Rollup merge of rust-lang#67233 - Luro02:cursor_traits, r=sfackler

Add PartialEq and Eq to Cursor

closes rust-lang#67226

src/libstd/io/cursor.rs

@@ -72,7 +72,7 @@ use core::convert::TryInto;
 /// }
 /// ```
 #[stable(feature = "rust1", since = "1.0.0")]
-#[derive(Clone, Debug, Default)]
+#[derive(Clone, Debug, Default, Eq, PartialEq)]
 pub struct Cursor<T> {
     inner: T,
     pos: u64,
@@ -942,4 +942,16 @@ mod tests {
         c.set_position(<usize>::max_value() as u64 + 1);
         assert!(c.write_all(&[1, 2, 3]).is_err());
     }
+
+    #[test]
+    fn test_partial_eq() {
+        assert_eq!(Cursor::new(Vec::<u8>::new()), Cursor::new(Vec::<u8>::new()));
+    }
+
+    #[test]
+    fn test_eq() {
+        struct AssertEq<T: Eq>(pub T);
+
+        let _: AssertEq<Cursor<Vec<u8>>> = AssertEq(Cursor::new(Vec::new()));
+    }
 }