Added reflect support for std::HashSet, BTreeSet and BTreeMap. (#12124)

# Objective

Added reflect support for `std::HashSet`, `BTreeSet` and `BTreeMap`.

The set support is limited to `reflect_value` since that's the level of
support prior art `bevy_util::HashSet` got.

## Changelog

Dropped `Hash` Requirement on `MapInfo` since it's not needed on
`BTreeMap`s.

crates/bevy_reflect/src/impls/std.rs

@@ -100,6 +100,8 @@ impl_reflect_value!(
     ::core::result::Result < T: Clone + Reflect + TypePath,
     E: Clone + Reflect + TypePath > ()
 );
+impl_reflect_value!(::std::collections::BTreeSet<T: Ord + Eq + Clone + Send + Sync>());
+impl_reflect_value!(::std::collections::HashSet<T: Hash + Eq + Clone + Send + Sync, S: TypePath + Clone + Send + Sync>());
 impl_reflect_value!(::bevy_utils::HashSet<T: Hash + Eq + Clone + Send + Sync>());
 impl_reflect_value!(::core::ops::Range<T: Clone + Send + Sync>());
 impl_reflect_value!(::core::ops::RangeInclusive<T: Clone + Send + Sync>());
@@ -620,6 +622,220 @@ impl_type_path!(::bevy_utils::hashbrown::hash_map::DefaultHashBuilder);
 impl_type_path!(::bevy_utils::NoOpHash);
 impl_type_path!(::bevy_utils::hashbrown::HashMap<K, V, S>);
 
+macro_rules! impl_reflect_for_btree_map {
+    ($ty:path) => {
+        impl<K, V> Map for $ty
+        where
+            K: FromReflect + TypePath + Eq + Ord,
+            V: FromReflect + TypePath,
+        {
+            fn get(&self, key: &dyn Reflect) -> Option<&dyn Reflect> {
+                key.downcast_ref::<K>()
+                    .and_then(|key| Self::get(self, key))
+                    .map(|value| value as &dyn Reflect)
+            }
+
+            fn get_mut(&mut self, key: &dyn Reflect) -> Option<&mut dyn Reflect> {
+                key.downcast_ref::<K>()
+                    .and_then(move |key| Self::get_mut(self, key))
+                    .map(|value| value as &mut dyn Reflect)
+            }
+
+            fn get_at(&self, index: usize) -> Option<(&dyn Reflect, &dyn Reflect)> {
+                self.iter()
+                    .nth(index)
+                    .map(|(key, value)| (key as &dyn Reflect, value as &dyn Reflect))
+            }
+
+            fn get_at_mut(&mut self, index: usize) -> Option<(&dyn Reflect, &mut dyn Reflect)> {
+                self.iter_mut()
+                    .nth(index)
+                    .map(|(key, value)| (key as &dyn Reflect, value as &mut dyn Reflect))
+            }
+
+            fn len(&self) -> usize {
+                Self::len(self)
+            }
+
+            fn iter(&self) -> MapIter {
+                MapIter::new(self)
+            }
+
+            fn drain(self: Box<Self>) -> Vec<(Box<dyn Reflect>, Box<dyn Reflect>)> {
+                self.into_iter()
+                    .map(|(key, value)| {
+                        (
+                            Box::new(key) as Box<dyn Reflect>,
+                            Box::new(value) as Box<dyn Reflect>,
+                        )
+                    })
+                    .collect()
+            }
+
+            fn clone_dynamic(&self) -> DynamicMap {
+                let mut dynamic_map = DynamicMap::default();
+                dynamic_map.set_represented_type(self.get_represented_type_info());
+                for (k, v) in self {
+                    let key = K::from_reflect(k).unwrap_or_else(|| {
+                        panic!(
+                            "Attempted to clone invalid key of type {}.",
+                            k.reflect_type_path()
+                        )
+                    });
+                    dynamic_map.insert_boxed(Box::new(key), v.clone_value());
+                }
+                dynamic_map
+            }
+
+            fn insert_boxed(
+                &mut self,
+                key: Box<dyn Reflect>,
+                value: Box<dyn Reflect>,
+            ) -> Option<Box<dyn Reflect>> {
+                let key = K::take_from_reflect(key).unwrap_or_else(|key| {
+                    panic!(
+                        "Attempted to insert invalid key of type {}.",
+                        key.reflect_type_path()
+                    )
+                });
+                let value = V::take_from_reflect(value).unwrap_or_else(|value| {
+                    panic!(
+                        "Attempted to insert invalid value of type {}.",
+                        value.reflect_type_path()
+                    )
+                });
+                self.insert(key, value)
+                    .map(|old_value| Box::new(old_value) as Box<dyn Reflect>)
+            }
+
+            fn remove(&mut self, key: &dyn Reflect) -> Option<Box<dyn Reflect>> {
+                let mut from_reflect = None;
+                key.downcast_ref::<K>()
+                    .or_else(|| {
+                        from_reflect = K::from_reflect(key);
+                        from_reflect.as_ref()
+                    })
+                    .and_then(|key| self.remove(key))
+                    .map(|value| Box::new(value) as Box<dyn Reflect>)
+            }
+        }
+
+        impl<K, V> Reflect for $ty
+        where
+            K: FromReflect + TypePath + Eq + Ord,
+            V: FromReflect + TypePath,
+        {
+            fn get_represented_type_info(&self) -> Option<&'static TypeInfo> {
+                Some(<Self as Typed>::type_info())
+            }
+
+            fn into_any(self: Box<Self>) -> Box<dyn Any> {
+                self
+            }
+
+            fn as_any(&self) -> &dyn Any {
+                self
+            }
+
+            fn as_any_mut(&mut self) -> &mut dyn Any {
+                self
+            }
+
+            #[inline]
+            fn into_reflect(self: Box<Self>) -> Box<dyn Reflect> {
+                self
+            }
+
+            fn as_reflect(&self) -> &dyn Reflect {
+                self
+            }
+
+            fn as_reflect_mut(&mut self) -> &mut dyn Reflect {
+                self
+            }
+
+            fn apply(&mut self, value: &dyn Reflect) {
+                map_apply(self, value);
+            }
+
+            fn set(&mut self, value: Box<dyn Reflect>) -> Result<(), Box<dyn Reflect>> {
+                *self = value.take()?;
+                Ok(())
+            }
+
+            fn reflect_kind(&self) -> ReflectKind {
+                ReflectKind::Map
+            }
+
+            fn reflect_ref(&self) -> ReflectRef {
+                ReflectRef::Map(self)
+            }
+
+            fn reflect_mut(&mut self) -> ReflectMut {
+                ReflectMut::Map(self)
+            }
+
+            fn reflect_owned(self: Box<Self>) -> ReflectOwned {
+                ReflectOwned::Map(self)
+            }
+
+            fn clone_value(&self) -> Box<dyn Reflect> {
+                Box::new(self.clone_dynamic())
+            }
+
+            fn reflect_partial_eq(&self, value: &dyn Reflect) -> Option<bool> {
+                map_partial_eq(self, value)
+            }
+        }
+
+        impl<K, V> Typed for $ty
+        where
+            K: FromReflect + TypePath + Eq + Ord,
+            V: FromReflect + TypePath,
+        {
+            fn type_info() -> &'static TypeInfo {
+                static CELL: GenericTypeInfoCell = GenericTypeInfoCell::new();
+                CELL.get_or_insert::<Self, _>(|| TypeInfo::Map(MapInfo::new::<Self, K, V>()))
+            }
+        }
+
+        impl<K, V> GetTypeRegistration for $ty
+        where
+            K: FromReflect + TypePath + Eq + Ord,
+            V: FromReflect + TypePath,
+        {
+            fn get_type_registration() -> TypeRegistration {
+                let mut registration = TypeRegistration::of::<Self>();
+                registration.insert::<ReflectFromPtr>(FromType::<Self>::from_type());
+                registration
+            }
+        }
+
+        impl<K, V> FromReflect for $ty
+        where
+            K: FromReflect + TypePath + Eq + Ord,
+            V: FromReflect + TypePath,
+        {
+            fn from_reflect(reflect: &dyn Reflect) -> Option<Self> {
+                if let ReflectRef::Map(ref_map) = reflect.reflect_ref() {
+                    let mut new_map = Self::new();
+                    for (key, value) in ref_map.iter() {
+                        let new_key = K::from_reflect(key)?;
+                        let new_value = V::from_reflect(value)?;
+                        new_map.insert(new_key, new_value);
+                    }
+                    Some(new_map)
+                } else {
+                    None
+                }
+            }
+        }
+    };
+}
+
+impl_reflect_for_btree_map!(::std::collections::BTreeMap<K, V>);
+impl_type_path!(::std::collections::BTreeMap<K, V>);
+
 impl<T: Reflect + TypePath, const N: usize> Array for [T; N] {
     #[inline]
     fn get(&self, index: usize) -> Option<&dyn Reflect> {
@@ -1658,6 +1874,7 @@ mod tests {
     use bevy_utils::HashMap;
     use bevy_utils::{Duration, Instant};
     use static_assertions::assert_impl_all;
+    use std::collections::BTreeMap;
     use std::f32::consts::{PI, TAU};
     use std::path::Path;
 
@@ -1732,6 +1949,21 @@ mod tests {
         assert!(!a.reflect_partial_eq(c).unwrap_or_default());
     }
 
+    #[test]
+    fn should_partial_eq_btree_map() {
+        let mut a = BTreeMap::new();
+        a.insert(0usize, 1.23_f64);
+        let b = a.clone();
+        let mut c = BTreeMap::new();
+        c.insert(0usize, 3.21_f64);
+
+        let a: &dyn Reflect = &a;
+        let b: &dyn Reflect = &b;
+        let c: &dyn Reflect = &c;
+        assert!(a.reflect_partial_eq(b).unwrap_or_default());
+        assert!(!a.reflect_partial_eq(c).unwrap_or_default());
+    }
+
     #[test]
     fn should_partial_eq_option() {
         let a: &dyn Reflect = &Some(123);

crates/bevy_reflect/src/map.rs

@@ -1,6 +1,5 @@
 use std::any::{Any, TypeId};
 use std::fmt::{Debug, Formatter};
-use std::hash::Hash;
 
 use bevy_reflect_derive::impl_type_path;
 use bevy_utils::{Entry, HashMap};
@@ -107,11 +106,8 @@ pub struct MapInfo {
 
 impl MapInfo {
     /// Create a new [`MapInfo`].
-    pub fn new<
-        TMap: Map + TypePath,
-        TKey: Hash + Reflect + TypePath,
-        TValue: Reflect + TypePath,
-    >() -> Self {
+    pub fn new<TMap: Map + TypePath, TKey: Reflect + TypePath, TValue: Reflect + TypePath>() -> Self
+    {
         Self {
             type_path: TypePathTable::of::<TMap>(),
             type_id: TypeId::of::<TMap>(),