Rollup merge of rust-lang#146979 - npmccallum:nanosecs, r=Mark-Simulacrum

Zalathar · web-flow · commit 5373eb126831 · 2025-09-29T11:56:42.000+10:00
constify Default on Nanoseconds
diff --git a/library/core/src/num/niche_types.rs b/library/core/src/num/niche_types.rs
@@ -112,7 +112,8 @@ impl Nanoseconds {
     pub const ZERO: Self = unsafe { Nanoseconds::new_unchecked(0) };
 }
 
-impl Default for Nanoseconds {
+#[rustc_const_unstable(feature = "const_default", issue = "143894")]
+impl const Default for Nanoseconds {
     #[inline]
     fn default() -> Self {
         Self::ZERO

Original file line number	Diff line number	Diff line change
`@@ -112,7 +112,8 @@ impl Nanoseconds {`
`112`	`112`	`pub const ZERO: Self = unsafe { Nanoseconds::new_unchecked(0) };`
`113`	`113`	`}`
`114`	`114`
`115`		`-impl Default for Nanoseconds {`
	`115`	`+#[rustc_const_unstable(feature = "const_default", issue = "143894")]`
	`116`	`+impl const Default for Nanoseconds {`
`116`	`117`	`#[inline]`
`117`	`118`	`fn default() -> Self {`
`118`	`119`	`Self::ZERO`