Rollup merge of #100604 - dtolnay:okorerr, r=m-ou-se

Remove unstable Result::into_ok_or_err

Pending FCP: rust-lang/rust#82223 (comment)

```@rustbot``` label +waiting-on-fcp

core/src/result.rs

@@ -1776,40 +1776,6 @@ impl<T, E> Result<Result<T, E>, E> {
     }
 }
 
-impl<T> Result<T, T> {
-    /// Returns the [`Ok`] value if `self` is `Ok`, and the [`Err`] value if
-    /// `self` is `Err`.
-    ///
-    /// In other words, this function returns the value (the `T`) of a
-    /// `Result<T, T>`, regardless of whether or not that result is `Ok` or
-    /// `Err`.
-    ///
-    /// This can be useful in conjunction with APIs such as
-    /// [`Atomic*::compare_exchange`], or [`slice::binary_search`], but only in
-    /// cases where you don't care if the result was `Ok` or not.
-    ///
-    /// [`Atomic*::compare_exchange`]: crate::sync::atomic::AtomicBool::compare_exchange
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// #![feature(result_into_ok_or_err)]
-    /// let ok: Result<u32, u32> = Ok(3);
-    /// let err: Result<u32, u32> = Err(4);
-    ///
-    /// assert_eq!(ok.into_ok_or_err(), 3);
-    /// assert_eq!(err.into_ok_or_err(), 4);
-    /// ```
-    #[inline]
-    #[unstable(feature = "result_into_ok_or_err", reason = "newly added", issue = "82223")]
-    pub const fn into_ok_or_err(self) -> T {
-        match self {
-            Ok(v) => v,
-            Err(v) => v,
-        }
-    }
-}
-
 // This is a separate function to reduce the code size of the methods
 #[cfg(not(feature = "panic_immediate_abort"))]
 #[inline(never)]

core/tests/lib.rs

@@ -75,7 +75,6 @@
 #![feature(const_pin)]
 #![feature(never_type)]
 #![feature(unwrap_infallible)]
-#![feature(result_into_ok_or_err)]
 #![feature(pointer_byte_offsets)]
 #![feature(portable_simd)]
 #![feature(ptr_metadata)]

core/tests/result.rs

@@ -95,15 +95,6 @@ fn test_unwrap_or() {
     assert_eq!(ok_err.unwrap_or(50), 50);
 }
 
-#[test]
-fn test_ok_or_err() {
-    let ok: Result<isize, isize> = Ok(100);
-    let err: Result<isize, isize> = Err(200);
-
-    assert_eq!(ok.into_ok_or_err(), 100);
-    assert_eq!(err.into_ok_or_err(), 200);
-}
-
 #[test]
 fn test_unwrap_or_else() {
     fn handler(msg: &'static str) -> isize {