From f8ee57be2c585c3fd8931eeb88994fbfcaa0f083 Mon Sep 17 00:00:00 2001 From: Joshua Nelson Date: Wed, 19 Jan 2022 13:43:27 -0600 Subject: [PATCH] `impl Display for io::ErrorKind` This avoids having to convert from `ErrorKind` to `Error` just to print the error message. --- library/std/src/io/error.rs | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-) diff --git a/library/std/src/io/error.rs b/library/std/src/io/error.rs index 210a9ec7183..074d693b831 100644 --- a/library/std/src/io/error.rs +++ b/library/std/src/io/error.rs @@ -361,13 +361,29 @@ impl ErrorKind { } } +#[stable(feature = "io_errorkind_display", since = "1.60.0")] +impl fmt::Display for ErrorKind { + /// Shows a human-readable description of the `ErrorKind`. + /// + /// This is similar to `impl Display for Error`, but doesn't require first converting to Error. + /// + /// # Examples + /// ``` + /// use std::io::ErrorKind; + /// assert_eq!("entity not found", ErrorKind::NotFound.to_string()); + /// ``` + fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result { + fmt.write_str(self.as_str()) + } +} + /// Intended for use for errors not exposed to the user, where allocating onto /// the heap (for normal construction via Error::new) is too costly. #[stable(feature = "io_error_from_errorkind", since = "1.14.0")] impl From for Error { /// Converts an [`ErrorKind`] into an [`Error`]. /// - /// This conversion allocates a new error with a simple representation of error kind. + /// This conversion creates a new error with a simple representation of error kind. /// /// # Examples ///