Use multipart suggestion in unnecessary_to_owned

3 files changed, 680 insertions, 95 deletions

diff --git a/tests/ui/unnecessary_to_owned.fixed b/tests/ui/unnecessary_to_owned.fixed
new file mode 100644
index 00000000000..fdcac8fb08d
--- /dev/null
+++ b/tests/ui/unnecessary_to_owned.fixed
@@ -0,0 +1,587 @@
+#![allow(
+    clippy::needless_borrow,
+    clippy::needless_borrows_for_generic_args,
+    clippy::ptr_arg,
+    clippy::manual_async_fn,
+    clippy::needless_lifetimes
+)]
+#![warn(clippy::unnecessary_to_owned, clippy::redundant_clone)]
+
+use std::borrow::Cow;
+use std::ffi::{CStr, CString, OsStr, OsString};
+use std::ops::Deref;
+
+#[derive(Clone)]
+struct X(String);
+
+impl Deref for X {
+    type Target = [u8];
+    fn deref(&self) -> &[u8] {
+        self.0.as_bytes()
+    }
+}
+
+impl AsRef<str> for X {
+    fn as_ref(&self) -> &str {
+        self.0.as_str()
+    }
+}
+
+#[allow(clippy::to_string_trait_impl)]
+impl ToString for X {
+    fn to_string(&self) -> String {
+        self.0.to_string()
+    }
+}
+
+impl X {
+    fn join(&self, other: impl AsRef<str>) -> Self {
+        let mut s = self.0.clone();
+        s.push_str(other.as_ref());
+        Self(s)
+    }
+}
+
+#[allow(dead_code)]
+#[derive(Clone)]
+enum FileType {
+    Account,
+    PrivateKey,
+    Certificate,
+}
+
+fn main() {
+    let c_str = CStr::from_bytes_with_nul(&[0]).unwrap();
+    let os_str = OsStr::new("x");
+    let path = std::path::Path::new("x");
+    let s = "x";
+    let array = ["x"];
+    let array_ref = &["x"];
+    let slice = &["x"][..];
+    let x = X(String::from("x"));
+    let x_ref = &x;
+
+    require_c_str(&Cow::from(c_str));
+    require_c_str(c_str);
+
+    require_os_str(os_str);
+    require_os_str(&Cow::from(os_str));
+    require_os_str(os_str);
+
+    require_path(path);
+    require_path(&Cow::from(path));
+    require_path(path);
+
+    require_str(s);
+    require_str(&Cow::from(s));
+    require_str(s);
+    require_str(x_ref.as_ref());
+
+    require_slice(slice);
+    require_slice(&Cow::from(slice));
+    require_slice(array.as_ref());
+    require_slice(array_ref.as_ref());
+    require_slice(slice);
+    require_slice(&x_ref.to_owned()); // No longer flagged because of #8759.
+
+    require_x(&Cow::<X>::Owned(x.clone()));
+    require_x(&x_ref.to_owned()); // No longer flagged because of #8759.
+
+    require_deref_c_str(c_str);
+    require_deref_os_str(os_str);
+    require_deref_path(path);
+    require_deref_str(s);
+    require_deref_slice(slice);
+
+    require_impl_deref_c_str(c_str);
+    require_impl_deref_os_str(os_str);
+    require_impl_deref_path(path);
+    require_impl_deref_str(s);
+    require_impl_deref_slice(slice);
+
+    require_deref_str_slice(s, slice);
+    require_deref_slice_str(slice, s);
+
+    require_as_ref_c_str(c_str);
+    require_as_ref_os_str(os_str);
+    require_as_ref_path(path);
+    require_as_ref_str(s);
+    require_as_ref_str(&x);
+    require_as_ref_slice(array);
+    require_as_ref_slice(array_ref);
+    require_as_ref_slice(slice);
+
+    require_impl_as_ref_c_str(c_str);
+    require_impl_as_ref_os_str(os_str);
+    require_impl_as_ref_path(path);
+    require_impl_as_ref_str(s);
+    require_impl_as_ref_str(&x);
+    require_impl_as_ref_slice(array);
+    require_impl_as_ref_slice(array_ref);
+    require_impl_as_ref_slice(slice);
+
+    require_as_ref_str_slice(s, array);
+    require_as_ref_str_slice(s, array_ref);
+    require_as_ref_str_slice(s, slice);
+    require_as_ref_slice_str(array, s);
+    require_as_ref_slice_str(array_ref, s);
+    require_as_ref_slice_str(slice, s);
+
+    let _ = x.join(x_ref);
+
+    let _ = slice.iter().copied();
+    let _ = slice.iter().copied();
+    let _ = [std::path::PathBuf::new()][..].iter().cloned();
+    let _ = [std::path::PathBuf::new()][..].iter().cloned();
+
+    let _ = slice.iter().copied();
+    let _ = slice.iter().copied();
+    let _ = [std::path::PathBuf::new()][..].iter().cloned();
+    let _ = [std::path::PathBuf::new()][..].iter().cloned();
+
+    let _ = check_files(&[FileType::Account]);
+
+    // negative tests
+    require_string(&s.to_string());
+    require_string(&Cow::from(s).into_owned());
+    require_string(&s.to_owned());
+    require_string(&x_ref.to_string());
+
+    // `X` isn't copy.
+    require_slice(&x.to_owned());
+    require_deref_slice(x.to_owned());
+
+    // The following should be flagged by `redundant_clone`, but not by this lint.
+    require_c_str(&CString::from_vec_with_nul(vec![0]).unwrap());
+    require_os_str(&OsString::from("x"));
+    require_path(&std::path::PathBuf::from("x"));
+    require_str(&String::from("x"));
+    require_slice(&[String::from("x")]);
+
+    let slice = [0u8; 1024];
+    let _ref_str: &str = core::str::from_utf8(&slice).expect("not UTF-8");
+    let _ref_str: &str = core::str::from_utf8(b"foo").unwrap();
+    let _ref_str: &str = core::str::from_utf8(b"foo".as_slice()).unwrap();
+    // Expression is of type `&String`, can't suggest `str::from_utf8` here
+    let _ref_string = &String::from_utf8(b"foo".to_vec()).unwrap();
+    macro_rules! arg_from_macro {
+        () => {
+            b"foo".to_vec()
+        };
+    }
+    macro_rules! string_from_utf8_from_macro {
+        () => {
+            &String::from_utf8(b"foo".to_vec()).unwrap()
+        };
+    }
+    let _ref_str: &str = &String::from_utf8(arg_from_macro!()).unwrap();
+    let _ref_str: &str = string_from_utf8_from_macro!();
+}
+
+fn require_c_str(_: &CStr) {}
+fn require_os_str(_: &OsStr) {}
+fn require_path(_: &std::path::Path) {}
+fn require_str(_: &str) {}
+fn require_slice<T>(_: &[T]) {}
+fn require_x(_: &X) {}
+
+fn require_deref_c_str<T: Deref<Target = CStr>>(_: T) {}
+fn require_deref_os_str<T: Deref<Target = OsStr>>(_: T) {}
+fn require_deref_path<T: Deref<Target = std::path::Path>>(_: T) {}
+fn require_deref_str<T: Deref<Target = str>>(_: T) {}
+fn require_deref_slice<T, U: Deref<Target = [T]>>(_: U) {}
+
+fn require_impl_deref_c_str(_: impl Deref<Target = CStr>) {}
+fn require_impl_deref_os_str(_: impl Deref<Target = OsStr>) {}
+fn require_impl_deref_path(_: impl Deref<Target = std::path::Path>) {}
+fn require_impl_deref_str(_: impl Deref<Target = str>) {}
+fn require_impl_deref_slice<T>(_: impl Deref<Target = [T]>) {}
+
+fn require_deref_str_slice<T: Deref<Target = str>, U, V: Deref<Target = [U]>>(_: T, _: V) {}
+fn require_deref_slice_str<T, U: Deref<Target = [T]>, V: Deref<Target = str>>(_: U, _: V) {}
+
+fn require_as_ref_c_str<T: AsRef<CStr>>(_: T) {}
+fn require_as_ref_os_str<T: AsRef<OsStr>>(_: T) {}
+fn require_as_ref_path<T: AsRef<std::path::Path>>(_: T) {}
+fn require_as_ref_str<T: AsRef<str>>(_: T) {}
+fn require_as_ref_slice<T, U: AsRef<[T]>>(_: U) {}
+
+fn require_impl_as_ref_c_str(_: impl AsRef<CStr>) {}
+fn require_impl_as_ref_os_str(_: impl AsRef<OsStr>) {}
+fn require_impl_as_ref_path(_: impl AsRef<std::path::Path>) {}
+fn require_impl_as_ref_str(_: impl AsRef<str>) {}
+fn require_impl_as_ref_slice<T>(_: impl AsRef<[T]>) {}
+
+fn require_as_ref_str_slice<T: AsRef<str>, U, V: AsRef<[U]>>(_: T, _: V) {}
+fn require_as_ref_slice_str<T, U: AsRef<[T]>, V: AsRef<str>>(_: U, _: V) {}
+
+// `check_files` is based on:
+// https://github.com/breard-r/acmed/blob/1f0dcc32aadbc5e52de6d23b9703554c0f925113/acmed/src/storage.rs#L262
+fn check_files(file_types: &[FileType]) -> bool {
+    for t in file_types {
+        let path = match get_file_path(t) {
+            Ok(p) => p,
+            Err(_) => {
+                return false;
+            },
+        };
+        if !path.is_file() {
+            return false;
+        }
+    }
+    true
+}
+
+fn get_file_path(_file_type: &FileType) -> Result<std::path::PathBuf, std::io::Error> {
+    Ok(std::path::PathBuf::new())
+}
+
+fn require_string(_: &String) {}
+
+#[clippy::msrv = "1.35"]
+fn _msrv_1_35() {
+    // `copied` was stabilized in 1.36, so clippy should use `cloned`.
+    let _ = &["x"][..].iter().cloned();
+}
+
+#[clippy::msrv = "1.36"]
+fn _msrv_1_36() {
+    let _ = &["x"][..].iter().copied();
+}
+
+// https://github.com/rust-lang/rust-clippy/issues/8507
+mod issue_8507 {
+    #![allow(dead_code)]
+
+    struct Opaque<P>(P);
+
+    pub trait Abstracted {}
+
+    impl<P> Abstracted for Opaque<P> {}
+
+    fn build<P>(p: P) -> Opaque<P>
+    where
+        P: AsRef<str>,
+    {
+        Opaque(p)
+    }
+
+    // Should not lint.
+    fn test_str(s: &str) -> Box<dyn Abstracted> {
+        Box::new(build(s.to_string()))
+    }
+
+    // Should not lint.
+    fn test_x(x: super::X) -> Box<dyn Abstracted> {
+        Box::new(build(x))
+    }
+
+    #[derive(Clone, Copy)]
+    struct Y(&'static str);
+
+    impl AsRef<str> for Y {
+        fn as_ref(&self) -> &str {
+            self.0
+        }
+    }
+
+    #[allow(clippy::to_string_trait_impl)]
+    impl ToString for Y {
+        fn to_string(&self) -> String {
+            self.0.to_string()
+        }
+    }
+
+    // Should lint because Y is copy.
+    fn test_y(y: Y) -> Box<dyn Abstracted> {
+        Box::new(build(y))
+    }
+}
+
+// https://github.com/rust-lang/rust-clippy/issues/8759
+mod issue_8759 {
+    #![allow(dead_code)]
+
+    #[derive(Default)]
+    struct View {}
+
+    impl std::borrow::ToOwned for View {
+        type Owned = View;
+        fn to_owned(&self) -> Self::Owned {
+            View {}
+        }
+    }
+
+    #[derive(Default)]
+    struct RenderWindow {
+        default_view: View,
+    }
+
+    impl RenderWindow {
+        fn default_view(&self) -> &View {
+            &self.default_view
+        }
+        fn set_view(&mut self, _view: &View) {}
+    }
+
+    fn main() {
+        let mut rw = RenderWindow::default();
+        rw.set_view(&rw.default_view().to_owned());
+    }
+}
+
+mod issue_8759_variant {
+    #![allow(dead_code)]
+
+    #[derive(Clone, Default)]
+    struct View {}
+
+    #[derive(Default)]
+    struct RenderWindow {
+        default_view: View,
+    }
+
+    impl RenderWindow {
+        fn default_view(&self) -> &View {
+            &self.default_view
+        }
+        fn set_view(&mut self, _view: &View) {}
+    }
+
+    fn main() {
+        let mut rw = RenderWindow::default();
+        rw.set_view(&rw.default_view().to_owned());
+    }
+}
+
+mod issue_9317 {
+    #![allow(dead_code)]
+
+    struct Bytes {}
+
+    #[allow(clippy::to_string_trait_impl)]
+    impl ToString for Bytes {
+        fn to_string(&self) -> String {
+            "123".to_string()
+        }
+    }
+
+    impl AsRef<[u8]> for Bytes {
+        fn as_ref(&self) -> &[u8] {
+            &[1, 2, 3]
+        }
+    }
+
+    fn consume<C: AsRef<[u8]>>(c: C) {
+        let _ = c;
+    }
+
+    pub fn main() {
+        let b = Bytes {};
+        // Should not lint.
+        consume(b.to_string());
+    }
+}
+
+mod issue_9351 {
+    #![allow(dead_code)]
+
+    use std::ops::Deref;
+    use std::path::{Path, PathBuf};
+
+    fn require_deref_path<T: Deref<Target = std::path::Path>>(x: T) -> T {
+        x
+    }
+
+    fn generic_arg_used_elsewhere<T: AsRef<Path>>(_x: T, _y: T) {}
+
+    fn id<T: AsRef<str>>(x: T) -> T {
+        x
+    }
+
+    fn predicates_are_satisfied(_x: impl std::fmt::Write) {}
+
+    // Should lint
+    fn single_return() -> impl AsRef<str> {
+        id("abc")
+    }
+
+    // Should not lint
+    fn multiple_returns(b: bool) -> impl AsRef<str> {
+        if b {
+            return String::new();
+        }
+
+        id("abc".to_string())
+    }
+
+    struct S1(String);
+
+    // Should not lint
+    fn fields1() -> S1 {
+        S1(id("abc".to_string()))
+    }
+
+    struct S2 {
+        s: String,
+    }
+
+    // Should not lint
+    fn fields2() {
+        let mut s = S2 { s: "abc".into() };
+        s.s = id("abc".to_string());
+    }
+
+    pub fn main() {
+        let path = std::path::Path::new("x");
+        let path_buf = path.to_owned();
+
+        // Should not lint.
+        let _x: PathBuf = require_deref_path(path.to_owned());
+        generic_arg_used_elsewhere(path.to_owned(), path_buf);
+        predicates_are_satisfied(id("abc".to_string()));
+    }
+}
+
+mod issue_9504 {
+    #![allow(dead_code)]
+
+    async fn foo<S: AsRef<str>>(_: S) {}
+    async fn bar() {
+        foo(std::path::PathBuf::new().to_string_lossy().to_string()).await;
+    }
+}
+
+mod issue_9771a {
+    #![allow(dead_code)]
+
+    use std::marker::PhantomData;
+
+    pub struct Key<K: AsRef<[u8]>, V: ?Sized>(K, PhantomData<V>);
+
+    impl<K: AsRef<[u8]>, V: ?Sized> Key<K, V> {
+        pub fn new(key: K) -> Key<K, V> {
+            Key(key, PhantomData)
+        }
+    }
+
+    pub fn pkh(pkh: &[u8]) -> Key<Vec<u8>, String> {
+        Key::new([b"pkh-", pkh].concat().to_vec())
+    }
+}
+
+mod issue_9771b {
+    #![allow(dead_code)]
+
+    pub struct Key<K: AsRef<[u8]>>(K);
+
+    pub fn from(c: &[u8]) -> Key<Vec<u8>> {
+        let v = [c].concat();
+        Key(v.to_vec())
+    }
+}
+
+// This is a watered down version of the code in: https://github.com/oxigraph/rio
+// The ICE is triggered by the call to `to_owned` on this line:
+// https://github.com/oxigraph/rio/blob/66635b9ff8e5423e58932353fa40d6e64e4820f7/testsuite/src/parser_evaluator.rs#L116
+mod issue_10021 {
+    #![allow(unused)]
+
+    pub struct Iri<T>(T);
+
+    impl<T: AsRef<str>> Iri<T> {
+        pub fn parse(iri: T) -> Result<Self, ()> {
+            unimplemented!()
+        }
+    }
+
+    pub fn parse_w3c_rdf_test_file(url: &str) -> Result<(), ()> {
+        let base_iri = Iri::parse(url.to_owned())?;
+        Ok(())
+    }
+}
+
+mod issue_10033 {
+    #![allow(dead_code)]
+    use std::fmt::Display;
+    use std::ops::Deref;
+
+    fn _main() {
+        let f = Foo;
+
+        // Not actually unnecessary - this calls `Foo`'s `Display` impl, not `str`'s (even though `Foo` does
+        // deref to `str`)
+        foo(&f.to_string());
+    }
+
+    fn foo(s: &str) {
+        println!("{}", s);
+    }
+
+    struct Foo;
+
+    impl Deref for Foo {
+        type Target = str;
+
+        fn deref(&self) -> &Self::Target {
+            "str"
+        }
+    }
+
+    impl Display for Foo {
+        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+            write!(f, "Foo")
+        }
+    }
+}
+
+mod issue_11952 {
+    use core::future::{Future, IntoFuture};
+
+    fn foo<'a, T: AsRef<[u8]>>(x: T, y: &'a i32) -> impl 'a + Future<Output = Result<(), ()>> {
+        async move {
+            let _y = y;
+            Ok(())
+        }
+    }
+
+    fn bar() {
+        IntoFuture::into_future(foo([], &0));
+    }
+}
+
+fn borrow_checks() {
+    use std::borrow::Borrow;
+    use std::collections::HashSet;
+
+    fn inner(a: &[&str]) {
+        let mut s = HashSet::from([vec!["a"]]);
+        s.remove(a); //~ ERROR: unnecessary use of `to_vec`
+    }
+
+    let mut s = HashSet::from(["a".to_string()]);
+    s.remove("b"); //~ ERROR: unnecessary use of `to_owned`
+    s.remove("b"); //~ ERROR: unnecessary use of `to_string`
+    // Should not warn.
+    s.remove("b");
+
+    let mut s = HashSet::from([vec!["a"]]);
+    s.remove(["b"].as_slice()); //~ ERROR: unnecessary use of `to_vec`
+    s.remove((&["b"]).as_slice()); //~ ERROR: unnecessary use of `to_vec`
+
+    // Should not warn.
+    s.remove(&["b"].to_vec().clone());
+    s.remove(["a"].as_slice());
+
+    trait SetExt {
+        fn foo<Q: Borrow<str>>(&self, _: &String);
+    }
+
+    impl<K> SetExt for HashSet<K> {
+        fn foo<Q: Borrow<str>>(&self, _: &String) {}
+    }
+
+    // Should not lint!
+    HashSet::<i32>::new().foo::<&str>(&"".to_owned());
+    HashSet::<String>::new().get(&1.to_string());
+}
diff --git a/tests/ui/unnecessary_to_owned.rs b/tests/ui/unnecessary_to_owned.rs
index da0c761f795..10a9727a9a7 100644
--- a/tests/ui/unnecessary_to_owned.rs
+++ b/tests/ui/unnecessary_to_owned.rs
@@ -7,8 +7,6 @@
 )]
 #![warn(clippy::unnecessary_to_owned, clippy::redundant_clone)]
 
-//@no-rustfix: need to change the suggestion to a multipart suggestion
-
 use std::borrow::Cow;
 use std::ffi::{CStr, CString, OsStr, OsString};
 use std::ops::Deref;
diff --git a/tests/ui/unnecessary_to_owned.stderr b/tests/ui/unnecessary_to_owned.stderr
index 396802e16d5..498ac68cdaa 100644
--- a/tests/ui/unnecessary_to_owned.stderr
+++ b/tests/ui/unnecessary_to_owned.stderr
@@ -1,11 +1,11 @@
 error: redundant clone
-  --> tests/ui/unnecessary_to_owned.rs:157:64
+  --> tests/ui/unnecessary_to_owned.rs:155:64
    |
 LL |     require_c_str(&CString::from_vec_with_nul(vec![0]).unwrap().to_owned());
    |                                                                ^^^^^^^^^^^ help: remove this
    |
 note: this value is dropped without further use
-  --> tests/ui/unnecessary_to_owned.rs:157:20
+  --> tests/ui/unnecessary_to_owned.rs:155:20
    |
 LL |     require_c_str(&CString::from_vec_with_nul(vec![0]).unwrap().to_owned());
    |                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -13,55 +13,55 @@ LL |     require_c_str(&CString::from_vec_with_nul(vec![0]).unwrap().to_owned())
    = help: to override `-D warnings` add `#[allow(clippy::redundant_clone)]`
 
 error: redundant clone
-  --> tests/ui/unnecessary_to_owned.rs:158:40
+  --> tests/ui/unnecessary_to_owned.rs:156:40
    |
 LL |     require_os_str(&OsString::from("x").to_os_string());
    |                                        ^^^^^^^^^^^^^^^ help: remove this
    |
 note: this value is dropped without further use
-  --> tests/ui/unnecessary_to_owned.rs:158:21
+  --> tests/ui/unnecessary_to_owned.rs:156:21
    |
 LL |     require_os_str(&OsString::from("x").to_os_string());
    |                     ^^^^^^^^^^^^^^^^^^^
 
 error: redundant clone
-  --> tests/ui/unnecessary_to_owned.rs:159:48
+  --> tests/ui/unnecessary_to_owned.rs:157:48
    |
 LL |     require_path(&std::path::PathBuf::from("x").to_path_buf());
    |                                                ^^^^^^^^^^^^^^ help: remove this
    |
 note: this value is dropped without further use
-  --> tests/ui/unnecessary_to_owned.rs:159:19
+  --> tests/ui/unnecessary_to_owned.rs:157:19
    |
 LL |     require_path(&std::path::PathBuf::from("x").to_path_buf());
    |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: redundant clone
-  --> tests/ui/unnecessary_to_owned.rs:160:35
+  --> tests/ui/unnecessary_to_owned.rs:158:35
    |
 LL |     require_str(&String::from("x").to_string());
    |                                   ^^^^^^^^^^^^ help: remove this
    |
 note: this value is dropped without further use
-  --> tests/ui/unnecessary_to_owned.rs:160:18
+  --> tests/ui/unnecessary_to_owned.rs:158:18
    |
 LL |     require_str(&String::from("x").to_string());
    |                  ^^^^^^^^^^^^^^^^^
 
 error: redundant clone
-  --> tests/ui/unnecessary_to_owned.rs:161:39
+  --> tests/ui/unnecessary_to_owned.rs:159:39
    |
 LL |     require_slice(&[String::from("x")].to_owned());
    |                                       ^^^^^^^^^^^ help: remove this
    |
 note: this value is dropped without further use
-  --> tests/ui/unnecessary_to_owned.rs:161:20
+  --> tests/ui/unnecessary_to_owned.rs:159:20
    |
 LL |     require_slice(&[String::from("x")].to_owned());
    |                    ^^^^^^^^^^^^^^^^^^^
 
 error: unnecessary use of `into_owned`
-  --> tests/ui/unnecessary_to_owned.rs:66:36
+  --> tests/ui/unnecessary_to_owned.rs:64:36
    |
 LL |     require_c_str(&Cow::from(c_str).into_owned());
    |                                    ^^^^^^^^^^^^^ help: remove this
@@ -70,415 +70,415 @@ LL |     require_c_str(&Cow::from(c_str).into_owned());
    = help: to override `-D warnings` add `#[allow(clippy::unnecessary_to_owned)]`
 
 error: unnecessary use of `to_owned`
-  --> tests/ui/unnecessary_to_owned.rs:67:19
+  --> tests/ui/unnecessary_to_owned.rs:65:19
    |
 LL |     require_c_str(&c_str.to_owned());
    |                   ^^^^^^^^^^^^^^^^^ help: use: `c_str`
 
 error: unnecessary use of `to_os_string`
-  --> tests/ui/unnecessary_to_owned.rs:69:20
+  --> tests/ui/unnecessary_to_owned.rs:67:20
    |
 LL |     require_os_str(&os_str.to_os_string());
    |                    ^^^^^^^^^^^^^^^^^^^^^^ help: use: `os_str`
 
 error: unnecessary use of `into_owned`
-  --> tests/ui/unnecessary_to_owned.rs:70:38
+  --> tests/ui/unnecessary_to_owned.rs:68:38
    |
 LL |     require_os_str(&Cow::from(os_str).into_owned());
    |                                      ^^^^^^^^^^^^^ help: remove this
 
 error: unnecessary use of `to_owned`
-  --> tests/ui/unnecessary_to_owned.rs:71:20
+  --> tests/ui/unnecessary_to_owned.rs:69:20
    |
 LL |     require_os_str(&os_str.to_owned());
    |                    ^^^^^^^^^^^^^^^^^^ help: use: `os_str`
 
 error: unnecessary use of `to_path_buf`
-  --> tests/ui/unnecessary_to_owned.rs:73:18
+  --> tests/ui/unnecessary_to_owned.rs:71:18
    |
 LL |     require_path(&path.to_path_buf());
    |                  ^^^^^^^^^^^^^^^^^^^ help: use: `path`
 
 error: unnecessary use of `into_owned`
-  --> tests/ui/unnecessary_to_owned.rs:74:34
+  --> tests/ui/unnecessary_to_owned.rs:72:34
    |
 LL |     require_path(&Cow::from(path).into_owned());
    |                                  ^^^^^^^^^^^^^ help: remove this
 
 error: unnecessary use of `to_owned`
-  --> tests/ui/unnecessary_to_owned.rs:75:18
+  --> tests/ui/unnecessary_to_owned.rs:73:18
    |
 LL |     require_path(&path.to_owned());
    |                  ^^^^^^^^^^^^^^^^ help: use: `path`
 
 error: unnecessary use of `to_string`
-  --> tests/ui/unnecessary_to_owned.rs:77:17
+  --> tests/ui/unnecessary_to_owned.rs:75:17
    |
 LL |     require_str(&s.to_string());
    |                 ^^^^^^^^^^^^^^ help: use: `s`
 
 error: unnecessary use of `into_owned`
-  --> tests/ui/unnecessary_to_owned.rs:78:30
+  --> tests/ui/unnecessary_to_owned.rs:76:30
    |
 LL |     require_str(&Cow::from(s).into_owned());
    |                              ^^^^^^^^^^^^^ help: remove this
 
 error: unnecessary use of `to_owned`
-  --> tests/ui/unnecessary_to_owned.rs:79:17
+  --> tests/ui/unnecessary_to_owned.rs:77:17
    |
 LL |     require_str(&s.to_owned());
    |                 ^^^^^^^^^^^^^ help: use: `s`
 
 error: unnecessary use of `to_string`
-  --> tests/ui/unnecessary_to_owned.rs:80:17
+  --> tests/ui/unnecessary_to_owned.rs:78:17
    |
 LL |     require_str(&x_ref.to_string());
    |                 ^^^^^^^^^^^^^^^^^^ help: use: `x_ref.as_ref()`
 
 error: unnecessary use of `to_vec`
-  --> tests/ui/unnecessary_to_owned.rs:82:19
+  --> tests/ui/unnecessary_to_owned.rs:80:19
    |
 LL |     require_slice(&slice.to_vec());
    |                   ^^^^^^^^^^^^^^^ help: use: `slice`
 
 error: unnecessary use of `into_owned`
-  --> tests/ui/unnecessary_to_owned.rs:83:36
+  --> tests/ui/unnecessary_to_owned.rs:81:36
    |
 LL |     require_slice(&Cow::from(slice).into_owned());
    |                                    ^^^^^^^^^^^^^ help: remove this
 
 error: unnecessary use of `to_owned`
-  --> tests/ui/unnecessary_to_owned.rs:84:19
+  --> tests/ui/unnecessary_to_owned.rs:82:19
    |
 LL |     require_slice(&array.to_owned());
    |                   ^^^^^^^^^^^^^^^^^ help: use: `array.as_ref()`
 
 error: unnecessary use of `to_owned`
-  --> tests/ui/unnecessary_to_owned.rs:85:19
+  --> tests/ui/unnecessary_to_owned.rs:83:19
    |
 LL |     require_slice(&array_ref.to_owned());
    |                   ^^^^^^^^^^^^^^^^^^^^^ help: use: `array_ref.as_ref()`
 
 error: unnecessary use of `to_owned`
-  --> tests/ui/unnecessary_to_owned.rs:86:19
+  --> tests/ui/unnecessary_to_owned.rs:84:19
    |
 LL |     require_slice(&slice.to_owned());
    |                   ^^^^^^^^^^^^^^^^^ help: use: `slice`
 
 error: unnecessary use of `into_owned`
-  --> tests/ui/unnecessary_to_owned.rs:89:42
+  --> tests/ui/unnecessary_to_owned.rs:87:42
    |
 LL |     require_x(&Cow::<X>::Owned(x.clone()).into_owned());
    |                                          ^^^^^^^^^^^^^ help: remove this
 
 error: unnecessary use of `to_owned`
-  --> tests/ui/unnecessary_to_owned.rs:92:25
+  --> tests/ui/unnecessary_to_owned.rs:90:25
    |
 LL |     require_deref_c_str(c_str.to_owned());
    |                         ^^^^^^^^^^^^^^^^ help: use: `c_str`
 
 error: unnecessary use of `to_owned`
-  --> tests/ui/unnecessary_to_owned.rs:93:26
+  --> tests/ui/unnecessary_to_owned.rs:91:26
    |
 LL |     require_deref_os_str(os_str.to_owned());
    |                          ^^^^^^^^^^^^^^^^^ help: use: `os_str`
 
 error: unnecessary use of `to_owned`
-  --> tests/ui/unnecessary_to_owned.rs:94:24
+  --> tests/ui/unnecessary_to_owned.rs:92:24
    |
 LL |     require_deref_path(path.to_owned());
    |                        ^^^^^^^^^^^^^^^ help: use: `path`
 
 error: unnecessary use of `to_owned`
-  --> tests/ui/unnecessary_to_owned.rs:95:23
+  --> tests/ui/unnecessary_to_owned.rs:93:23
    |
 LL |     require_deref_str(s.to_owned());
    |                       ^^^^^^^^^^^^ help: use: `s`
 
 error: unnecessary use of `to_owned`
-  --> tests/ui/unnecessary_to_owned.rs:96:25
+  --> tests/ui/unnecessary_to_owned.rs:94:25
    |
 LL |     require_deref_slice(slice.to_owned());
    |                         ^^^^^^^^^^^^^^^^ help: use: `slice`
 
 error: unnecessary use of `to_owned`
-  --> tests/ui/unnecessary_to_owned.rs:98:30
+  --> tests/ui/unnecessary_to_owned.rs:96:30
    |
 LL |     require_impl_deref_c_str(c_str.to_owned());
    |                              ^^^^^^^^^^^^^^^^ help: use: `c_str`
 
 error: unnecessary use of `to_owned`
-  --> tests/ui/unnecessary_to_owned.rs:99:31
+  --> tests/ui/unnecessary_to_owned.rs:97:31
    |
 LL |     require_impl_deref_os_str(os_str.to_owned());
    |                               ^^^^^^^^^^^^^^^^^ help: use: `os_str`
 
 error: unnecessary use of `to_owned`
-  --> tests/ui/unnecessary_to_owned.rs:100:29
+  --> tests/ui/unnecessary_to_owned.rs:98:29
    |
 LL |     require_impl_deref_path(path.to_owned());
    |                             ^^^^^^^^^^^^^^^ help: use: `path`
 
 error: unnecessary use of `to_owned`
-  --> tests/ui/unnecessary_to_owned.rs:101:28
+  --> tests/ui/unnecessary_to_owned.rs:99:28
    |
 LL |     require_impl_deref_str(s.to_owned());
    |                            ^^^^^^^^^^^^ help: use: `s`
 
 error: unnecessary use of `to_owned`
-  --> tests/ui/unnecessary_to_owned.rs:102:30
+  --> tests/ui/unnecessary_to_owned.rs:100:30
    |
 LL |     require_impl_deref_slice(slice.to_owned());
    |                              ^^^^^^^^^^^^^^^^ help: use: `slice`
 
 error: unnecessary use of `to_owned`
-  --> tests/ui/unnecessary_to_owned.rs:104:29
+  --> tests/ui/unnecessary_to_owned.rs:102:29
    |
 LL |     require_deref_str_slice(s.to_owned(), slice.to_owned());
    |                             ^^^^^^^^^^^^ help: use: `s`
 
 error: unnecessary use of `to_owned`
-  --> tests/ui/unnecessary_to_owned.rs:104:43
+  --> tests/ui/unnecessary_to_owned.rs:102:43
    |
 LL |     require_deref_str_slice(s.to_owned(), slice.to_owned());
    |                                           ^^^^^^^^^^^^^^^^ help: use: `slice`
 
 error: unnecessary use of `to_owned`
-  --> tests/ui/unnecessary_to_owned.rs:105:29
+  --> tests/ui/unnecessary_to_owned.rs:103:29
    |
 LL |     require_deref_slice_str(slice.to_owned(), s.to_owned());
    |                             ^^^^^^^^^^^^^^^^ help: use: `slice`
 
 error: unnecessary use of `to_owned`
-  --> tests/ui/unnecessary_to_owned.rs:105:47
+  --> tests/ui/unnecessary_to_owned.rs:103:47
    |
 LL |     require_deref_slice_str(slice.to_owned(), s.to_owned());
    |                                               ^^^^^^^^^^^^ help: use: `s`
 
 error: unnecessary use of `to_owned`
-  --> tests/ui/unnecessary_to_owned.rs:107:26
+  --> tests/ui/unnecessary_to_owned.rs:105:26
    |
 LL |     require_as_ref_c_str(c_str.to_owned());
    |                          ^^^^^^^^^^^^^^^^ help: use: `c_str`
 
 error: unnecessary use of `to_owned`
-  --> tests/ui/unnecessary_to_owned.rs:108:27
+  --> tests/ui/unnecessary_to_owned.rs:106:27
    |
 LL |     require_as_ref_os_str(os_str.to_owned());
    |                           ^^^^^^^^^^^^^^^^^ help: use: `os_str`
 
 error: unnecessary use of `to_owned`
-  --> tests/ui/unnecessary_to_owned.rs:109:25
+  --> tests/ui/unnecessary_to_owned.rs:107:25
    |
 LL |     require_as_ref_path(path.to_owned());
    |                         ^^^^^^^^^^^^^^^ help: use: `path`
 
 error: unnecessary use of `to_owned`
-  --> tests/ui/unnecessary_to_owned.rs:110:24
+  --> tests/ui/unnecessary_to_owned.rs:108:24
    |
 LL |     require_as_ref_str(s.to_owned());
    |                        ^^^^^^^^^^^^ help: use: `s`
 
 error: unnecessary use of `to_owned`
-  --> tests/ui/unnecessary_to_owned.rs:111:24
+  --> tests/ui/unnecessary_to_owned.rs:109:24
    |
 LL |     require_as_ref_str(x.to_owned());
    |                        ^^^^^^^^^^^^ help: use: `&x`
 
 error: unnecessary use of `to_owned`
-  --> tests/ui/unnecessary_to_owned.rs:112:26
+  --> tests/ui/unnecessary_to_owned.rs:110:26
    |
 LL |     require_as_ref_slice(array.to_owned());
    |                          ^^^^^^^^^^^^^^^^ help: use: `array`
 
 error: unnecessary use of `to_owned`
-  --> tests/ui/unnecessary_to_owned.rs:113:26
+  --> tests/ui/unnecessary_to_owned.rs:111:26
    |
 LL |     require_as_ref_slice(array_ref.to_owned());
    |                          ^^^^^^^^^^^^^^^^^^^^ help: use: `array_ref`
 
 error: unnecessary use of `to_owned`
-  --> tests/ui/unnecessary_to_owned.rs:114:26
+  --> tests/ui/unnecessary_to_owned.rs:112:26
    |
 LL |     require_as_ref_slice(slice.to_owned());
    |                          ^^^^^^^^^^^^^^^^ help: use: `slice`
 
 error: unnecessary use of `to_owned`
-  --> tests/ui/unnecessary_to_owned.rs:116:31
+  --> tests/ui/unnecessary_to_owned.rs:114:31
    |
 LL |     require_impl_as_ref_c_str(c_str.to_owned());
    |                               ^^^^^^^^^^^^^^^^ help: use: `c_str`
 
 error: unnecessary use of `to_owned`
-  --> tests/ui/unnecessary_to_owned.rs:117:32
+  --> tests/ui/unnecessary_to_owned.rs:115:32
    |
 LL |     require_impl_as_ref_os_str(os_str.to_owned());
    |                                ^^^^^^^^^^^^^^^^^ help: use: `os_str`
 
 error: unnecessary use of `to_owned`
-  --> tests/ui/unnecessary_to_owned.rs:118:30
+  --> tests/ui/unnecessary_to_owned.rs:116:30
    |
 LL |     require_impl_as_ref_path(path.to_owned());
    |                              ^^^^^^^^^^^^^^^ help: use: `path`
 
 error: unnecessary use of `to_owned`
-  --> tests/ui/unnecessary_to_owned.rs:119:29
+  --> tests/ui/unnecessary_to_owned.rs:117:29
    |
 LL |     require_impl_as_ref_str(s.to_owned());
    |                             ^^^^^^^^^^^^ help: use: `s`
 
 error: unnecessary use of `to_owned`
-  --> tests/ui/unnecessary_to_owned.rs:120:29
+  --> tests/ui/unnecessary_to_owned.rs:118:29
    |
 LL |     require_impl_as_ref_str(x.to_owned());
    |                             ^^^^^^^^^^^^ help: use: `&x`
 
 error: unnecessary use of `to_owned`
-  --> tests/ui/unnecessary_to_owned.rs:121:31
+  --> tests/ui/unnecessary_to_owned.rs:119:31
    |
 LL |     require_impl_as_ref_slice(array.to_owned());
    |                               ^^^^^^^^^^^^^^^^ help: use: `array`
 
 error: unnecessary use of `to_owned`
-  --> tests/ui/unnecessary_to_owned.rs:122:31
+  --> tests/ui/unnecessary_to_owned.rs:120:31
    |
 LL |     require_impl_as_ref_slice(array_ref.to_owned());
    |                               ^^^^^^^^^^^^^^^^^^^^ help: use: `array_ref`
 
 error: unnecessary use of `to_owned`
-  --> tests/ui/unnecessary_to_owned.rs:123:31
+  --> tests/ui/unnecessary_to_owned.rs:121:31
    |
 LL |     require_impl_as_ref_slice(slice.to_owned());
    |                               ^^^^^^^^^^^^^^^^ help: use: `slice`
 
 error: unnecessary use of `to_owned`
-  --> tests/ui/unnecessary_to_owned.rs:125:30
+  --> tests/ui/unnecessary_to_owned.rs:123:30
    |
 LL |     require_as_ref_str_slice(s.to_owned(), array.to_owned());
    |                              ^^^^^^^^^^^^ help: use: `s`
 
 error: unnecessary use of `to_owned`
-  --> tests/ui/unnecessary_to_owned.rs:125:44
+  --> tests/ui/unnecessary_to_owned.rs:123:44
    |
 LL |     require_as_ref_str_slice(s.to_owned(), array.to_owned());
    |                                            ^^^^^^^^^^^^^^^^ help: use: `array`
 
 error: unnecessary use of `to_owned`
-  --> tests/ui/unnecessary_to_owned.rs:126:30
+  --> tests/ui/unnecessary_to_owned.rs:124:30
    |
 LL |     require_as_ref_str_slice(s.to_owned(), array_ref.to_owned());
    |                              ^^^^^^^^^^^^ help: use: `s`
 
 error: unnecessary use of `to_owned`
-  --> tests/ui/unnecessary_to_owned.rs:126:44
+  --> tests/ui/unnecessary_to_owned.rs:124:44
    |
 LL |     require_as_ref_str_slice(s.to_owned(), array_ref.to_owned());
    |                                            ^^^^^^^^^^^^^^^^^^^^ help: use: `array_ref`
 
 error: unnecessary use of `to_owned`
-  --> tests/ui/unnecessary_to_owned.rs:127:30
+  --> tests/ui/unnecessary_to_owned.rs:125:30
    |
 LL |     require_as_ref_str_slice(s.to_owned(), slice.to_owned());
    |                              ^^^^^^^^^^^^ help: use: `s`
 
 error: unnecessary use of `to_owned`
-  --> tests/ui/unnecessary_to_owned.rs:127:44
+  --> tests/ui/unnecessary_to_owned.rs:125:44
    |
 LL |     require_as_ref_str_slice(s.to_owned(), slice.to_owned());
    |                                            ^^^^^^^^^^^^^^^^ help: use: `slice`
 
 error: unnecessary use of `to_owned`
-  --> tests/ui/unnecessary_to_owned.rs:128:30
+  --> tests/ui/unnecessary_to_owned.rs:126:30
    |
 LL |     require_as_ref_slice_str(array.to_owned(), s.to_owned());
    |                              ^^^^^^^^^^^^^^^^ help: use: `array`
 
 error: unnecessary use of `to_owned`
-  --> tests/ui/unnecessary_to_owned.rs:128:48
+  --> tests/ui/unnecessary_to_owned.rs:126:48
    |
 LL |     require_as_ref_slice_str(array.to_owned(), s.to_owned());
    |                                                ^^^^^^^^^^^^ help: use: `s`
 
 error: unnecessary use of `to_owned`
-  --> tests/ui/unnecessary_to_owned.rs:129:30
+  --> tests/ui/unnecessary_to_owned.rs:127:30
    |
 LL |     require_as_ref_slice_str(array_ref.to_owned(), s.to_owned());
    |                              ^^^^^^^^^^^^^^^^^^^^ help: use: `array_ref`
 
 error: unnecessary use of `to_owned`
-  --> tests/ui/unnecessary_to_owned.rs:129:52
+  --> tests/ui/unnecessary_to_owned.rs:127:52
    |
 LL |     require_as_ref_slice_str(array_ref.to_owned(), s.to_owned());
    |                                                    ^^^^^^^^^^^^ help: use: `s`
 
 error: unnecessary use of `to_owned`
-  --> tests/ui/unnecessary_to_owned.rs:130:30
+  --> tests/ui/unnecessary_to_owned.rs:128:30
    |
 LL |     require_as_ref_slice_str(slice.to_owned(), s.to_owned());
    |                              ^^^^^^^^^^^^^^^^ help: use: `slice`
 
 error: unnecessary use of `to_owned`
-  --> tests/ui/unnecessary_to_owned.rs:130:48
+  --> tests/ui/unnecessary_to_owned.rs:128:48
    |
 LL |     require_as_ref_slice_str(slice.to_owned(), s.to_owned());
    |                                                ^^^^^^^^^^^^ help: use: `s`
 
 error: unnecessary use of `to_string`
-  --> tests/ui/unnecessary_to_owned.rs:132:20
+  --> tests/ui/unnecessary_to_owned.rs:130:20
    |
 LL |     let _ = x.join(&x_ref.to_string());
    |                    ^^^^^^^^^^^^^^^^^^ help: use: `x_ref`
 
 error: unnecessary use of `to_vec`
-  --> tests/ui/unnecessary_to_owned.rs:134:13
+  --> tests/ui/unnecessary_to_owned.rs:132:13
    |
 LL |     let _ = slice.to_vec().into_iter();
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use: `slice.iter().copied()`
 
 error: unnecessary use of `to_owned`
-  --> tests/ui/unnecessary_to_owned.rs:135:13
+  --> tests/ui/unnecessary_to_owned.rs:133:13
    |
 LL |     let _ = slice.to_owned().into_iter();
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use: `slice.iter().copied()`
 
 error: unnecessary use of `to_vec`
-  --> tests/ui/unnecessary_to_owned.rs:136:13
+  --> tests/ui/unnecessary_to_owned.rs:134:13
    |
 LL |     let _ = [std::path::PathBuf::new()][..].to_vec().into_iter();
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use: `[std::path::PathBuf::new()][..].iter().cloned()`
 
 error: unnecessary use of `to_owned`
-  --> tests/ui/unnecessary_to_owned.rs:137:13
+  --> tests/ui/unnecessary_to_owned.rs:135:13
    |
 LL |     let _ = [std::path::PathBuf::new()][..].to_owned().into_iter();
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use: `[std::path::PathBuf::new()][..].iter().cloned()`
 
 error: unnecessary use of `to_vec`
-  --> tests/ui/unnecessary_to_owned.rs:139:13
+  --> tests/ui/unnecessary_to_owned.rs:137:13
    |
 LL |     let _ = IntoIterator::into_iter(slice.to_vec());
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use: `slice.iter().copied()`
 
 error: unnecessary use of `to_owned`
-  --> tests/ui/unnecessary_to_owned.rs:140:13
+  --> tests/ui/unnecessary_to_owned.rs:138:13
    |
 LL |     let _ = IntoIterator::into_iter(slice.to_owned());
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use: `slice.iter().copied()`
 
 error: unnecessary use of `to_vec`
-  --> tests/ui/unnecessary_to_owned.rs:141:13
+  --> tests/ui/unnecessary_to_owned.rs:139:13
    |
 LL |     let _ = IntoIterator::into_iter([std::path::PathBuf::new()][..].to_vec());
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use: `[std::path::PathBuf::new()][..].iter().cloned()`
 
 error: unnecessary use of `to_owned`
-  --> tests/ui/unnecessary_to_owned.rs:142:13
+  --> tests/ui/unnecessary_to_owned.rs:140:13
    |
 LL |     let _ = IntoIterator::into_iter([std::path::PathBuf::new()][..].to_owned());
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use: `[std::path::PathBuf::new()][..].iter().cloned()`
 
 error: allocating a new `String` only to create a temporary `&str` from it
-  --> tests/ui/unnecessary_to_owned.rs:164:26
+  --> tests/ui/unnecessary_to_owned.rs:162:26
    |
 LL |     let _ref_str: &str = &String::from_utf8(slice.to_vec()).expect("not UTF-8");
    |                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -490,7 +490,7 @@ LL +     let _ref_str: &str = core::str::from_utf8(&slice).expect("not UTF-8");
    |
 
 error: allocating a new `String` only to create a temporary `&str` from it
-  --> tests/ui/unnecessary_to_owned.rs:165:26
+  --> tests/ui/unnecessary_to_owned.rs:163:26
    |
 LL |     let _ref_str: &str = &String::from_utf8(b"foo".to_vec()).unwrap();
    |                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -502,7 +502,7 @@ LL +     let _ref_str: &str = core::str::from_utf8(b"foo").unwrap();
    |
 
 error: allocating a new `String` only to create a temporary `&str` from it
-  --> tests/ui/unnecessary_to_owned.rs:166:26
+  --> tests/ui/unnecessary_to_owned.rs:164:26
    |
 LL |     let _ref_str: &str = &String::from_utf8(b"foo".as_slice().to_owned()).unwrap();
    |                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -514,7 +514,7 @@ LL +     let _ref_str: &str = core::str::from_utf8(b"foo".as_slice()).unwrap();
    |
 
 error: unnecessary use of `to_vec`
-  --> tests/ui/unnecessary_to_owned.rs:223:14
+  --> tests/ui/unnecessary_to_owned.rs:221:14
    |
 LL |     for t in file_types.to_vec() {
    |              ^^^^^^^^^^^^^^^^^^^
@@ -526,61 +526,61 @@ LL ~         let path = match get_file_path(t) {
    |
 
 error: unnecessary use of `to_vec`
-  --> tests/ui/unnecessary_to_owned.rs:246:14
+  --> tests/ui/unnecessary_to_owned.rs:244:14
    |
 LL |     let _ = &["x"][..].to_vec().into_iter();
    |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use: `["x"][..].iter().cloned()`
 
 error: unnecessary use of `to_vec`
-  --> tests/ui/unnecessary_to_owned.rs:251:14
+  --> tests/ui/unnecessary_to_owned.rs:249:14
    |
 LL |     let _ = &["x"][..].to_vec().into_iter();
    |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use: `["x"][..].iter().copied()`
 
 error: unnecessary use of `to_string`
-  --> tests/ui/unnecessary_to_owned.rs:299:24
+  --> tests/ui/unnecessary_to_owned.rs:297:24
    |
 LL |         Box::new(build(y.to_string()))
    |                        ^^^^^^^^^^^^^ help: use: `y`
 
 error: unnecessary use of `to_string`
-  --> tests/ui/unnecessary_to_owned.rs:408:12
+  --> tests/ui/unnecessary_to_owned.rs:406:12
    |
 LL |         id("abc".to_string())
    |            ^^^^^^^^^^^^^^^^^ help: use: `"abc"`
 
 error: unnecessary use of `to_vec`
-  --> tests/ui/unnecessary_to_owned.rs:551:37
+  --> tests/ui/unnecessary_to_owned.rs:549:37
    |
 LL |         IntoFuture::into_future(foo([].to_vec(), &0));
    |                                     ^^^^^^^^^^^ help: use: `[]`
 
 error: unnecessary use of `to_vec`
-  --> tests/ui/unnecessary_to_owned.rs:561:18
+  --> tests/ui/unnecessary_to_owned.rs:559:18
    |
 LL |         s.remove(&a.to_vec());
    |                  ^^^^^^^^^^^ help: replace it with: `a`
 
 error: unnecessary use of `to_owned`
-  --> tests/ui/unnecessary_to_owned.rs:565:14
+  --> tests/ui/unnecessary_to_owned.rs:563:14
    |
 LL |     s.remove(&"b".to_owned());
    |              ^^^^^^^^^^^^^^^ help: replace it with: `"b"`
 
 error: unnecessary use of `to_string`
-  --> tests/ui/unnecessary_to_owned.rs:566:14
+  --> tests/ui/unnecessary_to_owned.rs:564:14
    |
 LL |     s.remove(&"b".to_string());
    |              ^^^^^^^^^^^^^^^^ help: replace it with: `"b"`
 
 error: unnecessary use of `to_vec`
-  --> tests/ui/unnecessary_to_owned.rs:571:14
+  --> tests/ui/unnecessary_to_owned.rs:569:14
    |
 LL |     s.remove(&["b"].to_vec());
    |              ^^^^^^^^^^^^^^^ help: replace it with: `["b"].as_slice()`
 
 error: unnecessary use of `to_vec`
-  --> tests/ui/unnecessary_to_owned.rs:572:14
+  --> tests/ui/unnecessary_to_owned.rs:570:14
    |
 LL |     s.remove(&(&["b"]).to_vec());
    |              ^^^^^^^^^^^^^^^^^^ help: replace it with: `(&["b"]).as_slice()`