Enable needless_pass_by_ref_mut

Author: nickdrozd

clippy_dev/src/utils.rs

@@ -58,7 +58,7 @@ pub struct File<'a> {
 impl<'a> File<'a> {
     /// Opens a file panicking on failure.
     #[track_caller]
-    pub fn open(path: &'a (impl AsRef<Path> + ?Sized), options: &mut OpenOptions) -> Self {
+    pub fn open(path: &'a (impl AsRef<Path> + ?Sized), options: &OpenOptions) -> Self {
         let path = path.as_ref();
         Self {
             inner: expect_action(options.open(path), ErrAction::Open, path),
@@ -68,7 +68,7 @@ impl<'a> File<'a> {
 
     /// Opens a file if it exists, panicking on any other failure.
     #[track_caller]
-    pub fn open_if_exists(path: &'a (impl AsRef<Path> + ?Sized), options: &mut OpenOptions) -> Option<Self> {
+    pub fn open_if_exists(path: &'a (impl AsRef<Path> + ?Sized), options: &OpenOptions) -> Option<Self> {
         let path = path.as_ref();
         match options.open(path) {
             Ok(inner) => Some(Self { inner, path }),

clippy_lints/src/vec.rs

@@ -106,7 +106,7 @@ enum VecToArray {
 impl UselessVec {
     /// Checks if the surrounding environment requires this expression to actually be of type
     /// `Vec<_>`, or if it can be changed to `&[]`/`[]` without causing type errors.
-    fn expr_usage_requires_vec(&mut self, cx: &LateContext<'_>, expr: &Expr<'_>) -> VecToArray {
+    fn expr_usage_requires_vec(&self, cx: &LateContext<'_>, expr: &Expr<'_>) -> VecToArray {
         match cx.tcx.parent_hir_node(expr.hir_id) {
             // search for `let foo = vec![_]` expressions where all uses of `foo`
             // adjust to slices or call a method that exist on slices (e.g. len)

tests/dogfood.rs

@@ -91,6 +91,8 @@ fn run_clippy_for_package(project: &str) -> bool {
         "clippy::pedantic",
         "-D",
         "clippy::dbg_macro",
+        "-D",
+        "clippy::needless_pass_by_ref_mut",
     ]);
     if !cfg!(feature = "internal") {
         // running a clippy built without internal lints on the clippy source