Constly impl TryV2 and FromResidual for Result

Author: usbalbin

library/core/src/result.rs

@@ -1871,7 +1871,8 @@ impl<A, E, V: FromIterator<A>> FromIterator<Result<A, E>> for Result<V, E> {
 }
 
 #[unstable(feature = "try_trait_v2", issue = "84277")]
-impl<T, E> ops::TryV2 for Result<T, E> {
+#[rustc_const_unstable(feature = "const_identity_convert", issue = "none")]
+impl<T, E> const ops::TryV2 for Result<T, E> {
     type Output = T;
     type Residual = Result<convert::Infallible, E>;
 
@@ -1890,7 +1891,8 @@ impl<T, E> ops::TryV2 for Result<T, E> {
 }
 
 #[unstable(feature = "try_trait_v2", issue = "84277")]
-impl<T, E, F: From<E>> ops::FromResidual<Result<convert::Infallible, E>> for Result<T, F> {
+#[rustc_const_unstable(feature = "const_identity_convert", issue = "none")]
+impl<T, E, F: From<E>> const ops::FromResidual<Result<convert::Infallible, E>> for Result<T, F> {
     #[inline]
     fn from_residual(residual: Result<convert::Infallible, E>) -> Self {
         match residual {