Use is_some_and/is_ok_and in less obvious spots

compiler/rustc_feature/src/lib.rs

@@ -84,7 +84,7 @@ impl UnstableFeatures {
     pub fn from_environment(krate: Option<&str>) -> Self {
         // `true` if this is a feature-staged build, i.e., on the beta or stable channel.
         let disable_unstable_features =
-            option_env!("CFG_DISABLE_UNSTABLE_FEATURES").map(|s| s != "0").unwrap_or(false);
+            option_env!("CFG_DISABLE_UNSTABLE_FEATURES").is_some_and(|s| s != "0");
         // Returns whether `krate` should be counted as unstable
         let is_unstable_crate =
             |var: &str| krate.is_some_and(|name| var.split(',').any(|new_krate| new_krate == name));