add some style improvement for [ifs_same_cond];

add `Arc`, `Mutex`, `Cell`, `RefCell`, `RWLock` as `ignore-interior-mutability` default config

Author: J-ZhengLi

clippy_lints/src/copies.rs

@@ -164,12 +164,14 @@ declare_clippy_lint! {
 
 pub struct CopyAndPaste {
     ignore_interior_mutability: Vec<String>,
+    ignored_ty_ids: FxHashSet<DefId>,
 }
 
 impl CopyAndPaste {
     pub fn new(ignore_interior_mutability: Vec<String>) -> Self {
         Self {
             ignore_interior_mutability,
+            ignored_ty_ids: FxHashSet::default(),
         }
     }
 }
@@ -182,17 +184,18 @@ impl_lint_pass!(CopyAndPaste => [
 ]);
 
 impl<'tcx> LateLintPass<'tcx> for CopyAndPaste {
+    fn check_crate(&mut self, cx: &LateContext<'tcx>) {
+        for ignored_ty in &self.ignore_interior_mutability {
+            let path: Vec<&str> = ignored_ty.split("::").collect();
+            for id in def_path_def_ids(cx, path.as_slice()) {
+                self.ignored_ty_ids.insert(id);
+            }
+        }
+    }
     fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
         if !expr.span.from_expansion() && matches!(expr.kind, ExprKind::If(..)) && !is_else_clause(cx.tcx, expr) {
             let (conds, blocks) = if_sequence(expr);
-            let mut ignored_ty_ids = FxHashSet::default();
-            for ignored_ty in &self.ignore_interior_mutability {
-                let path: Vec<&str> = ignored_ty.split("::").collect();
-                for id in def_path_def_ids(cx, path.as_slice()) {
-                    ignored_ty_ids.insert(id);
-                }
-            }
-            lint_same_cond(cx, &conds, &ignored_ty_ids);
+            lint_same_cond(cx, &conds, &self.ignored_ty_ids);
             lint_same_fns_in_if_cond(cx, &conds);
             let all_same =
                 !is_lint_allowed(cx, IF_SAME_THEN_ELSE, expr.hir_id) && lint_if_same_then_else(cx, &conds, &blocks);
@@ -575,22 +578,12 @@ fn method_caller_is_ignored_or_mutable(
     ignored_ty_ids: &FxHashSet<DefId>,
 ) -> bool {
     let caller_ty = cx.typeck_results().expr_ty(caller_expr);
-    let is_ignored_ty = if let Some(adt_id) = caller_ty.ty_adt_id() && ignored_ty_ids.contains(&adt_id) {
-        true
-    } else {
-        false
-    };
-
-    if is_ignored_ty
+    matches!(caller_ty.ty_adt_id(), Some(adt_id) if ignored_ty_ids.contains(&adt_id))
         || caller_ty.is_mutable_ptr()
+        // Check if a binding is mutable or not
         || path_to_local(caller_expr)
             .and_then(|hid| find_binding_init(cx, hid))
             .is_none()
-    {
-        return true;
-    }
-
-    false
 }
 
 /// Implementation of `IFS_SAME_COND`.

clippy_lints/src/utils/conf.rs

@@ -441,7 +441,13 @@ define_Conf! {
     ///
     /// A list of paths to types that should be treated like `Arc`, i.e. ignored but
     /// for the generic parameters for determining interior mutability
-    (ignore_interior_mutability: Vec<String> = Vec::from(["bytes::Bytes".into()])),
+    (ignore_interior_mutability: Vec<String> = Vec::from([
+        "bytes::Bytes".into(),
+        "std::sync::Arc".into(),
+        "std::sync::Mutex".into(),
+        "std::cell::Cell".into(),
+        "std::cell::RefCell".into(),
+    ])),
     /// Lint: UNINLINED_FORMAT_ARGS.
     ///
     /// Whether to allow mixed uninlined format args, e.g. `format!("{} {}", a, foo.bar)`

tests/ui-toml/ifs_same_cond/clippy.toml

@@ -1 +1 @@
-ignore-interior-mutability = ["std::cell::Cell"]
+ignore-interior-mutability = ["std::cell::Cell"]