Rollup merge of rust-lang#66570 - lzutao:stabilize-result-map_or, r=Dylan-DPC

stabilize Result::map_or

r? @SimonSapin
Closes rust-lang#66293

Author: Centril

src/libcore/result.rs

@@ -520,15 +520,14 @@ impl<T, E> Result<T, E> {
     /// # Examples
     ///
     /// ```
-    /// #![feature(result_map_or)]
     /// let x: Result<_, &str> = Ok("foo");
     /// assert_eq!(x.map_or(42, |v| v.len()), 3);
     ///
     /// let x: Result<&str, _> = Err("bar");
     /// assert_eq!(x.map_or(42, |v| v.len()), 42);
     /// ```
     #[inline]
-    #[unstable(feature = "result_map_or", issue = "66293")]
+    #[stable(feature = "result_map_or", since = "1.41.0")]
     pub fn map_or<U, F: FnOnce(T) -> U>(self, default: U, f: F) -> U {
         match self {
             Ok(t) => f(t),

src/librustc_mir/transform/const_prop.rs

@@ -517,7 +517,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
                     let left_bits = place_layout.size.bits();
                     let right_size = r.layout.size;
                     let r_bits = r.to_scalar().and_then(|r| r.to_bits(right_size));
-                    if r_bits.ok().map_or(false, |b| b >= left_bits as u128) {
+                    if r_bits.map_or(false, |b| b >= left_bits as u128) {
                         let lint_root = match &self.source_scopes[source_info.scope].local_data {
                             ClearCrossCrate::Set(data) => data.lint_root,
                             ClearCrossCrate::Clear => return None,

src/librustc_typeck/check/method/probe.rs

@@ -1456,7 +1456,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
                     pcx.method_name = Some(method_name);
                     pcx.assemble_inherent_candidates();
                     pcx.assemble_extension_candidates_for_traits_in_scope(hir::DUMMY_HIR_ID)
-                        .ok().map_or(None, |_| {
+                        .map_or(None, |_| {
                             pcx.pick_core()
                                 .and_then(|pick| pick.ok())
                                 .and_then(|pick| Some(pick.item))

src/libterm/terminfo/mod.rs

@@ -74,7 +74,7 @@ impl TermInfo {
             Err(..) => return Err(Error::TermUnset),
         };
 
-        if term.is_err() && env::var("MSYSCON").ok().map_or(false, |s| "mintty.exe" == s) {
+        if term.is_err() && env::var("MSYSCON").map_or(false, |s| "mintty.exe" == s) {
             // msys terminal
             Ok(msys_terminfo())
         } else {