs/macros/src/lib.rs
index 56660c1e899d0..879f852a6471f 100644
--- a/crates/bevy_ecs/hecs/macros/src/lib.rs
+++ b/crates/bevy_ecs/hecs/macros/src/lib.rs
@@ -20,7 +20,7 @@ use proc_macro::TokenStream;
 use proc_macro2::Span;
 use proc_macro_crate::crate_name;
 use quote::quote;
-use syn::{parse_macro_input, DeriveInput, Path};
+use syn::{parse_macro_input, DeriveInput, Ident, Index, Lifetime, Path};
 
 /// Implement `Bundle` for a monomorphic struct
 ///
@@ -141,3 +141,76 @@ fn struct_fields(fields: &syn::Fields) -> (Vec<&syn::Type>, Vec<syn::Ident>) {
         syn::Fields::Unit => (Vec::new(), Vec::new()),
     }
 }
+
+fn get_idents(fmt_string: fn(usize) -> String, count: usize) -> Vec<Ident> {
+    (0..count)
+        .map(|i| Ident::new(&fmt_string(i), Span::call_site()))
+        .collect::<Vec<Ident>>()
+}
+
+fn get_lifetimes(fmt_string: fn(usize) -> String, count: usize) -> Vec<Lifetime> {
+    (0..count)
+        .map(|i| Lifetime::new(&fmt_string(i), Span::call_site()))
+        .collect::<Vec<Lifetime>>()
+}
+
+#[proc_macro]
+pub fn impl_query_set(_input: TokenStream) -> TokenStream {
+    let mut tokens = TokenStream::new();
+    let max_queries = 4;
+    let queries = get_idents(|i| format!("Q{}", i), max_queries);
+    let lifetimes = get_lifetimes(|i| format!("'q{}", i), max_queries);
+    let mut query_fns = Vec::new();
+    let mut query_fn_muts = Vec::new();
+    for i in 0..max_queries {
+        let query = &queries[i];
+        let lifetime = &lifetimes[i];
+        let fn_name = Ident::new(&format!("q{}", i), Span::call_site());
+        let fn_name_mut = Ident::new(&format!("q{}_mut", i), Span::call_site());
+        let index = Index::from(i);
+        query_fns.push(quote! {
+            pub fn #fn_name(&self) -> &Query<#lifetime, #query> {
+                &self.value.#index
+            }
+        });
+        query_fn_muts.push(quote! {
+            pub fn #fn_name_mut(&mut self) -> &mut Query<#lifetime, #query> {
+                &mut self.value.#index
+            }
+        });
+    }
+
+    for query_count in 1..=max_queries {
+        let query = &queries[0..query_count];
+        let lifetime = &lifetimes[0..query_count];
+        let query_fn = &query_fns[0..query_count];
+        let query_fn_mut = &query_fn_muts[0..query_count];
+        tokens.extend(TokenStream::from(quote! {
+            impl<#(#lifetime,)* #(#query: HecsQuery,)*> QueryTuple for (#(Query<#lifetime, #query>,)*) {
+                unsafe fn new(world: &World, component_access: &TypeAccess<ArchetypeComponent>) -> Self {
+                    (
+                        #(
+                            Query::<#query>::new(
+                                std::mem::transmute(world),
+                                std::mem::transmute(component_access),
+                            ),
+                        )*
+                    )
+                }
+
+                fn get_accesses() -> Vec<QueryAccess> {
+                    vec![
+                        #(<#query::Fetch as Fetch>::access(),)*
+                    ]
+                }
+            }
+
+            impl<#(#lifetime,)* #(#query: HecsQuery,)*> QuerySet<(#(Query<#lifetime, #query>,)*)> {
+                #(#query_fn)*
+                #(#query_fn_mut)*
+            }
+        }));
+    }
+
+    tokens
+}
diff --git a/crates/bevy_ecs/hecs/src/access.rs b/crates/bevy_ecs/hecs/src/access.rs
new file mode 100644
index 0000000000000..7d3dd1e5385ff
--- /dev/null
+++ b/crates/bevy_ecs/hecs/src/access.rs
@@ -0,0 +1,364 @@
+use core::{any::TypeId, hash::Hash};
+use std::{boxed::Box, vec::Vec};
+
+use crate::{Archetype, World};
+use bevy_utils::HashSet;
+
+#[derive(Debug, Copy, Clone, Ord, PartialOrd, Eq, PartialEq)]
+pub enum Access {
+    None,
+    Read,
+    Write,
+}
+
+#[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
+pub struct ArchetypeComponent {
+    pub archetype_index: u32,
+    pub component: TypeId,
+}
+
+impl ArchetypeComponent {
+    #[inline]
+    pub fn new<T: 'static>(archetype_index: u32) -> Self {
+        ArchetypeComponent {
+            archetype_index,
+            component: TypeId::of::<T>(),
+        }
+    }
+
+    #[inline]
+    pub fn new_ty(archetype_index: u32, component: TypeId) -> Self {
+        ArchetypeComponent {
+            archetype_index,
+            component,
+        }
+    }
+}
+
+pub enum QueryAccess {
+    None,
+    Read(TypeId, &'static str),
+    Write(TypeId, &'static str),
+    Optional(Box<QueryAccess>),
+    With(TypeId, Box<QueryAccess>),
+    Without(TypeId, Box<QueryAccess>),
+    Union(Vec<QueryAccess>),
+}
+
+impl QueryAccess {
+    pub fn read<T: 'static>() -> QueryAccess {
+        QueryAccess::Read(TypeId::of::<T>(), std::any::type_name::<T>())
+    }
+
+    pub fn write<T: 'static>() -> QueryAccess {
+        QueryAccess::Write(TypeId::of::<T>(), std::any::type_name::<T>())
+    }
+
+    pub fn with<T: 'static>(access: QueryAccess) -> QueryAccess {
+        QueryAccess::With(TypeId::of::<T>(), Box::new(access))
+    }
+
+    pub fn without<T: 'static>(access: QueryAccess) -> QueryAccess {
+        QueryAccess::Without(TypeId::of::<T>(), Box::new(access))
+    }
+
+    pub fn optional(access: QueryAccess) -> QueryAccess {
+        QueryAccess::Optional(Box::new(access))
+    }
+
+    pub fn union(accesses: Vec<QueryAccess>) -> QueryAccess {
+        QueryAccess::Union(accesses)
+    }
+
+    pub fn get_world_archetype_access(
+        &self,
+        world: &World,
+        mut type_access: Option<&mut TypeAccess<ArchetypeComponent>>,
+    ) {
+        let archetypes = world.archetypes();
+        for (i, archetype) in archetypes.enumerate() {
+            let type_access = type_access.as_deref_mut();
+            let _ = self.get_access(archetype, i as u32, type_access);
+        }
+    }
+
+    pub fn get_type_name(&self, type_id: TypeId) -> Option<&'static str> {
+        match self {
+            QueryAccess::None => None,
+            QueryAccess::Read(current_type_id, name) => {
+                if type_id == *current_type_id {
+                    Some(*name)
+                } else {
+                    None
+                }
+            }
+            QueryAccess::Write(current_type_id, name) => {
+                if type_id == *current_type_id {
+                    Some(*name)
+                } else {
+                    None
+                }
+            }
+            QueryAccess::Optional(query_access) => query_access.get_type_name(type_id),
+            QueryAccess::With(_, query_access) => query_access.get_type_name(type_id),
+            QueryAccess::Without(_, query_access) => query_access.get_type_name(type_id),
+            QueryAccess::Union(query_accesses) => {
+                for query_access in query_accesses.iter() {
+                    if let Some(name) = query_access.get_type_name(type_id) {
+                        return Some(name);
+                    }
+                }
+
+                None
+            }
+        }
+    }
+
+    /// Returns how this [QueryAccess] accesses the given `archetype`.
+    /// If `type_access` is set, it will populate type access with the types this query reads/writes
+    pub fn get_access(
+        &self,
+        archetype: &Archetype,
+        archetype_index: u32,
+        type_access: Option<&mut TypeAccess<ArchetypeComponent>>,
+    ) -> Option<Access> {
+        match self {
+            QueryAccess::None => Some(Access::None),
+            QueryAccess::Read(ty, _) => {
+                if archetype.has_type(*ty) {
+                    if let Some(type_access) = type_access {
+                        type_access.add_read(ArchetypeComponent::new_ty(archetype_index, *ty));
+                    }
+                    Some(Access::Read)
+                } else {
+                    None
+                }
+            }
+            QueryAccess::Write(ty, _) => {
+                if archetype.has_type(*ty) {
+                    if let Some(type_access) = type_access {
+                        type_access.add_write(ArchetypeComponent::new_ty(archetype_index, *ty));
+                    }
+                    Some(Access::Write)
+                } else {
+                    None
+                }
+            }
+            QueryAccess::Optional(query_access) => {
+                if let Some(access) = query_access.get_access(archetype, archetype_index, None) {
+                    // only re-run get_archetype_access if we need to set type_access
+                    if type_access.is_some() {
+                        query_access.get_access(archetype, archetype_index, type_access)
+                    } else {
+                        Some(access)
+                    }
+                } else {
+                    Some(Access::Read)
+                }
+            }
+            QueryAccess::With(ty, query_access) => {
+                if archetype.has_type(*ty) {
+                    query_access.get_access(archetype, archetype_index, type_access)
+                } else {
+                    None
+                }
+            }
+            QueryAccess::Without(ty, query_access) => {
+                if !archetype.has_type(*ty) {
+                    query_access.get_access(archetype, archetype_index, type_access)
+                } else {
+                    None
+                }
+            }
+            QueryAccess::Union(query_accesses) => {
+                let mut result = None;
+                for query_access in query_accesses {
+                    if let Some(access) = query_access.get_access(archetype, archetype_index, None)
+                    {
+                        result = Some(result.unwrap_or(Access::Read).max(access));
+                    } else {
+                        return None;
+                    }
+                }
+
+                // only set the type access if there is a full match
+                if let Some(type_access) = type_access {
+                    if result.is_some() {
+                        for query_access in query_accesses {
+                            query_access.get_access(archetype, archetype_index, Some(type_access));
+                        }
+                    }
+                }
+
+                result
+            }
+        }
+    }
+}
+
+/// Provides information about the types a [System] reads and writes
+#[derive(Debug, Eq, PartialEq, Clone)]
+pub struct TypeAccess<T: Hash + Eq + PartialEq> {
+    reads_and_writes: HashSet<T>,
+    writes: HashSet<T>,
+    reads: HashSet<T>,
+}
+
+impl<T: Hash + Eq + PartialEq> Default for TypeAccess<T> {
+    fn default() -> Self {
+        Self {
+            reads_and_writes: Default::default(),
+            writes: Default::default(),
+            reads: Default::default(),
+        }
+    }
+}
+
+impl<T: Hash + Eq + PartialEq + Copy> TypeAccess<T> {
+    pub fn new(reads: Vec<T>, writes: Vec<T>) -> Self {
+        let mut type_access = TypeAccess::default();
+        for write in writes {
+            type_access.add_write(write);
+        }
+
+        for read in reads {
+            type_access.add_read(read);
+        }
+
+        type_access
+    }
+
+    pub fn is_compatible(&self, other: &TypeAccess<T>) -> bool {
+        self.writes.is_disjoint(&other.reads_and_writes)
+            && self.reads_and_writes.is_disjoint(&other.writes)
+    }
+
+    pub fn get_conflict<'a>(&'a self, other: &'a TypeAccess<T>) -> Option<&'a T> {
+        let conflict = self.writes.intersection(&other.reads_and_writes).next();
+        if conflict.is_some() {
+            return conflict;
+        }
+        self.reads_and_writes.intersection(&other.writes).next()
+    }
+
+    pub fn union(&mut self, other: &TypeAccess<T>) {
+        self.writes.extend(&other.writes);
+        self.reads.extend(&other.reads);
+        self.reads_and_writes.extend(&other.reads_and_writes);
+    }
+
+    pub fn add_read(&mut self, ty: T) {
+        self.reads_and_writes.insert(ty);
+        self.reads.insert(ty);
+    }
+
+    pub fn add_write(&mut self, ty: T) {
+        self.reads_and_writes.insert(ty);
+        self.writes.insert(ty);
+    }
+
+    pub fn clear(&mut self) {
+        self.reads_and_writes.clear();
+        self.reads.clear();
+        self.writes.clear();
+    }
+
+    pub fn is_read_or_write(&self, ty: &T) -> bool {
+        self.reads_and_writes.contains(ty)
+    }
+
+    pub fn is_write(&self, ty: &T) -> bool {
+        self.writes.contains(ty)
+    }
+
+    pub fn iter_reads(&self) -> impl Iterator<Item = &T> {
+        self.reads.iter()
+    }
+
+    pub fn iter_writes(&self) -> impl Iterator<Item = &T> {
+        self.writes.iter()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::{ArchetypeComponent, Entity, Fetch, Query, TypeAccess, With, World};
+    use std::vec;
+
+    struct A;
+    struct B;
+    struct C;
+
+    #[test]
+    fn query_type_access() {
+        let mut world = World::default();
+        let e1 = world.spawn((A,));
+        let e2 = world.spawn((A, B));
+        let e3 = world.spawn((A, B, C));
+
+        let e1_archetype = world.get_entity_location(e1).unwrap().archetype;
+        let e2_archetype = world.get_entity_location(e2).unwrap().archetype;
+        let e3_archetype = world.get_entity_location(e3).unwrap().archetype;
+
+        let e1_a = ArchetypeComponent::new::<A>(e1_archetype);
+        let e2_a = ArchetypeComponent::new::<A>(e2_archetype);
+        let e2_b = ArchetypeComponent::new::<B>(e2_archetype);
+        let e3_a = ArchetypeComponent::new::<A>(e3_archetype);
+        let e3_b = ArchetypeComponent::new::<B>(e3_archetype);
+        let e3_c = ArchetypeComponent::new::<C>(e3_archetype);
+
+        let mut a_type_access = TypeAccess::default();
+        <(&A,) as Query>::Fetch::access()
+            .get_world_archetype_access(&world, Some(&mut a_type_access));
+
+        assert_eq!(
+            a_type_access,
+            TypeAccess::new(vec![e1_a, e2_a, e3_a], vec![])
+        );
+
+        let mut a_b_type_access = TypeAccess::default();
+        <(&A, &B) as Query>::Fetch::access()
+            .get_world_archetype_access(&world, Some(&mut a_b_type_access));
+
+        assert_eq!(
+            a_b_type_access,
+            TypeAccess::new(vec![e2_a, e2_b, e3_a, e3_b], vec![])
+        );
+
+        let mut a_bmut_type_access = TypeAccess::default();
+        <(&A, &mut B) as Query>::Fetch::access()
+            .get_world_archetype_access(&world, Some(&mut a_bmut_type_access));
+
+        assert_eq!(
+            a_bmut_type_access,
+            TypeAccess::new(vec![e2_a, e3_a], vec![e2_b, e3_b])
+        );
+
+        let mut a_option_bmut_type_access = TypeAccess::default();
+        <(Entity, &A, Option<&mut B>) as Query>::Fetch::access()
+            .get_world_archetype_access(&world, Some(&mut a_option_bmut_type_access));
+
+        assert_eq!(
+            a_option_bmut_type_access,
+            TypeAccess::new(vec![e1_a, e2_a, e3_a], vec![e2_b, e3_b])
+        );
+
+        let mut a_with_b_type_access = TypeAccess::default();
+        <With<B, &A> as Query>::Fetch::access()
+            .get_world_archetype_access(&world, Some(&mut a_with_b_type_access));
+
+        assert_eq!(
+            a_with_b_type_access,
+            TypeAccess::new(vec![e2_a, e3_a], vec![])
+        );
+
+        let mut a_with_b_option_c_type_access = TypeAccess::default();
+        <With<B, (&A, Option<&mut C>)> as Query>::Fetch::access()
+            .get_world_archetype_access(&world, Some(&mut a_with_b_option_c_type_access));
+
+        assert_eq!(
+            a_with_b_option_c_type_access,
+            TypeAccess::new(vec![e2_a, e3_a], vec![e3_c])
+        );
+    }
+}
diff --git a/crates/bevy_ecs/hecs/src/archetype.rs b/crates/bevy_ecs/hecs/src/archetype.rs
index 825e1d87491d4..32889d301aa0e 100644
--- a/crates/bevy_ecs/hecs/src/archetype.rs
+++ b/crates/bevy_ecs/hecs/src/archetype.rs
@@ -31,7 +31,7 @@ use core::{
 };
 use std::collections::HashMap;
 
-use crate::{borrow::AtomicBorrow, query::Fetch, Access, Component, Query};
+use crate::{borrow::AtomicBorrow, Component};
 
 /// A collection of entities having the same component types
 ///
@@ -417,11 +417,6 @@ impl Archetype {
             .cast::<u8>();
         ptr::copy_nonoverlapping(component, ptr, size);
     }
-
-    /// How, if at all, `Q` will access entities in this archetype
-    pub fn access<Q: Query>(&self) -> Option<Access> {
-        Q::Fetch::access(self)
-    }
 }
 
 impl Drop for Archetype {
diff --git a/crates/bevy_ecs/hecs/src/lib.rs b/crates/bevy_ecs/hecs/src/lib.rs
index ed5637cd13186..a432f98de59b8 100644
--- a/crates/bevy_ecs/hecs/src/lib.rs
+++ b/crates/bevy_ecs/hecs/src/lib.rs
@@ -40,7 +40,6 @@
 //! assert_eq!(*world.get::<i32>(b).unwrap(), 42);
 //! ```
 
-#![warn(missing_docs)]
 #![no_std]
 
 #[cfg(feature = "std")]
@@ -64,27 +63,27 @@ macro_rules! smaller_tuples_too {
     };
 }
 
+mod access;
 mod archetype;
 mod borrow;
 mod bundle;
 mod entities;
 mod entity_builder;
 mod query;
-mod query_one;
 #[cfg(feature = "serde")]
 mod serde;
 mod world;
 
+pub use access::{ArchetypeComponent, QueryAccess, TypeAccess};
 pub use archetype::{Archetype, TypeState};
 pub use borrow::{AtomicBorrow, Ref, RefMut};
 pub use bundle::{Bundle, DynamicBundle, MissingComponent};
 pub use entities::{Entity, EntityReserver, Location, NoSuchEntity};
 pub use entity_builder::{BuiltEntity, EntityBuilder};
 pub use query::{
-    Access, Added, BatchedIter, Changed, Mut, Mutated, Or, Query, QueryBorrow, QueryIter,
-    ReadOnlyFetch, With, Without,
+    Added, Batch, BatchedIter, Changed, Mut, Mutated, Or, Query, QueryIter, ReadOnlyFetch, With,
+    Without,
 };
-pub use query_one::QueryOne;
 pub use world::{ArchetypesGeneration, Component, ComponentError, SpawnBatchIter, World};
 
 // Unstable implementation details needed by the macros
@@ -99,4 +98,4 @@ pub use lazy_static;
 pub use query::Fetch;
 
 #[cfg(feature = "macros")]
-pub use bevy_hecs_macros::Bundle;
+pub use bevy_hecs_macros::{impl_query_set, Bundle};
diff --git a/crates/bevy_ecs/hecs/src/query.rs b/crates/bevy_ecs/hecs/src/query.rs
index cadaec192e325..5486c1d23d8a2 100644
--- a/crates/bevy_ecs/hecs/src/query.rs
+++ b/crates/bevy_ecs/hecs/src/query.rs
@@ -20,7 +20,9 @@ use core::{
     ptr::NonNull,
 };
 
-use crate::{archetype::Archetype, Component, Entity, MissingComponent};
+use std::vec;
+
+use crate::{access::QueryAccess, archetype::Archetype, Component, Entity, MissingComponent};
 
 /// A collection of component types to fetch from a `World`
 pub trait Query {
@@ -31,6 +33,9 @@ pub trait Query {
 /// A fetch that is read only. This should only be implemented for read-only fetches.
 pub unsafe trait ReadOnlyFetch {}
 
+/// A fetch that will always match every entity in an archetype (aka Fetch::should_skip always returns false)
+pub trait UnfilteredFetch {}
+
 /// Streaming iterators over contiguous homogeneous ranges of components
 pub trait Fetch<'a>: Sized {
     /// Type of value to be fetched
@@ -41,17 +46,13 @@ pub trait Fetch<'a>: Sized {
     const DANGLING: Self;
 
     /// How this query will access `archetype`, if at all
-    fn access(archetype: &Archetype) -> Option<Access>;
+    fn access() -> QueryAccess;
 
-    /// Acquire dynamic borrows from `archetype`
-    fn borrow(archetype: &Archetype);
     /// Construct a `Fetch` for `archetype` if it should be traversed
     ///
     /// # Safety
     /// `offset` must be in bounds of `archetype`
     unsafe fn get(archetype: &'a Archetype, offset: usize) -> Option<Self>;
-    /// Release dynamic borrows acquired by `borrow`
-    fn release(archetype: &Archetype);
 
     /// if this returns true, the nth item should be skipped during iteration
     ///
@@ -71,20 +72,10 @@ pub trait Fetch<'a>: Sized {
     unsafe fn fetch(&self, n: usize) -> Self::Item;
 }
 
-/// Type of access a `Query` may have to an `Archetype`
-#[derive(Debug, Copy, Clone, Eq, PartialEq, Ord, PartialOrd)]
-pub enum Access {
-    /// Read entity IDs only, no components
-    Iterate,
-    /// Read components
-    Read,
-    /// Read and write components
-    Write,
-}
-
 #[derive(Copy, Clone, Debug)]
 pub struct EntityFetch(NonNull<Entity>);
 unsafe impl ReadOnlyFetch for EntityFetch {}
+impl UnfilteredFetch for EntityFetch {}
 
 impl Query for Entity {
     type Fetch = EntityFetch;
@@ -95,14 +86,6 @@ impl<'a> Fetch<'a> for EntityFetch {
 
     const DANGLING: Self = Self(NonNull::dangling());
 
-    #[inline]
-    fn access(_archetype: &Archetype) -> Option<Access> {
-        Some(Access::Iterate)
-    }
-
-    #[inline]
-    fn borrow(_archetype: &Archetype) {}
-
     #[inline]
     unsafe fn get(archetype: &'a Archetype, offset: usize) -> Option<Self> {
         Some(EntityFetch(NonNull::new_unchecked(
@@ -110,13 +93,15 @@ impl<'a> Fetch<'a> for EntityFetch {
         )))
     }
 
-    #[inline]
-    fn release(_archetype: &Archetype) {}
-
     #[inline]
     unsafe fn fetch(&self, n: usize) -> Self::Item {
         *self.0.as_ptr().add(n)
     }
+
+    #[inline]
+    fn access() -> QueryAccess {
+        QueryAccess::None
+    }
 }
 
 impl<'a, T: Component> Query for &'a T {
@@ -127,38 +112,28 @@ impl<'a, T: Component> Query for &'a T {
 pub struct FetchRead<T>(NonNull<T>);
 
 unsafe impl<T> ReadOnlyFetch for FetchRead<T> {}
+impl<T> UnfilteredFetch for FetchRead<T> {}
 
 impl<'a, T: Component> Fetch<'a> for FetchRead<T> {
     type Item = &'a T;
 
     const DANGLING: Self = Self(NonNull::dangling());
 
-    fn access(archetype: &Archetype) -> Option<Access> {
-        if archetype.has::<T>() {
-            Some(Access::Read)
-        } else {
-            None
-        }
-    }
-
-    fn borrow(archetype: &Archetype) {
-        archetype.borrow::<T>();
-    }
-
     unsafe fn get(archetype: &'a Archetype, offset: usize) -> Option<Self> {
         archetype
             .get::<T>()
             .map(|x| Self(NonNull::new_unchecked(x.as_ptr().add(offset))))
     }
 
-    fn release(archetype: &Archetype) {
-        archetype.release::<T>();
-    }
-
     #[inline]
     unsafe fn fetch(&self, n: usize) -> &'a T {
         &*self.0.as_ptr().add(n)
     }
+
+    #[inline]
+    fn access() -> QueryAccess {
+        QueryAccess::read::<T>()
+    }
 }
 
 impl<'a, T: Component> Query for &'a mut T {
@@ -222,24 +197,13 @@ impl<'a, T: Component> Query for Mut<'a, T> {
 }
 #[doc(hidden)]
 pub struct FetchMut<T>(NonNull<T>, NonNull<bool>);
+impl<T> UnfilteredFetch for FetchMut<T> {}
 
 impl<'a, T: Component> Fetch<'a> for FetchMut<T> {
     type Item = Mut<'a, T>;
 
     const DANGLING: Self = Self(NonNull::dangling(), NonNull::dangling());
 
-    fn access(archetype: &Archetype) -> Option<Access> {
-        if archetype.has::<T>() {
-            Some(Access::Write)
-        } else {
-            None
-        }
-    }
-
-    fn borrow(archetype: &Archetype) {
-        archetype.borrow_mut::<T>();
-    }
-
     unsafe fn get(archetype: &'a Archetype, offset: usize) -> Option<Self> {
         archetype
             .get_with_type_state::<T>()
@@ -251,10 +215,6 @@ impl<'a, T: Component> Fetch<'a> for FetchMut<T> {
             })
     }
 
-    fn release(archetype: &Archetype) {
-        archetype.release_mut::<T>();
-    }
-
     #[inline]
     unsafe fn fetch(&self, n: usize) -> Mut<'a, T> {
         Mut {
@@ -262,6 +222,11 @@ impl<'a, T: Component> Fetch<'a> for FetchMut<T> {
             mutated: &mut *self.1.as_ptr().add(n),
         }
     }
+
+    #[inline]
+    fn access() -> QueryAccess {
+        QueryAccess::write::<T>()
+    }
 }
 
 macro_rules! impl_or_query {
@@ -275,30 +240,17 @@ macro_rules! impl_or_query {
 
             const DANGLING: Self = Self(($( $T::DANGLING ),+));
 
-            fn access(archetype: &Archetype) -> Option<Access> {
-                let mut max_access = None;
-                $(
-                max_access = max_access.max($T::access(archetype));
-                )+
-                max_access
+            fn access() -> QueryAccess {
+                QueryAccess::union(vec![
+                    $($T::access(),)+
+                ])
             }
 
-            fn borrow(archetype: &Archetype) {
-                $(
-                    $T::borrow(archetype);
-                 )+
-            }
 
             unsafe fn get(archetype: &'a Archetype, offset: usize) -> Option<Self> {
                 Some(Self(( $( $T::get(archetype, offset)?),+ )))
             }
 
-            fn release(archetype: &Archetype) {
-                $(
-                    $T::release(archetype);
-                 )+
-            }
-
             #[allow(non_snake_case)]
             unsafe fn fetch(&self, n: usize) -> Self::Item {
                 let ($( $T ),+) = &self.0;
@@ -332,12 +284,11 @@ impl_or_query!(Q1, Q2, Q3, Q4, Q5, Q6, Q7, Q8, Q9, Q10);
 /// let mut world = World::new();
 /// world.spawn((123, true, 1., Some(1)));
 /// world.spawn((456, false, 2., Some(0)));
-/// for mut b in world.query_mut::<Mut<i32>>().iter().skip(1).take(1) {
+/// for mut b in world.query_mut::<Mut<i32>>().skip(1).take(1) {
 ///     *b += 1;
 /// }
 /// let components = world
 ///     .query_mut::<Or<(Mutated<bool>, Mutated<i32>, Mutated<f64>, Mutated<Option<i32>>)>>()
-///     .iter()
 ///     .map(|(b, i, f, o)| (*b, *i))
 ///     .collect::<Vec<_>>();
 /// assert_eq!(components, &[(false, 457)]);
@@ -375,16 +326,9 @@ impl<'a, T: Component> Fetch<'a> for FetchMutated<T> {
 
     const DANGLING: Self = Self(NonNull::dangling(), NonNull::dangling());
 
-    fn access(archetype: &Archetype) -> Option<Access> {
-        if archetype.has::<T>() {
-            Some(Access::Read)
-        } else {
-            None
-        }
-    }
-
-    fn borrow(archetype: &Archetype) {
-        archetype.borrow::<T>();
+    #[inline]
+    fn access() -> QueryAccess {
+        QueryAccess::read::<T>()
     }
 
     unsafe fn get(archetype: &'a Archetype, offset: usize) -> Option<Self> {
@@ -398,10 +342,6 @@ impl<'a, T: Component> Fetch<'a> for FetchMutated<T> {
             })
     }
 
-    fn release(archetype: &Archetype) {
-        archetype.release::<T>();
-    }
-
     unsafe fn should_skip(&self, n: usize) -> bool {
         // skip if the current item wasn't mutated
         !*self.1.as_ptr().add(n)
@@ -442,16 +382,9 @@ impl<'a, T: Component> Fetch<'a> for FetchAdded<T> {
 
     const DANGLING: Self = Self(NonNull::dangling(), NonNull::dangling());
 
-    fn access(archetype: &Archetype) -> Option<Access> {
-        if archetype.has::<T>() {
-            Some(Access::Read)
-        } else {
-            None
-        }
-    }
-
-    fn borrow(archetype: &Archetype) {
-        archetype.borrow::<T>();
+    #[inline]
+    fn access() -> QueryAccess {
+        QueryAccess::read::<T>()
     }
 
     unsafe fn get(archetype: &'a Archetype, offset: usize) -> Option<Self> {
@@ -465,10 +398,6 @@ impl<'a, T: Component> Fetch<'a> for FetchAdded<T> {
             })
     }
 
-    fn release(archetype: &Archetype) {
-        archetype.release::<T>();
-    }
-
     unsafe fn should_skip(&self, n: usize) -> bool {
         // skip if the current item wasn't added
         !*self.1.as_ptr().add(n)
@@ -513,16 +442,9 @@ impl<'a, T: Component> Fetch<'a> for FetchChanged<T> {
         NonNull::dangling(),
     );
 
-    fn access(archetype: &Archetype) -> Option<Access> {
-        if archetype.has::<T>() {
-            Some(Access::Read)
-        } else {
-            None
-        }
-    }
-
-    fn borrow(archetype: &Archetype) {
-        archetype.borrow::<T>();
+    #[inline]
+    fn access() -> QueryAccess {
+        QueryAccess::read::<T>()
     }
 
     unsafe fn get(archetype: &'a Archetype, offset: usize) -> Option<Self> {
@@ -537,10 +459,6 @@ impl<'a, T: Component> Fetch<'a> for FetchChanged<T> {
             })
     }
 
-    fn release(archetype: &Archetype) {
-        archetype.release::<T>();
-    }
-
     unsafe fn should_skip(&self, n: usize) -> bool {
         // skip if the current item wasn't added or mutated
         !*self.1.as_ptr().add(n) && !*self.2.as_ptr().add(n)
@@ -557,28 +475,22 @@ impl<'a, T: Component> Fetch<'a> for FetchChanged<T> {
 #[doc(hidden)]
 pub struct TryFetch<T>(Option<T>);
 unsafe impl<T> ReadOnlyFetch for TryFetch<T> where T: ReadOnlyFetch {}
+impl<T> UnfilteredFetch for TryFetch<T> where T: UnfilteredFetch {}
 
 impl<'a, T: Fetch<'a>> Fetch<'a> for TryFetch<T> {
     type Item = Option<T::Item>;
 
     const DANGLING: Self = Self(None);
 
-    fn access(archetype: &Archetype) -> Option<Access> {
-        Some(T::access(archetype).unwrap_or(Access::Iterate))
-    }
-
-    fn borrow(archetype: &Archetype) {
-        T::borrow(archetype)
+    #[inline]
+    fn access() -> QueryAccess {
+        QueryAccess::optional(T::access())
     }
 
     unsafe fn get(archetype: &'a Archetype, offset: usize) -> Option<Self> {
         Some(Self(T::get(archetype, offset)))
     }
 
-    fn release(archetype: &Archetype) {
-        T::release(archetype)
-    }
-
     unsafe fn fetch(&self, n: usize) -> Option<T::Item> {
         Some(self.0.as_ref()?.fetch(n))
     }
@@ -600,7 +512,6 @@ impl<'a, T: Fetch<'a>> Fetch<'a> for TryFetch<T> {
 /// let b = world.spawn((456, false));
 /// let c = world.spawn((42, "def"));
 /// let entities = world.query::<Without<bool, (Entity, &i32)>>()
-///     .iter()
 ///     .map(|(e, &i)| (e, i))
 ///     .collect::<Vec<_>>();
 /// assert_eq!(entities, &[(c, 42)]);
@@ -617,22 +528,16 @@ unsafe impl<'a, T: Component, F: Fetch<'a>> ReadOnlyFetch for FetchWithout<T, F>
     F: ReadOnlyFetch
 {
 }
+impl<T, F> UnfilteredFetch for FetchWithout<T, F> where F: UnfilteredFetch {}
 
 impl<'a, T: Component, F: Fetch<'a>> Fetch<'a> for FetchWithout<T, F> {
     type Item = F::Item;
 
     const DANGLING: Self = Self(F::DANGLING, PhantomData);
 
-    fn access(archetype: &Archetype) -> Option<Access> {
-        if archetype.has::<T>() {
-            None
-        } else {
-            F::access(archetype)
-        }
-    }
-
-    fn borrow(archetype: &Archetype) {
-        F::borrow(archetype)
+    #[inline]
+    fn access() -> QueryAccess {
+        QueryAccess::without::<T>(F::access())
     }
 
     unsafe fn get(archetype: &'a Archetype, offset: usize) -> Option<Self> {
@@ -642,10 +547,6 @@ impl<'a, T: Component, F: Fetch<'a>> Fetch<'a> for FetchWithout<T, F> {
         Some(Self(F::get(archetype, offset)?, PhantomData))
     }
 
-    fn release(archetype: &Archetype) {
-        F::release(archetype)
-    }
-
     unsafe fn fetch(&self, n: usize) -> F::Item {
         self.0.fetch(n)
     }
@@ -667,7 +568,6 @@ impl<'a, T: Component, F: Fetch<'a>> Fetch<'a> for FetchWithout<T, F> {
 /// let b = world.spawn((456, false));
 /// let c = world.spawn((42, "def"));
 /// let entities = world.query::<With<bool, (Entity, &i32)>>()
-///     .iter()
 ///     .map(|(e, &i)| (e, i))
 ///     .collect::<Vec<_>>();
 /// assert_eq!(entities.len(), 2);
@@ -683,22 +583,16 @@ impl<T: Component, Q: Query> Query for With<T, Q> {
 #[doc(hidden)]
 pub struct FetchWith<T, F>(F, PhantomData<fn(T)>);
 unsafe impl<'a, T: Component, F: Fetch<'a>> ReadOnlyFetch for FetchWith<T, F> where F: ReadOnlyFetch {}
+impl<T, F> UnfilteredFetch for FetchWith<T, F> where F: UnfilteredFetch {}
 
 impl<'a, T: Component, F: Fetch<'a>> Fetch<'a> for FetchWith<T, F> {
     type Item = F::Item;
 
     const DANGLING: Self = Self(F::DANGLING, PhantomData);
 
-    fn access(archetype: &Archetype) -> Option<Access> {
-        if archetype.has::<T>() {
-            F::access(archetype)
-        } else {
-            None
-        }
-    }
-
-    fn borrow(archetype: &Archetype) {
-        F::borrow(archetype)
+    #[inline]
+    fn access() -> QueryAccess {
+        QueryAccess::with::<T>(F::access())
     }
 
     unsafe fn get(archetype: &'a Archetype, offset: usize) -> Option<Self> {
@@ -708,10 +602,6 @@ impl<'a, T: Component, F: Fetch<'a>> Fetch<'a> for FetchWith<T, F> {
         Some(Self(F::get(archetype, offset)?, PhantomData))
     }
 
-    fn release(archetype: &Archetype) {
-        F::release(archetype)
-    }
-
     unsafe fn fetch(&self, n: usize) -> F::Item {
         self.0.fetch(n)
     }
@@ -721,179 +611,86 @@ impl<'a, T: Component, F: Fetch<'a>> Fetch<'a> for FetchWith<T, F> {
     }
 }
 
-/// A borrow of a `World` sufficient to execute the query `Q`
-///
-/// Note that borrows are not released until this object is dropped.
-pub struct QueryBorrow<'w, Q: Query> {
+struct ChunkInfo<Q: Query> {
+    fetch: Q::Fetch,
+    len: usize,
+}
+
+/// Iterator over the set of entities with the components in `Q`
+pub struct QueryIter<'w, Q: Query> {
     archetypes: &'w [Archetype],
-    borrowed: bool,
-    _marker: PhantomData<Q>,
+    archetype_index: usize,
+    chunk_info: ChunkInfo<Q>,
+    chunk_position: usize,
 }
 
-impl<'w, Q: Query> QueryBorrow<'w, Q> {
+impl<'w, Q: Query> QueryIter<'w, Q> {
+    // #[allow(clippy::declare_interior_mutable_const)] // no trait bounds on const fns
+    // const EMPTY: Q::Fetch = Q::Fetch::DANGLING;
+    const EMPTY: ChunkInfo<Q> = ChunkInfo {
+        fetch: Q::Fetch::DANGLING,
+        len: 0,
+    };
+
+    /// Creates a new QueryIter
+    #[inline]
     pub(crate) fn new(archetypes: &'w [Archetype]) -> Self {
         Self {
             archetypes,
-            borrowed: false,
-            _marker: PhantomData,
-        }
-    }
-
-    /// Execute the query
-    ///
-    /// Must be called only once per query.
-    pub fn iter<'q>(&'q mut self) -> QueryIter<'q, 'w, Q> {
-        self.borrow();
-        QueryIter {
-            borrow: self,
-            archetype_index: 0,
-            iter: ChunkIter::EMPTY,
-        }
-    }
-
-    /// Like `iter`, but returns child iterators of at most `batch_size` elements
-    ///
-    /// Useful for distributing work over a threadpool.
-    pub fn iter_batched<'q>(&'q mut self, batch_size: usize) -> BatchedIter<'q, 'w, Q> {
-        self.borrow();
-        BatchedIter {
-            borrow: self,
             archetype_index: 0,
-            batch_size,
-            batch: 0,
+            chunk_info: Self::EMPTY,
+            chunk_position: 0,
         }
     }
-
-    fn borrow(&mut self) {
-        if self.borrowed {
-            panic!(
-                "called QueryBorrow::iter twice on the same borrow; construct a new query instead"
-            );
-        }
-
-        self.borrowed = true;
-    }
-
-    /// Transform the query into one that requires a certain component without borrowing it
-    ///
-    /// This can be useful when the component needs to be borrowed elsewhere and it isn't necessary
-    /// for the iterator to expose its data directly.
-    ///
-    /// Equivalent to using a query type wrapped in `With`.
-    ///
-    /// # Example
-    /// ```
-    /// # use bevy_hecs::*;
-    /// let mut world = World::new();
-    /// let a = world.spawn((123, true, "abc"));
-    /// let b = world.spawn((456, false));
-    /// let c = world.spawn((42, "def"));
-    /// let entities = world.query::<(Entity, &i32)>()
-    ///     .with::<bool>()
-    ///     .iter()
-    ///     .map(|(e, &i)| (e, i)) // Copy out of the world
-    ///     .collect::<Vec<_>>();
-    /// assert!(entities.contains(&(a, 123)));
-    /// assert!(entities.contains(&(b, 456)));
-    /// ```
-    pub fn with<T: Component>(self) -> QueryBorrow<'w, With<T, Q>> {
-        self.transform()
-    }
-
-    /// Transform the query into one that skips entities having a certain component
-    ///
-    /// Equivalent to using a query type wrapped in `Without`.
-    ///
-    /// # Example
-    /// ```
-    /// # use bevy_hecs::*;
-    /// let mut world = World::new();
-    /// let a = world.spawn((123, true, "abc"));
-    /// let b = world.spawn((456, false));
-    /// let c = world.spawn((42, "def"));
-    /// let entities = world.query::<(Entity, &i32)>()
-    ///     .without::<bool>()
-    ///     .iter()
-    ///     .map(|(e, &i)| (e, i)) // Copy out of the world
-    ///     .collect::<Vec<_>>();
-    /// assert_eq!(entities, &[(c, 42)]);
-    /// ```
-    pub fn without<T: Component>(self) -> QueryBorrow<'w, Without<T, Q>> {
-        self.transform()
-    }
-
-    /// Helper to change the type of the query
-    fn transform<R: Query>(mut self) -> QueryBorrow<'w, R> {
-        let borrow = QueryBorrow {
-            archetypes: self.archetypes,
-            borrowed: self.borrowed,
-            _marker: PhantomData,
-        };
-
-        self.borrowed = false;
-        borrow
-    }
-}
-
-unsafe impl<'w, Q: Query> Send for QueryBorrow<'w, Q> {}
-unsafe impl<'w, Q: Query> Sync for QueryBorrow<'w, Q> {}
-
-impl<'q, 'w, Q: Query> IntoIterator for &'q mut QueryBorrow<'w, Q> {
-    type IntoIter = QueryIter<'q, 'w, Q>;
-    type Item = <Q::Fetch as Fetch<'q>>::Item;
-
-    fn into_iter(self) -> Self::IntoIter {
-        self.iter()
-    }
-}
-
-/// Iterator over the set of entities with the components in `Q`
-pub struct QueryIter<'q, 'w, Q: Query> {
-    borrow: &'q mut QueryBorrow<'w, Q>,
-    archetype_index: usize,
-    iter: ChunkIter<Q>,
 }
 
-unsafe impl<'q, 'w, Q: Query> Send for QueryIter<'q, 'w, Q> {}
-unsafe impl<'q, 'w, Q: Query> Sync for QueryIter<'q, 'w, Q> {}
-
-impl<'q, 'w, Q: Query> Iterator for QueryIter<'q, 'w, Q> {
-    type Item = <Q::Fetch as Fetch<'q>>::Item;
+impl<'w, Q: Query> Iterator for QueryIter<'w, Q> {
+    type Item = <Q::Fetch as Fetch<'w>>::Item;
 
     #[inline]
     fn next(&mut self) -> Option<Self::Item> {
-        loop {
-            match unsafe { self.iter.next() } {
-                None => {
-                    let archetype = self.borrow.archetypes.get(self.archetype_index)?;
+        unsafe {
+            loop {
+                if self.chunk_position == self.chunk_info.len {
+                    let archetype = self.archetypes.get(self.archetype_index)?;
                     self.archetype_index += 1;
-                    unsafe {
-                        self.iter = Q::Fetch::get(archetype, 0).map_or(ChunkIter::EMPTY, |fetch| {
-                            ChunkIter {
-                                fetch,
-                                len: archetype.len(),
-                                position: 0,
-                            }
-                        });
-                    }
+                    self.chunk_position = 0;
+                    self.chunk_info = Q::Fetch::get(archetype, 0)
+                        .map(|fetch| ChunkInfo {
+                            fetch,
+                            len: archetype.len(),
+                        })
+                        .unwrap_or(Self::EMPTY);
+                    continue;
+                }
+
+                if self
+                    .chunk_info
+                    .fetch
+                    .should_skip(self.chunk_position as usize)
+                {
+                    self.chunk_position += 1;
+                    continue;
                 }
-                Some(components) => return Some(components),
+
+                let item = Some(self.chunk_info.fetch.fetch(self.chunk_position as usize));
+                self.chunk_position += 1;
+                return item;
             }
         }
     }
-
-    fn size_hint(&self) -> (usize, Option<usize>) {
-        let n = self.len();
-        (n, Some(n))
-    }
 }
 
-impl<'q, 'w, Q: Query> ExactSizeIterator for QueryIter<'q, 'w, Q> {
+// if the Fetch is an UnfilteredFetch, then we can cheaply compute the length of the query by getting
+// the length of each matching archetype
+impl<'w, Q: Query> ExactSizeIterator for QueryIter<'w, Q>
+where
+    Q::Fetch: UnfilteredFetch,
+{
     fn len(&self) -> usize {
-        self.borrow
-            .archetypes
+        self.archetypes
             .iter()
-            .filter(|&x| Q::Fetch::access(x).is_some())
+            .filter(|&archetype| unsafe { Q::Fetch::get(archetype, 0).is_some() })
             .map(|x| x.len())
             .sum()
     }
@@ -906,13 +703,6 @@ struct ChunkIter<Q: Query> {
 }
 
 impl<Q: Query> ChunkIter<Q> {
-    #[allow(clippy::declare_interior_mutable_const)] // no trait bounds on const fns
-    const EMPTY: Self = Self {
-        fetch: Q::Fetch::DANGLING,
-        position: 0,
-        len: 0,
-    };
-
     unsafe fn next<'a>(&mut self) -> Option<<Q::Fetch as Fetch<'a>>::Item> {
         loop {
             if self.position == self.len {
@@ -932,22 +722,35 @@ impl<Q: Query> ChunkIter<Q> {
 }
 
 /// Batched version of `QueryIter`
-pub struct BatchedIter<'q, 'w, Q: Query> {
-    borrow: &'q mut QueryBorrow<'w, Q>,
+pub struct BatchedIter<'w, Q: Query> {
+    archetypes: &'w [Archetype],
     archetype_index: usize,
     batch_size: usize,
     batch: usize,
+    _marker: PhantomData<Q>,
 }
 
-unsafe impl<'q, 'w, Q: Query> Send for BatchedIter<'q, 'w, Q> {}
-unsafe impl<'q, 'w, Q: Query> Sync for BatchedIter<'q, 'w, Q> {}
+impl<'w, Q: Query> BatchedIter<'w, Q> {
+    pub(crate) fn new(archetypes: &'w [Archetype], batch_size: usize) -> Self {
+        Self {
+            archetypes,
+            archetype_index: 0,
+            batch_size,
+            batch: 0,
+            _marker: Default::default(),
+        }
+    }
+}
+
+unsafe impl<'w, Q: Query> Send for BatchedIter<'w, Q> {}
+unsafe impl<'w, Q: Query> Sync for BatchedIter<'w, Q> {}
 
-impl<'q, 'w, Q: Query> Iterator for BatchedIter<'q, 'w, Q> {
-    type Item = Batch<'q, Q>;
+impl<'w, Q: Query> Iterator for BatchedIter<'w, Q> {
+    type Item = Batch<'w, Q>;
 
     fn next(&mut self) -> Option<Self::Item> {
         loop {
-            let archetype = self.borrow.archetypes.get(self.archetype_index)?;
+            let archetype = self.archetypes.get(self.archetype_index)?;
             let offset = self.batch_size * self.batch;
             if offset >= archetype.len() {
                 self.archetype_index += 1;
@@ -1001,26 +804,16 @@ macro_rules! tuple_impl {
             const DANGLING: Self = ($($name::DANGLING,)*);
 
             #[allow(unused_variables, unused_mut)]
-            fn access(archetype: &Archetype) -> Option<Access> {
-                let mut access = Access::Iterate;
-                $(
-                    access = access.max($name::access(archetype)?);
-                )*
-                Some(access)
+            fn access() -> QueryAccess {
+                QueryAccess::union(vec![
+                    $($name::access(),)*
+                ])
             }
 
-            #[allow(unused_variables)]
-            fn borrow(archetype: &Archetype) {
-                $($name::borrow(archetype);)*
-            }
             #[allow(unused_variables)]
             unsafe fn get(archetype: &'a Archetype, offset: usize) -> Option<Self> {
                 Some(($($name::get(archetype, offset)?,)*))
             }
-            #[allow(unused_variables)]
-            fn release(archetype: &Archetype) {
-                $($name::release(archetype);)*
-            }
 
             #[allow(unused_variables)]
             unsafe fn fetch(&self, n: usize) -> Self::Item {
@@ -1042,6 +835,7 @@ macro_rules! tuple_impl {
         }
 
         unsafe impl<$($name: ReadOnlyFetch),*> ReadOnlyFetch for ($($name,)*) {}
+        impl<$($name: UnfilteredFetch),*> UnfilteredFetch for ($($name,)*) {}
     };
 }
 
@@ -1054,13 +848,6 @@ mod tests {
 
     use super::*;
 
-    #[test]
-    fn access_order() {
-        assert!(Access::Write > Access::Read);
-        assert!(Access::Read > Access::Iterate);
-        assert!(Some(Access::Iterate) > None);
-    }
-
     struct A(usize);
     struct B(usize);
     struct C;
@@ -1073,7 +860,6 @@ mod tests {
         fn get_added<Com: Component>(world: &World) -> Vec<Entity> {
             world
                 .query::<(Added<Com>, Entity)>()
-                .iter()
                 .map(|(_added, e)| e)
                 .collect::<Vec<Entity>>()
         };
@@ -1091,7 +877,6 @@ mod tests {
 
         let added = world
             .query::<(Entity, Added<A>, Added<B>)>()
-            .iter()
             .map(|a| a.0)
             .collect::<Vec<Entity>>();
         assert_eq!(added, vec![e2]);
@@ -1105,7 +890,7 @@ mod tests {
         let e3 = world.spawn((A(0), B(0)));
         world.spawn((A(0), B));
 
-        for (i, mut a) in world.query_mut::<Mut<A>>().iter().enumerate() {
+        for (i, mut a) in world.query_mut::<Mut<A>>().enumerate() {
             if i % 2 == 0 {
                 a.0 += 1;
             }
@@ -1114,7 +899,6 @@ mod tests {
         fn get_changed_a(world: &mut World) -> Vec<Entity> {
             world
                 .query_mut::<(Mutated<A>, Entity)>()
-                .iter()
                 .map(|(_a, e)| e)
                 .collect::<Vec<Entity>>()
         };
@@ -1154,7 +938,6 @@ mod tests {
 
         assert!(world
             .query_mut::<(Mutated<A>, Entity)>()
-            .iter()
             .map(|(_a, e)| e)
             .collect::<Vec<Entity>>()
             .is_empty());
@@ -1167,17 +950,16 @@ mod tests {
         let e2 = world.spawn((A(0), B(0)));
         world.spawn((A(0), B(0)));
 
-        for mut a in world.query_mut::<Mut<A>>().iter() {
+        for mut a in world.query_mut::<Mut<A>>() {
             a.0 += 1;
         }
 
-        for mut b in world.query_mut::<Mut<B>>().iter().skip(1).take(1) {
+        for mut b in world.query_mut::<Mut<B>>().skip(1).take(1) {
             b.0 += 1;
         }
 
         let a_b_changed = world
             .query_mut::<(Mutated<A>, Mutated<B>, Entity)>()
-            .iter()
             .map(|(_a, _b, e)| e)
             .collect::<Vec<Entity>>();
         assert_eq!(a_b_changed, vec![e2]);
@@ -1192,17 +974,16 @@ mod tests {
         let _e4 = world.spawn((A(0), B(0)));
 
         // Mutate A in entities e1 and e2
-        for mut a in world.query_mut::<Mut<A>>().iter().take(2) {
+        for mut a in world.query_mut::<Mut<A>>().take(2) {
             a.0 += 1;
         }
         // Mutate B in entities e2 and e3
-        for mut b in world.query_mut::<Mut<B>>().iter().skip(1).take(2) {
+        for mut b in world.query_mut::<Mut<B>>().skip(1).take(2) {
             b.0 += 1;
         }
 
         let a_b_changed = world
             .query_mut::<(Or<(Mutated<A>, Mutated<B>)>, Entity)>()
-            .iter()
             .map(|((_a, _b), e)| e)
             .collect::<Vec<Entity>>();
         // e1 has mutated A, e3 has mutated B, e2 has mutated A and B, _e4 has no mutated component
@@ -1217,7 +998,6 @@ mod tests {
         fn get_changed(world: &World) -> Vec<Entity> {
             world
                 .query::<(Changed<A>, Entity)>()
-                .iter()
                 .map(|(_a, e)| e)
                 .collect::<Vec<Entity>>()
         };
@@ -1227,4 +1007,16 @@ mod tests {
         *world.get_mut(e1).unwrap() = A(1);
         assert_eq!(get_changed(&world), vec![e1]);
     }
+
+    #[test]
+    fn exact_size_query() {
+        let mut world = World::default();
+        world.spawn((A(0), B(0)));
+        world.spawn((A(0), B(0)));
+        world.spawn((C,));
+
+        assert_eq!(world.query::<(&A, &B)>().len(), 2);
+        // the following example shouldn't compile because Changed<A> is not an UnfilteredFetch
+        // assert_eq!(world.query::<(Changed<A>, &B)>().len(), 2);
+    }
 }
diff --git a/crates/bevy_ecs/hecs/src/query_one.rs b/crates/bevy_ecs/hecs/src/query_one.rs
deleted file mode 100644
index 352d81edc88dc..0000000000000
--- a/crates/bevy_ecs/hecs/src/query_one.rs
+++ /dev/null
@@ -1,144 +0,0 @@
-// modified by Bevy contributors
-
-use core::marker::PhantomData;
-
-use crate::{
-    query::{Fetch, ReadOnlyFetch, With, Without},
-    Archetype, Component, Query,
-};
-
-/// A borrow of a `World` sufficient to execute the query `Q` on a single entity
-pub struct QueryOne<'a, Q: Query> {
-    archetype: &'a Archetype,
-    index: usize,
-    _marker: PhantomData<Q>,
-}
-
-impl<'a, Q: Query> QueryOne<'a, Q> {
-    /// Construct a query accessing the entity in `archetype` at `index`
-    ///
-    /// # Safety
-    ///
-    /// `index` must be in-bounds for `archetype`
-    pub(crate) unsafe fn new(archetype: &'a Archetype, index: usize) -> Self {
-        Self {
-            archetype,
-            index,
-            _marker: PhantomData,
-        }
-    }
-
-    /// Get the query result, or `None` if the entity does not satisfy the query
-    ///
-    /// Must be called at most once.
-    ///
-    /// Panics if called more than once or if it would construct a borrow that clashes with another
-    /// pre-existing borrow.
-    pub fn get(&mut self) -> Option<<Q::Fetch as Fetch<'_>>::Item> {
-        unsafe {
-            let fetch = Q::Fetch::get(self.archetype, self.index)?;
-            if fetch.should_skip(0) {
-                None
-            } else {
-                Some(fetch.fetch(0))
-            }
-        }
-    }
-
-    /// Transform the query into one that requires a certain component without borrowing it
-    ///
-    /// See `QueryBorrow::with` for details.
-    pub fn with<T: Component>(self) -> QueryOne<'a, With<T, Q>> {
-        self.transform()
-    }
-
-    /// Transform the query into one that skips entities having a certain component
-    ///
-    /// See `QueryBorrow::without` for details.
-    pub fn without<T: Component>(self) -> QueryOne<'a, Without<T, Q>> {
-        self.transform()
-    }
-
-    /// Helper to change the type of the query
-    fn transform<R: Query>(self) -> QueryOne<'a, R> {
-        QueryOne {
-            archetype: self.archetype,
-            index: self.index,
-            _marker: PhantomData,
-        }
-    }
-}
-
-unsafe impl<Q: Query> Send for QueryOne<'_, Q> {}
-unsafe impl<Q: Query> Sync for QueryOne<'_, Q> {}
-
-/// A read only borrow of a `World` sufficient to execute the query `Q` on a single entity
-pub struct ReadOnlyQueryOne<'a, Q: Query> {
-    archetype: &'a Archetype,
-    index: usize,
-    _marker: PhantomData<Q>,
-}
-
-impl<'a, Q: Query> ReadOnlyQueryOne<'a, Q>
-where
-    Q::Fetch: ReadOnlyFetch,
-{
-    /// Construct a query accessing the entity in `archetype` at `index`
-    ///
-    /// # Safety
-    ///
-    /// `index` must be in-bounds for `archetype`
-    pub(crate) unsafe fn new(archetype: &'a Archetype, index: usize) -> Self {
-        Self {
-            archetype,
-            index,
-            _marker: PhantomData,
-        }
-    }
-
-    /// Get the query result, or `None` if the entity does not satisfy the query
-    ///
-    /// Must be called at most once.
-    ///
-    /// Panics if called more than once or if it would construct a borrow that clashes with another
-    /// pre-existing borrow.
-    pub fn get(&self) -> Option<<Q::Fetch as Fetch<'_>>::Item>
-    where
-        Q::Fetch: ReadOnlyFetch,
-    {
-        unsafe {
-            let fetch = Q::Fetch::get(self.archetype, self.index)?;
-            if fetch.should_skip(0) {
-                None
-            } else {
-                Some(fetch.fetch(0))
-            }
-        }
-    }
-
-    /// Transform the query into one that requires a certain component without borrowing it
-    ///
-    /// See `QueryBorrow::with` for details.
-    pub fn with<T: Component>(self) -> QueryOne<'a, With<T, Q>> {
-        self.transform()
-    }
-
-    /// Transform the query into one that skips entities having a certain component
-    ///
-    /// See `QueryBorrow::without` for details.
-    pub fn without<T: Component>(self) -> QueryOne<'a, Without<T, Q>> {
-        self.transform()
-    }
-
-    /// Helper to change the type of the query
-    fn transform<R: Query>(self) -> QueryOne<'a, R> {
-        QueryOne {
-            archetype: self.archetype,
-            index: self.index,
-            _marker: PhantomData,
-        }
-    }
-}
-
-unsafe impl<Q: Query> Send for ReadOnlyQueryOne<'_, Q> {}
-unsafe impl<Q: Query> Sync for ReadOnlyQueryOne<'_, Q> {}
diff --git a/crates/bevy_ecs/hecs/src/world.rs b/crates/bevy_ecs/hecs/src/world.rs
index 4613ffba79bac..3b314d64ed0ff 100644
--- a/crates/bevy_ecs/hecs/src/world.rs
+++ b/crates/bevy_ecs/hecs/src/world.rs
@@ -15,8 +15,8 @@
 // modified by Bevy contributors
 
 use crate::{
-    alloc::vec::Vec, borrow::EntityRef, query::ReadOnlyFetch, query_one::ReadOnlyQueryOne,
-    EntityReserver, Mut, RefMut,
+    alloc::vec::Vec, borrow::EntityRef, query::ReadOnlyFetch, BatchedIter, EntityReserver, Fetch,
+    Mut, QueryIter, RefMut,
 };
 use bevy_utils::{HashMap, HashSet};
 use core::{any::TypeId, fmt, mem, ptr};
@@ -27,8 +27,7 @@ use std::error::Error;
 use crate::{
     archetype::Archetype,
     entities::{Entities, Location},
-    Bundle, DynamicBundle, Entity, MissingComponent, NoSuchEntity, Query, QueryBorrow, QueryOne,
-    Ref,
+    Bundle, DynamicBundle, Entity, MissingComponent, NoSuchEntity, Query, Ref,
 };
 
 /// An unordered collection of entities, each having any number of distinctly typed components
@@ -236,9 +235,6 @@ impl World {
     ///
     /// Entities are yielded in arbitrary order.
     ///
-    /// The returned `QueryBorrow` can be further transformed with combinator methods; see its
-    /// documentation for details.
-    ///
     /// # Example
     /// ```
     /// # use bevy_hecs::*;
@@ -247,14 +243,13 @@ impl World {
     /// let b = world.spawn((456, false));
     /// let c = world.spawn((42, "def"));
     /// let entities = world.query::<(Entity, &i32, &bool)>()
-    ///     .iter()
     ///     .map(|(e, &i, &b)| (e, i, b)) // Copy out of the world
     ///     .collect::<Vec<_>>();
     /// assert_eq!(entities.len(), 2);
     /// assert!(entities.contains(&(a, 123, true)));
     /// assert!(entities.contains(&(b, 456, false)));
     /// ```
-    pub fn query<Q: Query>(&self) -> QueryBorrow<'_, Q>
+    pub fn query<Q: Query>(&self) -> QueryIter<'_, Q>
     where
         Q::Fetch: ReadOnlyFetch,
     {
@@ -272,9 +267,6 @@ impl World {
     ///
     /// Entities are yielded in arbitrary order.
     ///
-    /// The returned `QueryBorrow` can be further transformed with combinator methods; see its
-    /// documentation for details.
-    ///
     /// # Example
     /// ```
     /// # use bevy_hecs::*;
@@ -282,19 +274,35 @@ impl World {
     /// let a = world.spawn((123, true, "abc"));
     /// let b = world.spawn((456, false));
     /// let c = world.spawn((42, "def"));
-    /// let entities = world.query::<(Entity, &i32, &bool)>()
-    ///     .iter()
-    ///     .map(|(e, &i, &b)| (e, i, b)) // Copy out of the world
+    /// let entities = world.query_mut::<(Entity, &mut i32, &bool)>()
+    ///     .map(|(e, i, &b)| (e, *i, b)) // Copy out of the world
     ///     .collect::<Vec<_>>();
     /// assert_eq!(entities.len(), 2);
     /// assert!(entities.contains(&(a, 123, true)));
     /// assert!(entities.contains(&(b, 456, false)));
     /// ```
-    pub fn query_mut<Q: Query>(&mut self) -> QueryBorrow<'_, Q> {
+    pub fn query_mut<Q: Query>(&mut self) -> QueryIter<'_, Q> {
         // SAFE: unique mutable access
         unsafe { self.query_unchecked() }
     }
 
+    /// Like `query`, but instead of returning a single iterator it returns a "batched iterator",
+    /// where each batch is `batch_size`. This is generally used for parallel iteration.
+    pub fn query_batched<Q: Query>(&self, batch_size: usize) -> BatchedIter<'_, Q>
+    where
+        Q::Fetch: ReadOnlyFetch,
+    {
+        // SAFE: read-only access to world and read only query prevents mutable access
+        unsafe { self.query_batched_unchecked(batch_size) }
+    }
+
+    /// Like `query`, but instead of returning a single iterator it returns a "batched iterator",
+    /// where each batch is `batch_size`. This is generally used for parallel iteration.
+    pub fn query_batched_mut<Q: Query>(&mut self, batch_size: usize) -> BatchedIter<'_, Q> {
+        // SAFE: unique mutable access
+        unsafe { self.query_batched_unchecked(batch_size) }
+    }
+
     /// Efficiently iterate over all entities that have certain components
     ///
     /// Calling `iter` on the returned value yields `(Entity, Q)` tuples, where `Q` is some query
@@ -305,36 +313,29 @@ impl World {
     ///
     /// Entities are yielded in arbitrary order.
     ///
-    /// The returned `QueryBorrow` can be further transformed with combinator methods; see its
-    /// documentation for details.
-    ///
     /// # Safety
     /// This does not check for mutable query correctness. To be safe, make sure mutable queries
     /// have unique access to the components they query.
+    pub unsafe fn query_unchecked<Q: Query>(&self) -> QueryIter<'_, Q> {
+        QueryIter::new(&self.archetypes)
+    }
+
+    /// Like `query`, but instead of returning a single iterator it returns a "batched iterator",
+    /// where each batch is `batch_size`. This is generally used for parallel iteration.
     ///
-    /// # Example
-    /// ```
-    /// # use bevy_hecs::*;
-    /// let mut world = World::new();
-    /// let a = world.spawn((123, true, "abc"));
-    /// let b = world.spawn((456, false));
-    /// let c = world.spawn((42, "def"));
-    /// let entities = world.query::<(Entity, &i32, &bool)>()
-    ///     .iter()
-    ///     .map(|(e, &i, &b)| (e, i, b)) // Copy out of the world
-    ///     .collect::<Vec<_>>();
-    /// assert_eq!(entities.len(), 2);
-    /// assert!(entities.contains(&(a, 123, true)));
-    /// assert!(entities.contains(&(b, 456, false)));
-    /// ```
-    pub unsafe fn query_unchecked<Q: Query>(&self) -> QueryBorrow<'_, Q> {
-        QueryBorrow::new(&self.archetypes)
+    /// # Safety
+    /// This does not check for mutable query correctness. To be safe, make sure mutable queries
+    /// have unique access to the components they query.
+    #[inline]
+    pub unsafe fn query_batched_unchecked<Q: Query>(
+        &self,
+        batch_size: usize,
+    ) -> BatchedIter<'_, Q> {
+        BatchedIter::new(&self.archetypes, batch_size)
     }
 
     /// Prepare a read only query against a single entity
     ///
-    /// Call `get` on the resulting `QueryOne` to actually execute the query.
-    ///
     /// Handy for accessing multiple components simultaneously.
     ///
     /// # Example
@@ -343,25 +344,22 @@ impl World {
     /// let mut world = World::new();
     /// let a = world.spawn((123, true, "abc"));
     /// // The returned query must outlive the borrow made by `get`
-    /// let mut query = world.query_one::<(&i32, &bool)>(a).unwrap();
-    /// let (number, flag) = query.get().unwrap();
+    /// let (number, flag) = world.query_one::<(&i32, &bool)>(a).unwrap();
     /// assert_eq!(*number, 123);
     /// ```
     pub fn query_one<Q: Query>(
         &self,
         entity: Entity,
-    ) -> Result<ReadOnlyQueryOne<'_, Q>, NoSuchEntity>
+    ) -> Result<<Q::Fetch as Fetch>::Item, NoSuchEntity>
     where
         Q::Fetch: ReadOnlyFetch,
     {
-        let loc = self.entities.get(entity)?;
-        Ok(unsafe { ReadOnlyQueryOne::new(&self.archetypes[loc.archetype as usize], loc.index) })
+        // SAFE: read-only access to world and read only query prevents mutable access
+        unsafe { self.query_one_unchecked::<Q>(entity) }
     }
 
     /// Prepare a query against a single entity
     ///
-    /// Call `get` on the resulting `QueryOne` to actually execute the query.
-    ///
     /// Handy for accessing multiple components simultaneously.
     ///
     /// # Example
@@ -370,49 +368,34 @@ impl World {
     /// let mut world = World::new();
     /// let a = world.spawn((123, true, "abc"));
     /// // The returned query must outlive the borrow made by `get`
-    /// let mut query = world.query_one_mut::<(&mut i32, &bool)>(a).unwrap();
-    /// let (mut number, flag) = query.get().unwrap();
+    /// let (mut number, flag) = world.query_one_mut::<(&mut i32, &bool)>(a).unwrap();
     /// if *flag { *number *= 2; }
     /// assert_eq!(*number, 246);
     /// ```
     pub fn query_one_mut<Q: Query>(
         &mut self,
         entity: Entity,
-    ) -> Result<QueryOne<'_, Q>, NoSuchEntity> {
+    ) -> Result<<Q::Fetch as Fetch>::Item, NoSuchEntity> {
         // SAFE: unique mutable access to world
-        unsafe { self.query_one_mut_unchecked(entity) }
+        unsafe { self.query_one_unchecked::<Q>(entity) }
     }
 
     /// Prepare a query against a single entity, without checking the safety of mutable queries
     ///
-    /// Call `get` on the resulting `QueryOne` to actually execute the query.
-    ///
     /// Handy for accessing multiple components simultaneously.
     ///
     /// # Safety
     /// This does not check for mutable query correctness. To be safe, make sure mutable queries
     /// have unique access to the components they query.
-    ///
-    /// # Example
-    /// ```
-    /// # use bevy_hecs::*;
-    /// let mut world = World::new();
-    /// let a = world.spawn((123, true, "abc"));
-    /// // The returned query must outlive the borrow made by `get`
-    /// let mut query = world.query_one_mut::<(&mut i32, &bool)>(a).unwrap();
-    /// let (mut number, flag) = query.get().unwrap();
-    /// if *flag { *number *= 2; }
-    /// assert_eq!(*number, 246);
-    /// ```
-    pub unsafe fn query_one_mut_unchecked<Q: Query>(
+    pub unsafe fn query_one_unchecked<Q: Query>(
         &self,
         entity: Entity,
-    ) -> Result<QueryOne<'_, Q>, NoSuchEntity> {
+    ) -> Result<<Q::Fetch as Fetch>::Item, NoSuchEntity> {
         let loc = self.entities.get(entity)?;
-        Ok(QueryOne::new(
-            &self.archetypes[loc.archetype as usize],
-            loc.index,
-        ))
+        <Q::Fetch as Fetch>::get(&self.archetypes[loc.archetype as usize], 0)
+            .filter(|fetch| !fetch.should_skip(loc.index))
+            .map(|fetch| fetch.fetch(loc.index))
+            .ok_or(NoSuchEntity)
     }
 
     /// Borrow the `T` component of `entity`
diff --git a/crates/bevy_ecs/hecs/tests/tests.rs b/crates/bevy_ecs/hecs/tests/tests.rs
index 773f9d4c84ca4..4ebd7d5c6a89e 100644
--- a/crates/bevy_ecs/hecs/tests/tests.rs
+++ b/crates/bevy_ecs/hecs/tests/tests.rs
@@ -34,9 +34,9 @@ fn despawn() {
     let mut world = World::new();
     let e = world.spawn(("abc", 123));
     let f = world.spawn(("def", 456));
-    assert_eq!(world.query::<()>().iter().count(), 2);
+    assert_eq!(world.query::<()>().count(), 2);
     world.despawn(e).unwrap();
-    assert_eq!(world.query::<()>().iter().count(), 1);
+    assert_eq!(world.query::<()>().count(), 1);
     assert!(world.get::<&str>(e).is_err());
     assert!(world.get::<i32>(e).is_err());
     assert_eq!(*world.get::<&str>(f).unwrap(), "def");
@@ -51,14 +51,13 @@ fn query_all() {
 
     let ents = world
         .query::<(Entity, &i32, &&str)>()
-        .iter()
         .map(|(e, &i, &s)| (e, i, s))
         .collect::<Vec<_>>();
     assert_eq!(ents.len(), 2);
     assert!(ents.contains(&(e, 123, "abc")));
     assert!(ents.contains(&(f, 456, "def")));
 
-    let ents = world.query::<Entity>().iter().collect::<Vec<_>>();
+    let ents = world.query::<Entity>().collect::<Vec<_>>();
     assert_eq!(ents.len(), 2);
     assert!(ents.contains(&e));
     assert!(ents.contains(&f));
@@ -71,7 +70,6 @@ fn query_single_component() {
     let f = world.spawn(("def", 456, true));
     let ents = world
         .query::<(Entity, &i32)>()
-        .iter()
         .map(|(e, &i)| (e, i))
         .collect::<Vec<_>>();
     assert_eq!(ents.len(), 2);
@@ -84,7 +82,7 @@ fn query_missing_component() {
     let mut world = World::new();
     world.spawn(("abc", 123));
     world.spawn(("def", 456));
-    assert!(world.query::<(&bool, &i32)>().iter().next().is_none());
+    assert!(world.query::<(&bool, &i32)>().next().is_none());
 }
 
 #[test]
@@ -94,7 +92,6 @@ fn query_sparse_component() {
     let f = world.spawn(("def", 456, true));
     let ents = world
         .query::<(Entity, &bool)>()
-        .iter()
         .map(|(e, &b)| (e, b))
         .collect::<Vec<_>>();
     assert_eq!(ents, &[(f, true)]);
@@ -107,7 +104,6 @@ fn query_optional_component() {
     let f = world.spawn(("def", 456, true));
     let ents = world
         .query::<(Entity, Option<&bool>, &i32)>()
-        .iter()
         .map(|(e, b, &i)| (e, b.copied(), i))
         .collect::<Vec<_>>();
     assert_eq!(ents.len(), 2);
@@ -140,7 +136,6 @@ fn dynamic_components() {
     assert_eq!(
         world
             .query::<(Entity, &i32, &bool)>()
-            .iter()
             .map(|(e, &i, &b)| (e, i, b))
             .collect::<Vec<_>>(),
         &[(e, 42, true)]
@@ -149,7 +144,6 @@ fn dynamic_components() {
     assert_eq!(
         world
             .query::<(Entity, &i32, &bool)>()
-            .iter()
             .map(|(e, &i, &b)| (e, i, b))
             .collect::<Vec<_>>(),
         &[]
@@ -157,7 +151,6 @@ fn dynamic_components() {
     assert_eq!(
         world
             .query::<(Entity, &bool, &&str)>()
-            .iter()
             .map(|(e, &b, &s)| (e, b, s))
             .collect::<Vec<_>>(),
         &[(e, true, "abc")]
@@ -222,17 +215,6 @@ fn clear() {
     assert_eq!(world.iter().count(), 0);
 }
 
-#[test]
-#[should_panic(expected = "twice on the same borrow")]
-fn alias() {
-    let mut world = World::new();
-    world.spawn(("abc", 123));
-    world.spawn(("def", 456, true));
-    let mut q = world.query_mut::<Entity>();
-    let _a = q.iter().collect::<Vec<_>>();
-    let _b = q.iter().collect::<Vec<_>>();
-}
-
 #[test]
 fn remove_missing() {
     let mut world = World::new();
@@ -246,22 +228,15 @@ fn query_batched() {
     let a = world.spawn(());
     let b = world.spawn(());
     let c = world.spawn((42,));
-    assert_eq!(world.query::<()>().iter_batched(1).count(), 3);
-    assert_eq!(world.query::<()>().iter_batched(2).count(), 2);
-    assert_eq!(
-        world.query::<()>().iter_batched(2).flat_map(|x| x).count(),
-        3
-    );
+    assert_eq!(world.query_batched::<()>(1).count(), 3);
+    assert_eq!(world.query_batched::<()>(2).count(), 2);
+    assert_eq!(world.query_batched::<()>(2).flat_map(|x| x).count(), 3);
     // different archetypes are always in different batches
-    assert_eq!(world.query::<()>().iter_batched(3).count(), 2);
-    assert_eq!(
-        world.query::<()>().iter_batched(3).flat_map(|x| x).count(),
-        3
-    );
-    assert_eq!(world.query::<()>().iter_batched(4).count(), 2);
+    assert_eq!(world.query_batched::<()>(3).count(), 2);
+    assert_eq!(world.query_batched::<()>(3).flat_map(|x| x).count(), 3);
+    assert_eq!(world.query_batched::<()>(4).count(), 2);
     let entities = world
-        .query::<Entity>()
-        .iter_batched(1)
+        .query_batched::<Entity>(1)
         .flat_map(|x| x)
         .map(|e| e)
         .collect::<Vec<_>>();
@@ -276,7 +251,7 @@ fn query_batched() {
 fn spawn_batch() {
     let mut world = World::new();
     world.spawn_batch((0..100).map(|x| (x, "abc")));
-    let entities = world.query::<&i32>().iter().map(|&x| x).collect::<Vec<_>>();
+    let entities = world.query::<&i32>().map(|&x| x).collect::<Vec<_>>();
     assert_eq!(entities.len(), 100);
 }
 
@@ -286,13 +261,10 @@ fn query_one() {
     let a = world.spawn(("abc", 123));
     let b = world.spawn(("def", 456));
     let c = world.spawn(("ghi", 789, true));
-    assert_eq!(world.query_one::<&i32>(a).unwrap().get(), Some(&123));
-    assert_eq!(world.query_one::<&i32>(b).unwrap().get(), Some(&456));
-    assert!(world.query_one::<(&i32, &bool)>(a).unwrap().get().is_none());
-    assert_eq!(
-        world.query_one::<(&i32, &bool)>(c).unwrap().get(),
-        Some((&789, &true))
-    );
+    assert_eq!(world.query_one::<&i32>(a), Ok(&123));
+    assert_eq!(world.query_one::<&i32>(b), Ok(&456));
+    assert!(world.query_one::<(&i32, &bool)>(a).is_err());
+    assert_eq!(world.query_one::<(&i32, &bool)>(c), Ok((&789, &true)));
     world.despawn(a).unwrap();
     assert!(world.query_one::<&i32>(a).is_err());
 }
@@ -371,29 +343,21 @@ fn added_tracking() {
     let mut world = World::new();
     let a = world.spawn((123,));
 
-    assert_eq!(world.query::<&i32>().iter().count(), 1);
-    assert_eq!(world.query::<Added<i32>>().iter().count(), 1);
-    assert_eq!(world.query_mut::<&i32>().iter().count(), 1);
-    assert_eq!(world.query_mut::<Added<i32>>().iter().count(), 1);
-    assert!(world.query_one::<&i32>(a).unwrap().get().is_some());
-    assert!(world.query_one::<Added<i32>>(a).unwrap().get().is_some());
-    assert!(world.query_one_mut::<&i32>(a).unwrap().get().is_some());
-    assert!(world
-        .query_one_mut::<Added<i32>>(a)
-        .unwrap()
-        .get()
-        .is_some());
+    assert_eq!(world.query::<&i32>().count(), 1);
+    assert_eq!(world.query::<Added<i32>>().count(), 1);
+    assert_eq!(world.query_mut::<&i32>().count(), 1);
+    assert_eq!(world.query_mut::<Added<i32>>().count(), 1);
+    assert!(world.query_one::<&i32>(a).is_ok());
+    assert!(world.query_one::<Added<i32>>(a).is_ok());
+    assert!(world.query_one_mut::<&i32>(a).is_ok());
+    assert!(world.query_one_mut::<Added<i32>>(a).is_ok());
 
     world.clear_trackers();
 
-    assert_eq!(world.query::<&i32>().iter().count(), 1);
-    assert_eq!(world.query::<Added<i32>>().iter().count(), 0);
-    assert_eq!(world.query_mut::<&i32>().iter().count(), 1);
-    assert_eq!(world.query_mut::<Added<i32>>().iter().count(), 0);
-    assert!(world.query_one_mut::<&i32>(a).unwrap().get().is_some());
-    assert!(world
-        .query_one_mut::<Added<i32>>(a)
-        .unwrap()
-        .get()
-        .is_none());
+    assert_eq!(world.query::<&i32>().count(), 1);
+    assert_eq!(world.query::<Added<i32>>().count(), 0);
+    assert_eq!(world.query_mut::<&i32>().count(), 1);
+    assert_eq!(world.query_mut::<Added<i32>>().count(), 0);
+    assert!(world.query_one_mut::<&i32>(a).is_ok());
+    assert!(world.query_one_mut::<Added<i32>>(a).is_err());
 }
diff --git a/crates/bevy_ecs/src/lib.rs b/crates/bevy_ecs/src/lib.rs
index af269a27b2ec0..96e284b92174e 100644
--- a/crates/bevy_ecs/src/lib.rs
+++ b/crates/bevy_ecs/src/lib.rs
@@ -16,7 +16,7 @@ pub mod prelude {
             Commands, IntoForEachSystem, IntoQuerySystem, IntoThreadLocalSystem, Query, System,
         },
         world::WorldBuilderSource,
-        Added, Bundle, Changed, Component, Entity, Mut, Mutated, Or, Ref, RefMut, With, Without,
-        World,
+        Added, Bundle, Changed, Component, Entity, Mut, Mutated, Or, QuerySet, Ref, RefMut, With,
+        Without, World,
     };
 }
diff --git a/crates/bevy_ecs/src/resource/resource_query.rs b/crates/bevy_ecs/src/resource/resource_query.rs
index 267f45a8a09e8..ef1105b55de62 100644
--- a/crates/bevy_ecs/src/resource/resource_query.rs
+++ b/crates/bevy_ecs/src/resource/resource_query.rs
@@ -1,15 +1,13 @@
 use super::{FromResources, Resources};
-use crate::{
-    system::{SystemId, TypeAccess},
-    Resource, ResourceIndex,
-};
-use bevy_hecs::smaller_tuples_too;
+use crate::{system::SystemId, Resource, ResourceIndex};
+use bevy_hecs::{smaller_tuples_too, TypeAccess};
 use core::{
-    any::TypeId,
     ops::{Deref, DerefMut},
     ptr::NonNull,
 };
-use std::marker::PhantomData;
+use std::{any::TypeId, marker::PhantomData};
+
+// TODO: align TypeAccess api with Query::Fetch
 
 /// A shared borrow of a Resource
 /// that will only return in a query if the Resource has been changed
@@ -183,7 +181,7 @@ pub trait FetchResource<'a>: Sized {
     /// Type of value to be fetched
     type Item: UnsafeClone;
 
-    fn access() -> TypeAccess;
+    fn access() -> TypeAccess<TypeId>;
     fn borrow(resources: &Resources);
     fn release(resources: &Resources);
 
@@ -219,9 +217,9 @@ impl<'a, T: Resource> FetchResource<'a> for FetchResourceRead<T> {
         resources.release::<T>();
     }
 
-    fn access() -> TypeAccess {
+    fn access() -> TypeAccess<TypeId> {
         let mut access = TypeAccess::default();
-        access.immutable.insert(TypeId::of::<T>());
+        access.add_read(TypeId::of::<T>());
         access
     }
 }
@@ -254,9 +252,9 @@ impl<'a, T: Resource> FetchResource<'a> for FetchResourceChanged<T> {
         resources.release::<T>();
     }
 
-    fn access() -> TypeAccess {
+    fn access() -> TypeAccess<TypeId> {
         let mut access = TypeAccess::default();
-        access.immutable.insert(TypeId::of::<T>());
+        access.add_read(TypeId::of::<T>());
         access
     }
 }
@@ -286,9 +284,9 @@ impl<'a, T: Resource> FetchResource<'a> for FetchResourceWrite<T> {
         resources.release_mut::<T>();
     }
 
-    fn access() -> TypeAccess {
+    fn access() -> TypeAccess<TypeId> {
         let mut access = TypeAccess::default();
-        access.mutable.insert(TypeId::of::<T>());
+        access.add_write(TypeId::of::<T>());
         access
     }
 }
@@ -328,9 +326,9 @@ impl<'a, T: Resource + FromResources> FetchResource<'a> for FetchResourceLocalMu
         resources.release_mut::<T>();
     }
 
-    fn access() -> TypeAccess {
+    fn access() -> TypeAccess<TypeId> {
         let mut access = TypeAccess::default();
-        access.mutable.insert(TypeId::of::<T>());
+        access.add_write(TypeId::of::<T>());
         access
     }
 }
@@ -361,7 +359,7 @@ macro_rules! tuple_impl {
             }
 
             #[allow(unused_mut)]
-            fn access() -> TypeAccess {
+            fn access() -> TypeAccess<TypeId> {
                 let mut access = TypeAccess::default();
                 $(access.union(&$name::access());)*
                 access
@@ -422,7 +420,7 @@ macro_rules! tuple_impl_or {
             }
 
             #[allow(unused_mut)]
-            fn access() -> TypeAccess {
+            fn access() -> TypeAccess<TypeId> {
                 let mut access = TypeAccess::default();
                 $(access.union(&$name::access());)*
                 access
diff --git a/crates/bevy_ecs/src/schedule/parallel_executor.rs b/crates/bevy_ecs/src/schedule/parallel_executor.rs
index cdde687a32433..bbba641a50f99 100644
--- a/crates/bevy_ecs/src/schedule/parallel_executor.rs
+++ b/crates/bevy_ecs/src/schedule/parallel_executor.rs
@@ -1,9 +1,9 @@
 use super::Schedule;
 use crate::{
     resource::Resources,
-    system::{ArchetypeAccess, System, ThreadLocalExecution, TypeAccess},
+    system::{System, ThreadLocalExecution},
 };
-use bevy_hecs::{ArchetypesGeneration, World};
+use bevy_hecs::{ArchetypesGeneration, TypeAccess, World};
 use bevy_tasks::{ComputeTaskPool, CountdownEvent, TaskPool};
 use fixedbitset::FixedBitSet;
 use std::ops::Range;
@@ -11,8 +11,8 @@ use std::ops::Range;
 /// Executes each schedule stage in parallel by analyzing system dependencies.
 /// System execution order is undefined except under the following conditions:
 /// * systems in earlier stages run before systems in later stages
-/// * in a given stage, systems that mutate archetype X cannot run before systems registered before them that read/write archetype X
-/// * in a given stage, systems the read archetype X cannot run before systems registered before them that write archetype X
+/// * in a given stage, systems that mutate [archetype+component] X cannot run before systems registered before them that read/write [archetype+component] X
+/// * in a given stage, systems the read [archetype+component] X cannot run before systems registered before them that write [archetype+component] X
 /// * in a given stage, systems that mutate resource Y cannot run before systems registered before them that read/write resource Y
 /// * in a given stage, systems the read resource Y cannot run before systems registered before them that write resource Y
 
@@ -70,6 +70,28 @@ impl ParallelExecutor {
 
         self.last_schedule_generation = schedule_generation;
     }
+
+    pub fn print_order(&self, schedule: &Schedule) {
+        println!("----------------------------");
+        for (stage_name, executor_stage) in schedule.stage_order.iter().zip(self.stages.iter()) {
+            println!("stage {:?}", stage_name);
+            if let Some(stage_systems) = schedule.stages.get(stage_name) {
+                for (i, system) in stage_systems.iter().enumerate() {
+                    println!("  {}-{}", i, system.name());
+                    println!(
+                        "      dependencies({:?})",
+                        executor_stage.system_dependencies[i]
+                            .ones()
+                            .collect::<Vec<usize>>()
+                    );
+                    println!(
+                        "      dependants({:?})",
+                        executor_stage.system_dependents[i]
+                    );
+                }
+            }
+        }
+    }
 }
 
 #[derive(Debug, Clone)]
@@ -146,9 +168,9 @@ impl ExecutorStage {
             self.last_archetypes_generation != world.archetypes_generation();
 
         if schedule_changed || archetypes_generation_changed {
-            // update each system's archetype access to latest world archetypes
+            // update each system's [archetype+component] access to latest world archetypes
             for system_index in prepare_system_index_range.clone() {
-                systems[system_index].update_archetype_access(world);
+                systems[system_index].update(world);
 
                 // Clear this so that the next block of code that populates it doesn't insert
                 // duplicates
@@ -157,11 +179,11 @@ impl ExecutorStage {
             }
 
             // calculate dependencies between systems and build execution order
-            let mut current_archetype_access = ArchetypeAccess::default();
+            let mut current_archetype_access = TypeAccess::default();
             let mut current_resource_access = TypeAccess::default();
             for system_index in prepare_system_index_range.clone() {
                 let system = &systems[system_index];
-                let archetype_access = system.archetype_access();
+                let archetype_access = system.archetype_component_access();
                 match system.thread_local_execution() {
                     ThreadLocalExecution::NextFlush => {
                         let resource_access = system.resource_access();
@@ -183,7 +205,7 @@ impl ExecutorStage {
 
                                 // if earlier system is incompatible, make the current system dependent
                                 if !earlier_system
-                                    .archetype_access()
+                                    .archetype_component_access()
                                     .is_compatible(archetype_access)
                                     || !earlier_system
                                         .resource_access()
@@ -538,14 +560,14 @@ mod tests {
             commands.spawn((1u32,));
         }
 
-        fn read(query: Query<&u32>, mut entities: Query<Entity>) {
+        fn read(query: Query<&u32>, entities: Query<Entity>) {
             for entity in &mut entities.iter() {
                 // query.get() does a "system permission check" that will fail if the entity is from a
                 // new archetype which hasnt been "prepared yet"
                 query.get::<u32>(entity).unwrap();
             }
 
-            assert_eq!(1, entities.iter().iter().count());
+            assert_eq!(1, entities.iter().count());
         }
 
         schedule.add_system_to_stage("PreArchetypeChange", insert.system());
@@ -569,14 +591,14 @@ mod tests {
             world.spawn((1u32,));
         }
 
-        fn read(query: Query<&u32>, mut entities: Query<Entity>) {
+        fn read(query: Query<&u32>, entities: Query<Entity>) {
             for entity in &mut entities.iter() {
                 // query.get() does a "system permission check" that will fail if the entity is from a
                 // new archetype which hasnt been "prepared yet"
                 query.get::<u32>(entity).unwrap();
             }
 
-            assert_eq!(1, entities.iter().iter().count());
+            assert_eq!(1, entities.iter().count());
         }
 
         schedule.add_system_to_stage("update", insert.thread_local_system());
@@ -625,7 +647,6 @@ mod tests {
 
         fn read_u32(completed_systems: Res<CompletedSystems>, _query: Query<&u32>) {
             let mut completed_systems = completed_systems.completed_systems.lock();
-            assert!(!completed_systems.contains(READ_U32_WRITE_U64_SYSTEM_NAME));
             completed_systems.insert(READ_U32_SYSTEM_NAME);
         }
 
@@ -639,7 +660,6 @@ mod tests {
             _query: Query<(&u32, &mut u64)>,
         ) {
             let mut completed_systems = completed_systems.completed_systems.lock();
-            assert!(completed_systems.contains(READ_U32_SYSTEM_NAME));
             assert!(!completed_systems.contains(READ_U64_SYSTEM_NAME));
             completed_systems.insert(READ_U32_WRITE_U64_SYSTEM_NAME);
         }
@@ -734,7 +754,7 @@ mod tests {
 
             assert_eq!(
                 executor.stages[0].system_dependents,
-                vec![vec![2], vec![], vec![3], vec![]]
+                vec![vec![], vec![], vec![3], vec![]]
             );
             assert_eq!(
                 executor.stages[1].system_dependents,
@@ -746,8 +766,6 @@ mod tests {
             );
 
             let stage_0_len = executor.stages[0].system_dependencies.len();
-            let mut read_u32_write_u64_deps = FixedBitSet::with_capacity(stage_0_len);
-            read_u32_write_u64_deps.insert(0);
             let mut read_u64_deps = FixedBitSet::with_capacity(stage_0_len);
             read_u64_deps.insert(2);
 
@@ -756,7 +774,7 @@ mod tests {
                 vec![
                     FixedBitSet::with_capacity(stage_0_len),
                     FixedBitSet::with_capacity(stage_0_len),
-                    read_u32_write_u64_deps,
+                    FixedBitSet::with_capacity(stage_0_len),
                     read_u64_deps,
                 ]
             );
diff --git a/crates/bevy_ecs/src/schedule/schedule.rs b/crates/bevy_ecs/src/schedule/schedule.rs
index 88a2b21e6476c..050b066040bd5 100644
--- a/crates/bevy_ecs/src/schedule/schedule.rs
+++ b/crates/bevy_ecs/src/schedule/schedule.rs
@@ -150,7 +150,7 @@ impl Schedule {
                 for system in stage_systems.iter_mut() {
                     #[cfg(feature = "profiler")]
                     crate::profiler_start(resources, system.name().clone());
-                    system.update_archetype_access(world);
+                    system.update(world);
                     match system.thread_local_execution() {
                         ThreadLocalExecution::NextFlush => system.run(world, resources),
                         ThreadLocalExecution::Immediate => {
diff --git a/crates/bevy_ecs/src/system/commands.rs b/crates/bevy_ecs/src/system/commands.rs
index f0b2218009ec2..6f6981c771c05 100644
--- a/crates/bevy_ecs/src/system/commands.rs
+++ b/crates/bevy_ecs/src/system/commands.rs
@@ -207,7 +207,7 @@ impl CommandsInternal {
     }
 }
 
-/// A queue of [Command]s to run on the current [World] and [Resources]
+/// A queue of [Command]s to run on the current [World] and [Resources]. Todo: remove arc here
 #[derive(Default, Clone)]
 pub struct Commands {
     pub commands: Arc<Mutex<CommandsInternal>>,
@@ -357,7 +357,6 @@ mod tests {
         command_buffer.apply(&mut world, &mut resources);
         let results = world
             .query::<(&u32, &u64)>()
-            .iter()
             .map(|(a, b)| (*a, *b))
             .collect::<Vec<_>>();
         assert_eq!(results, vec![(1u32, 2u64)]);
@@ -368,7 +367,6 @@ mod tests {
         command_buffer.apply(&mut world, &mut resources);
         let results2 = world
             .query::<(&u32, &u64)>()
-            .iter()
             .map(|(a, b)| (*a, *b))
             .collect::<Vec<_>>();
         assert_eq!(results2, vec![]);
diff --git a/crates/bevy_ecs/src/system/into_system.rs b/crates/bevy_ecs/src/system/into_system.rs
index cfad1b9ca2441..aec14cc0a34a0 100644
--- a/crates/bevy_ecs/src/system/into_system.rs
+++ b/crates/bevy_ecs/src/system/into_system.rs
@@ -1,19 +1,19 @@
 pub use super::Query;
-use super::TypeAccess;
 use crate::{
     resource::{FetchResource, ResourceQuery, Resources, UnsafeClone},
-    system::{ArchetypeAccess, Commands, System, SystemId, ThreadLocalExecution},
+    system::{Commands, System, SystemId, ThreadLocalExecution},
+    QueryAccess, QuerySet, QueryTuple, TypeAccess,
 };
-use bevy_hecs::{Fetch, Query as HecsQuery, World};
-use std::borrow::Cow;
+use bevy_hecs::{ArchetypeComponent, Fetch, Query as HecsQuery, World};
+use std::{any::TypeId, borrow::Cow};
 
 #[derive(Debug)]
-pub(crate) struct SystemFn<State, F, ThreadLocalF, Init, SetArchetypeAccess>
+pub(crate) struct SystemFn<State, F, ThreadLocalF, Init, Update>
 where
-    F: FnMut(&World, &Resources, &ArchetypeAccess, &mut State) + Send + Sync,
+    F: FnMut(&World, &Resources, &mut State) + Send + Sync,
     ThreadLocalF: FnMut(&mut World, &mut Resources, &mut State) + Send + Sync,
     Init: FnMut(&mut World, &mut Resources, &mut State) + Send + Sync,
-    SetArchetypeAccess: FnMut(&World, &mut ArchetypeAccess, &mut State) + Send + Sync,
+    Update: FnMut(&World, &mut TypeAccess<ArchetypeComponent>, &mut State) + Send + Sync,
     State: Send + Sync,
 {
     pub state: State,
@@ -21,35 +21,34 @@ where
     pub thread_local_func: ThreadLocalF,
     pub init_func: Init,
     pub thread_local_execution: ThreadLocalExecution,
-    pub resource_access: TypeAccess,
+    pub resource_access: TypeAccess<TypeId>,
     pub name: Cow<'static, str>,
     pub id: SystemId,
-    pub archetype_access: ArchetypeAccess,
-    pub set_archetype_access: SetArchetypeAccess,
+    pub archetype_component_access: TypeAccess<ArchetypeComponent>,
+    pub update_func: Update,
 }
 
-impl<State, F, ThreadLocalF, Init, SetArchetypeAccess> System
-    for SystemFn<State, F, ThreadLocalF, Init, SetArchetypeAccess>
+impl<State, F, ThreadLocalF, Init, Update> System for SystemFn<State, F, ThreadLocalF, Init, Update>
 where
-    F: FnMut(&World, &Resources, &ArchetypeAccess, &mut State) + Send + Sync,
+    F: FnMut(&World, &Resources, &mut State) + Send + Sync,
     ThreadLocalF: FnMut(&mut World, &mut Resources, &mut State) + Send + Sync,
     Init: FnMut(&mut World, &mut Resources, &mut State) + Send + Sync,
-    SetArchetypeAccess: FnMut(&World, &mut ArchetypeAccess, &mut State) + Send + Sync,
+    Update: FnMut(&World, &mut TypeAccess<ArchetypeComponent>, &mut State) + Send + Sync,
     State: Send + Sync,
 {
     fn name(&self) -> Cow<'static, str> {
         self.name.clone()
     }
 
-    fn update_archetype_access(&mut self, world: &World) {
-        (self.set_archetype_access)(world, &mut self.archetype_access, &mut self.state);
+    fn update(&mut self, world: &World) {
+        (self.update_func)(world, &mut self.archetype_component_access, &mut self.state);
     }
 
-    fn archetype_access(&self) -> &ArchetypeAccess {
-        &self.archetype_access
+    fn archetype_component_access(&self) -> &TypeAccess<ArchetypeComponent> {
+        &self.archetype_component_access
     }
 
-    fn resource_access(&self) -> &TypeAccess {
+    fn resource_access(&self) -> &TypeAccess<TypeId> {
         &self.resource_access
     }
 
@@ -59,7 +58,7 @@ where
 
     #[inline]
     fn run(&mut self, world: &World, resources: &Resources) {
-        (self.func)(world, resources, &self.archetype_access, &mut self.state);
+        (self.func)(world, resources, &mut self.state);
     }
 
     fn run_thread_local(&mut self, world: &mut World, resources: &mut Resources) {
@@ -80,6 +79,11 @@ pub trait IntoForEachSystem<CommandBuffer, R, C> {
     fn system(self) -> Box<dyn System>;
 }
 
+struct ForEachState {
+    commands: Commands,
+    query_access: QueryAccess,
+}
+
 macro_rules! impl_into_foreach_system {
     (($($commands: ident)*), ($($resource: ident),*), ($($component: ident),*)) => {
         impl<Func, $($resource,)* $($component,)*> IntoForEachSystem<($($commands,)*), ($($resource,)*), ($($component,)*)> for Func
@@ -100,34 +104,38 @@ macro_rules! impl_into_foreach_system {
             fn system(mut self) -> Box<dyn System> {
                 let id = SystemId::new();
                 Box::new(SystemFn {
-                    state: Commands::default(),
+                    state: ForEachState {
+                        commands: Commands::default(),
+                        query_access: <($($component,)*) as HecsQuery>::Fetch::access(),
+                    },
                     thread_local_execution: ThreadLocalExecution::NextFlush,
                     name: core::any::type_name::<Self>().into(),
                     id,
-                    func: move |world, resources, _archetype_access, state| {
+                    func: move |world, resources, state| {
                         {
+                            let state_commands = &state.commands;
                             if let Some(($($resource,)*)) = resources.query_system::<($($resource,)*)>(id) {
                                 // SAFE: the scheduler has ensured that there is no archetype clashing here
                                 unsafe {
-                                    for ($($component,)*) in world.query_unchecked::<($($component,)*)>().iter() {
-                                        fn_call!(self, ($($commands, state)*), ($($resource),*), ($($component),*))
+                                    for ($($component,)*) in world.query_unchecked::<($($component,)*)>() {
+                                        fn_call!(self, ($($commands, state_commands)*), ($($resource),*), ($($component),*))
                                     }
                                 }
                             }
                         }
                     },
                     thread_local_func: move |world, resources, state| {
-                        state.apply(world, resources);
+                        state.commands.apply(world, resources);
                     },
                     init_func: move |world, resources, state| {
                         <($($resource,)*)>::initialize(resources, Some(id));
-                        state.set_entity_reserver(world.get_entity_reserver())
+                        state.commands.set_entity_reserver(world.get_entity_reserver())
                     },
                     resource_access: <<($($resource,)*) as ResourceQuery>::Fetch as FetchResource>::access(),
-                    archetype_access: ArchetypeAccess::default(),
-                    set_archetype_access: |world, archetype_access, _state| {
-                        archetype_access.clear();
-                        archetype_access.set_access_for_query::<($($component,)*)>(world);
+                    archetype_component_access: TypeAccess::default(),
+                    update_func: |world, archetype_component_access, state| {
+                        archetype_component_access.clear();
+                        state.query_access.get_world_archetype_access(world, Some(archetype_component_access));
                     },
                 })
             }
@@ -136,26 +144,31 @@ macro_rules! impl_into_foreach_system {
 }
 
 struct QuerySystemState {
-    archetype_accesses: Vec<ArchetypeAccess>,
+    query_accesses: Vec<Vec<QueryAccess>>,
+    query_type_names: Vec<&'static str>,
+    archetype_component_accesses: Vec<TypeAccess<ArchetypeComponent>>,
     commands: Commands,
 }
 
 /// Converts `Self` into a Query System
-pub trait IntoQuerySystem<Commands, R, Q> {
+pub trait IntoQuerySystem<Commands, R, Q, QS> {
     fn system(self) -> Box<dyn System>;
 }
 
 macro_rules! impl_into_query_system {
-    (($($commands: ident)*), ($($resource: ident),*), ($($query: ident),*)) => {
-        impl<Func, $($resource,)* $($query,)*> IntoQuerySystem<($($commands,)*), ($($resource,)*), ($($query,)*)> for Func where
+    (($($commands: ident)*), ($($resource: ident),*), ($($query: ident),*), ($($query_set: ident),*)) => {
+        impl<Func, $($resource,)* $($query,)* $($query_set,)*> IntoQuerySystem<($($commands,)*), ($($resource,)*), ($($query,)*), ($($query_set,)*)> for Func where
             Func:
-                FnMut($($commands,)* $($resource,)* $(Query<$query>,)*) +
+                FnMut($($commands,)* $($resource,)* $(Query<$query>,)* $(QuerySet<$query_set>,)*) +
                 FnMut(
                     $($commands,)*
                     $(<<$resource as ResourceQuery>::Fetch as FetchResource>::Item,)*
-                    $(Query<$query>,)*) +
+                    $(Query<$query>,)*
+                    $(QuerySet<$query_set>,)*
+                ) +
                 Send + Sync +'static,
             $($query: HecsQuery,)*
+            $($query_set: QueryTuple,)*
             $($resource: ResourceQuery,)*
         {
             #[allow(non_snake_case)]
@@ -165,28 +178,46 @@ macro_rules! impl_into_query_system {
             #[allow(unused_mut)]
             fn system(mut self) -> Box<dyn System> {
                 let id = SystemId::new();
-                $(let $query = ArchetypeAccess::default();)*
+                let query_accesses = vec![
+                    $(vec![<$query::Fetch as Fetch>::access()],)*
+                    $($query_set::get_accesses(),)*
+                ];
+                let query_type_names = vec![
+                    $(std::any::type_name::<$query>(),)*
+                    $(std::any::type_name::<$query_set>(),)*
+                ];
+                let archetype_component_accesses = vec![TypeAccess::default(); query_accesses.len()];
                 Box::new(SystemFn {
                     state: QuerySystemState {
-                        archetype_accesses: vec![
-                            $($query,)*
-                        ],
+                        query_accesses,
+                        query_type_names,
+                        archetype_component_accesses,
                         commands: Commands::default(),
                     },
                     thread_local_execution: ThreadLocalExecution::NextFlush,
                     id,
                     name: core::any::type_name::<Self>().into(),
-                    func: move |world, resources, archetype_access, state| {
+                    func: move |world, resources, state| {
                         {
                             if let Some(($($resource,)*)) = resources.query_system::<($($resource,)*)>(id) {
                                 let mut i = 0;
                                 $(
-                                    let $query = Query::<$query>::new(world, &state.archetype_accesses[i]);
+                                    let $query = Query::<$query>::new(
+                                        world,
+                                        &state.archetype_component_accesses[i]
+                                    );
+                                    i += 1;
+                                )*
+                                $(
+                                    let $query_set = QuerySet::<$query_set>::new(
+                                        world,
+                                        &state.archetype_component_accesses[i]
+                                    );
                                     i += 1;
                                 )*
 
                                 let commands = &state.commands;
-                                fn_call!(self, ($($commands, commands)*), ($($resource),*), ($($query),*))
+                                fn_call!(self, ($($commands, commands)*), ($($resource),*), ($($query),*), ($($query_set),*))
                             }
                         }
                     },
@@ -199,18 +230,40 @@ macro_rules! impl_into_query_system {
 
                     },
                     resource_access: <<($($resource,)*) as ResourceQuery>::Fetch as FetchResource>::access(),
-                    archetype_access: ArchetypeAccess::default(),
-                    set_archetype_access: |world, archetype_access, state| {
-                        archetype_access.clear();
-                        let mut i = 0;
-                        let mut access: &mut ArchetypeAccess;
-                        $(
-                            access = &mut state.archetype_accesses[i];
-                            access.clear();
-                            access.set_access_for_query::<$query>(world);
-                            archetype_access.union(access);
-                            i += 1;
-                         )*
+                    archetype_component_access: TypeAccess::default(),
+                    update_func: |world, archetype_component_access, state| {
+                        archetype_component_access.clear();
+                        let mut conflict_index = None;
+                        let mut conflict_name = None;
+                        for (i, (query_accesses, component_access)) in state.query_accesses.iter().zip(state.archetype_component_accesses.iter_mut()).enumerate() {
+                            component_access.clear();
+                            for query_access in query_accesses.iter() {
+                                query_access.get_world_archetype_access(world, Some(component_access));
+                            }
+                            if !component_access.is_compatible(archetype_component_access) {
+                                conflict_index = Some(i);
+                                conflict_name = component_access.get_conflict(archetype_component_access).and_then(|archetype_component|
+                                    query_accesses
+                                        .iter()
+                                        .filter_map(|query_access| query_access.get_type_name(archetype_component.component))
+                                        .next());
+                                break;
+                            }
+                            archetype_component_access.union(component_access);
+                        }
+                        if let Some(conflict_index) = conflict_index {
+                            let mut conflicts_with_index = None;
+                            for prior_index in 0..conflict_index {
+                                if !state.archetype_component_accesses[conflict_index].is_compatible(&state.archetype_component_accesses[prior_index]) {
+                                    conflicts_with_index = Some(prior_index);
+                                }
+                            }
+                            panic!("System {} has conflicting queries. {} conflicts with the component access [{}] in this prior query: {}",
+                                core::any::type_name::<Self>(),
+                                state.query_type_names[conflict_index],
+                                conflict_name.unwrap_or("Unknown"),
+                                conflicts_with_index.map(|index| state.query_type_names[index]).unwrap_or("Unknown"));
+                        }
                     },
                 })
             }
@@ -219,6 +272,9 @@ macro_rules! impl_into_query_system {
 }
 
 macro_rules! fn_call {
+    ($self:ident, ($($commands: ident, $commands_var: ident)*), ($($resource: ident),*), ($($a: ident),*), ($($b: ident),*)) => {
+        unsafe { $self($($commands_var.clone(),)* $($resource.unsafe_clone(),)* $($a,)* $($b,)*) }
+    };
     ($self:ident, ($($commands: ident, $commands_var: ident)*), ($($resource: ident),*), ($($a: ident),*)) => {
         unsafe { $self($($commands_var.clone(),)* $($resource.unsafe_clone(),)* $($a,)*) }
     };
@@ -230,9 +286,18 @@ macro_rules! fn_call {
 macro_rules! impl_into_query_systems {
     (($($resource: ident,)*), ($($query: ident),*)) => {
         #[rustfmt::skip]
-        impl_into_query_system!((), ($($resource),*), ($($query),*));
+        impl_into_query_system!((), ($($resource),*), ($($query),*), ());
+        #[rustfmt::skip]
+        impl_into_query_system!((), ($($resource),*), ($($query),*), (QS1));
+        #[rustfmt::skip]
+        impl_into_query_system!((), ($($resource),*), ($($query),*), (QS1, QS2));
+
+        #[rustfmt::skip]
+        impl_into_query_system!((Commands), ($($resource),*), ($($query),*), ());
         #[rustfmt::skip]
-        impl_into_query_system!((Commands), ($($resource),*), ($($query),*));
+        impl_into_query_system!((Commands), ($($resource),*), ($($query),*), (QS1));
+        #[rustfmt::skip]
+        impl_into_query_system!((Commands), ($($resource),*), ($($query),*), (QS1, QS2));
     }
 }
 
@@ -319,14 +384,14 @@ where
             thread_local_func: move |world, resources, _| {
                 self.run(world, resources);
             },
-            func: |_, _, _, _| {},
+            func: |_, _, _| {},
             init_func: |_, _, _| {},
-            set_archetype_access: |_, _, _| {},
+            update_func: |_, _, _| {},
             thread_local_execution: ThreadLocalExecution::Immediate,
             name: core::any::type_name::<F>().into(),
             id: SystemId::new(),
             resource_access: TypeAccess::default(),
-            archetype_access: ArchetypeAccess::default(),
+            archetype_component_access: TypeAccess::default(),
         })
     }
 }
@@ -351,10 +416,11 @@ mod tests {
     use crate::{
         resource::{ResMut, Resources},
         schedule::Schedule,
-        ChangedRes, Mut,
+        ChangedRes, Mut, QuerySet,
     };
     use bevy_hecs::{Entity, With, World};
 
+    #[derive(Debug, Eq, PartialEq)]
     struct A;
     struct B;
     struct C;
@@ -364,12 +430,12 @@ mod tests {
     fn query_system_gets() {
         fn query_system(
             mut ran: ResMut<bool>,
-            mut entity_query: Query<With<A, Entity>>,
+            entity_query: Query<With<A, Entity>>,
             b_query: Query<&B>,
             a_c_query: Query<(&A, &C)>,
             d_query: Query<&D>,
         ) {
-            let entities = entity_query.iter().iter().collect::<Vec<Entity>>();
+            let entities = entity_query.iter().collect::<Vec<Entity>>();
             assert!(
                 b_query.get::<B>(entities[0]).is_err(),
                 "entity 0 should not have B"
@@ -379,8 +445,9 @@ mod tests {
                 "entity 1 should have B"
             );
             assert!(
-                b_query.get::<A>(entities[1]).is_ok(),
-                "entity 1 should have A, and it should (unintuitively) be accessible from b_query because b_query grabs read access to the (A,B) archetype");
+                b_query.get::<A>(entities[1]).is_err(),
+                "entity 1 should have A, but b_query shouldn't have access to it"
+            );
             assert!(
                 b_query.get::<D>(entities[3]).is_err(),
                 "entity 3 should have D, but it shouldn't be accessible from b_query"
@@ -447,4 +514,83 @@ mod tests {
         schedule.run(&mut world, &mut resources);
         assert_eq!(*(world.get::<i32>(ent).unwrap()), 2);
     }
+
+    #[test]
+    #[should_panic]
+    fn conflicting_query_mut_system() {
+        fn sys(_q1: Query<&mut A>, _q2: Query<&mut A>) {}
+
+        let mut world = World::default();
+        let mut resources = Resources::default();
+        world.spawn((A,));
+
+        let mut schedule = Schedule::default();
+        schedule.add_stage("update");
+        schedule.add_system_to_stage("update", sys.system());
+
+        schedule.run(&mut world, &mut resources);
+    }
+
+    #[test]
+    #[should_panic]
+    fn conflicting_query_immut_system() {
+        fn sys(_q1: Query<&A>, _q2: Query<&mut A>) {}
+
+        let mut world = World::default();
+        let mut resources = Resources::default();
+        world.spawn((A,));
+
+        let mut schedule = Schedule::default();
+        schedule.add_stage("update");
+        schedule.add_system_to_stage("update", sys.system());
+
+        schedule.run(&mut world, &mut resources);
+    }
+
+    #[test]
+    fn query_set_system() {
+        fn sys(_set: QuerySet<(Query<&mut A>, Query<&B>)>) {}
+
+        let mut world = World::default();
+        let mut resources = Resources::default();
+        world.spawn((A,));
+
+        let mut schedule = Schedule::default();
+        schedule.add_stage("update");
+        schedule.add_system_to_stage("update", sys.system());
+
+        schedule.run(&mut world, &mut resources);
+    }
+
+    #[test]
+    #[should_panic]
+    fn conflicting_query_with_query_set_system() {
+        fn sys(_query: Query<&mut A>, _set: QuerySet<(Query<&mut A>, Query<&B>)>) {}
+
+        let mut world = World::default();
+        let mut resources = Resources::default();
+        world.spawn((A,));
+
+        let mut schedule = Schedule::default();
+        schedule.add_stage("update");
+        schedule.add_system_to_stage("update", sys.system());
+
+        schedule.run(&mut world, &mut resources);
+    }
+
+    #[test]
+    #[should_panic]
+    fn conflicting_query_sets_system() {
+        fn sys(_set_1: QuerySet<(Query<&mut A>,)>, _set_2: QuerySet<(Query<&mut A>, Query<&B>)>) {}
+
+        let mut world = World::default();
+        let mut resources = Resources::default();
+        world.spawn((A,));
+
+        let mut schedule = Schedule::default();
+        schedule.add_stage("update");
+        schedule.add_system_to_stage("update", sys.system());
+
+        schedule.run(&mut world, &mut resources);
+    }
 }
diff --git a/crates/bevy_ecs/src/system/query.rs b/crates/bevy_ecs/src/system/query.rs
deleted file mode 100644
index 455b70ddd328a..0000000000000
--- a/crates/bevy_ecs/src/system/query.rs
+++ /dev/null
@@ -1,451 +0,0 @@
-use crate::ArchetypeAccess;
-use bevy_hecs::{
-    Archetype, Component, ComponentError, Entity, Fetch, Query as HecsQuery, Ref, RefMut, With,
-    Without, World,
-};
-use bevy_tasks::ParallelIterator;
-use std::{fmt, marker::PhantomData};
-
-/// Provides scoped access to a World according to a given [HecsQuery]
-#[derive(Debug)]
-pub struct Query<'a, Q: HecsQuery> {
-    pub(crate) world: &'a World,
-    pub(crate) archetype_access: &'a ArchetypeAccess,
-    _marker: PhantomData<Q>,
-}
-
-/// An error that occurs when using a [Query]
-#[derive(Debug)]
-pub enum QueryError {
-    CannotReadArchetype,
-    CannotWriteArchetype,
-    ComponentError(ComponentError),
-    NoSuchEntity,
-}
-
-impl<'a, Q: HecsQuery> Query<'a, Q> {
-    #[inline]
-    pub fn new(world: &'a World, archetype_access: &'a ArchetypeAccess) -> Self {
-        Self {
-            world,
-            archetype_access,
-            _marker: PhantomData::default(),
-        }
-    }
-
-    #[inline]
-    pub fn iter(&mut self) -> QueryBorrowChecked<'_, Q> {
-        QueryBorrowChecked::new(&self.world.archetypes, self.archetype_access)
-    }
-
-    // TODO: find a way to make `iter`, `get`, `get_mut`, and `entity` safe without using tracking pointers with global locks
-
-    /// Gets a reference to the entity's component of the given type. This will fail if the entity does not have
-    /// the given component type or if the given component type does not match this query.
-    pub fn get<T: Component>(&self, entity: Entity) -> Result<Ref<T>, QueryError> {
-        if let Some(location) = self.world.get_entity_location(entity) {
-            if self
-                .archetype_access
-                .accessed
-                .contains(location.archetype as usize)
-            {
-                // SAFE: we have already checked that the entity/component matches our archetype access. and systems are scheduled to run with safe archetype access
-                unsafe {
-                    self.world
-                        .get_ref_at_location_unchecked(location)
-                        .map_err(QueryError::ComponentError)
-                }
-            } else {
-                Err(QueryError::CannotReadArchetype)
-            }
-        } else {
-            Err(QueryError::ComponentError(ComponentError::NoSuchEntity))
-        }
-    }
-
-    pub fn entity(&mut self, entity: Entity) -> Result<QueryOneChecked<'_, Q>, QueryError> {
-        if let Some(location) = self.world.get_entity_location(entity) {
-            if self
-                .archetype_access
-                .accessed
-                .contains(location.archetype as usize)
-            {
-                // SAFE: we have already checked that the entity matches our archetype. and systems are scheduled to run with safe archetype access
-                Ok(unsafe {
-                    QueryOneChecked::new(
-                        &self.world.archetypes[location.archetype as usize],
-                        location.index,
-                    )
-                })
-            } else {
-                Err(QueryError::CannotReadArchetype)
-            }
-        } else {
-            Err(QueryError::NoSuchEntity)
-        }
-    }
-
-    /// Gets a mutable reference to the entity's component of the given type. This will fail if the entity does not have
-    /// the given component type or if the given component type does not match this query.
-    pub fn get_mut<T: Component>(&self, entity: Entity) -> Result<RefMut<'_, T>, QueryError> {
-        let location = match self.world.get_entity_location(entity) {
-            None => return Err(QueryError::ComponentError(ComponentError::NoSuchEntity)),
-            Some(location) => location,
-        };
-
-        if self
-            .archetype_access
-            .mutable
-            .contains(location.archetype as usize)
-        {
-            // SAFE: RefMut does exclusivity checks and we have already validated the entity
-            unsafe {
-                self.world
-                    .get_ref_mut_at_location_unchecked(location)
-                    .map_err(QueryError::ComponentError)
-            }
-        } else {
-            Err(QueryError::CannotWriteArchetype)
-        }
-    }
-
-    pub fn removed<C: Component>(&self) -> &[Entity] {
-        self.world.removed::<C>()
-    }
-
-    /// Sets the entity's component to the given value. This will fail if the entity does not already have
-    /// the given component type or if the given component type does not match this query.
-    pub fn set<T: Component>(&mut self, entity: Entity, component: T) -> Result<(), QueryError> {
-        let mut current = self.get_mut::<T>(entity)?;
-        *current = component;
-        Ok(())
-    }
-}
-
-/// A borrow of a `World` sufficient to execute the query `Q`
-///
-/// Note that borrows are not released until this object is dropped.
-pub struct QueryBorrowChecked<'w, Q: HecsQuery> {
-    archetypes: &'w [Archetype],
-    archetype_access: &'w ArchetypeAccess,
-    borrowed: bool,
-    _marker: PhantomData<Q>,
-}
-
-impl<'w, Q: HecsQuery> fmt::Debug for QueryBorrowChecked<'w, Q> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.debug_struct("QueryBorrowChecked")
-            .field("archetypes", &self.archetypes)
-            .field("archetype_access", self.archetype_access)
-            .field("borrowed", &self.borrowed)
-            .field("_marker", &self._marker)
-            .finish()
-    }
-}
-
-impl<'w, Q: HecsQuery> QueryBorrowChecked<'w, Q> {
-    pub(crate) fn new(archetypes: &'w [Archetype], archetype_access: &'w ArchetypeAccess) -> Self {
-        Self {
-            archetypes,
-            borrowed: false,
-            archetype_access,
-            _marker: PhantomData,
-        }
-    }
-
-    /// Execute the query
-    ///
-    /// Must be called only once per query.
-    #[inline]
-    pub fn iter<'q>(&'q mut self) -> QueryIter<'q, 'w, Q> {
-        self.borrow();
-        QueryIter {
-            borrow: self,
-            archetype_index: 0,
-            iter: ChunkIter::EMPTY,
-        }
-    }
-
-    /// Like `iter`, but returns child iterators of at most `batch_size`
-    /// elements
-    ///
-    /// Useful for distributing work over a threadpool using the
-    /// ParallelIterator interface.
-    ///
-    /// Batch size needs to be chosen based on the task being done in
-    /// parallel. The elements in each batch are computed serially, while
-    /// the batches themselves are computed in parallel.
-    ///
-    /// A too small batch size can cause too much overhead, since scheduling
-    /// each batch could take longer than running the batch. On the other
-    /// hand, a too large batch size risks that one batch is still running
-    /// long after the rest have finished.
-    pub fn par_iter<'q>(&'q mut self, batch_size: usize) -> ParIter<'q, 'w, Q> {
-        self.borrow();
-        ParIter {
-            borrow: self,
-            archetype_index: 0,
-            batch_size,
-            batch: 0,
-        }
-    }
-
-    fn borrow(&mut self) {
-        if self.borrowed {
-            panic!(
-                "called QueryBorrowChecked::iter twice on the same borrow; construct a new query instead"
-            );
-        }
-
-        for index in self.archetype_access.accessed.ones() {
-            Q::Fetch::borrow(&self.archetypes[index]);
-        }
-
-        self.borrowed = true;
-    }
-}
-
-unsafe impl<'w, Q: HecsQuery> Send for QueryBorrowChecked<'w, Q> {}
-unsafe impl<'w, Q: HecsQuery> Sync for QueryBorrowChecked<'w, Q> {}
-
-impl<'w, Q: HecsQuery> Drop for QueryBorrowChecked<'w, Q> {
-    #[inline]
-    fn drop(&mut self) {
-        if self.borrowed {
-            for index in self.archetype_access.accessed.ones() {
-                Q::Fetch::release(&self.archetypes[index]);
-            }
-        }
-    }
-}
-
-impl<'q, 'w, Q: HecsQuery> IntoIterator for &'q mut QueryBorrowChecked<'w, Q> {
-    type IntoIter = QueryIter<'q, 'w, Q>;
-    type Item = <Q::Fetch as Fetch<'q>>::Item;
-
-    #[inline]
-    fn into_iter(self) -> Self::IntoIter {
-        self.iter()
-    }
-}
-
-/// Iterator over the set of entities with the components in `Q`
-pub struct QueryIter<'q, 'w, Q: HecsQuery> {
-    borrow: &'q mut QueryBorrowChecked<'w, Q>,
-    archetype_index: usize,
-    iter: ChunkIter<Q>,
-}
-
-unsafe impl<'q, 'w, Q: HecsQuery> Send for QueryIter<'q, 'w, Q> {}
-unsafe impl<'q, 'w, Q: HecsQuery> Sync for QueryIter<'q, 'w, Q> {}
-
-impl<'q, 'w, Q: HecsQuery> Iterator for QueryIter<'q, 'w, Q> {
-    type Item = <Q::Fetch as Fetch<'q>>::Item;
-
-    #[inline]
-    fn next(&mut self) -> Option<Self::Item> {
-        loop {
-            match unsafe { self.iter.next() } {
-                None => {
-                    let archetype = self.borrow.archetypes.get(self.archetype_index)?;
-                    self.archetype_index += 1;
-                    unsafe {
-                        self.iter = Q::Fetch::get(archetype, 0).map_or(ChunkIter::EMPTY, |fetch| {
-                            ChunkIter {
-                                fetch,
-                                len: archetype.len(),
-                                position: 0,
-                            }
-                        });
-                    }
-                }
-                Some(components) => return Some(components),
-            }
-        }
-    }
-
-    fn size_hint(&self) -> (usize, Option<usize>) {
-        let n = self.len();
-        (n, Some(n))
-    }
-}
-
-impl<'q, 'w, Q: HecsQuery> ExactSizeIterator for QueryIter<'q, 'w, Q> {
-    fn len(&self) -> usize {
-        self.borrow
-            .archetypes
-            .iter()
-            .filter(|&x| Q::Fetch::access(x).is_some())
-            .map(|x| x.len())
-            .sum()
-    }
-}
-
-struct ChunkIter<Q: HecsQuery> {
-    fetch: Q::Fetch,
-    position: usize,
-    len: usize,
-}
-
-impl<Q: HecsQuery> ChunkIter<Q> {
-    #[allow(clippy::declare_interior_mutable_const)] // no trait bounds on const fns
-    const EMPTY: Self = Self {
-        fetch: Q::Fetch::DANGLING,
-        position: 0,
-        len: 0,
-    };
-
-    unsafe fn next<'a>(&mut self) -> Option<<Q::Fetch as Fetch<'a>>::Item> {
-        loop {
-            if self.position == self.len {
-                return None;
-            }
-
-            if self.fetch.should_skip(self.position as usize) {
-                self.position += 1;
-                continue;
-            }
-
-            let item = Some(self.fetch.fetch(self.position as usize));
-            self.position += 1;
-            return item;
-        }
-    }
-}
-/// Batched version of `QueryIter`
-pub struct ParIter<'q, 'w, Q: HecsQuery> {
-    borrow: &'q mut QueryBorrowChecked<'w, Q>,
-    archetype_index: usize,
-    batch_size: usize,
-    batch: usize,
-}
-
-impl<'q, 'w, Q: HecsQuery> ParallelIterator<Batch<'q, Q>> for ParIter<'q, 'w, Q> {
-    type Item = <Q::Fetch as Fetch<'q>>::Item;
-
-    fn next_batch(&mut self) -> Option<Batch<'q, Q>> {
-        loop {
-            let archetype = self.borrow.archetypes.get(self.archetype_index)?;
-            let offset = self.batch_size * self.batch;
-            if offset >= archetype.len() {
-                self.archetype_index += 1;
-                self.batch = 0;
-                continue;
-            }
-            if let Some(fetch) = unsafe { Q::Fetch::get(archetype, offset as usize) } {
-                self.batch += 1;
-                return Some(Batch {
-                    _marker: PhantomData,
-                    state: ChunkIter {
-                        fetch,
-                        len: self.batch_size.min(archetype.len() - offset),
-                        position: 0,
-                    },
-                });
-            } else {
-                self.archetype_index += 1;
-                debug_assert_eq!(
-                    self.batch, 0,
-                    "query fetch should always reject at the first batch or not at all"
-                );
-                continue;
-            }
-        }
-    }
-}
-
-/// A sequence of entities yielded by `ParIter`
-pub struct Batch<'q, Q: HecsQuery> {
-    _marker: PhantomData<&'q ()>,
-    state: ChunkIter<Q>,
-}
-
-impl<'q, 'w, Q: HecsQuery> Iterator for Batch<'q, Q> {
-    type Item = <Q::Fetch as Fetch<'q>>::Item;
-
-    fn next(&mut self) -> Option<Self::Item> {
-        let components = unsafe { self.state.next()? };
-        Some(components)
-    }
-}
-
-unsafe impl<'q, Q: HecsQuery> Send for Batch<'q, Q> {}
-
-/// A borrow of a `World` sufficient to execute the query `Q` on a single entity
-#[derive(Debug)]
-pub struct QueryOneChecked<'a, Q: HecsQuery> {
-    archetype: &'a Archetype,
-    index: usize,
-    borrowed: bool,
-    _marker: PhantomData<Q>,
-}
-
-impl<'a, Q: HecsQuery> QueryOneChecked<'a, Q> {
-    /// Construct a query accessing the entity in `archetype` at `index`
-    ///
-    /// # Safety
-    ///
-    /// `index` must be in-bounds for `archetype`
-    pub(crate) unsafe fn new(archetype: &'a Archetype, index: usize) -> Self {
-        Self {
-            archetype,
-            index,
-            borrowed: false,
-            _marker: PhantomData,
-        }
-    }
-
-    /// Get the query result, or `None` if the entity does not satisfy the query
-    ///
-    /// Must be called at most once.
-    ///
-    /// Panics if called more than once or if it would construct a borrow that clashes with another
-    /// pre-existing borrow.
-    pub fn get(&mut self) -> Option<<Q::Fetch as Fetch<'_>>::Item> {
-        unsafe {
-            let fetch = Q::Fetch::get(self.archetype, self.index as usize)?;
-            self.borrowed = true;
-            if fetch.should_skip(0) {
-                None
-            } else {
-                Q::Fetch::borrow(self.archetype);
-                Some(fetch.fetch(0))
-            }
-        }
-    }
-
-    /// Transform the query into one that requires a certain component without borrowing it
-    ///
-    /// See `QueryBorrow::with` for details.
-    pub fn with<T: Component>(self) -> QueryOneChecked<'a, With<T, Q>> {
-        self.transform()
-    }
-
-    /// Transform the query into one that skips entities having a certain component
-    ///
-    /// See `QueryBorrow::without` for details.
-    pub fn without<T: Component>(self) -> QueryOneChecked<'a, Without<T, Q>> {
-        self.transform()
-    }
-
-    /// Helper to change the type of the query
-    fn transform<R: HecsQuery>(self) -> QueryOneChecked<'a, R> {
-        QueryOneChecked {
-            archetype: self.archetype,
-            index: self.index,
-            borrowed: self.borrowed,
-            _marker: PhantomData,
-        }
-    }
-}
-
-impl<Q: HecsQuery> Drop for QueryOneChecked<'_, Q> {
-    fn drop(&mut self) {
-        if self.borrowed {
-            Q::Fetch::release(self.archetype);
-        }
-    }
-}
-
-unsafe impl<Q: HecsQuery> Send for QueryOneChecked<'_, Q> {}
-unsafe impl<Q: HecsQuery> Sync for QueryOneChecked<'_, Q> {}
diff --git a/crates/bevy_ecs/src/system/query/mod.rs b/crates/bevy_ecs/src/system/query/mod.rs
new file mode 100644
index 0000000000000..efe15ed041817
--- /dev/null
+++ b/crates/bevy_ecs/src/system/query/mod.rs
@@ -0,0 +1,203 @@
+mod query_set;
+
+pub use query_set::*;
+
+use bevy_hecs::{
+    ArchetypeComponent, Batch, BatchedIter, Component, ComponentError, Entity, Fetch, Mut,
+    Query as HecsQuery, QueryIter, ReadOnlyFetch, TypeAccess, World,
+};
+use bevy_tasks::ParallelIterator;
+use std::marker::PhantomData;
+
+/// Provides scoped access to a World according to a given [HecsQuery]
+#[derive(Debug)]
+pub struct Query<'a, Q: HecsQuery> {
+    pub(crate) world: &'a World,
+    pub(crate) component_access: &'a TypeAccess<ArchetypeComponent>,
+    _marker: PhantomData<Q>,
+}
+
+/// An error that occurs when using a [Query]
+#[derive(Debug)]
+pub enum QueryError {
+    CannotReadArchetype,
+    CannotWriteArchetype,
+    ComponentError(ComponentError),
+    NoSuchEntity,
+}
+
+impl<'a, Q: HecsQuery> Query<'a, Q> {
+    #[inline]
+    pub fn new(world: &'a World, component_access: &'a TypeAccess<ArchetypeComponent>) -> Self {
+        Self {
+            world,
+            component_access,
+            _marker: PhantomData::default(),
+        }
+    }
+
+    /// Iterates over the query results. This can only be called for read-only queries
+    pub fn iter(&self) -> QueryIter<'_, Q>
+    where
+        Q::Fetch: ReadOnlyFetch,
+    {
+        // SAFE: system runs without conflicts with other systems. same-system queries have runtime borrow checks when they conflict
+        unsafe { self.world.query_unchecked() }
+    }
+
+    /// Iterates over the query results
+    pub fn iter_mut(&mut self) -> QueryIter<'_, Q> {
+        // SAFE: system runs without conflicts with other systems. same-system queries have runtime borrow checks when they conflict
+        unsafe { self.world.query_unchecked() }
+    }
+
+    /// Iterates over the query results
+    /// # Safety
+    /// This allows aliased mutability. You must make sure this call does not result in multiple mutable references to the same component
+    pub unsafe fn iter_unsafe(&self) -> QueryIter<'_, Q> {
+        // SAFE: system runs without conflicts with other systems. same-system queries have runtime borrow checks when they conflict
+        self.world.query_unchecked()
+    }
+
+    #[inline]
+    pub fn par_iter(&self, batch_size: usize) -> ParIter<'_, Q>
+    where
+        Q::Fetch: ReadOnlyFetch,
+    {
+        // SAFE: system runs without conflicts with other systems. same-system queries have runtime borrow checks when they conflict
+        unsafe { ParIter::new(self.world.query_batched_unchecked(batch_size)) }
+    }
+
+    #[inline]
+    pub fn par_iter_mut(&mut self, batch_size: usize) -> ParIter<'_, Q> {
+        // SAFE: system runs without conflicts with other systems. same-system queries have runtime borrow checks when they conflict
+        unsafe { ParIter::new(self.world.query_batched_unchecked(batch_size)) }
+    }
+
+    /// Gets the query result for the given `entity`
+    pub fn entity(&self, entity: Entity) -> Result<<Q::Fetch as Fetch>::Item, QueryError>
+    where
+        Q::Fetch: ReadOnlyFetch,
+    {
+        // SAFE: system runs without conflicts with other systems. same-system queries have runtime borrow checks when they conflict
+        unsafe {
+            self.world
+                .query_one_unchecked::<Q>(entity)
+                .map_err(|_err| QueryError::NoSuchEntity)
+        }
+    }
+
+    /// Gets the query result for the given `entity`
+    pub fn entity_mut(&mut self, entity: Entity) -> Result<<Q::Fetch as Fetch>::Item, QueryError> {
+        // SAFE: system runs without conflicts with other systems. same-system queries have runtime borrow checks when they conflict
+        unsafe {
+            self.world
+                .query_one_unchecked::<Q>(entity)
+                .map_err(|_err| QueryError::NoSuchEntity)
+        }
+    }
+
+    /// Gets the query result for the given `entity`
+    /// # Safety
+    /// This allows aliased mutability. You must make sure this call does not result in multiple mutable references to the same component
+    pub unsafe fn entity_unsafe(
+        &self,
+        entity: Entity,
+    ) -> Result<<Q::Fetch as Fetch>::Item, QueryError> {
+        self.world
+            .query_one_unchecked::<Q>(entity)
+            .map_err(|_err| QueryError::NoSuchEntity)
+    }
+
+    /// Gets a reference to the entity's component of the given type. This will fail if the entity does not have
+    /// the given component type or if the given component type does not match this query.
+    pub fn get<T: Component>(&self, entity: Entity) -> Result<&T, QueryError> {
+        if let Some(location) = self.world.get_entity_location(entity) {
+            if self
+                .component_access
+                .is_read_or_write(&ArchetypeComponent::new::<T>(location.archetype))
+            {
+                // SAFE: we have already checked that the entity/component matches our archetype access. and systems are scheduled to run with safe archetype access
+                unsafe {
+                    self.world
+                        .get_at_location_unchecked(location)
+                        .map_err(QueryError::ComponentError)
+                }
+            } else {
+                Err(QueryError::CannotReadArchetype)
+            }
+        } else {
+            Err(QueryError::ComponentError(ComponentError::NoSuchEntity))
+        }
+    }
+
+    /// Gets a mutable reference to the entity's component of the given type. This will fail if the entity does not have
+    /// the given component type or if the given component type does not match this query.
+    pub fn get_mut<T: Component>(&mut self, entity: Entity) -> Result<Mut<'_, T>, QueryError> {
+        let location = match self.world.get_entity_location(entity) {
+            None => return Err(QueryError::ComponentError(ComponentError::NoSuchEntity)),
+            Some(location) => location,
+        };
+
+        if self
+            .component_access
+            .is_write(&ArchetypeComponent::new::<T>(location.archetype))
+        {
+            // SAFE: RefMut does exclusivity checks and we have already validated the entity
+            unsafe {
+                self.world
+                    .get_mut_at_location_unchecked(location)
+                    .map_err(QueryError::ComponentError)
+            }
+        } else {
+            Err(QueryError::CannotWriteArchetype)
+        }
+    }
+
+    /// Gets a mutable reference to the entity's component of the given type. This will fail if the entity does not have
+    /// the given component type
+    /// # Safety
+    /// This allows aliased mutability. You must make sure this call does not result in multiple mutable references to the same component
+    pub unsafe fn get_unsafe<T: Component>(
+        &self,
+        entity: Entity,
+    ) -> Result<Mut<'_, T>, QueryError> {
+        self.world
+            .get_mut_unchecked(entity)
+            .map_err(QueryError::ComponentError)
+    }
+
+    pub fn removed<C: Component>(&self) -> &[Entity] {
+        self.world.removed::<C>()
+    }
+
+    /// Sets the entity's component to the given value. This will fail if the entity does not already have
+    /// the given component type or if the given component type does not match this query.
+    pub fn set<T: Component>(&mut self, entity: Entity, component: T) -> Result<(), QueryError> {
+        let mut current = self.get_mut::<T>(entity)?;
+        *current = component;
+        Ok(())
+    }
+}
+
+/// Parallel version of QueryIter
+pub struct ParIter<'w, Q: HecsQuery> {
+    batched_iter: BatchedIter<'w, Q>,
+}
+
+impl<'w, Q: HecsQuery> ParIter<'w, Q> {
+    pub fn new(batched_iter: BatchedIter<'w, Q>) -> Self {
+        Self { batched_iter }
+    }
+}
+
+unsafe impl<'w, Q: HecsQuery> Send for ParIter<'w, Q> {}
+
+impl<'w, Q: HecsQuery> ParallelIterator<Batch<'w, Q>> for ParIter<'w, Q> {
+    type Item = <Q::Fetch as Fetch<'w>>::Item;
+
+    #[inline]
+    fn next_batch(&mut self) -> Option<Batch<'w, Q>> {
+        self.batched_iter.next()
+    }
+}
diff --git a/crates/bevy_ecs/src/system/query/query_set.rs b/crates/bevy_ecs/src/system/query/query_set.rs
new file mode 100644
index 0000000000000..616ad04055bc4
--- /dev/null
+++ b/crates/bevy_ecs/src/system/query/query_set.rs
@@ -0,0 +1,25 @@
+use crate::Query;
+use bevy_hecs::{
+    impl_query_set, ArchetypeComponent, Fetch, Query as HecsQuery, QueryAccess, TypeAccess, World,
+};
+
+pub struct QuerySet<T: QueryTuple> {
+    value: T,
+}
+
+impl_query_set!();
+
+pub trait QueryTuple {
+    /// # Safety
+    /// this might cast world and component access to the relevant Self lifetimes. verify that this is safe in each impl
+    unsafe fn new(world: &World, component_access: &TypeAccess<ArchetypeComponent>) -> Self;
+    fn get_accesses() -> Vec<QueryAccess>;
+}
+
+impl<T: QueryTuple> QuerySet<T> {
+    pub fn new(world: &World, component_access: &TypeAccess<ArchetypeComponent>) -> Self {
+        QuerySet {
+            value: unsafe { T::new(world, component_access) },
+        }
+    }
+}
diff --git a/crates/bevy_ecs/src/system/system.rs b/crates/bevy_ecs/src/system/system.rs
index 7eecf6c416992..75d4cc370a1d4 100644
--- a/crates/bevy_ecs/src/system/system.rs
+++ b/crates/bevy_ecs/src/system/system.rs
@@ -1,7 +1,5 @@
 use crate::resource::Resources;
-use bevy_hecs::{Access, Query, World};
-use bevy_utils::HashSet;
-use fixedbitset::FixedBitSet;
+use bevy_hecs::{ArchetypeComponent, TypeAccess, World};
 use std::{any::TypeId, borrow::Cow};
 
 /// Determines the strategy used to run the `run_thread_local` function in a [System]
@@ -25,130 +23,11 @@ impl SystemId {
 pub trait System: Send + Sync {
     fn name(&self) -> Cow<'static, str>;
     fn id(&self) -> SystemId;
-    fn update_archetype_access(&mut self, world: &World);
-    fn archetype_access(&self) -> &ArchetypeAccess;
-    fn resource_access(&self) -> &TypeAccess;
+    fn update(&mut self, world: &World);
+    fn archetype_component_access(&self) -> &TypeAccess<ArchetypeComponent>;
+    fn resource_access(&self) -> &TypeAccess<TypeId>;
     fn thread_local_execution(&self) -> ThreadLocalExecution;
     fn run(&mut self, world: &World, resources: &Resources);
     fn run_thread_local(&mut self, world: &mut World, resources: &mut Resources);
     fn initialize(&mut self, _world: &mut World, _resources: &mut Resources) {}
 }
-
-/// Provides information about the archetypes a [System] reads and writes
-#[derive(Debug, Default)]
-pub struct ArchetypeAccess {
-    pub accessed: FixedBitSet, // union of both immutable and mutable
-    pub mutable: FixedBitSet,
-}
-
-// credit to Ratysz from the Yaks codebase
-impl ArchetypeAccess {
-    pub fn is_compatible(&self, other: &ArchetypeAccess) -> bool {
-        self.mutable.is_disjoint(&other.accessed) && self.accessed.is_disjoint(&other.mutable)
-    }
-
-    pub fn union(&mut self, other: &ArchetypeAccess) {
-        self.mutable.union_with(&other.mutable);
-        self.accessed.union_with(&other.accessed);
-    }
-
-    pub fn set_access_for_query<Q>(&mut self, world: &World)
-    where
-        Q: Query,
-    {
-        let iterator = world.archetypes();
-        let bits = iterator.len();
-        self.accessed.grow(bits);
-        self.mutable.grow(bits);
-        iterator
-            .enumerate()
-            .filter_map(|(index, archetype)| archetype.access::<Q>().map(|access| (index, access)))
-            .for_each(|(archetype, access)| match access {
-                Access::Read => self.accessed.set(archetype, true),
-                Access::Write => {
-                    self.accessed.set(archetype, true);
-                    self.mutable.set(archetype, true);
-                }
-                Access::Iterate => (),
-            });
-    }
-
-    pub fn clear(&mut self) {
-        self.accessed.clear();
-        self.mutable.clear();
-    }
-}
-
-/// Provides information about the types a [System] reads and writes
-#[derive(Debug, Default, Eq, PartialEq, Clone)]
-pub struct TypeAccess {
-    pub immutable: HashSet<TypeId>,
-    pub mutable: HashSet<TypeId>,
-}
-
-impl TypeAccess {
-    pub fn is_compatible(&self, other: &TypeAccess) -> bool {
-        self.mutable.is_disjoint(&other.mutable)
-            && self.mutable.is_disjoint(&other.immutable)
-            && self.immutable.is_disjoint(&other.mutable)
-    }
-
-    pub fn union(&mut self, other: &TypeAccess) {
-        self.mutable.extend(&other.mutable);
-        self.immutable.extend(&other.immutable);
-    }
-
-    pub fn clear(&mut self) {
-        self.immutable.clear();
-        self.mutable.clear();
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use super::{ArchetypeAccess, TypeAccess};
-    use crate::resource::{FetchResource, Res, ResMut, ResourceQuery};
-    use bevy_hecs::World;
-    use std::any::TypeId;
-
-    struct A;
-    struct B;
-    struct C;
-
-    #[test]
-    fn query_archetype_access() {
-        let mut world = World::default();
-        let e1 = world.spawn((A,));
-        let e2 = world.spawn((A, B));
-        let e3 = world.spawn((A, B, C));
-
-        let mut access = ArchetypeAccess::default();
-        access.set_access_for_query::<(&A,)>(&world);
-
-        let e1_archetype = world.get_entity_location(e1).unwrap().archetype as usize;
-        let e2_archetype = world.get_entity_location(e2).unwrap().archetype as usize;
-        let e3_archetype = world.get_entity_location(e3).unwrap().archetype as usize;
-
-        assert!(access.accessed.contains(e1_archetype));
-        assert!(access.accessed.contains(e2_archetype));
-        assert!(access.accessed.contains(e3_archetype));
-
-        let mut access = ArchetypeAccess::default();
-        access.set_access_for_query::<(&A, &B)>(&world);
-
-        assert!(access.accessed.contains(e1_archetype) == false);
-        assert!(access.accessed.contains(e2_archetype));
-        assert!(access.accessed.contains(e3_archetype));
-    }
-
-    #[test]
-    fn resource_query_access() {
-        let access =
-            <<(Res<A>, ResMut<B>, Res<C>) as ResourceQuery>::Fetch as FetchResource>::access();
-        let mut expected_access = TypeAccess::default();
-        expected_access.immutable.insert(TypeId::of::<A>());
-        expected_access.immutable.insert(TypeId::of::<C>());
-        expected_access.mutable.insert(TypeId::of::<B>());
-        assert_eq!(access, expected_access);
-    }
-}
diff --git a/crates/bevy_pbr/src/render_graph/lights_node.rs b/crates/bevy_pbr/src/render_graph/lights_node.rs
index c9381ffcba6c4..ffc573394d5fe 100644
--- a/crates/bevy_pbr/src/render_graph/lights_node.rs
+++ b/crates/bevy_pbr/src/render_graph/lights_node.rs
@@ -80,12 +80,12 @@ pub fn lights_node_system(
     render_resource_context: Res<Box<dyn RenderResourceContext>>,
     // TODO: this write on RenderResourceBindings will prevent this system from running in parallel with other systems that do the same
     mut render_resource_bindings: ResMut<RenderResourceBindings>,
-    mut query: Query<(&Light, &GlobalTransform)>,
+    query: Query<(&Light, &GlobalTransform)>,
 ) {
     let state = &mut state;
     let render_resource_context = &**render_resource_context;
 
-    let light_count = query.iter().iter().count();
+    let light_count = query.iter().count();
     let size = std::mem::size_of::<LightRaw>();
     let light_count_size = std::mem::size_of::<LightCount>();
     let light_array_size = size * light_count;
@@ -133,7 +133,6 @@ pub fn lights_node_system(
 
             // light array
             for ((light, global_transform), slot) in query
-                .iter()
                 .iter()
                 .zip(data[light_count_size..current_light_uniform_size].chunks_exact_mut(size))
             {
diff --git a/crates/bevy_render/src/camera/active_cameras.rs b/crates/bevy_render/src/camera/active_cameras.rs
index 5c41049710484..9384774b15c52 100644
--- a/crates/bevy_render/src/camera/active_cameras.rs
+++ b/crates/bevy_render/src/camera/active_cameras.rs
@@ -23,11 +23,11 @@ impl ActiveCameras {
 
 pub fn active_cameras_system(
     mut active_cameras: ResMut<ActiveCameras>,
-    mut query: Query<(Entity, &Camera)>,
+    query: Query<(Entity, &Camera)>,
 ) {
     for (name, active_camera) in active_cameras.cameras.iter_mut() {
         if active_camera.is_none() {
-            for (camera_entity, camera) in &mut query.iter() {
+            for (camera_entity, camera) in query.iter() {
                 if let Some(ref current_name) = camera.name {
                     if current_name == name {
                         *active_camera = Some(camera_entity);
diff --git a/crates/bevy_render/src/camera/camera.rs b/crates/bevy_render/src/camera/camera.rs
index 9a873a9d31289..c58287a5dec12 100644
--- a/crates/bevy_render/src/camera/camera.rs
+++ b/crates/bevy_render/src/camera/camera.rs
@@ -1,6 +1,6 @@
 use super::CameraProjection;
 use bevy_app::prelude::{EventReader, Events};
-use bevy_ecs::{Added, Component, Entity, Local, Query, Res};
+use bevy_ecs::{Added, Component, Entity, Local, Query, QuerySet, Res};
 use bevy_math::Mat4;
 use bevy_property::Properties;
 use bevy_window::{WindowCreated, WindowId, WindowResized, Windows};
@@ -38,8 +38,10 @@ pub fn camera_system<T: CameraProjection + Component>(
     window_resized_events: Res<Events<WindowResized>>,
     window_created_events: Res<Events<WindowCreated>>,
     windows: Res<Windows>,
-    mut query: Query<(Entity, &mut Camera, &mut T)>,
-    mut query_added: Query<(Entity, Added<Camera>)>,
+    mut queries: QuerySet<(
+        Query<(Entity, &mut Camera, &mut T)>,
+        Query<(Entity, Added<Camera>)>,
+    )>,
 ) {
     let mut changed_window_ids = Vec::new();
     // handle resize events. latest events are handled first because we only want to resize each window once
@@ -69,10 +71,10 @@ pub fn camera_system<T: CameraProjection + Component>(
     }
 
     let mut added_cameras = vec![];
-    for (entity, _camera) in &mut query_added.iter() {
+    for (entity, _camera) in &mut queries.q1().iter() {
         added_cameras.push(entity);
     }
-    for (entity, mut camera, mut camera_projection) in &mut query.iter() {
+    for (entity, mut camera, mut camera_projection) in queries.q0_mut().iter_mut() {
         if let Some(window) = windows.get(camera.window) {
             if changed_window_ids.contains(&window.id()) || added_cameras.contains(&entity) {
                 camera_projection.update(window.width() as usize, window.height() as usize);
diff --git a/crates/bevy_render/src/camera/visible_entities.rs b/crates/bevy_render/src/camera/visible_entities.rs
index e518da2a7b763..5b1abb76c9bfb 100644
--- a/crates/bevy_render/src/camera/visible_entities.rs
+++ b/crates/bevy_render/src/camera/visible_entities.rs
@@ -25,16 +25,16 @@ impl VisibleEntities {
 
 pub fn visible_entities_system(
     mut camera_query: Query<(&Camera, &GlobalTransform, &mut VisibleEntities)>,
-    mut draw_query: Query<(Entity, &Draw)>,
+    draw_query: Query<(Entity, &Draw)>,
     draw_transform_query: Query<(&Draw, &GlobalTransform)>,
 ) {
-    for (camera, camera_global_transform, mut visible_entities) in &mut camera_query.iter() {
+    for (camera, camera_global_transform, mut visible_entities) in camera_query.iter_mut() {
         visible_entities.value.clear();
         let camera_position = camera_global_transform.translation;
 
         let mut no_transform_order = 0.0;
         let mut transparent_entities = Vec::new();
-        for (entity, draw) in &mut draw_query.iter() {
+        for (entity, draw) in draw_query.iter() {
             if !draw.is_visible {
                 continue;
             }
diff --git a/crates/bevy_render/src/draw.rs b/crates/bevy_render/src/draw.rs
index 39ea3cbc587a9..303055b124631 100644
--- a/crates/bevy_render/src/draw.rs
+++ b/crates/bevy_render/src/draw.rs
@@ -215,20 +215,14 @@ impl<'a> FetchResource<'a> for FetchDrawContext {
         }
     }
 
-    fn access() -> TypeAccess {
+    fn access() -> TypeAccess<TypeId> {
         let mut access = TypeAccess::default();
-        access
-            .mutable
-            .insert(TypeId::of::<Assets<PipelineDescriptor>>());
-        access.mutable.insert(TypeId::of::<Assets<Shader>>());
-        access.mutable.insert(TypeId::of::<PipelineCompiler>());
-        access
-            .immutable
-            .insert(TypeId::of::<Box<dyn RenderResourceContext>>());
-        access
-            .immutable
-            .insert(TypeId::of::<VertexBufferDescriptors>());
-        access.immutable.insert(TypeId::of::<SharedBuffers>());
+        access.add_write(TypeId::of::<Assets<PipelineDescriptor>>());
+        access.add_write(TypeId::of::<Assets<Shader>>());
+        access.add_write(TypeId::of::<PipelineCompiler>());
+        access.add_read(TypeId::of::<Box<dyn RenderResourceContext>>());
+        access.add_read(TypeId::of::<VertexBufferDescriptors>());
+        access.add_read(TypeId::of::<SharedBuffers>());
         access
     }
 }
@@ -388,7 +382,7 @@ pub trait Drawable {
 }
 
 pub fn clear_draw_system(mut query: Query<&mut Draw>) {
-    for mut draw in &mut query.iter() {
+    for mut draw in query.iter_mut() {
         draw.clear_render_commands();
     }
 }
diff --git a/crates/bevy_render/src/mesh/mesh.rs b/crates/bevy_render/src/mesh/mesh.rs
index 592869959cf5f..3500f0e04b436 100644
--- a/crates/bevy_render/src/mesh/mesh.rs
+++ b/crates/bevy_render/src/mesh/mesh.rs
@@ -575,7 +575,7 @@ pub fn mesh_resource_provider_system(
     }
 
     // TODO: remove this once batches are pipeline specific and deprecate assigned_meshes draw target
-    for (handle, mut render_pipelines) in &mut query.iter() {
+    for (handle, mut render_pipelines) in query.iter_mut() {
         if let Some(mesh) = meshes.get(handle) {
             for render_pipeline in render_pipelines.pipelines.iter_mut() {
                 render_pipeline.specialization.primitive_topology = mesh.primitive_topology;
diff --git a/crates/bevy_render/src/pipeline/render_pipelines.rs b/crates/bevy_render/src/pipeline/render_pipelines.rs
index 0d66933bb34a0..c7317473fdd60 100644
--- a/crates/bevy_render/src/pipeline/render_pipelines.rs
+++ b/crates/bevy_render/src/pipeline/render_pipelines.rs
@@ -79,7 +79,7 @@ pub fn draw_render_pipelines_system(
     meshes: Res<Assets<Mesh>>,
     mut query: Query<(&mut Draw, &mut RenderPipelines, &Handle<Mesh>)>,
 ) {
-    for (mut draw, mut render_pipelines, mesh_handle) in &mut query.iter() {
+    for (mut draw, mut render_pipelines, mesh_handle) in query.iter_mut() {
         if !draw.is_visible {
             continue;
         }
diff --git a/crates/bevy_render/src/render_graph/nodes/pass_node.rs b/crates/bevy_render/src/render_graph/nodes/pass_node.rs
index a693a212aed3f..4492b305643e3 100644
--- a/crates/bevy_render/src/render_graph/nodes/pass_node.rs
+++ b/crates/bevy_render/src/render_graph/nodes/pass_node.rs
@@ -224,11 +224,9 @@ where
                     // attempt to draw each visible entity
                     let mut draw_state = DrawState::default();
                     for visible_entity in visible_entities.iter() {
-                        if let Ok(query_one) = world.query_one::<Q>(visible_entity.entity) {
-                            if query_one.get().is_none() {
-                                // visible entity does not match the Pass query
-                                continue;
-                            }
+                        if world.query_one::<Q>(visible_entity.entity).is_err() {
+                            // visible entity does not match the Pass query
+                            continue;
                         }
 
                         let draw = if let Ok(draw) = world.get::<Draw>(visible_entity.entity) {
diff --git a/crates/bevy_render/src/render_graph/nodes/render_resources_node.rs b/crates/bevy_render/src/render_graph/nodes/render_resources_node.rs
index dbf4cabe10310..9fe24487484db 100644
--- a/crates/bevy_render/src/render_graph/nodes/render_resources_node.rs
+++ b/crates/bevy_render/src/render_graph/nodes/render_resources_node.rs
@@ -433,7 +433,7 @@ fn render_resources_node_system<T: RenderResources>(
     let render_resource_context = &**render_resource_context;
     uniform_buffer_arrays.begin_update();
     // initialize uniform buffer arrays using the first RenderResources
-    if let Some((_, first, _, _)) = query.iter().iter().next() {
+    if let Some((_, first, _, _)) = query.iter_mut().next() {
         uniform_buffer_arrays.initialize(first);
     }
 
@@ -441,7 +441,7 @@ fn render_resources_node_system<T: RenderResources>(
         uniform_buffer_arrays.remove_bindings(*entity);
     }
 
-    for (entity, uniforms, draw, mut render_pipelines) in &mut query.iter() {
+    for (entity, uniforms, draw, mut render_pipelines) in query.iter_mut() {
         if !draw.is_visible {
             continue;
         }
@@ -463,7 +463,7 @@ fn render_resources_node_system<T: RenderResources>(
             staging_buffer,
             0..state.uniform_buffer_arrays.staging_buffer_size as u64,
             &mut |mut staging_buffer, _render_resource_context| {
-                for (entity, uniforms, draw, mut render_pipelines) in &mut query.iter() {
+                for (entity, uniforms, draw, mut render_pipelines) in query.iter_mut() {
                     if !draw.is_visible {
                         continue;
                     }
@@ -487,7 +487,7 @@ fn render_resources_node_system<T: RenderResources>(
     } else {
         // TODO: can we just remove this?
         let mut staging_buffer: [u8; 0] = [];
-        for (entity, uniforms, draw, mut render_pipelines) in &mut query.iter() {
+        for (entity, uniforms, draw, mut render_pipelines) in query.iter_mut() {
             if !draw.is_visible {
                 continue;
             }
@@ -640,7 +640,7 @@ fn asset_render_resources_node_system<T: RenderResources + Asset>(
         }
     }
 
-    for (asset_handle, draw, mut render_pipelines) in &mut query.iter() {
+    for (asset_handle, draw, mut render_pipelines) in query.iter_mut() {
         if !draw.is_visible {
             continue;
         }
diff --git a/crates/bevy_render/src/shader/shader_defs.rs b/crates/bevy_render/src/shader/shader_defs.rs
index 8224417736132..b8ff477745acd 100644
--- a/crates/bevy_render/src/shader/shader_defs.rs
+++ b/crates/bevy_render/src/shader/shader_defs.rs
@@ -64,7 +64,7 @@ pub fn shader_defs_system<T>(mut query: Query<(&T, &mut RenderPipelines)>)
 where
     T: ShaderDefs + Send + Sync + 'static,
 {
-    for (shader_defs, mut render_pipelines) in &mut query.iter() {
+    for (shader_defs, mut render_pipelines) in query.iter_mut() {
         for shader_def in shader_defs.iter_shader_defs() {
             for render_pipeline in render_pipelines.pipelines.iter_mut() {
                 render_pipeline
@@ -79,7 +79,7 @@ where
 
 /// Clears each [RenderPipelines]' shader defs collection
 pub fn clear_shader_defs_system(mut query: Query<&mut RenderPipelines>) {
-    for mut render_pipelines in &mut query.iter() {
+    for mut render_pipelines in query.iter_mut() {
         for render_pipeline in render_pipelines.pipelines.iter_mut() {
             render_pipeline
                 .specialization
@@ -97,7 +97,7 @@ pub fn asset_shader_defs_system<T: Asset>(
 ) where
     T: ShaderDefs + Send + Sync + 'static,
 {
-    for (asset_handle, mut render_pipelines) in &mut query.iter() {
+    for (asset_handle, mut render_pipelines) in query.iter_mut() {
         let shader_defs = assets.get(asset_handle).unwrap();
         for shader_def in shader_defs.iter_shader_defs() {
             for render_pipeline in render_pipelines.pipelines.iter_mut() {
diff --git a/crates/bevy_sprite/src/sprite.rs b/crates/bevy_sprite/src/sprite.rs
index 048123b0c1352..9efc960dc6a9d 100644
--- a/crates/bevy_sprite/src/sprite.rs
+++ b/crates/bevy_sprite/src/sprite.rs
@@ -41,7 +41,7 @@ pub fn sprite_system(
     textures: Res<Assets<Texture>>,
     mut query: Query<(&mut Sprite, &Handle<ColorMaterial>)>,
 ) {
-    for (mut sprite, handle) in &mut query.iter() {
+    for (mut sprite, handle) in query.iter_mut() {
         match sprite.resize_mode {
             SpriteResizeMode::Manual => continue,
             SpriteResizeMode::Automatic => {
diff --git a/crates/bevy_transform/src/hierarchy/hierarchy.rs b/crates/bevy_transform/src/hierarchy/hierarchy.rs
index facd85b38f92c..3be2d22f6ab8c 100644
--- a/crates/bevy_transform/src/hierarchy/hierarchy.rs
+++ b/crates/bevy_transform/src/hierarchy/hierarchy.rs
@@ -12,17 +12,10 @@ pub fn run_on_hierarchy<T, S>(
 where
     T: Clone,
 {
-    // TODO: not a huge fan of this pattern. are there ways to do recursive updates in legion without allocations?
-    // TODO: the problem above might be resolvable with world splitting
-    let children = children_query
-        .get::<Children>(entity)
-        .ok()
-        .map(|children| children.0.iter().cloned().collect::<Vec<Entity>>());
-
     let parent_result = run(state, entity, parent_result, previous_result);
     previous_result = None;
-    if let Some(children) = children {
-        for child in children {
+    if let Ok(children) = children_query.entity(entity) {
+        for child in children.iter().cloned() {
             previous_result = run_on_hierarchy(
                 children_query,
                 state,
@@ -51,6 +44,7 @@ fn despawn_with_children_recursive(world: &mut World, entity: Entity) {
             children.retain(|c| *c != entity);
         }
     }
+
     // then despawn the entity and all of its children
     despawn_with_children_recursive_inner(world, entity);
 }
@@ -135,7 +129,6 @@ mod tests {
 
         let results = world
             .query::<(&u32, &u64)>()
-            .iter()
             .map(|(a, b)| (*a, *b))
             .collect::<Vec<_>>();
 
diff --git a/crates/bevy_transform/src/hierarchy/hierarchy_maintenance_system.rs b/crates/bevy_transform/src/hierarchy/hierarchy_maintenance_system.rs
index c3f2f338d7982..7957fa658fbbd 100644
--- a/crates/bevy_transform/src/hierarchy/hierarchy_maintenance_system.rs
+++ b/crates/bevy_transform/src/hierarchy/hierarchy_maintenance_system.rs
@@ -5,18 +5,16 @@ use smallvec::SmallVec;
 
 pub fn parent_update_system(
     mut commands: Commands,
-    mut removed_parent_query: Query<Without<Parent, (Entity, &PreviousParent)>>,
+    removed_parent_query: Query<Without<Parent, (Entity, &PreviousParent)>>,
     // TODO: ideally this only runs when the Parent component has changed
     mut changed_parent_query: Query<(Entity, &Parent, Option<&mut PreviousParent>)>,
-    children_query: Query<&mut Children>,
+    mut children_query: Query<&mut Children>,
 ) {
     // Entities with a missing `Parent` (ie. ones that have a `PreviousParent`), remove
     // them from the `Children` of the `PreviousParent`.
-    for (entity, previous_parent) in &mut removed_parent_query.iter() {
+    for (entity, previous_parent) in removed_parent_query.iter() {
         log::trace!("Parent was removed from {:?}", entity);
-        if let Ok(mut previous_parent_children) =
-            children_query.get_mut::<Children>(previous_parent.0)
-        {
+        if let Ok(mut previous_parent_children) = children_query.entity_mut(previous_parent.0) {
             log::trace!(" > Removing {:?} from it's prev parent's children", entity);
             previous_parent_children.0.retain(|e| *e != entity);
             commands.remove_one::<PreviousParent>(entity);
@@ -27,7 +25,7 @@ pub fn parent_update_system(
     let mut children_additions = HashMap::<Entity, SmallVec<[Entity; 8]>>::default();
 
     // Entities with a changed Parent (that also have a PreviousParent, even if None)
-    for (entity, parent, possible_previous_parent) in &mut changed_parent_query.iter() {
+    for (entity, parent, possible_previous_parent) in changed_parent_query.iter_mut() {
         log::trace!("Parent changed for {:?}", entity);
         if let Some(mut previous_parent) = possible_previous_parent {
             // New and previous point to the same Entity, carry on, nothing to see here.
diff --git a/crates/bevy_transform/src/transform_propagate_system.rs b/crates/bevy_transform/src/transform_propagate_system.rs
index a76ea3af566e6..625eefa160460 100644
--- a/crates/bevy_transform/src/transform_propagate_system.rs
+++ b/crates/bevy_transform/src/transform_propagate_system.rs
@@ -2,10 +2,15 @@ use crate::components::*;
 use bevy_ecs::prelude::*;
 
 pub fn transform_propagate_system(
-    mut root_query: Query<Without<Parent, (Option<&Children>, &Transform, &mut GlobalTransform)>>,
-    mut transform_query: Query<(&Transform, &mut GlobalTransform, Option<&Children>)>,
+    mut root_query: Query<
+        Without<
+            Parent,
+            With<GlobalTransform, (Option<&Children>, &Transform, &mut GlobalTransform)>,
+        >,
+    >,
+    mut transform_query: Query<With<Parent, (&Transform, &mut GlobalTransform, Option<&Children>)>>,
 ) {
-    for (children, transform, mut global_transform) in &mut root_query.iter() {
+    for (children, transform, mut global_transform) in root_query.iter_mut() {
         *global_transform = GlobalTransform::from(*transform);
 
         if let Some(children) = children {
@@ -18,16 +23,15 @@ pub fn transform_propagate_system(
 
 fn propagate_recursive(
     parent: &GlobalTransform,
-    transform_query: &mut Query<(&Transform, &mut GlobalTransform, Option<&Children>)>,
+    transform_query: &mut Query<
+        With<Parent, (&Transform, &mut GlobalTransform, Option<&Children>)>,
+    >,
     entity: Entity,
 ) {
     log::trace!("Updating Transform for {:?}", entity);
 
     let global_matrix = {
-        if let (Ok(transform), Ok(mut global_transform)) = (
-            transform_query.get::<Transform>(entity),
-            transform_query.get_mut::<GlobalTransform>(entity),
-        ) {
+        if let Ok((transform, mut global_transform, _)) = transform_query.entity_mut(entity) {
             *global_transform = parent.mul_transform(*transform);
             *global_transform
         } else {
diff --git a/crates/bevy_ui/src/flex/mod.rs b/crates/bevy_ui/src/flex/mod.rs
index e885bb9abfda2..de829f22b42b0 100644
--- a/crates/bevy_ui/src/flex/mod.rs
+++ b/crates/bevy_ui/src/flex/mod.rs
@@ -160,10 +160,10 @@ unsafe impl Sync for FlexSurface {}
 pub fn flex_node_system(
     windows: Res<Windows>,
     mut flex_surface: ResMut<FlexSurface>,
-    mut root_node_query: Query<With<Node, Without<Parent, Entity>>>,
-    mut node_query: Query<With<Node, (Entity, Changed<Style>, Option<&CalculatedSize>)>>,
-    mut changed_size_query: Query<With<Node, (Entity, &Style, Changed<CalculatedSize>)>>,
-    mut children_query: Query<With<Node, (Entity, Changed<Children>)>>,
+    root_node_query: Query<With<Node, Without<Parent, Entity>>>,
+    node_query: Query<With<Node, (Entity, Changed<Style>, Option<&CalculatedSize>)>>,
+    changed_size_query: Query<With<Node, (Entity, &Style, Changed<CalculatedSize>)>>,
+    children_query: Query<With<Node, (Entity, Changed<Children>)>>,
     mut node_transform_query: Query<(Entity, &mut Node, &mut Transform, Option<&Parent>)>,
 ) {
     // update window root nodes
@@ -172,7 +172,7 @@ pub fn flex_node_system(
     }
 
     // update changed nodes
-    for (entity, style, calculated_size) in &mut node_query.iter() {
+    for (entity, style, calculated_size) in node_query.iter() {
         // TODO: remove node from old hierarchy if its root has changed
         if let Some(calculated_size) = calculated_size {
             flex_surface.upsert_leaf(entity, &style, *calculated_size);
@@ -181,7 +181,7 @@ pub fn flex_node_system(
         }
     }
 
-    for (entity, style, calculated_size) in &mut changed_size_query.iter() {
+    for (entity, style, calculated_size) in changed_size_query.iter() {
         flex_surface.upsert_leaf(entity, &style, *calculated_size);
     }
 
@@ -189,18 +189,18 @@ pub fn flex_node_system(
 
     // update window children (for now assuming all Nodes live in the primary window)
     if let Some(primary_window) = windows.get_primary() {
-        flex_surface.set_window_children(primary_window.id(), root_node_query.iter().iter());
+        flex_surface.set_window_children(primary_window.id(), root_node_query.iter());
     }
 
     // update children
-    for (entity, children) in &mut children_query.iter() {
+    for (entity, children) in children_query.iter() {
         flex_surface.update_children(entity, &children);
     }
 
     // compute layouts
     flex_surface.compute_window_layouts();
 
-    for (entity, mut node, mut transform, parent) in &mut node_transform_query.iter() {
+    for (entity, mut node, mut transform, parent) in node_transform_query.iter_mut() {
         let layout = flex_surface.get_layout(entity).unwrap();
         node.size = Vec2::new(layout.size.width, layout.size.height);
         let position = &mut transform.translation;
diff --git a/crates/bevy_ui/src/focus.rs b/crates/bevy_ui/src/focus.rs
index 1f23cdd104a4e..88e6af5c0ec2f 100644
--- a/crates/bevy_ui/src/focus.rs
+++ b/crates/bevy_ui/src/focus.rs
@@ -56,8 +56,7 @@ pub fn ui_focus_system(
     }
 
     if mouse_button_input.just_released(MouseButton::Left) {
-        for (_entity, _node, _global_transform, interaction, _focus_policy) in
-            &mut node_query.iter()
+        for (_entity, _node, _global_transform, interaction, _focus_policy) in node_query.iter_mut()
         {
             if let Some(mut interaction) = interaction {
                 if *interaction == Interaction::Clicked {
@@ -71,9 +70,8 @@ pub fn ui_focus_system(
     let mut hovered_entity = None;
 
     {
-        let mut query_iter = node_query.iter();
-        let mut moused_over_z_sorted_nodes = query_iter
-            .iter()
+        let mut moused_over_z_sorted_nodes = node_query
+            .iter_mut()
             .filter_map(
                 |(entity, node, global_transform, interaction, focus_policy)| {
                     let position = global_transform.translation;
diff --git a/crates/bevy_ui/src/update.rs b/crates/bevy_ui/src/update.rs
index bafa9fa9c01e1..fdb25f34c0404 100644
--- a/crates/bevy_ui/src/update.rs
+++ b/crates/bevy_ui/src/update.rs
@@ -8,18 +8,13 @@ use bevy_transform::{
 pub const UI_Z_STEP: f32 = 0.001;
 
 pub fn ui_z_system(
-    mut root_node_query: Query<With<Node, Without<Parent, Entity>>>,
+    root_node_query: Query<With<Node, Without<Parent, Entity>>>,
     mut node_query: Query<(Entity, &Node, &mut Transform)>,
     children_query: Query<&Children>,
 ) {
     let mut current_global_z = 0.0;
 
-    // PERF: we can probably avoid an allocation here by making root_node_query and node_query non-overlapping
-    let root_nodes = (&mut root_node_query.iter())
-        .iter()
-        .collect::<Vec<Entity>>();
-
-    for entity in root_nodes {
+    for entity in root_node_query.iter() {
         if let Some(result) = hierarchy::run_on_hierarchy(
             &children_query,
             &mut node_query,
@@ -46,8 +41,9 @@ fn update_node_entity(
     };
     let global_z = z + parent_global_z;
 
-    let mut transform = node_query.get_mut::<Transform>(entity).ok()?;
-    transform.translation.set_z(z);
+    if let Ok(mut transform) = node_query.get_mut::<Transform>(entity) {
+        transform.translation.set_z(z);
+    }
 
     Some(global_z)
 }
diff --git a/crates/bevy_ui/src/widget/image.rs b/crates/bevy_ui/src/widget/image.rs
index 2772666e9c10c..242880fc4a856 100644
--- a/crates/bevy_ui/src/widget/image.rs
+++ b/crates/bevy_ui/src/widget/image.rs
@@ -21,7 +21,7 @@ pub fn image_node_system(
     textures: Res<Assets<Texture>>,
     mut query: Query<(&Image, &mut CalculatedSize, &Handle<ColorMaterial>)>,
 ) {
-    for (_image, mut calculated_size, material_handle) in &mut query.iter() {
+    for (_image, mut calculated_size, material_handle) in query.iter_mut() {
         if let Some(texture) = materials
             .get(material_handle)
             .and_then(|material| material.texture.as_ref())
diff --git a/crates/bevy_ui/src/widget/text.rs b/crates/bevy_ui/src/widget/text.rs
index 0b9c155c8bdef..47db1442279c8 100644
--- a/crates/bevy_ui/src/widget/text.rs
+++ b/crates/bevy_ui/src/widget/text.rs
@@ -1,6 +1,6 @@
 use crate::{CalculatedSize, Node};
 use bevy_asset::{Assets, Handle};
-use bevy_ecs::{Changed, Entity, Local, Query, Res, ResMut};
+use bevy_ecs::{Changed, Entity, Local, Query, QuerySet, Res, ResMut};
 use bevy_math::Size;
 use bevy_render::{
     draw::{Draw, DrawContext, Drawable},
@@ -30,33 +30,33 @@ pub fn text_system(
     fonts: Res<Assets<Font>>,
     mut font_atlas_sets: ResMut<Assets<FontAtlasSet>>,
     mut texture_atlases: ResMut<Assets<TextureAtlas>>,
-    mut query: Query<(Entity, Changed<Text>, &mut CalculatedSize)>,
-    mut text_query: Query<(&Text, &mut CalculatedSize)>,
+    mut queries: QuerySet<(
+        Query<(Entity, Changed<Text>, &mut CalculatedSize)>,
+        Query<(&Text, &mut CalculatedSize)>,
+    )>,
 ) {
     // add queued text to atlases
     let mut new_queued_text = Vec::new();
     for entity in queued_text.entities.drain(..) {
-        if let Ok(mut result) = text_query.entity(entity) {
-            if let Some((text, mut calculated_size)) = result.get() {
-                let font_atlases = font_atlas_sets
-                    .get_or_insert_with(text.font.id, || FontAtlasSet::new(text.font.clone_weak()));
-                // TODO: this call results in one or more TextureAtlases, whose render resources are created in the RENDER_GRAPH_SYSTEMS
-                // stage. That logic runs _before_ the DRAW stage, which means we cant call add_glyphs_to_atlas in the draw stage
-                // without our render resources being a frame behind. Therefore glyph atlasing either needs its own system or the TextureAtlas
-                // resource generation needs to happen AFTER the render graph systems. maybe draw systems should execute within the
-                // render graph so ordering like this can be taken into account? Maybe the RENDER_GRAPH_SYSTEMS stage should be removed entirely
-                // in favor of node.update()? Regardless, in the immediate short term the current approach is fine.
-                if let Some(width) = font_atlases.add_glyphs_to_atlas(
-                    &fonts,
-                    &mut texture_atlases,
-                    &mut textures,
-                    text.style.font_size,
-                    &text.value,
-                ) {
-                    calculated_size.size = Size::new(width, text.style.font_size);
-                } else {
-                    new_queued_text.push(entity);
-                }
+        if let Ok((text, mut calculated_size)) = queries.q1_mut().entity_mut(entity) {
+            let font_atlases = font_atlas_sets
+                .get_or_insert_with(text.font.id, || FontAtlasSet::new(text.font.clone_weak()));
+            // TODO: this call results in one or more TextureAtlases, whose render resources are created in the RENDER_GRAPH_SYSTEMS
+            // stage. That logic runs _before_ the DRAW stage, which means we cant call add_glyphs_to_atlas in the draw stage
+            // without our render resources being a frame behind. Therefore glyph atlasing either needs its own system or the TextureAtlas
+            // resource generation needs to happen AFTER the render graph systems. maybe draw systems should execute within the
+            // render graph so ordering like this can be taken into account? Maybe the RENDER_GRAPH_SYSTEMS stage should be removed entirely
+            // in favor of node.update()? Regardless, in the immediate short term the current approach is fine.
+            if let Some(width) = font_atlases.add_glyphs_to_atlas(
+                &fonts,
+                &mut texture_atlases,
+                &mut textures,
+                text.style.font_size,
+                &text.value,
+            ) {
+                calculated_size.size = Size::new(width, text.style.font_size);
+            } else {
+                new_queued_text.push(entity);
             }
         }
     }
@@ -64,7 +64,7 @@ pub fn text_system(
     queued_text.entities = new_queued_text;
 
     // add changed text to atlases
-    for (entity, text, mut calculated_size) in &mut query.iter() {
+    for (entity, text, mut calculated_size) in queries.q0_mut().iter_mut() {
         let font_atlases = font_atlas_sets
             .get_or_insert_with(text.font.id, || FontAtlasSet::new(text.font.clone_weak()));
         // TODO: this call results in one or more TextureAtlases, whose render resources are created in the RENDER_GRAPH_SYSTEMS
@@ -98,7 +98,7 @@ pub fn draw_text_system(
     mut asset_render_resource_bindings: ResMut<AssetRenderResourceBindings>,
     mut query: Query<(&mut Draw, &Text, &Node, &GlobalTransform)>,
 ) {
-    for (mut draw, text, node, global_transform) in &mut query.iter() {
+    for (mut draw, text, node, global_transform) in query.iter_mut() {
         if let Some(font) = fonts.get(&text.font) {
             let position = global_transform.translation - (node.size / 2.0).extend(0.0);
             let mut drawable_text = DrawableText {
diff --git a/examples/2d/sprite_sheet.rs b/examples/2d/sprite_sheet.rs
index 1d4e38f5512e7..662c2ab174d35 100644
--- a/examples/2d/sprite_sheet.rs
+++ b/examples/2d/sprite_sheet.rs
@@ -12,7 +12,7 @@ fn animate_sprite_system(
     texture_atlases: Res<Assets<TextureAtlas>>,
     mut query: Query<(&mut Timer, &mut TextureAtlasSprite, &Handle<TextureAtlas>)>,
 ) {
-    for (timer, mut sprite, texture_atlas_handle) in &mut query.iter() {
+    for (timer, mut sprite, texture_atlas_handle) in query.iter_mut() {
         if timer.finished {
             let texture_atlas = texture_atlases.get(texture_atlas_handle).unwrap();
             sprite.index = ((sprite.index as usize + 1) % texture_atlas.textures.len()) as u32;
diff --git a/examples/3d/parenting.rs b/examples/3d/parenting.rs
index 1cf5233339a6e..17b7d8c787580 100644
--- a/examples/3d/parenting.rs
+++ b/examples/3d/parenting.rs
@@ -16,7 +16,7 @@ struct Rotator;
 
 /// rotates the parent, which will result in the child also rotating
 fn rotator_system(time: Res<Time>, mut query: Query<(&Rotator, &mut Transform)>) {
-    for (_rotator, mut transform) in &mut query.iter() {
+    for (_rotator, mut transform) in query.iter_mut() {
         transform.rotation *= Quat::from_rotation_x(3.0 * time.delta_seconds);
     }
 }
diff --git a/examples/3d/spawner.rs b/examples/3d/spawner.rs
index d76e7ffde13e1..62b7ce8a7bb1a 100644
--- a/examples/3d/spawner.rs
+++ b/examples/3d/spawner.rs
@@ -23,7 +23,7 @@ fn move_cubes(
     mut materials: ResMut<Assets<StandardMaterial>>,
     mut query: Query<(&mut Transform, &Handle<StandardMaterial>)>,
 ) {
-    for (mut transform, material_handle) in &mut query.iter() {
+    for (mut transform, material_handle) in query.iter_mut() {
         let material = materials.get_mut(material_handle).unwrap();
         transform.translation += Vec3::new(1.0, 0.0, 0.0) * time.delta_seconds;
         material.albedo =
diff --git a/examples/3d/z_sort_debug.rs b/examples/3d/z_sort_debug.rs
index ad98326230d99..001f4b76d0094 100644
--- a/examples/3d/z_sort_debug.rs
+++ b/examples/3d/z_sort_debug.rs
@@ -20,17 +20,17 @@ struct Rotator;
 
 /// rotates the parent, which will result in the child also rotating
 fn rotator_system(time: Res<Time>, mut query: Query<(&Rotator, &mut Transform)>) {
-    for (_rotator, mut transform) in &mut query.iter() {
+    for (_rotator, mut transform) in query.iter_mut() {
         transform.rotation *= Quat::from_rotation_x(3.0 * time.delta_seconds);
     }
 }
 
 fn camera_order_color_system(
     mut materials: ResMut<Assets<StandardMaterial>>,
-    mut camera_query: Query<(&Camera, &VisibleEntities)>,
+    camera_query: Query<(&Camera, &VisibleEntities)>,
     material_query: Query<&Handle<StandardMaterial>>,
 ) {
-    for (_camera, visible_entities) in &mut camera_query.iter() {
+    for (_camera, visible_entities) in camera_query.iter() {
         for visible_entity in visible_entities.iter() {
             if let Ok(material_handle) =
                 material_query.get::<Handle<StandardMaterial>>(visible_entity.entity)
diff --git a/examples/ecs/ecs_guide.rs b/examples/ecs/ecs_guide.rs
index 3a8bf1f1d3b69..eff93b72d0c49 100644
--- a/examples/ecs/ecs_guide.rs
+++ b/examples/ecs/ecs_guide.rs
@@ -85,7 +85,7 @@ fn new_round_system(game_rules: Res<GameRules>, mut game_state: ResMut<GameState
 
 // This system updates the score for each entity with the "Player" and "Score" component.
 fn score_system(mut query: Query<(&Player, &mut Score)>) {
-    for (player, mut score) in &mut query.iter() {
+    for (player, mut score) in query.iter_mut() {
         let scored_a_point = random::<bool>();
         if scored_a_point {
             score.value += 1;
@@ -110,9 +110,9 @@ fn score_system(mut query: Query<(&Player, &mut Score)>) {
 fn score_check_system(
     game_rules: Res<GameRules>,
     mut game_state: ResMut<GameState>,
-    mut query: Query<(&Player, &Score)>,
+    query: Query<(&Player, &Score)>,
 ) {
-    for (player, score) in &mut query.iter() {
+    for (player, score) in query.iter() {
         if score.value == game_rules.winning_score {
             game_state.winning_player = Some(player.name.clone());
         }
@@ -237,8 +237,8 @@ struct State {
 
 // NOTE: this doesn't do anything relevant to our game, it is just here for illustrative purposes
 #[allow(dead_code)]
-fn local_state_system(mut state: Local<State>, mut query: Query<(&Player, &Score)>) {
-    for (player, score) in &mut query.iter() {
+fn local_state_system(mut state: Local<State>, query: Query<(&Player, &Score)>) {
+    for (player, score) in query.iter() {
         println!("processed: {} {}", player.name, score.value);
     }
     println!("this system ran {} times", state.counter);
diff --git a/examples/ecs/hierarchy.rs b/examples/ecs/hierarchy.rs
index 47733dfd0a044..2badb53ab3c8d 100644
--- a/examples/ecs/hierarchy.rs
+++ b/examples/ecs/hierarchy.rs
@@ -91,18 +91,21 @@ fn setup(
 fn rotate(
     mut commands: Commands,
     time: Res<Time>,
-    mut parents_query: Query<(Entity, &mut Transform, &mut Children, &Sprite)>,
-    children_query: Query<(&mut Transform, &Sprite)>,
+    mut parents_query: Query<(Entity, &mut Children, &Sprite)>,
+    mut transform_query: Query<With<Sprite, &mut Transform>>,
 ) {
     let angle = std::f32::consts::PI / 2.0;
-    for (parent, mut transform, mut children, _) in &mut parents_query.iter() {
-        transform.rotate(Quat::from_rotation_z(-angle * time.delta_seconds));
+    for (parent, mut children, _) in parents_query.iter_mut() {
+        if let Ok(mut transform) = transform_query.entity_mut(parent) {
+            transform.rotate(Quat::from_rotation_z(-angle * time.delta_seconds));
+        }
 
         // To iterate through the entities children, just treat the Children component as a Vec
         // Alternatively, you could query entities that have a Parent component
         for child in children.iter() {
-            let mut transform = children_query.get_mut::<Transform>(*child).unwrap();
-            transform.rotate(Quat::from_rotation_z(angle * 2.0 * time.delta_seconds));
+            if let Ok(mut transform) = transform_query.entity_mut(*child) {
+                transform.rotate(Quat::from_rotation_z(angle * 2.0 * time.delta_seconds));
+            }
         }
 
         // To demonstrate removing children, we'll start to remove the children after a couple of seconds
@@ -115,7 +118,6 @@ fn rotate(
         }
 
         if time.seconds_since_startup >= 4.0 {
-            // Alternatively, you can use .despawn_recursive()
             // This will remove the entity from its parent's list of children, as well as despawn
             // any children the entity has.
             commands.despawn_recursive(parent);
diff --git a/examples/ecs/parallel_query.rs b/examples/ecs/parallel_query.rs
index 50a0be44014ee..86a9a16cf0a3b 100644
--- a/examples/ecs/parallel_query.rs
+++ b/examples/ecs/parallel_query.rs
@@ -35,8 +35,7 @@ fn move_system(pool: Res<ComputeTaskPool>, mut sprites: Query<(&mut Transform, &
     // See the ParallelIterator documentation for more information on when
     // to use or not use ParallelIterator over a normal Iterator.
     sprites
-        .iter()
-        .par_iter(32)
+        .par_iter_mut(32)
         .for_each(&pool, |(mut transform, velocity)| {
             transform.translation += velocity.0.extend(0.0);
         });
@@ -56,10 +55,9 @@ fn bounce_system(
     let bottom = height as f32 / -2.0;
     let top = height as f32 / 2.0;
     sprites
-        .iter()
         // Batch size of 32 is chosen to limit the overhead of
         // ParallelIterator, since negating a vector is very inexpensive.
-        .par_iter(32)
+        .par_iter_mut(32)
         // Filter out sprites that don't need to be bounced
         .filter(|(transform, _)| {
             !(left < transform.translation.x()
diff --git a/examples/game/breakout.rs b/examples/game/breakout.rs
index 6bfaf149fc59a..f2dddc760809e 100644
--- a/examples/game/breakout.rs
+++ b/examples/game/breakout.rs
@@ -161,7 +161,7 @@ fn paddle_movement_system(
     keyboard_input: Res<Input<KeyCode>>,
     mut query: Query<(&Paddle, &mut Transform)>,
 ) {
-    for (paddle, mut transform) in &mut query.iter() {
+    for (paddle, mut transform) in query.iter_mut() {
         let mut direction = 0.0;
         if keyboard_input.pressed(KeyCode::Left) {
             direction -= 1.0;
@@ -183,13 +183,13 @@ fn ball_movement_system(time: Res<Time>, mut ball_query: Query<(&Ball, &mut Tran
     // clamp the timestep to stop the ball from escaping when the game starts
     let delta_seconds = f32::min(0.2, time.delta_seconds);
 
-    for (ball, mut transform) in &mut ball_query.iter() {
+    for (ball, mut transform) in ball_query.iter_mut() {
         transform.translation += ball.velocity * delta_seconds;
     }
 }
 
 fn scoreboard_system(scoreboard: Res<Scoreboard>, mut query: Query<&mut Text>) {
-    for mut text in &mut query.iter() {
+    for mut text in query.iter_mut() {
         text.value = format!("Score: {}", scoreboard.score);
     }
 }
@@ -198,14 +198,14 @@ fn ball_collision_system(
     mut commands: Commands,
     mut scoreboard: ResMut<Scoreboard>,
     mut ball_query: Query<(&mut Ball, &Transform, &Sprite)>,
-    mut collider_query: Query<(Entity, &Collider, &Transform, &Sprite)>,
+    collider_query: Query<(Entity, &Collider, &Transform, &Sprite)>,
 ) {
-    for (mut ball, ball_transform, sprite) in &mut ball_query.iter() {
+    for (mut ball, ball_transform, sprite) in ball_query.iter_mut() {
         let ball_size = sprite.size;
         let velocity = &mut ball.velocity;
 
         // check collision with walls
-        for (collider_entity, collider, transform, sprite) in &mut collider_query.iter() {
+        for (collider_entity, collider, transform, sprite) in collider_query.iter() {
             let collision = collide(
                 ball_transform.translation,
                 ball_size,
diff --git a/examples/scene/scene.rs b/examples/scene/scene.rs
index eb2a5c9727742..d7861a21c41a1 100644
--- a/examples/scene/scene.rs
+++ b/examples/scene/scene.rs
@@ -65,8 +65,8 @@ fn load_scene_system(asset_server: Res<AssetServer>, mut scene_spawner: ResMut<S
 
 // This system prints all ComponentA components in our world. Try making a change to a ComponentA in load_scene_example.scn.
 // You should immediately see the changes appear in the console.
-fn print_system(mut query: Query<(Entity, Changed<ComponentA>)>) {
-    for (entity, component_a) in &mut query.iter() {
+fn print_system(query: Query<(Entity, Changed<ComponentA>)>) {
+    for (entity, component_a) in query.iter() {
         println!("  Entity({})", entity.id());
         println!(
             "    ComponentA: {{ x: {} y: {} }}\n",
diff --git a/examples/ui/button.rs b/examples/ui/button.rs
index 5bb2f7d989361..0c7bf6f439310 100644
--- a/examples/ui/button.rs
+++ b/examples/ui/button.rs
@@ -35,9 +35,9 @@ fn button_system(
         &mut Handle<ColorMaterial>,
         &Children,
     )>,
-    text_query: Query<&mut Text>,
+    mut text_query: Query<&mut Text>,
 ) {
-    for (_button, interaction, mut material, children) in &mut interaction_query.iter() {
+    for (_button, interaction, mut material, children) in interaction_query.iter_mut() {
         let mut text = text_query.get_mut::<Text>(children[0]).unwrap();
         match *interaction {
             Interaction::Clicked => {
diff --git a/examples/ui/font_atlas_debug.rs b/examples/ui/font_atlas_debug.rs
index 26375ce2dfff1..5dc2c22db9453 100644
--- a/examples/ui/font_atlas_debug.rs
+++ b/examples/ui/font_atlas_debug.rs
@@ -62,7 +62,7 @@ fn atlas_render_system(
 }
 
 fn text_update_system(mut state: ResMut<State>, time: Res<Time>, mut query: Query<&mut Text>) {
-    for mut text in &mut query.iter() {
+    for mut text in query.iter_mut() {
         state.timer.tick(time.delta_seconds);
         let c = rand::random::<u8>() as char;
         if !text.value.contains(c) && state.timer.finished {
diff --git a/examples/ui/text.rs b/examples/ui/text.rs
index 9df065d5adc10..b8dce8b958b03 100644
--- a/examples/ui/text.rs
+++ b/examples/ui/text.rs
@@ -17,7 +17,7 @@ fn main() {
 struct FpsText;
 
 fn text_update_system(diagnostics: Res<Diagnostics>, mut query: Query<(&mut Text, &FpsText)>) {
-    for (mut text, _tag) in &mut query.iter() {
+    for (mut text, _tag) in query.iter_mut() {
         if let Some(fps) = diagnostics.get(FrameTimeDiagnosticsPlugin::FPS) {
             if let Some(average) = fps.average() {
                 text.value = format!("FPS: {:.2}", average);