Stabilize refcell_replace_swap feature, closes #43570

Author: jmcomets

src/libcore/cell.rs

@@ -711,15 +711,14 @@ impl<T> RefCell<T> {
     /// # Examples
     ///
     /// ```
-    /// #![feature(refcell_replace_swap)]
     /// use std::cell::RefCell;
     /// let cell = RefCell::new(5);
     /// let old_value = cell.replace_with(|&mut old| old + 1);
     /// assert_eq!(old_value, 5);
     /// assert_eq!(cell, RefCell::new(6));
     /// ```
     #[inline]
-    #[unstable(feature = "refcell_replace_swap", issue="43570")]
+    #[stable(feature = "refcell_replace_swap", since="1.35.0")]
     pub fn replace_with<F: FnOnce(&mut T) -> T>(&self, f: F) -> T {
         let mut_borrow = &mut *self.borrow_mut();
         let replacement = f(mut_borrow);

src/libcore/tests/lib.rs

@@ -16,7 +16,6 @@
 #![feature(pattern)]
 #![feature(range_is_empty)]
 #![feature(raw)]
-#![feature(refcell_replace_swap)]
 #![feature(slice_patterns)]
 #![feature(sort_internals)]
 #![feature(specialization)]

src/librustc/lib.rs

@@ -45,7 +45,6 @@
 #![feature(proc_macro_internals)]
 #![feature(optin_builtin_traits)]
 #![feature(range_is_empty)]
-#![feature(refcell_replace_swap)]
 #![feature(rustc_diagnostic_macros)]
 #![feature(rustc_attrs)]
 #![feature(slice_patterns)]

src/librustc_typeck/lib.rs

@@ -64,7 +64,6 @@ This API is completely unstable and subject to change.
 #![feature(crate_visibility_modifier)]
 #![feature(exhaustive_patterns)]
 #![feature(nll)]
-#![feature(refcell_replace_swap)]
 #![feature(rustc_diagnostic_macros)]
 #![feature(slice_patterns)]
 #![feature(never_type)]

src/libsyntax/feature_gate.rs

@@ -703,6 +703,8 @@ declare_features! (
     (accepted, extern_crate_self, "1.34.0", Some(56409), None),
     // support for arbitrary delimited token streams in non-macro attributes
     (accepted, unrestricted_attribute_tokens, "1.34.0", Some(55208), None),
+    // add replace and swap functions to RefCell
+    (accepted, refcell_replace_swap, "1.35.0", Some(43570), None),
 );
 
 // If you change this, please modify `src/doc/unstable-book` as well. You must