Add support for ResMut

bevy_lint/src/lints/borrow_of_reborrowable.rs

@@ -56,14 +56,20 @@ declare_bevy_lint! {
     "parameter takes `&mut Commands` instead of a re-borrowed `Commands`",
 }
 
+declare_bevy_lint! {
+    pub BORROW_OF_RESOURCE,
+    PEDANTIC,
+    "parameter takes `&mut ResMut` instead of a re-borrowed `ResMut`",
+}
+
 declare_bevy_lint! {
     pub BORROW_OF_QUERY,
     PEDANTIC,
     "parameter takes `&mut Query` instead of a re-borrowed `Query`",
 }
 
 declare_lint_pass! {
-    BorrowOfReborrowable => [BORROW_OF_COMMANDS.lint, BORROW_OF_QUERY.lint]
+    BorrowOfReborrowable => [BORROW_OF_COMMANDS.lint, BORROW_OF_RESOURCE.lint, BORROW_OF_QUERY.lint]
 }
 
 impl<'tcx> LateLintPass<'tcx> for BorrowOfReborrowable {
@@ -147,7 +153,7 @@ enum Reborrowable {
     // PtrMut,
     Query,
     // QueryIterationCursor,
-    // ResMut,
+    ResMut,
 }
 
 impl Reborrowable {
@@ -158,6 +164,8 @@ impl Reborrowable {
             Some(Self::EntityCommands)
         } else if match_type(cx, ty, &crate::paths::QUERY) {
             Some(Self::Query)
+        } else if match_type(cx, ty, &crate::paths::RES_MUT) {
+            Some(Self::ResMut)
         } else {
             None
         }
@@ -168,6 +176,7 @@ impl Reborrowable {
             Self::Commands => BORROW_OF_COMMANDS.lint,
             Self::EntityCommands => BORROW_OF_COMMANDS.lint,
             Self::Query => BORROW_OF_QUERY.lint,
+            Self::ResMut => BORROW_OF_RESOURCE.lint,
         }
     }
 
@@ -181,6 +190,7 @@ impl Reborrowable {
             Self::Commands => "Commands",
             Self::EntityCommands => "EntityCommands",
             Self::Query => "Query",
+            Self::ResMut => "ResMut",
         }
     }
 

bevy_lint/src/lints/mod.rs

@@ -14,6 +14,7 @@ pub mod plugin_not_ending_in_plugin;
 
 pub(crate) static LINTS: &[&BevyLint] = &[
     borrow_of_reborrowable::BORROW_OF_COMMANDS,
+    borrow_of_reborrowable::BORROW_OF_RESOURCE,
     borrow_of_reborrowable::BORROW_OF_QUERY,
     insert_event_resource::INSERT_EVENT_RESOURCE,
     main_return_without_appexit::MAIN_RETURN_WITHOUT_APPEXIT,

bevy_lint/src/paths.rs

@@ -17,5 +17,6 @@ pub const PLUGIN: [&str; 3] = ["bevy_app", "plugin", "Plugin"];
 pub const QUERY: [&str; 4] = ["bevy_ecs", "system", "query", "Query"];
 pub const QUERY_STATE: [&str; 4] = ["bevy_ecs", "query", "state", "QueryState"];
 pub const REFLECT: [&str; 3] = ["bevy_reflect", "reflect", "Reflect"];
+pub const RES_MUT: [&str; 3] = ["bevy_ecs", "change_detection", "ResMut"];
 pub const RESOURCE: [&str; 4] = ["bevy_ecs", "system", "system_param", "Resource"];
 pub const WORLD: [&str; 3] = ["bevy_ecs", "world", "World"];

bevy_lint/tests/ui/borrow_of_reborrowable/resource.rs

@@ -0,0 +1,51 @@
+//! This tests the `borrow_of_reborrowable` lint, specifically when triggered on the `ResMut` type.
+
+#![feature(register_tool)]
+#![register_tool(bevy)]
+#![deny(bevy::borrow_of_resource)]
+
+use bevy::prelude::*;
+
+#[derive(Resource)]
+struct Data(String);
+
+// OK: Lint does not apply to immutable references
+fn immutable_reference(_res: &ResMut<Data>) {
+    // ...
+}
+
+//~| HELP: use `ResMut` instead
+//~v ERROR: parameter takes `&mut ResMut` instead of a re-borrowed `ResMut`
+fn mutable_reference(_res: &mut ResMut<Data>) {
+    // ...
+}
+
+//~| HELP: use `ResMut` instead
+//~v ERROR: parameter takes `&mut ResMut` instead of a re-borrowed `ResMut`
+fn mutable_reference_return<'a>(_res: &'a mut ResMut<Data>) -> usize {
+    123
+}
+
+// OK: Lint does not apply when return type relies on reference lifetime
+fn mutable_reference_bounded_return<'a>(res: &'a mut ResMut<Data>) -> &'a mut String {
+    &mut res.0
+}
+
+// OK: Lint does not apply when return type relies on reference lifetime
+fn mutable_reference_bounded_return_complex<'a>(
+    res: &'a mut ResMut<Data>,
+) -> Vec<(usize, &'a mut String)> {
+    vec![(1, &mut res.0)]
+}
+
+fn main() {
+    fn some_system(mut res: ResMut<Data>) {
+        immutable_reference(&res);
+        mutable_reference(&mut res);
+        _ = mutable_reference_return(&mut res);
+        _ = mutable_reference_bounded_return(&mut res);
+        _ = mutable_reference_bounded_return_complex(&mut res);
+    }
+
+    App::new().add_systems(Update, some_system).run();
+}

bevy_lint/tests/ui/borrow_of_reborrowable/resource.stderr

@@ -0,0 +1,20 @@
+error: parameter takes `&mut ResMut` instead of a re-borrowed `ResMut`
+  --> tests/ui/borrow_of_reborrowable/resource.rs:19:22
+   |
+19 | fn mutable_reference(_res: &mut ResMut<Data>) {
+   |                      ^^^^^^^^^^^^^^^^^^^^^^^ help: use `ResMut` instead: `mut _res: bevy::prelude::ResMut<'_, Data>`
+   |
+note: the lint level is defined here
+  --> tests/ui/borrow_of_reborrowable/resource.rs:5:9
+   |
+5  | #![deny(bevy::borrow_of_resource)]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: parameter takes `&mut ResMut` instead of a re-borrowed `ResMut`
+  --> tests/ui/borrow_of_reborrowable/resource.rs:25:33
+   |
+25 | fn mutable_reference_return<'a>(_res: &'a mut ResMut<Data>) -> usize {
+   |                                 ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `ResMut` instead: `mut _res: bevy::prelude::ResMut<'_, Data>`
+
+error: aborting due to 2 previous errors
+