X-Git-Url: https://git.lizzy.rs/?a=blobdiff_plain;f=clippy_lints%2Fsrc%2Fredundant_clone.rs;h=954e702a1f8875e49db76c5c80f5a795762c5703;hb=03960ebab26a1b1d2d43540f47aca6670bdc1e54;hp=b3988973256c4c16cad3c8306c6e43cf4916b062;hpb=2955db493ef9ceaf4cc9bcd3b83680c0206d001d;p=rust.git

diff --git a/clippy_lints/src/redundant_clone.rs b/clippy_lints/src/redundant_clone.rs
index b3988973256..954e702a1f8 100644
--- a/clippy_lints/src/redundant_clone.rs
+++ b/clippy_lints/src/redundant_clone.rs
@@ -3,7 +3,7 @@
 use clippy_utils::ty::{has_drop, is_copy, is_type_diagnostic_item, walk_ptrs_ty_depth};
 use clippy_utils::{fn_has_unsatisfiable_preds, match_def_path, paths};
 use if_chain::if_chain;
-use rustc_data_structures::{fx::FxHashMap, transitive_relation::TransitiveRelation};
+use rustc_data_structures::fx::FxHashMap;
 use rustc_errors::Applicability;
 use rustc_hir::intravisit::FnKind;
 use rustc_hir::{def_id, Body, FnDecl, HirId};
@@ -71,7 +71,7 @@ macro_rules! unwrap_or_continue {
 declare_lint_pass!(RedundantClone => [REDUNDANT_CLONE]);
 
 impl<'tcx> LateLintPass<'tcx> for RedundantClone {
-    #[allow(clippy::too_many_lines)]
+    #[expect(clippy::too_many_lines)]
     fn check_fn(
         &mut self,
         cx: &LateContext<'tcx>,
@@ -512,7 +512,7 @@ fn call_return_effect(
 /// For example, `b = &a; c = &a;` will make `b` and (transitively) `c`
 /// possible borrowers of `a`.
 struct PossibleBorrowerVisitor<'a, 'tcx> {
-    possible_borrower: TransitiveRelation<mir::Local>,
+    possible_borrower: TransitiveRelation,
     body: &'a mir::Body<'tcx>,
     cx: &'a LateContext<'tcx>,
     possible_origin: FxHashMap<mir::Local, HybridBitSet<mir::Local>>,
@@ -543,18 +543,10 @@ fn into_map(
                 continue;
             }
 
-            let borrowers = self.possible_borrower.reachable_from(&row);
+            let mut borrowers = self.possible_borrower.reachable_from(row, self.body.local_decls.len());
+            borrowers.remove(mir::Local::from_usize(0));
             if !borrowers.is_empty() {
-                let mut bs = HybridBitSet::new_empty(self.body.local_decls.len());
-                for &c in borrowers {
-                    if c != mir::Local::from_usize(0) {
-                        bs.insert(c);
-                    }
-                }
-
-                if !bs.is_empty() {
-                    map.insert(row, bs);
-                }
+                map.insert(row, borrowers);
             }
         }
 
@@ -644,7 +636,7 @@ fn visit_terminator(&mut self, terminator: &mir::Terminator<'_>, _loc: mir::Loca
 /// For exampel, `_1 = &mut _2` generate _1: {_2,...}
 /// Known Problems: not sure all borrowed are tracked
 struct PossibleOriginVisitor<'a, 'tcx> {
-    possible_origin: TransitiveRelation<mir::Local>,
+    possible_origin: TransitiveRelation,
     body: &'a mir::Body<'tcx>,
 }
 
@@ -663,18 +655,10 @@ fn into_map(self, cx: &LateContext<'tcx>) -> FxHashMap<mir::Local, HybridBitSet<
                 continue;
             }
 
-            let borrowers = self.possible_origin.reachable_from(&row);
+            let mut borrowers = self.possible_origin.reachable_from(row, self.body.local_decls.len());
+            borrowers.remove(mir::Local::from_usize(0));
             if !borrowers.is_empty() {
-                let mut bs = HybridBitSet::new_empty(self.body.local_decls.len());
-                for &c in borrowers {
-                    if c != mir::Local::from_usize(0) {
-                        bs.insert(c);
-                    }
-                }
-
-                if !bs.is_empty() {
-                    map.insert(row, bs);
-                }
+                map.insert(row, borrowers);
             }
         }
         map
@@ -766,3 +750,28 @@ fn local_is_alive_at(&mut self, local: mir::Local, at: mir::Location) -> bool {
         self.maybe_live.contains(local)
     }
 }
+
+#[derive(Default)]
+struct TransitiveRelation {
+    relations: FxHashMap<mir::Local, Vec<mir::Local>>,
+}
+impl TransitiveRelation {
+    fn add(&mut self, a: mir::Local, b: mir::Local) {
+        self.relations.entry(a).or_default().push(b);
+    }
+
+    fn reachable_from(&self, a: mir::Local, domain_size: usize) -> HybridBitSet<mir::Local> {
+        let mut seen = HybridBitSet::new_empty(domain_size);
+        let mut stack = vec![a];
+        while let Some(u) = stack.pop() {
+            if let Some(edges) = self.relations.get(&u) {
+                for &v in edges {
+                    if seen.insert(v) {
+                        stack.push(v);
+                    }
+                }
+            }
+        }
+        seen
+    }
+}