diff --git a/crates/red_knot_python_semantic/src/types.rs b/crates/red_knot_python_semantic/src/types.rs
index 3eb267638a..ca28059d45 100644
--- a/crates/red_knot_python_semantic/src/types.rs
+++ b/crates/red_knot_python_semantic/src/types.rs
@@ -361,6 +361,7 @@ impl<'db> Type<'db> {
 #[salsa::interned]
 pub struct FunctionType<'db> {
     /// name of the function at definition
+    #[return_ref]
     pub name: ast::name::Name,
 
     definition: Definition<'db>,
@@ -408,6 +409,7 @@ impl<'db> FunctionType<'db> {
 #[salsa::interned]
 pub struct ClassType<'db> {
     /// Name of the class at definition
+    #[return_ref]
     pub name: ast::name::Name,
 
     definition: Definition<'db>,
@@ -464,6 +466,7 @@ impl<'db> ClassType<'db> {
 #[salsa::interned]
 pub struct UnionType<'db> {
     /// The union type includes values in any of these types.
+    #[return_ref]
     elements: FxOrderSet<Type<'db>>,
 }
 
@@ -476,6 +479,7 @@ impl<'db> UnionType<'db> {
 #[salsa::interned]
 pub struct IntersectionType<'db> {
     /// The intersection type includes only values in all of these types.
+    #[return_ref]
     positive: FxOrderSet<Type<'db>>,
 
     /// The intersection type does not include any value in any of these types.
@@ -483,6 +487,7 @@ pub struct IntersectionType<'db> {
     /// Negation types aren't expressible in annotations, and are most likely to arise from type
     /// narrowing along with intersections (e.g. `if not isinstance(...)`), so we represent them
     /// directly in intersections rather than as a separate type.
+    #[return_ref]
     negative: FxOrderSet<Type<'db>>,
 }
 
diff --git a/crates/red_knot_python_semantic/src/types/builder.rs b/crates/red_knot_python_semantic/src/types/builder.rs
index 5b7593837b..1688ea7f19 100644
--- a/crates/red_knot_python_semantic/src/types/builder.rs
+++ b/crates/red_knot_python_semantic/src/types/builder.rs
@@ -49,7 +49,7 @@ impl<'db> UnionBuilder<'db> {
     pub(crate) fn add(mut self, ty: Type<'db>) -> Self {
         match ty {
             Type::Union(union) => {
-                self.elements.extend(&union.elements(self.db));
+                self.elements.extend(union.elements(self.db));
             }
             Type::Never => {}
             _ => {
@@ -284,7 +284,7 @@ mod tests {
 
     impl<'db> UnionType<'db> {
         fn elements_vec(self, db: &'db TestDb) -> Vec<Type<'db>> {
-            self.elements(db).into_iter().collect()
+            self.elements(db).into_iter().copied().collect()
         }
     }
 
@@ -389,11 +389,11 @@ mod tests {
 
     impl<'db> IntersectionType<'db> {
         fn pos_vec(self, db: &'db TestDb) -> Vec<Type<'db>> {
-            self.positive(db).into_iter().collect()
+            self.positive(db).into_iter().copied().collect()
         }
 
         fn neg_vec(self, db: &'db TestDb) -> Vec<Type<'db>> {
-            self.negative(db).into_iter().collect()
+            self.negative(db).into_iter().copied().collect()
         }
     }
 
diff --git a/crates/red_knot_python_semantic/src/types/display.rs b/crates/red_knot_python_semantic/src/types/display.rs
index b703bb51ed..8c3cf67ff5 100644
--- a/crates/red_knot_python_semantic/src/types/display.rs
+++ b/crates/red_knot_python_semantic/src/types/display.rs
@@ -33,7 +33,7 @@ impl Display for DisplayType<'_> {
             }
             // TODO functions and classes should display using a fully qualified name
             Type::Class(class) => write!(f, "Literal[{}]", class.name(self.db)),
-            Type::Instance(class) => f.write_str(&class.name(self.db)),
+            Type::Instance(class) => f.write_str(class.name(self.db)),
             Type::Function(function) => write!(f, "Literal[{}]", function.name(self.db)),
             Type::Union(union) => union.display(self.db).fmt(f),
             Type::Intersection(intersection) => intersection.display(self.db).fmt(f),
diff --git a/crates/red_knot_workspace/src/lint.rs b/crates/red_knot_workspace/src/lint.rs
index 72db387168..1bb3a6a3f2 100644
--- a/crates/red_knot_workspace/src/lint.rs
+++ b/crates/red_knot_workspace/src/lint.rs
@@ -164,7 +164,7 @@ fn lint_bad_override(context: &SemanticLintContext, class: &ast::StmtClassDef) {
         if ty.has_decorator(db, override_ty) {
             let method_name = ty.name(db);
             if class_ty
-                .inherited_class_member(db, &method_name)
+                .inherited_class_member(db, method_name)
                 .is_unbound()
             {
                 // TODO should have a qualname() method to support nested classes
diff --git a/crates/red_knot_workspace/src/workspace.rs b/crates/red_knot_workspace/src/workspace.rs
index 0bd22ffe2c..02c901871b 100644
--- a/crates/red_knot_workspace/src/workspace.rs
+++ b/crates/red_knot_workspace/src/workspace.rs
@@ -297,7 +297,6 @@ impl Workspace {
     }
 }
 
-#[salsa::tracked]
 impl Package {
     pub fn root(self, db: &dyn Db) -> &SystemPath {
         self.root_buf(db)