Refactor manual error impls with derive

Note that thiserror was already a dependency, so this is just cleaning
up the code and making it more concise.

crates/bevy_ecs/src/query/error.rs

@@ -1,41 +1,28 @@
-use std::fmt;
+use thiserror::Error;
 
 use crate::entity::Entity;
 
 /// An error that occurs when retrieving a specific [`Entity`]'s query result from [`Query`](crate::system::Query) or [`QueryState`](crate::query::QueryState).
 // TODO: return the type_name as part of this error
-#[derive(Debug, PartialEq, Eq, Clone, Copy)]
+#[derive(Debug, PartialEq, Eq, Clone, Copy, Error)]
 pub enum QueryEntityError {
     /// The given [`Entity`]'s components do not match the query.
     ///
     /// Either it does not have a requested component, or it has a component which the query filters out.
+    #[error("The components of entity {0:?} components do not match the query")]
     QueryDoesNotMatch(Entity),
     /// The given [`Entity`] does not exist.
+    #[error("The entity {0:?} does not exist")]
     NoSuchEntity(Entity),
     /// The [`Entity`] was requested mutably more than once.
     ///
     /// See [`QueryState::get_many_mut`](crate::query::QueryState::get_many_mut) for an example.
+    #[error("The entity {0:?} was requested mutably more than once")]
     AliasedMutability(Entity),
 }
 
-impl std::error::Error for QueryEntityError {}
-
-impl fmt::Display for QueryEntityError {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        match self {
-            QueryEntityError::QueryDoesNotMatch(_) => {
-                write!(f, "The given entity's components do not match the query.")
-            }
-            QueryEntityError::NoSuchEntity(_) => write!(f, "The requested entity does not exist."),
-            QueryEntityError::AliasedMutability(_) => {
-                write!(f, "The entity was requested mutably more than once.")
-            }
-        }
-    }
-}
-
 /// An error that occurs when retrieving a specific [`Entity`]'s component from a [`Query`](crate::system::Query).
-#[derive(Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq, Eq, Error)]
 pub enum QueryComponentError {
     /// The [`Query`](crate::system::Query) does not have read access to the requested component.
     ///
@@ -66,6 +53,7 @@ pub enum QueryComponentError {
     /// }
     /// # bevy_ecs::system::assert_is_system(get_missing_read_access_error);
     /// ```
+    #[error("This query does not have read access to the requested component")]
     MissingReadAccess,
     /// The [`Query`](crate::system::Query) does not have write access to the requested component.
     ///
@@ -93,59 +81,24 @@ pub enum QueryComponentError {
     /// }
     /// # bevy_ecs::system::assert_is_system(get_missing_write_access_error);
     /// ```
+    #[error("This query does not have write access to the requested component")]
     MissingWriteAccess,
     /// The given [`Entity`] does not have the requested component.
+    #[error("The given entity does not have the requested component")]
     MissingComponent,
     /// The requested [`Entity`] does not exist.
+    #[error("The requested entity does not exist")]
     NoSuchEntity,
 }
 
-impl std::error::Error for QueryComponentError {}
-
-impl std::fmt::Display for QueryComponentError {
-    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
-        match self {
-            QueryComponentError::MissingReadAccess => {
-                write!(
-                    f,
-                    "This query does not have read access to the requested component."
-                )
-            }
-            QueryComponentError::MissingWriteAccess => {
-                write!(
-                    f,
-                    "This query does not have write access to the requested component."
-                )
-            }
-            QueryComponentError::MissingComponent => {
-                write!(f, "The given entity does not have the requested component.")
-            }
-            QueryComponentError::NoSuchEntity => {
-                write!(f, "The requested entity does not exist.")
-            }
-        }
-    }
-}
-
 /// An error that occurs when evaluating a [`Query`](crate::system::Query) or [`QueryState`](crate::query::QueryState) as a single expected result via
 /// [`get_single`](crate::system::Query::get_single) or [`get_single_mut`](crate::system::Query::get_single_mut).
-#[derive(Debug)]
+#[derive(Debug, Error)]
 pub enum QuerySingleError {
     /// No entity fits the query.
+    #[error("No entities fit the query {0}")]
     NoEntities(&'static str),
     /// Multiple entities fit the query.
+    #[error("Multiple entities fit the query {0}")]
     MultipleEntities(&'static str),
 }
-
-impl std::error::Error for QuerySingleError {}
-
-impl std::fmt::Display for QuerySingleError {
-    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
-        match self {
-            QuerySingleError::NoEntities(query) => write!(f, "No entities fit the query {query}"),
-            QuerySingleError::MultipleEntities(query) => {
-                write!(f, "Multiple entities fit the query {query}!")
-            }
-        }
-    }
-}