Add note about possible future improvement

m-ou-se · dtolnay · web-flow · commit 2140d80a9d69 · 2020-10-01T17:32:23.000+02:00
Co-authored-by: David Tolnay &lt;dtolnay@gmail.com&gt;
diff --git a/compiler/rustc_feature/src/lib.rs b/compiler/rustc_feature/src/lib.rs
@@ -113,6 +113,8 @@ fn find_lang_feature_issue(feature: Symbol) -> Option<NonZeroU32> {
 }
 
 const fn to_nonzero(n: Option<u32>) -> Option<NonZeroU32> {
+    // Can be replaced with `n.and_then(NonZeroU32::new)` if that is ever usable
+    // in const context. Requires https://github.com/rust-lang/rfcs/pull/2632.
     match n {
         None => None,
         Some(n) => NonZeroU32::new(n),

Original file line number	Diff line number	Diff line change
`@@ -113,6 +113,8 @@ fn find_lang_feature_issue(feature: Symbol) -> Option<NonZeroU32> {`
`113`	`113`	`}`
`114`	`114`
`115`	`115`	`const fn to_nonzero(n: Option<u32>) -> Option<NonZeroU32> {`
	`116`	+ // Can be replaced with `n.and_then(NonZeroU32::new)` if that is ever usable
	`117`	`+ // in const context. Requires https://github.com/rust-lang/rfcs/pull/2632.`
`116`	`118`	`match n {`
`117`	`119`	`None => None,`
`118`	`120`	`Some(n) => NonZeroU32::new(n),`