NotAllOnes cheaper as_inner

kornelski · kornelski · commit cb50cf31bf64 · 2025-02-11T17:28:33.000Z
diff --git a/library/core/src/num/niche_types.rs b/library/core/src/num/niche_types.rs
@@ -58,7 +58,8 @@ macro_rules! define_valid_range_type {
             pub const fn as_inner(self) -> $int {
                 // SAFETY: This is a transparent wrapper, so unwrapping it is sound
                 // (Not using `.0` due to MCP#807.)
-                unsafe { crate::mem::transmute(self) }
+                // SAFETY: size is already asserted in the const block above
+                unsafe { crate::intrinsics::transmute_unchecked(self) }
             }
         }
 

Original file line number	Diff line number	Diff line change
`@@ -58,7 +58,8 @@ macro_rules! define_valid_range_type {`
`58`	`58`	`pub const fn as_inner(self) -> $int {`
`59`	`59`	`// SAFETY: This is a transparent wrapper, so unwrapping it is sound`
`60`	`60`	// (Not using `.0` due to MCP#807.)
`61`		`- unsafe { crate::mem::transmute(self) }`
	`61`	`+ // SAFETY: size is already asserted in the const block above`
	`62`	`+ unsafe { crate::intrinsics::transmute_unchecked(self) }`
`62`	`63`	`}`
`63`	`64`	`}`
`64`	`65`