diff options
| -rw-r--r-- | library/core/src/result.rs | 73 |
1 files changed, 37 insertions, 36 deletions
diff --git a/library/core/src/result.rs b/library/core/src/result.rs index 6810e44d81e..382a5711641 100644 --- a/library/core/src/result.rs +++ b/library/core/src/result.rs @@ -1211,6 +1211,43 @@ impl<T, E> Result<T, E> { } } + /// Returns the contained [`Err`] value, but never panics. + /// + /// Unlike [`unwrap_err`], this method is known to never panic on the + /// result types it is implemented for. Therefore, it can be used + /// instead of `unwrap_err` as a maintainability safeguard that will fail + /// to compile if the ok type of the `Result` is later changed + /// to a type that can actually occur. + /// + /// [`unwrap_err`]: Result::unwrap_err + /// + /// # Examples + /// + /// Basic usage: + /// + /// ``` + /// # #![feature(never_type)] + /// # #![feature(unwrap_infallible)] + /// + /// fn only_bad_news() -> Result<!, String> { + /// Err("Oops, it failed".into()) + /// } + /// + /// let error: String = only_bad_news().into_err(); + /// println!("{}", error); + /// ``` + #[unstable(feature = "unwrap_infallible", reason = "newly added", issue = "61695")] + #[inline] + pub fn into_err(self) -> E + where + T: Into<!>, + { + match self { + Ok(x) => x.into(), + Err(e) => e, + } + } + //////////////////////////////////////////////////////////////////////// // Boolean operations on the values, eager and lazy ///////////////////////////////////////////////////////////////////////// @@ -1536,42 +1573,6 @@ impl<T: Clone, E> Result<&mut T, E> { } } -#[unstable(feature = "unwrap_infallible", reason = "newly added", issue = "61695")] -impl<T: Into<!>, E> Result<T, E> { - /// Returns the contained [`Err`] value, but never panics. - /// - /// Unlike [`unwrap_err`], this method is known to never panic on the - /// result types it is implemented for. Therefore, it can be used - /// instead of `unwrap_err` as a maintainability safeguard that will fail - /// to compile if the ok type of the `Result` is later changed - /// to a type that can actually occur. - /// - /// [`unwrap_err`]: Result::unwrap_err - /// - /// # Examples - /// - /// Basic usage: - /// - /// ``` - /// # #![feature(never_type)] - /// # #![feature(unwrap_infallible)] - /// - /// fn only_bad_news() -> Result<!, String> { - /// Err("Oops, it failed".into()) - /// } - /// - /// let error: String = only_bad_news().into_err(); - /// println!("{}", error); - /// ``` - #[inline] - pub fn into_err(self) -> E { - match self { - Ok(x) => x.into(), - Err(e) => e, - } - } -} - impl<T, E> Result<Option<T>, E> { /// Transposes a `Result` of an `Option` into an `Option` of a `Result`. /// |