diff --git a/CHANGELOG.md b/CHANGELOG.md
index bd3a04e34ae3..aaa53d8a6cb8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5523,6 +5523,7 @@ Released 2018-09-13
[`needless_late_init`]: https://rust-lang.github.io/rust-clippy/master/index.html#needless_late_init
[`needless_lifetimes`]: https://rust-lang.github.io/rust-clippy/master/index.html#needless_lifetimes
[`needless_match`]: https://rust-lang.github.io/rust-clippy/master/index.html#needless_match
+[`needless_maybe_sized`]: https://rust-lang.github.io/rust-clippy/master/index.html#needless_maybe_sized
[`needless_option_as_deref`]: https://rust-lang.github.io/rust-clippy/master/index.html#needless_option_as_deref
[`needless_option_take`]: https://rust-lang.github.io/rust-clippy/master/index.html#needless_option_take
[`needless_parens_on_range_literals`]: https://rust-lang.github.io/rust-clippy/master/index.html#needless_parens_on_range_literals
diff --git a/clippy_lints/src/declared_lints.rs b/clippy_lints/src/declared_lints.rs
index 5ff7d8e51343..dd16e13e7add 100644
--- a/clippy_lints/src/declared_lints.rs
+++ b/clippy_lints/src/declared_lints.rs
@@ -527,6 +527,7 @@ pub(crate) static LINTS: &[&crate::LintInfo] = &[
crate::needless_for_each::NEEDLESS_FOR_EACH_INFO,
crate::needless_if::NEEDLESS_IF_INFO,
crate::needless_late_init::NEEDLESS_LATE_INIT_INFO,
+ crate::needless_maybe_sized::NEEDLESS_MAYBE_SIZED_INFO,
crate::needless_parens_on_range_literals::NEEDLESS_PARENS_ON_RANGE_LITERALS_INFO,
crate::needless_pass_by_ref_mut::NEEDLESS_PASS_BY_REF_MUT_INFO,
crate::needless_pass_by_value::NEEDLESS_PASS_BY_VALUE_INFO,
diff --git a/clippy_lints/src/lib.rs b/clippy_lints/src/lib.rs
index e2aac58bf979..bfddbffe9b23 100644
--- a/clippy_lints/src/lib.rs
+++ b/clippy_lints/src/lib.rs
@@ -254,6 +254,7 @@ mod needless_else;
mod needless_for_each;
mod needless_if;
mod needless_late_init;
+mod needless_maybe_sized;
mod needless_parens_on_range_literals;
mod needless_pass_by_ref_mut;
mod needless_pass_by_value;
@@ -1032,6 +1033,7 @@ pub fn register_lints(store: &mut rustc_lint::LintStore, conf: &'static Conf) {
store.register_late_pass(|_| Box::new(no_mangle_with_rust_abi::NoMangleWithRustAbi));
store.register_late_pass(|_| Box::new(collection_is_never_read::CollectionIsNeverRead));
store.register_late_pass(|_| Box::new(missing_assert_message::MissingAssertMessage));
+ store.register_late_pass(|_| Box::new(needless_maybe_sized::NeedlessMaybeSized));
store.register_late_pass(|_| Box::new(redundant_async_block::RedundantAsyncBlock));
store.register_late_pass(|_| Box::new(let_with_type_underscore::UnderscoreTyped));
store.register_late_pass(|_| Box::new(allow_attributes::AllowAttribute));
diff --git a/clippy_lints/src/needless_maybe_sized.rs b/clippy_lints/src/needless_maybe_sized.rs
new file mode 100644
index 000000000000..06ae1723a03d
--- /dev/null
+++ b/clippy_lints/src/needless_maybe_sized.rs
@@ -0,0 +1,164 @@
+use clippy_utils::diagnostics::span_lint_and_then;
+use rustc_errors::Applicability;
+use rustc_hir::def_id::{DefId, DefIdMap};
+use rustc_hir::{GenericBound, Generics, PolyTraitRef, TraitBoundModifier, WherePredicate};
+use rustc_lint::{LateContext, LateLintPass};
+use rustc_middle::ty::{ClauseKind, PredicatePolarity};
+use rustc_session::declare_lint_pass;
+use rustc_span::symbol::Ident;
+
+declare_clippy_lint! {
+ /// ### What it does
+ /// Lints `?Sized` bounds applied to type parameters that cannot be unsized
+ ///
+ /// ### Why is this bad?
+ /// The `?Sized` bound is misleading because it cannot be satisfied by an
+ /// unsized type
+ ///
+ /// ### Example
+ /// ```rust
+ /// // `T` cannot be unsized because `Clone` requires it to be `Sized`
+ /// fn f<T: Clone + ?Sized>(t: &T) {}
+ /// ```
+ /// Use instead:
+ /// ```rust
+ /// fn f<T: Clone>(t: &T) {}
+ ///
+ /// // or choose alternative bounds for `T` so that it can be unsized
+ /// ```
+ #[clippy::version = "1.79.0"]
+ pub NEEDLESS_MAYBE_SIZED,
+ suspicious,
+ "a `?Sized` bound that is unusable due to a `Sized` requirement"
+}
+declare_lint_pass!(NeedlessMaybeSized => [NEEDLESS_MAYBE_SIZED]);
+
+#[allow(clippy::struct_field_names)]
+struct Bound<'tcx> {
+ /// The [`DefId`] of the type parameter the bound refers to
+ param: DefId,
+ ident: Ident,
+
+ trait_bound: &'tcx PolyTraitRef<'tcx>,
+ modifier: TraitBoundModifier,
+
+ predicate_pos: usize,
+ bound_pos: usize,
+}
+
+/// Finds all of the [`Bound`]s that refer to a type parameter and are not from a macro expansion
+fn type_param_bounds<'tcx>(generics: &'tcx Generics<'tcx>) -> impl Iterator<Item = Bound<'tcx>> {
+ generics
+ .predicates
+ .iter()
+ .enumerate()
+ .filter_map(|(predicate_pos, predicate)| {
+ let WherePredicate::BoundPredicate(bound_predicate) = predicate else {
+ return None;
+ };
+
+ let (param, ident) = bound_predicate.bounded_ty.as_generic_param()?;
+
+ Some(
+ bound_predicate
+ .bounds
+ .iter()
+ .enumerate()
+ .filter_map(move |(bound_pos, bound)| match bound {
+ &GenericBound::Trait(ref trait_bound, modifier) => Some(Bound {
+ param,
+ ident,
+ trait_bound,
+ modifier,
+ predicate_pos,
+ bound_pos,
+ }),
+ GenericBound::Outlives(_) => None,
+ })
+ .filter(|bound| !bound.trait_bound.span.from_expansion()),
+ )
+ })
+ .flatten()
+}
+
+/// Searches the supertraits of the trait referred to by `trait_bound` recursively, returning the
+/// path taken to find a `Sized` bound if one is found
+fn path_to_sized_bound(cx: &LateContext<'_>, trait_bound: &PolyTraitRef<'_>) -> Option<Vec<DefId>> {
+ fn search(cx: &LateContext<'_>, path: &mut Vec<DefId>) -> bool {
+ let trait_def_id = *path.last().unwrap();
+
+ if Some(trait_def_id) == cx.tcx.lang_items().sized_trait() {
+ return true;
+ }
+
+ for &(predicate, _) in cx.tcx.super_predicates_of(trait_def_id).predicates {
+ if let ClauseKind::Trait(trait_predicate) = predicate.kind().skip_binder()
+ && trait_predicate.polarity == PredicatePolarity::Positive
+ && !path.contains(&trait_predicate.def_id())
+ {
+ path.push(trait_predicate.def_id());
+ if search(cx, path) {
+ return true;
+ }
+ path.pop();
+ }
+ }
+
+ false
+ }
+
+ let mut path = vec![trait_bound.trait_ref.trait_def_id()?];
+ search(cx, &mut path).then_some(path)
+}
+
+impl LateLintPass<'_> for NeedlessMaybeSized {
+ fn check_generics(&mut self, cx: &LateContext<'_>, generics: &Generics<'_>) {
+ let Some(sized_trait) = cx.tcx.lang_items().sized_trait() else {
+ return;
+ };
+
+ let maybe_sized_params: DefIdMap<_> = type_param_bounds(generics)
+ .filter(|bound| {
+ bound.trait_bound.trait_ref.trait_def_id() == Some(sized_trait)
+ && bound.modifier == TraitBoundModifier::Maybe
+ })
+ .map(|bound| (bound.param, bound))
+ .collect();
+
+ for bound in type_param_bounds(generics) {
+ if bound.modifier == TraitBoundModifier::None
+ && let Some(sized_bound) = maybe_sized_params.get(&bound.param)
+ && let Some(path) = path_to_sized_bound(cx, bound.trait_bound)
+ {
+ span_lint_and_then(
+ cx,
+ NEEDLESS_MAYBE_SIZED,
+ sized_bound.trait_bound.span,
+ "`?Sized` bound is ignored because of a `Sized` requirement",
+ |diag| {
+ let ty_param = sized_bound.ident;
+ diag.span_note(
+ bound.trait_bound.span,
+ format!("`{ty_param}` cannot be unsized because of the bound"),
+ );
+
+ for &[current_id, next_id] in path.array_windows() {
+ let current = cx.tcx.item_name(current_id);
+ let next = cx.tcx.item_name(next_id);
+ diag.note(format!("...because `{current}` has the bound `{next}`"));
+ }
+
+ diag.span_suggestion_verbose(
+ generics.span_for_bound_removal(sized_bound.predicate_pos, sized_bound.bound_pos),
+ "change the bounds that require `Sized`, or remove the `?Sized` bound",
+ "",
+ Applicability::MaybeIncorrect,
+ );
+ },
+ );
+
+ return;
+ }
+ }
+ }
+}
diff --git a/tests/ui-toml/type_repetition_in_bounds/main.rs b/tests/ui-toml/type_repetition_in_bounds/main.rs
index 2454c10382df..7f93d2071c9d 100644
--- a/tests/ui-toml/type_repetition_in_bounds/main.rs
+++ b/tests/ui-toml/type_repetition_in_bounds/main.rs
@@ -1,3 +1,4 @@
+#![allow(clippy::needless_maybe_sized)]
#![warn(clippy::type_repetition_in_bounds)]
fn f<T>()
diff --git a/tests/ui-toml/type_repetition_in_bounds/main.stderr b/tests/ui-toml/type_repetition_in_bounds/main.stderr
index 6005f76b94be..c5102c39d1cf 100644
--- a/tests/ui-toml/type_repetition_in_bounds/main.stderr
+++ b/tests/ui-toml/type_repetition_in_bounds/main.stderr
@@ -1,5 +1,5 @@
error: this type has already been used as a bound predicate
- --> tests/ui-toml/type_repetition_in_bounds/main.rs:13:5
+ --> tests/ui-toml/type_repetition_in_bounds/main.rs:14:5
|
LL | T: Unpin + PartialEq,
| ^^^^^^^^^^^^^^^^^^^^
diff --git a/tests/ui/auxiliary/proc_macros.rs b/tests/ui/auxiliary/proc_macros.rs
index 3303eb145678..4a81a191e726 100644
--- a/tests/ui/auxiliary/proc_macros.rs
+++ b/tests/ui/auxiliary/proc_macros.rs
@@ -57,7 +57,7 @@ fn group_with_span(delimiter: Delimiter, stream: TokenStream, span: Span) -> Gro
const ESCAPE_CHAR: char = '$';
/// Takes a single token followed by a sequence of tokens. Returns the sequence of tokens with their
-/// span set to that of the first token. Tokens may be escaped with either `#ident` or `#(tokens)`.
+/// span set to that of the first token. Tokens may be escaped with either `$ident` or `$(tokens)`.
#[proc_macro]
pub fn with_span(input: TokenStream) -> TokenStream {
let mut iter = input.into_iter();
@@ -71,7 +71,7 @@ pub fn with_span(input: TokenStream) -> TokenStream {
}
/// Takes a sequence of tokens and return the tokens with the span set such that they appear to be
-/// from an external macro. Tokens may be escaped with either `#ident` or `#(tokens)`.
+/// from an external macro. Tokens may be escaped with either `$ident` or `$(tokens)`.
#[proc_macro]
pub fn external(input: TokenStream) -> TokenStream {
let mut res = TokenStream::new();
@@ -83,7 +83,7 @@ pub fn external(input: TokenStream) -> TokenStream {
}
/// Copies all the tokens, replacing all their spans with the given span. Tokens can be escaped
-/// either by `#ident` or `#(tokens)`.
+/// either by `$ident` or `$(tokens)`.
fn write_with_span(s: Span, mut input: IntoIter, out: &mut TokenStream) -> Result<()> {
while let Some(tt) = input.next() {
match tt {
diff --git a/tests/ui/needless_maybe_sized.fixed b/tests/ui/needless_maybe_sized.fixed
new file mode 100644
index 000000000000..4d24a7cee619
--- /dev/null
+++ b/tests/ui/needless_maybe_sized.fixed
@@ -0,0 +1,116 @@
+//@aux-build:proc_macros.rs
+
+#![allow(unused, clippy::multiple_bound_locations)]
+#![warn(clippy::needless_maybe_sized)]
+
+extern crate proc_macros;
+use proc_macros::external;
+
+fn directly<T: Sized>(t: &T) {}
+
+trait A: Sized {}
+trait B: A {}
+
+fn depth_1<T: A>(t: &T) {}
+fn depth_2<T: B>(t: &T) {}
+
+// We only need to show one
+fn multiple_paths<T: A + B>(t: &T) {}
+
+fn in_where<T>(t: &T)
+where
+ T: Sized,
+{
+}
+
+fn mixed_1<T: Sized>(t: &T)
+{
+}
+
+fn mixed_2<T>(t: &T)
+where
+ T: Sized,
+{
+}
+
+fn mixed_3<T>(t: &T)
+where
+ T: Sized,
+{
+}
+
+struct Struct<T: Sized>(T);
+
+impl<T: Sized> Struct<T> {
+ fn method<U: Sized>(&self) {}
+}
+
+enum Enum<T: Sized + 'static> {
+ Variant(&'static T),
+}
+
+union Union<'a, T: Sized> {
+ a: &'a T,
+}
+
+trait Trait<T: Sized> {
+ fn trait_method<U: Sized>() {}
+
+ type GAT<U: Sized>;
+
+ type Assoc: Sized + ?Sized; // False negative
+}
+
+trait SecondInTrait: Send + Sized {}
+fn second_in_trait<T: SecondInTrait>() {}
+
+fn impl_trait(_: &(impl Sized)) {}
+
+trait GenericTrait<T>: Sized {}
+fn in_generic_trait<T: GenericTrait<U>, U>() {}
+
+mod larger_graph {
+ // C1 C2 Sized
+ // \ /\ /
+ // B1 B2
+ // \ /
+ // A1
+
+ trait C1 {}
+ trait C2 {}
+ trait B1: C1 + C2 {}
+ trait B2: C2 + Sized {}
+ trait A1: B1 + B2 {}
+
+ fn larger_graph<T: A1>() {}
+}
+
+// Should not lint
+
+fn sized<T: Sized>() {}
+fn maybe_sized<T: ?Sized>() {}
+
+struct SeparateBounds<T: ?Sized>(T);
+impl<T: Sized> SeparateBounds<T> {}
+
+trait P {}
+trait Q: P {}
+
+fn ok_depth_1<T: P + ?Sized>() {}
+fn ok_depth_2<T: Q + ?Sized>() {}
+
+external! {
+ fn in_macro<T: Clone + ?Sized>(t: &T) {}
+
+ fn with_local_clone<T: $Clone + ?Sized>(t: &T) {}
+}
+
+#[derive(Clone)]
+struct InDerive<T: ?Sized> {
+ t: T,
+}
+
+struct Refined<T: ?Sized>(T);
+impl<T: Sized> Refined<T> {}
+
+fn main() {}
diff --git a/tests/ui/needless_maybe_sized.rs b/tests/ui/needless_maybe_sized.rs
new file mode 100644
index 000000000000..ef66f9a4f2ae
--- /dev/null
+++ b/tests/ui/needless_maybe_sized.rs
@@ -0,0 +1,119 @@
+//@aux-build:proc_macros.rs
+
+#![allow(unused, clippy::multiple_bound_locations)]
+#![warn(clippy::needless_maybe_sized)]
+
+extern crate proc_macros;
+use proc_macros::external;
+
+fn directly<T: Sized + ?Sized>(t: &T) {}
+
+trait A: Sized {}
+trait B: A {}
+
+fn depth_1<T: A + ?Sized>(t: &T) {}
+fn depth_2<T: B + ?Sized>(t: &T) {}
+
+// We only need to show one
+fn multiple_paths<T: A + B + ?Sized>(t: &T) {}
+
+fn in_where<T>(t: &T)
+where
+ T: Sized + ?Sized,
+{
+}
+
+fn mixed_1<T: Sized>(t: &T)
+where
+ T: ?Sized,
+{
+}
+
+fn mixed_2<T: ?Sized>(t: &T)
+where
+ T: Sized,
+{
+}
+
+fn mixed_3<T>(t: &T)
+where
+ T: Sized,
+ T: ?Sized,
+{
+}
+
+struct Struct<T: Sized + ?Sized>(T);
+
+impl<T: Sized + ?Sized> Struct<T> {
+ fn method<U: Sized + ?Sized>(&self) {}
+}
+
+enum Enum<T: Sized + ?Sized + 'static> {
+ Variant(&'static T),
+}
+
+union Union<'a, T: Sized + ?Sized> {
+ a: &'a T,
+}
+
+trait Trait<T: Sized + ?Sized> {
+ fn trait_method<U: Sized + ?Sized>() {}
+
+ type GAT<U: Sized + ?Sized>;
+
+ type Assoc: Sized + ?Sized; // False negative
+}
+
+trait SecondInTrait: Send + Sized {}
+fn second_in_trait<T: ?Sized + SecondInTrait>() {}
+
+fn impl_trait(_: &(impl Sized + ?Sized)) {}
+
+trait GenericTrait<T>: Sized {}
+fn in_generic_trait<T: GenericTrait<U> + ?Sized, U>() {}
+
+mod larger_graph {
+ // C1 C2 Sized
+ // \ /\ /
+ // B1 B2
+ // \ /
+ // A1
+
+ trait C1 {}
+ trait C2 {}
+ trait B1: C1 + C2 {}
+ trait B2: C2 + Sized {}
+ trait A1: B1 + B2 {}
+
+ fn larger_graph<T: A1 + ?Sized>() {}
+}
+
+// Should not lint
+
+fn sized<T: Sized>() {}
+fn maybe_sized<T: ?Sized>() {}
+
+struct SeparateBounds<T: ?Sized>(T);
+impl<T: Sized> SeparateBounds<T> {}
+
+trait P {}
+trait Q: P {}
+
+fn ok_depth_1<T: P + ?Sized>() {}
+fn ok_depth_2<T: Q + ?Sized>() {}
+
+external! {
+ fn in_macro<T: Clone + ?Sized>(t: &T) {}
+
+ fn with_local_clone<T: $Clone + ?Sized>(t: &T) {}
+}
+
+#[derive(Clone)]
+struct InDerive<T: ?Sized> {
+ t: T,
+}
+
+struct Refined<T: ?Sized>(T);
+impl<T: Sized> Refined<T> {}
+
+fn main() {}
diff --git a/tests/ui/needless_maybe_sized.stderr b/tests/ui/needless_maybe_sized.stderr
new file mode 100644
index 000000000000..3b1d2b49b062
--- /dev/null
+++ b/tests/ui/needless_maybe_sized.stderr
@@ -0,0 +1,353 @@
+error: `?Sized` bound is ignored because of a `Sized` requirement
+ --> tests/ui/needless_maybe_sized.rs:9:24
+ |
+LL | fn directly<T: Sized + ?Sized>(t: &T) {}
+ | ^^^^^^
+ |
+note: `T` cannot be unsized because of the bound
+ --> tests/ui/needless_maybe_sized.rs:9:16
+ |
+LL | fn directly<T: Sized + ?Sized>(t: &T) {}
+ | ^^^^^
+ = note: `-D clippy::needless-maybe-sized` implied by `-D warnings`
+ = help: to override `-D warnings` add `#[allow(clippy::needless_maybe_sized)]`
+help: change the bounds that require `Sized`, or remove the `?Sized` bound
+ |
+LL - fn directly<T: Sized + ?Sized>(t: &T) {}
+LL + fn directly<T: Sized>(t: &T) {}
+ |
+
+error: `?Sized` bound is ignored because of a `Sized` requirement
+ --> tests/ui/needless_maybe_sized.rs:14:19
+ |
+LL | fn depth_1<T: A + ?Sized>(t: &T) {}
+ | ^^^^^^
+ |
+note: `T` cannot be unsized because of the bound
+ --> tests/ui/needless_maybe_sized.rs:14:15
+ |
+LL | fn depth_1<T: A + ?Sized>(t: &T) {}
+ | ^
+ = note: ...because `A` has the bound `Sized`
+help: change the bounds that require `Sized`, or remove the `?Sized` bound
+ |
+LL - fn depth_1<T: A + ?Sized>(t: &T) {}
+LL + fn depth_1<T: A>(t: &T) {}
+ |
+
+error: `?Sized` bound is ignored because of a `Sized` requirement
+ --> tests/ui/needless_maybe_sized.rs:15:19
+ |
+LL | fn depth_2<T: B + ?Sized>(t: &T) {}
+ | ^^^^^^
+ |
+note: `T` cannot be unsized because of the bound
+ --> tests/ui/needless_maybe_sized.rs:15:15
+ |
+LL | fn depth_2<T: B + ?Sized>(t: &T) {}
+ | ^
+ = note: ...because `B` has the bound `A`
+ = note: ...because `A` has the bound `Sized`
+help: change the bounds that require `Sized`, or remove the `?Sized` bound
+ |
+LL - fn depth_2<T: B + ?Sized>(t: &T) {}
+LL + fn depth_2<T: B>(t: &T) {}
+ |
+
+error: `?Sized` bound is ignored because of a `Sized` requirement
+ --> tests/ui/needless_maybe_sized.rs:18:30
+ |
+LL | fn multiple_paths<T: A + B + ?Sized>(t: &T) {}
+ | ^^^^^^
+ |
+note: `T` cannot be unsized because of the bound
+ --> tests/ui/needless_maybe_sized.rs:18:22
+ |
+LL | fn multiple_paths<T: A + B + ?Sized>(t: &T) {}
+ | ^
+ = note: ...because `A` has the bound `Sized`
+help: change the bounds that require `Sized`, or remove the `?Sized` bound
+ |
+LL - fn multiple_paths<T: A + B + ?Sized>(t: &T) {}
+LL + fn multiple_paths<T: A + B>(t: &T) {}
+ |
+
+error: `?Sized` bound is ignored because of a `Sized` requirement
+ --> tests/ui/needless_maybe_sized.rs:22:16
+ |
+LL | T: Sized + ?Sized,
+ | ^^^^^^
+ |
+note: `T` cannot be unsized because of the bound
+ --> tests/ui/needless_maybe_sized.rs:22:8
+ |
+LL | T: Sized + ?Sized,
+ | ^^^^^
+help: change the bounds that require `Sized`, or remove the `?Sized` bound
+ |
+LL - T: Sized + ?Sized,
+LL + T: Sized,
+ |
+
+error: `?Sized` bound is ignored because of a `Sized` requirement
+ --> tests/ui/needless_maybe_sized.rs:28:8
+ |
+LL | T: ?Sized,
+ | ^^^^^^
+ |
+note: `T` cannot be unsized because of the bound
+ --> tests/ui/needless_maybe_sized.rs:26:15
+ |
+LL | fn mixed_1<T: Sized>(t: &T)
+ | ^^^^^
+help: change the bounds that require `Sized`, or remove the `?Sized` bound
+ |
+LL - where
+LL - T: ?Sized,
+ |
+
+error: `?Sized` bound is ignored because of a `Sized` requirement
+ --> tests/ui/needless_maybe_sized.rs:32:15
+ |
+LL | fn mixed_2<T: ?Sized>(t: &T)
+ | ^^^^^^
+ |
+note: `T` cannot be unsized because of the bound
+ --> tests/ui/needless_maybe_sized.rs:34:8
+ |
+LL | T: Sized,
+ | ^^^^^
+help: change the bounds that require `Sized`, or remove the `?Sized` bound
+ |
+LL - fn mixed_2<T: ?Sized>(t: &T)
+LL + fn mixed_2<T>(t: &T)
+ |
+
+error: `?Sized` bound is ignored because of a `Sized` requirement
+ --> tests/ui/needless_maybe_sized.rs:41:8
+ |
+LL | T: ?Sized,
+ | ^^^^^^
+ |
+note: `T` cannot be unsized because of the bound
+ --> tests/ui/needless_maybe_sized.rs:40:8
+ |
+LL | T: Sized,
+ | ^^^^^
+help: change the bounds that require `Sized`, or remove the `?Sized` bound
+ |
+LL - T: Sized,
+LL - T: ?Sized,
+LL + T: Sized,
+ |
+
+error: `?Sized` bound is ignored because of a `Sized` requirement
+ --> tests/ui/needless_maybe_sized.rs:45:26
+ |
+LL | struct Struct<T: Sized + ?Sized>(T);
+ | ^^^^^^
+ |
+note: `T` cannot be unsized because of the bound
+ --> tests/ui/needless_maybe_sized.rs:45:18
+ |
+LL | struct Struct<T: Sized + ?Sized>(T);
+ | ^^^^^
+help: change the bounds that require `Sized`, or remove the `?Sized` bound
+ |
+LL - struct Struct<T: Sized + ?Sized>(T);
+LL + struct Struct<T: Sized>(T);
+ |
+
+error: `?Sized` bound is ignored because of a `Sized` requirement
+ --> tests/ui/needless_maybe_sized.rs:47:17
+ |
+LL | impl<T: Sized + ?Sized> Struct<T> {
+ | ^^^^^^
+ |
+note: `T` cannot be unsized because of the bound
+ --> tests/ui/needless_maybe_sized.rs:47:9
+ |
+LL | impl<T: Sized + ?Sized> Struct<T> {
+ | ^^^^^
+help: change the bounds that require `Sized`, or remove the `?Sized` bound
+ |
+LL - impl<T: Sized + ?Sized> Struct<T> {
+LL + impl<T: Sized> Struct<T> {
+ |
+
+error: `?Sized` bound is ignored because of a `Sized` requirement
+ --> tests/ui/needless_maybe_sized.rs:48:26
+ |
+LL | fn method<U: Sized + ?Sized>(&self) {}
+ | ^^^^^^
+ |
+note: `U` cannot be unsized because of the bound
+ --> tests/ui/needless_maybe_sized.rs:48:18
+ |
+LL | fn method<U: Sized + ?Sized>(&self) {}
+ | ^^^^^
+help: change the bounds that require `Sized`, or remove the `?Sized` bound
+ |
+LL - fn method<U: Sized + ?Sized>(&self) {}
+LL + fn method<U: Sized>(&self) {}
+ |
+
+error: `?Sized` bound is ignored because of a `Sized` requirement
+ --> tests/ui/needless_maybe_sized.rs:51:22
+ |
+LL | enum Enum<T: Sized + ?Sized + 'static> {
+ | ^^^^^^
+ |
+note: `T` cannot be unsized because of the bound
+ --> tests/ui/needless_maybe_sized.rs:51:14
+ |
+LL | enum Enum<T: Sized + ?Sized + 'static> {
+ | ^^^^^
+help: change the bounds that require `Sized`, or remove the `?Sized` bound
+ |
+LL - enum Enum<T: Sized + ?Sized + 'static> {
+LL + enum Enum<T: Sized + 'static> {
+ |
+
+error: `?Sized` bound is ignored because of a `Sized` requirement
+ --> tests/ui/needless_maybe_sized.rs:55:28
+ |
+LL | union Union<'a, T: Sized + ?Sized> {
+ | ^^^^^^
+ |
+note: `T` cannot be unsized because of the bound
+ --> tests/ui/needless_maybe_sized.rs:55:20
+ |
+LL | union Union<'a, T: Sized + ?Sized> {
+ | ^^^^^
+help: change the bounds that require `Sized`, or remove the `?Sized` bound
+ |
+LL - union Union<'a, T: Sized + ?Sized> {
+LL + union Union<'a, T: Sized> {
+ |
+
+error: `?Sized` bound is ignored because of a `Sized` requirement
+ --> tests/ui/needless_maybe_sized.rs:59:24
+ |
+LL | trait Trait<T: Sized + ?Sized> {
+ | ^^^^^^
+ |
+note: `T` cannot be unsized because of the bound
+ --> tests/ui/needless_maybe_sized.rs:59:16
+ |
+LL | trait Trait<T: Sized + ?Sized> {
+ | ^^^^^
+help: change the bounds that require `Sized`, or remove the `?Sized` bound
+ |
+LL - trait Trait<T: Sized + ?Sized> {
+LL + trait Trait<T: Sized> {
+ |
+
+error: `?Sized` bound is ignored because of a `Sized` requirement
+ --> tests/ui/needless_maybe_sized.rs:60:32
+ |
+LL | fn trait_method<U: Sized + ?Sized>() {}
+ | ^^^^^^
+ |
+note: `U` cannot be unsized because of the bound
+ --> tests/ui/needless_maybe_sized.rs:60:24
+ |
+LL | fn trait_method<U: Sized + ?Sized>() {}
+ | ^^^^^
+help: change the bounds that require `Sized`, or remove the `?Sized` bound
+ |
+LL - fn trait_method<U: Sized + ?Sized>() {}
+LL + fn trait_method<U: Sized>() {}
+ |
+
+error: `?Sized` bound is ignored because of a `Sized` requirement
+ --> tests/ui/needless_maybe_sized.rs:62:25
+ |
+LL | type GAT<U: Sized + ?Sized>;
+ | ^^^^^^
+ |
+note: `U` cannot be unsized because of the bound
+ --> tests/ui/needless_maybe_sized.rs:62:17
+ |
+LL | type GAT<U: Sized + ?Sized>;
+ | ^^^^^
+help: change the bounds that require `Sized`, or remove the `?Sized` bound
+ |
+LL - type GAT<U: Sized + ?Sized>;
+LL + type GAT<U: Sized>;
+ |
+
+error: `?Sized` bound is ignored because of a `Sized` requirement
+ --> tests/ui/needless_maybe_sized.rs:68:23
+ |
+LL | fn second_in_trait<T: ?Sized + SecondInTrait>() {}
+ | ^^^^^^
+ |
+note: `T` cannot be unsized because of the bound
+ --> tests/ui/needless_maybe_sized.rs:68:32
+ |
+LL | fn second_in_trait<T: ?Sized + SecondInTrait>() {}
+ | ^^^^^^^^^^^^^
+ = note: ...because `SecondInTrait` has the bound `Sized`
+help: change the bounds that require `Sized`, or remove the `?Sized` bound
+ |
+LL - fn second_in_trait<T: ?Sized + SecondInTrait>() {}
+LL + fn second_in_trait<T: SecondInTrait>() {}
+ |
+
+error: `?Sized` bound is ignored because of a `Sized` requirement
+ --> tests/ui/needless_maybe_sized.rs:70:33
+ |
+LL | fn impl_trait(_: &(impl Sized + ?Sized)) {}
+ | ^^^^^^
+ |
+note: `impl Sized + ?Sized` cannot be unsized because of the bound
+ --> tests/ui/needless_maybe_sized.rs:70:25
+ |
+LL | fn impl_trait(_: &(impl Sized + ?Sized)) {}
+ | ^^^^^
+help: change the bounds that require `Sized`, or remove the `?Sized` bound
+ |
+LL - fn impl_trait(_: &(impl Sized + ?Sized)) {}
+LL + fn impl_trait(_: &(impl Sized)) {}
+ |
+
+error: `?Sized` bound is ignored because of a `Sized` requirement
+ --> tests/ui/needless_maybe_sized.rs:73:42
+ |
+LL | fn in_generic_trait<T: GenericTrait<U> + ?Sized, U>() {}
+ | ^^^^^^
+ |
+note: `T` cannot be unsized because of the bound
+ --> tests/ui/needless_maybe_sized.rs:73:24
+ |
+LL | fn in_generic_trait<T: GenericTrait<U> + ?Sized, U>() {}
+ | ^^^^^^^^^^^^^^^
+ = note: ...because `GenericTrait` has the bound `Sized`
+help: change the bounds that require `Sized`, or remove the `?Sized` bound
+ |
+LL - fn in_generic_trait<T: GenericTrait<U> + ?Sized, U>() {}
+LL + fn in_generic_trait<T: GenericTrait<U>, U>() {}
+ |
+
+error: `?Sized` bound is ignored because of a `Sized` requirement
+ --> tests/ui/needless_maybe_sized.rs:88:29
+ |
+LL | fn larger_graph<T: A1 + ?Sized>() {}
+ | ^^^^^^
+ |
+note: `T` cannot be unsized because of the bound
+ --> tests/ui/needless_maybe_sized.rs:88:24
+ |
+LL | fn larger_graph<T: A1 + ?Sized>() {}
+ | ^^
+ = note: ...because `A1` has the bound `B2`
+ = note: ...because `B2` has the bound `Sized`
+help: change the bounds that require `Sized`, or remove the `?Sized` bound
+ |
+LL - fn larger_graph<T: A1 + ?Sized>() {}
+LL + fn larger_graph<T: A1>() {}
+ |
+
+error: aborting due to 20 previous errors
+
diff --git a/tests/ui/type_repetition_in_bounds.rs b/tests/ui/type_repetition_in_bounds.rs
index 0039c805b7df..d325887bfba3 100644
--- a/tests/ui/type_repetition_in_bounds.rs
+++ b/tests/ui/type_repetition_in_bounds.rs
@@ -1,5 +1,9 @@
#![deny(clippy::type_repetition_in_bounds)]
-#![allow(clippy::extra_unused_type_parameters, clippy::multiple_bound_locations)]
+#![allow(
+ clippy::extra_unused_type_parameters,
+ clippy::multiple_bound_locations,
+ clippy::needless_maybe_sized
+)]
use serde::Deserialize;
use std::ops::{Add, AddAssign, Div, DivAssign, Mul, MulAssign, Sub, SubAssign};
diff --git a/tests/ui/type_repetition_in_bounds.stderr b/tests/ui/type_repetition_in_bounds.stderr
index e9c6b41aaa8e..77944c950457 100644
--- a/tests/ui/type_repetition_in_bounds.stderr
+++ b/tests/ui/type_repetition_in_bounds.stderr
@@ -1,5 +1,5 @@
error: this type has already been used as a bound predicate
- --> tests/ui/type_repetition_in_bounds.rs:10:5
+ --> tests/ui/type_repetition_in_bounds.rs:14:5
|
LL | T: Clone,
| ^^^^^^^^
@@ -12,7 +12,7 @@ LL | #![deny(clippy::type_repetition_in_bounds)]
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
error: this type has already been used as a bound predicate
- --> tests/ui/type_repetition_in_bounds.rs:28:5
+ --> tests/ui/type_repetition_in_bounds.rs:32:5
|
LL | Self: Copy + Default + Ord,
| ^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -20,7 +20,7 @@ LL | Self: Copy + Default + Ord,
= help: consider combining the bounds: `Self: Clone + Copy + Default + Ord`
error: this type has already been used as a bound predicate
- --> tests/ui/type_repetition_in_bounds.rs:103:5
+ --> tests/ui/type_repetition_in_bounds.rs:107:5
|
LL | T: Clone,
| ^^^^^^^^
@@ -28,7 +28,7 @@ LL | T: Clone,
= help: consider combining the bounds: `T: ?Sized + Clone`
error: this type has already been used as a bound predicate
- --> tests/ui/type_repetition_in_bounds.rs:109:5
+ --> tests/ui/type_repetition_in_bounds.rs:113:5
|
LL | T: ?Sized,
| ^^^^^^^^^
@@ -36,7 +36,7 @@ LL | T: ?Sized,
= help: consider combining the bounds: `T: Clone + ?Sized`
error: this type has already been used as a bound predicate
- --> tests/ui/type_repetition_in_bounds.rs:135:9
+ --> tests/ui/type_repetition_in_bounds.rs:139:9
|
LL | T: Trait<Option<usize>, Box<[String]>, bool> + 'static,
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^