diff --git a/clippy_lints/src/trait_bounds.rs b/clippy_lints/src/trait_bounds.rs
index b5f11b4acae..4ccda15068b 100644
--- a/clippy_lints/src/trait_bounds.rs
+++ b/clippy_lints/src/trait_bounds.rs
@@ -37,12 +37,12 @@ declare_clippy_lint! {
#[clippy::version = "1.38.0"]
pub TYPE_REPETITION_IN_BOUNDS,
nursery,
- "types are repeated unnecessary in trait bounds use `+` instead of using `T: _, T: _`"
+ "types are repeated unnecessarily in trait bounds, use `+` instead of using `T: _, T: _`"
}
declare_clippy_lint! {
/// ### What it does
- /// Checks for cases where generics are being used and multiple
+ /// Checks for cases where generics or trait objects are being used and multiple
/// syntax specifications for trait bounds are used simultaneously.
///
/// ### Why is this bad?
@@ -167,6 +167,61 @@ impl<'tcx> LateLintPass<'tcx> for TraitBounds {
}
}
}
+
+ fn check_ty(&mut self, cx: &LateContext<'tcx>, ty: &'tcx Ty<'tcx>) {
+ if_chain! {
+ if let TyKind::Ref(.., mut_ty) = &ty.kind;
+ if let TyKind::TraitObject(bounds, ..) = mut_ty.ty.kind;
+ if bounds.len() > 2;
+ then {
+
+ // Build up a hash of every trait we've seen
+ // When we see a trait for the first time, add it to unique_traits
+ // so we can later use it to build a string of all traits exactly once, without duplicates
+
+ let mut seen_def_ids = FxHashSet::default();
+ let mut unique_traits = Vec::new();
+
+ // Iterate the bounds and add them to our seen hash
+ // If we haven't yet seen it, add it to the fixed traits
+ for bound in bounds.iter() {
+ let Some(def_id) = bound.trait_ref.trait_def_id() else { continue; };
+
+ let new_trait = seen_def_ids.insert(def_id);
+
+ if new_trait {
+ unique_traits.push(bound);
+ }
+ }
+
+ // If the number of unique traits isn't the same as the number of traits in the bounds,
+ // there must be 1 or more duplicates
+ if bounds.len() != unique_traits.len() {
+ let mut bounds_span = bounds[0].span;
+
+ for bound in bounds.iter().skip(1) {
+ bounds_span = bounds_span.to(bound.span);
+ }
+
+ let fixed_trait_snippet = unique_traits
+ .iter()
+ .filter_map(|b| snippet_opt(cx, b.span))
+ .collect::<Vec<_>>()
+ .join(" + ");
+
+ span_lint_and_sugg(
+ cx,
+ TRAIT_DUPLICATION_IN_BOUNDS,
+ bounds_span,
+ "this trait bound is already specified in trait declaration",
+ "try",
+ fixed_trait_snippet,
+ Applicability::MaybeIncorrect,
+ );
+ }
+ }
+ }
+ }
}
impl TraitBounds {
diff --git a/tests/ui/trait_duplication_in_bounds.fixed b/tests/ui/trait_duplication_in_bounds.fixed
index eef8024b131..fdac0e4cb1e 100644
--- a/tests/ui/trait_duplication_in_bounds.fixed
+++ b/tests/ui/trait_duplication_in_bounds.fixed
@@ -2,6 +2,8 @@
#![deny(clippy::trait_duplication_in_bounds)]
#![allow(unused)]
+use std::any::Any;
+
fn bad_foo<T: Clone + Copy, U: Clone + Copy>(arg0: T, argo1: U) {
unimplemented!();
}
@@ -109,4 +111,12 @@ fn qualified_path<T: std::clone::Clone + foo::Clone>(arg0: T) {
unimplemented!();
}
+fn good_trait_object(arg0: &(dyn Any + Send)) {
+ unimplemented!();
+}
+
+fn bad_trait_object(arg0: &(dyn Any + Send)) {
+ unimplemented!();
+}
+
fn main() {}
diff --git a/tests/ui/trait_duplication_in_bounds.rs b/tests/ui/trait_duplication_in_bounds.rs
index a7a1caf2880..a0300da5555 100644
--- a/tests/ui/trait_duplication_in_bounds.rs
+++ b/tests/ui/trait_duplication_in_bounds.rs
@@ -2,6 +2,8 @@
#![deny(clippy::trait_duplication_in_bounds)]
#![allow(unused)]
+use std::any::Any;
+
fn bad_foo<T: Clone + Clone + Clone + Copy, U: Clone + Copy>(arg0: T, argo1: U) {
unimplemented!();
}
@@ -109,4 +111,12 @@ fn qualified_path<T: std::clone::Clone + Clone + foo::Clone>(arg0: T) {
unimplemented!();
}
+fn good_trait_object(arg0: &(dyn Any + Send)) {
+ unimplemented!();
+}
+
+fn bad_trait_object(arg0: &(dyn Any + Send + Send)) {
+ unimplemented!();
+}
+
fn main() {}
diff --git a/tests/ui/trait_duplication_in_bounds.stderr b/tests/ui/trait_duplication_in_bounds.stderr
index af800ba7888..539b6114ca3 100644
--- a/tests/ui/trait_duplication_in_bounds.stderr
+++ b/tests/ui/trait_duplication_in_bounds.stderr
@@ -1,5 +1,5 @@
error: these bounds contain repeated elements
- --> $DIR/trait_duplication_in_bounds.rs:5:15
+ --> $DIR/trait_duplication_in_bounds.rs:7:15
|
LL | fn bad_foo<T: Clone + Clone + Clone + Copy, U: Clone + Copy>(arg0: T, argo1: U) {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `Clone + Copy`
@@ -11,46 +11,52 @@ LL | #![deny(clippy::trait_duplication_in_bounds)]
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
error: these where clauses contain repeated elements
- --> $DIR/trait_duplication_in_bounds.rs:11:8
+ --> $DIR/trait_duplication_in_bounds.rs:13:8
|
LL | T: Clone + Clone + Clone + Copy,
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `Clone + Copy`
error: these bounds contain repeated elements
- --> $DIR/trait_duplication_in_bounds.rs:39:26
+ --> $DIR/trait_duplication_in_bounds.rs:41:26
|
LL | trait BadSelfTraitBound: Clone + Clone + Clone {
| ^^^^^^^^^^^^^^^^^^^^^ help: try: `Clone`
error: these where clauses contain repeated elements
- --> $DIR/trait_duplication_in_bounds.rs:46:15
+ --> $DIR/trait_duplication_in_bounds.rs:48:15
|
LL | Self: Clone + Clone + Clone;
| ^^^^^^^^^^^^^^^^^^^^^ help: try: `Clone`
error: these bounds contain repeated elements
- --> $DIR/trait_duplication_in_bounds.rs:60:24
+ --> $DIR/trait_duplication_in_bounds.rs:62:24
|
LL | trait BadTraitBound<T: Clone + Clone + Clone + Copy, U: Clone + Copy> {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `Clone + Copy`
error: these where clauses contain repeated elements
- --> $DIR/trait_duplication_in_bounds.rs:67:12
+ --> $DIR/trait_duplication_in_bounds.rs:69:12
|
LL | T: Clone + Clone + Clone + Copy,
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `Clone + Copy`
error: these bounds contain repeated elements
- --> $DIR/trait_duplication_in_bounds.rs:100:19
+ --> $DIR/trait_duplication_in_bounds.rs:102:19
|
LL | fn bad_generic<T: GenericTrait<u64> + GenericTrait<u32> + GenericTrait<u64>>(arg0: T) {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `GenericTrait<u64> + GenericTrait<u32>`
error: these bounds contain repeated elements
- --> $DIR/trait_duplication_in_bounds.rs:108:22
+ --> $DIR/trait_duplication_in_bounds.rs:110:22
|
LL | fn qualified_path<T: std::clone::Clone + Clone + foo::Clone>(arg0: T) {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `std::clone::Clone + foo::Clone`
-error: aborting due to 8 previous errors
+error: this trait bound is already specified in trait declaration
+ --> $DIR/trait_duplication_in_bounds.rs:118:33
+ |
+LL | fn bad_trait_object(arg0: &(dyn Any + Send + Send)) {
+ | ^^^^^^^^^^^^^^^^^ help: try: `Any + Send`
+
+error: aborting due to 9 previous errors