changed function signature according to the rust library team request

Author: yonikremer

library/core/src/iter/traits/iterator.rs

@@ -1,5 +1,4 @@
 use crate::array;
-use crate::borrow::Borrow;
 use crate::cmp::{self, Ordering};
 use crate::num::NonZero;
 use crate::ops::{ChangeOutputType, ControlFlow, FromResidual, Residual, Try};
@@ -4124,15 +4123,13 @@ pub trait Iterator {
     /// assert!((1..1000).contain(&500));
     /// ```
     #[unstable(feature = "contains", reason = "new API", issue = "127494")]
-    fn contain<Q>(&mut self, item: Q) -> bool
+    fn contain<Q: Sized>(&mut self, item: Q) -> bool
     where
-        Self::Item: PartialEq,
-        Q: Borrow<Self::Item>,
+        Self::Item: PartialEq<Q>,
         Self: Sized,
     {
-        let borrowed_item: &Self::Item = item.borrow();
         for element in self {
-            if element == *borrowed_item {
+            if element == item {
                 return true;
             }
         }

library/core/tests/iter/mod.rs

@@ -99,8 +99,3 @@ pub fn extend_for_unit() {
     }
     assert_eq!(x, 5);
 }
-
-#[test]
-fn test_edge_case_handling_iterator_with_large_number_of_elements() {
-    assert!((1..1000).contain(&500));
-}

library/core/tests/iter/traits/iterator.rs

@@ -629,7 +629,7 @@ fn test_edge_case_handling_none_values() {
 
 #[test]
 fn test_edge_case_handling_empty_iterator() {
-    assert!(!vec![].iter().contain(&1));
+    assert!(!Vec::<i32>::new().iter().contain(&1));
 }
 
 #[test]
@@ -646,12 +646,31 @@ fn test_edge_case_handling_iterator_with_custom_struct() {
     assert!([Item { value: 1 }, Item { value: 2 }].iter().contain(&Item { value: 2 }));
 }
 
+// #[test]
+// fn test_str_iterator_contain_string() {
+//     assert!(["a", "b", "c"].iter().contain("b".to_owned()));
+//     assert!(!["a", "b", "c"].iter().contain("d".to_owned()));
+// }
+
 #[test]
-fn test_str_iterator_contain_string() {
-    assert!([&"a", &"b", &"c"].iter().contain("b".to_string()));
-    assert!(!&["a", "b", "c"].iter().contain("d".to_string()));
+fn test_str_iterator_contain_string_slice() {
+    assert!(["a", "b", "c"].iter().contain(&"b"));
+    assert!(!["a", "b", "c"].iter().contain(&"d"));
 }
 
+#[test]
+fn test_string_iterator_contain_str_slice() {
+    assert!(["a".to_owned(), "b".to_owned(), "c".to_owned()].iter().contain("b"));
+    assert!(!["a".to_owned(), "b".to_owned(), "c".to_owned()].iter().contain("d"));
+}
+
+
+#[test]
+fn test_edge_case_handling_iterator_with_large_number_of_elements() {
+    assert!((1..1000).contain(500));
+}
+
+
 // just tests by whether or not this compiles
 fn _empty_impl_all_auto_traits<T>() {
     use std::panic::{RefUnwindSafe, UnwindSafe};