Add more ui tests for unnecessary_to_owned

Author: GuillaumeGomez

tests/ui/unnecessary_to_owned.fixed

@@ -530,3 +530,25 @@ mod issue_11952 {
         IntoFuture::into_future(foo([], &0));
     }
 }
+
+fn borrow_checks() {
+    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`
+
+    // Should not warn.
+    s.remove(&["b"].to_vec().clone());
+    s.remove(["a"].as_slice());
+}

tests/ui/unnecessary_to_owned.rs

@@ -530,3 +530,25 @@ mod issue_11952 {
         IntoFuture::into_future(foo([].to_vec(), &0));
     }
 }
+
+fn borrow_checks() {
+    use std::collections::HashSet;
+
+    fn inner(a: &[&str]) {
+        let mut s = HashSet::from([vec!["a"]]);
+        s.remove(&a.to_vec()); //~ ERROR: unnecessary use of `to_vec`
+    }
+
+    let mut s = HashSet::from(["a".to_string()]);
+    s.remove(&"b".to_owned()); //~ ERROR: unnecessary use of `to_owned`
+    s.remove(&"b".to_string()); //~ ERROR: unnecessary use of `to_string`
+    // Should not warn.
+    s.remove("b");
+
+    let mut s = HashSet::from([vec!["a"]]);
+    s.remove(&["b"].to_vec()); //~ ERROR: unnecessary use of `to_vec`
+
+    // Should not warn.
+    s.remove(&["b"].to_vec().clone());
+    s.remove(["a"].as_slice());
+}

tests/ui/unnecessary_to_owned.stderr

@@ -523,5 +523,29 @@ error: unnecessary use of `to_vec`
 LL |         IntoFuture::into_future(foo([].to_vec(), &0));
    |                                     ^^^^^^^^^^^ help: use: `[]`
 
-error: aborting due to 80 previous errors
+error: unnecessary use of `to_vec`
+  --> tests/ui/unnecessary_to_owned.rs:539:18
+   |
+LL |         s.remove(&a.to_vec());
+   |                  ^^^^^^^^^^^ help: replace it with: `a`
+
+error: unnecessary use of `to_owned`
+  --> tests/ui/unnecessary_to_owned.rs:543:14
+   |
+LL |     s.remove(&"b".to_owned());
+   |              ^^^^^^^^^^^^^^^ help: replace it with: `"b"`
+
+error: unnecessary use of `to_string`
+  --> tests/ui/unnecessary_to_owned.rs:544:14
+   |
+LL |     s.remove(&"b".to_string());
+   |              ^^^^^^^^^^^^^^^^ help: replace it with: `"b"`
+
+error: unnecessary use of `to_vec`
+  --> tests/ui/unnecessary_to_owned.rs:549:14
+   |
+LL |     s.remove(&["b"].to_vec());
+   |              ^^^^^^^^^^^^^^^ help: replace it with: `["b"].as_slice()`
+
+error: aborting due to 84 previous errors