make use of Result::map_or

Author: tesuji

src/librustc_mir/transform/const_prop.rs

@@ -505,7 +505,7 @@ 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

@@ -1460,7 +1460,7 @@ 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 {