use from_reflect for DynamicMap and simplify implementation

Author: soqb

crates/bevy_reflect/src/impls/std.rs

@@ -396,7 +396,12 @@ impl<K: FromReflect + Eq + Hash, V: FromReflect> Map for HashMap<K, V> {
     }
 
     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>)
     }

crates/bevy_reflect/src/map.rs

@@ -253,15 +253,11 @@ impl Map for DynamicMap {
     }
 
     fn remove(&mut self, key: &dyn Reflect) -> Option<Box<dyn Reflect>> {
-        match self.indices.entry(key.reflect_hash().expect(HASH_ERROR)) {
-            Entry::Occupied(entry) => {
-                let index = *entry.get();
-                entry.remove();
-                let (_key, value) = self.values.remove(index);
-                Some(value)
-            }
-            Entry::Vacant(_) => None,
-        }
+        let index = self
+            .indices
+            .remove(&key.reflect_hash().expect(HASH_ERROR))?;
+        let (_key, value) = self.values.remove(index);
+        Some(value)
     }
 
     fn drain(self: Box<Self>) -> Vec<(Box<dyn Reflect>, Box<dyn Reflect>)> {