diff options
| -rw-r--r-- | library/core/src/result.rs | 51 |
1 files changed, 26 insertions, 25 deletions
diff --git a/library/core/src/result.rs b/library/core/src/result.rs index 09feb7e0eda..e74e70125b8 100644 --- a/library/core/src/result.rs +++ b/library/core/src/result.rs @@ -925,6 +925,32 @@ impl<T, E> Result<T, E> { self.as_ref().map(|t| t.deref()) } + /// Converts from `Result<T, E>` (or `&mut Result<T, E>`) to `Result<&mut <T as DerefMut>::Target, &mut E>`. + /// + /// Coerces the [`Ok`] variant of the original [`Result`] via [`DerefMut`](crate::ops::DerefMut) + /// and returns the new [`Result`]. + /// + /// # Examples + /// + /// ``` + /// let mut s = "HELLO".to_string(); + /// let mut x: Result<String, u32> = Ok("hello".to_string()); + /// let y: Result<&mut str, &mut u32> = Ok(&mut s); + /// assert_eq!(x.as_deref_mut().map(|x| { x.make_ascii_uppercase(); x }), y); + /// + /// let mut i = 42; + /// let mut x: Result<String, u32> = Err(42); + /// let y: Result<&mut str, &mut u32> = Err(&mut i); + /// assert_eq!(x.as_deref_mut().map(|x| { x.make_ascii_uppercase(); x }), y); + /// ``` + #[stable(feature = "inner_deref", since = "1.47.0")] + pub fn as_deref_mut(&mut self) -> Result<&mut T::Target, &mut E> + where + T: DerefMut, + { + self.as_mut().map(|t| t.deref_mut()) + } + ///////////////////////////////////////////////////////////////////////// // Iterator constructors ///////////////////////////////////////////////////////////////////////// @@ -1532,31 +1558,6 @@ impl<T: Into<!>, E> Result<T, E> { } } -impl<T: DerefMut, E> Result<T, E> { - /// Converts from `Result<T, E>` (or `&mut Result<T, E>`) to `Result<&mut <T as DerefMut>::Target, &mut E>`. - /// - /// Coerces the [`Ok`] variant of the original [`Result`] via [`DerefMut`](crate::ops::DerefMut) - /// and returns the new [`Result`]. - /// - /// # Examples - /// - /// ``` - /// let mut s = "HELLO".to_string(); - /// let mut x: Result<String, u32> = Ok("hello".to_string()); - /// let y: Result<&mut str, &mut u32> = Ok(&mut s); - /// assert_eq!(x.as_deref_mut().map(|x| { x.make_ascii_uppercase(); x }), y); - /// - /// let mut i = 42; - /// let mut x: Result<String, u32> = Err(42); - /// let y: Result<&mut str, &mut u32> = Err(&mut i); - /// assert_eq!(x.as_deref_mut().map(|x| { x.make_ascii_uppercase(); x }), y); - /// ``` - #[stable(feature = "inner_deref", since = "1.47.0")] - pub fn as_deref_mut(&mut self) -> Result<&mut T::Target, &mut E> { - self.as_mut().map(|t| t.deref_mut()) - } -} - impl<T, E> Result<Option<T>, E> { /// Transposes a `Result` of an `Option` into an `Option` of a `Result`. /// |