From 2fce223b8ef947c8b98863f7446e8b061ea704dc Mon Sep 17 00:00:00 2001
From: Shun Sakai <sorairolake@protonmail.ch>
Date: Fri, 20 Sep 2024 20:02:07 +0900
Subject: [PATCH] feat: Make `Error` trait available in `no_std` mode

---
 .github/workflows/CI.yaml |  4 ++--
 CHANGELOG.adoc            |  7 +++++++
 Cargo.toml                |  2 +-
 README.md                 |  2 +-
 clippy.toml               |  2 +-
 src/error.rs              | 12 +++---------
 src/exit_code.rs          |  8 +++-----
 7 files changed, 18 insertions(+), 19 deletions(-)

diff --git a/.github/workflows/CI.yaml b/.github/workflows/CI.yaml
index 0af2cf7..367c65c 100644
--- a/.github/workflows/CI.yaml
+++ b/.github/workflows/CI.yaml
@@ -24,7 +24,7 @@ jobs:
           - aarch64-apple-darwin
           - x86_64-pc-windows-msvc
         toolchain:
-          - 1.62.0 # MSRV
+          - 1.81.0 # MSRV
           - stable
           - nightly
         include:
@@ -67,7 +67,7 @@ jobs:
           - aarch64-apple-darwin
           - x86_64-pc-windows-msvc
         toolchain:
-          - 1.74.0
+          - 1.81.0
           - stable
           - nightly
         include:
diff --git a/CHANGELOG.adoc b/CHANGELOG.adoc
index e2b7204..5437948 100644
--- a/CHANGELOG.adoc
+++ b/CHANGELOG.adoc
@@ -18,6 +18,13 @@ project adheres to https://semver.org/[Semantic Versioning].
 
 === Changed
 
+* Make `Error` trait available in `no_std` mode ({pull-request-url}/116[#116])
+* Bump MSRV to 1.81.0 ({pull-request-url}/116[#116])
+
+== {compare-url}/v0.8.4\...HEAD[Unreleased]
+
+=== Changed
+
 * Change MSRV to 1.62.0 ({pull-request-url}/131[#131])
 
 == {compare-url}/v0.8.3\...v0.8.4[0.8.4] - 2024-10-31
diff --git a/Cargo.toml b/Cargo.toml
index fbe3580..7225b37 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -8,7 +8,7 @@ name = "sysexits"
 version = "0.8.4"
 authors = ["Shun Sakai <sorairolake@protonmail.ch>"]
 edition = "2021"
-rust-version = "1.62.0"
+rust-version = "1.81.0"
 description = "The system exit codes as defined by <sysexits.h>"
 documentation = "https://docs.rs/sysexits"
 readme = "README.md"
diff --git a/README.md b/README.md
index f238260..e91e172 100644
--- a/README.md
+++ b/README.md
@@ -53,7 +53,7 @@ See the [documentation][docs-url] for more details.
 
 ## Minimum supported Rust version
 
-The minimum supported Rust version (MSRV) of this library is v1.62.0.
+The minimum supported Rust version (MSRV) of this library is v1.81.0.
 
 ## Source code
 
diff --git a/clippy.toml b/clippy.toml
index 770283e..c037fdb 100644
--- a/clippy.toml
+++ b/clippy.toml
@@ -2,4 +2,4 @@
 #
 # SPDX-License-Identifier: Apache-2.0 OR MIT
 
-msrv = "1.62.0"
+msrv = "1.81.0"
diff --git a/src/error.rs b/src/error.rs
index 9acc177..b926dd7 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -5,7 +5,7 @@
 
 //! Error types for this crate.
 
-use core::fmt;
+use core::{error::Error, fmt};
 
 /// The error type indicating that [`ExitCode`](crate::ExitCode) was out of
 /// range.
@@ -20,8 +20,7 @@ impl fmt::Display for ExitCodeRangeError {
     }
 }
 
-#[cfg(feature = "std")]
-impl std::error::Error for ExitCodeRangeError {}
+impl Error for ExitCodeRangeError {}
 
 #[cfg(feature = "std")]
 /// An error which can be returned when converting an
@@ -61,7 +60,7 @@ impl fmt::Display for TryFromExitStatusError {
 }
 
 #[cfg(feature = "std")]
-impl std::error::Error for TryFromExitStatusError {}
+impl Error for TryFromExitStatusError {}
 
 #[cfg(test)]
 mod tests {
@@ -97,11 +96,8 @@ mod tests {
         );
     }
 
-    #[cfg(feature = "std")]
     #[test]
     fn source_exit_code_range_error() {
-        use std::error::Error;
-
         assert!(ExitCodeRangeError.source().is_none());
     }
 
@@ -190,8 +186,6 @@ mod tests {
     #[cfg(feature = "std")]
     #[test]
     fn source_try_from_exit_status_error() {
-        use std::error::Error;
-
         assert!(TryFromExitStatusError::new(Some(1)).source().is_none());
         assert!(TryFromExitStatusError::new(None).source().is_none());
     }
diff --git a/src/exit_code.rs b/src/exit_code.rs
index a89999f..665b66c 100644
--- a/src/exit_code.rs
+++ b/src/exit_code.rs
@@ -12,6 +12,8 @@ mod convert;
 mod fmt;
 pub mod result;
 
+use core::error::Error;
+
 /// `ExitCode` is a type that represents the system exit code constants as
 /// defined by [`<sysexits.h>`].
 ///
@@ -272,8 +274,7 @@ impl ExitCode {
     }
 }
 
-#[cfg(feature = "std")]
-impl std::error::Error for ExitCode {}
+impl Error for ExitCode {}
 
 #[cfg(feature = "std")]
 impl std::process::Termination for ExitCode {
@@ -633,11 +634,8 @@ mod tests {
         assert!(ExitCode::Config.is_failure());
     }
 
-    #[cfg(feature = "std")]
     #[test]
     fn source() {
-        use std::error::Error;
-
         assert!(ExitCode::Ok.source().is_none());
         assert!(ExitCode::Usage.source().is_none());
         assert!(ExitCode::DataErr.source().is_none());