Constify Residual behind const_try

Author: onestacked

library/core/src/ops/control_flow.rs

@@ -126,6 +126,7 @@ impl<B, C> const ops::FromResidual for ControlFlow<B, C> {
 }
 
 #[unstable(feature = "try_trait_v2_residual", issue = "91285")]
+#[rustc_const_unstable(feature = "const_try", issue = "74935")]
 impl<B, C> const ops::Residual<C> for ControlFlow<B, convert::Infallible> {
     type TryType = ControlFlow<B, C>;
 }

library/core/src/option.rs

@@ -2321,7 +2321,8 @@ impl<T> ops::FromResidual<ops::Yeet<()>> for Option<T> {
 }
 
 #[unstable(feature = "try_trait_v2_residual", issue = "91285")]
-impl<T> ops::Residual<T> for Option<convert::Infallible> {
+#[rustc_const_unstable(feature = "const_try", issue = "74935")]
+impl<T> const ops::Residual<T> for Option<convert::Infallible> {
     type TryType = Option<T>;
 }
 

library/core/src/result.rs

@@ -2116,6 +2116,7 @@ impl<T, E, F: From<E>> ops::FromResidual<ops::Yeet<E>> for Result<T, F> {
 }
 
 #[unstable(feature = "try_trait_v2_residual", issue = "91285")]
-impl<T, E> ops::Residual<T> for Result<convert::Infallible, E> {
+#[rustc_const_unstable(feature = "const_try", issue = "74935")]
+impl<T, E> const ops::Residual<T> for Result<convert::Infallible, E> {
     type TryType = Result<T, E>;
 }