crypto-common: use core::error::Error trait; MSRV 1.81 (#1660)

The `core::error::Error` trait is now stable, meaning we no longer need
to gate impls for it on a `std` feature.

Author: tarcieri

.github/workflows/crypto-common.yml

@@ -2,9 +2,9 @@ name: crypto-common
 
 on:
   pull_request:
-      paths:
-        - "crypto-common/**"
-        - "Cargo.*"
+    paths:
+      - "crypto-common/**"
+      - "Cargo.*"
   push:
     branches: master
 
@@ -22,7 +22,7 @@ jobs:
     strategy:
       matrix:
         rust:
-          - 1.65.0 # MSRV
+          - 1.81.0 # MSRV
           - stable
         target:
           - thumbv7em-none-eabi
@@ -39,14 +39,14 @@ jobs:
   minimal-versions:
     uses: RustCrypto/actions/.github/workflows/minimal-versions.yml@master
     with:
-        working-directory: ${{ github.workflow }}
+      working-directory: ${{ github.workflow }}
 
   test:
     runs-on: ubuntu-latest
     strategy:
       matrix:
         rust:
-          - 1.65.0 # MSRV
+          - 1.81.0 # MSRV
           - stable
     steps:
       - uses: actions/checkout@v4

crypto-common/Cargo.toml

@@ -6,7 +6,7 @@ authors = ["RustCrypto Developers"]
 license = "MIT OR Apache-2.0"
 readme = "README.md"
 edition = "2021"
-rust-version = "1.65"
+rust-version = "1.81"
 documentation = "https://docs.rs/crypto-common"
 repository = "https://github.com/RustCrypto/traits"
 keywords = ["crypto", "traits"]

crypto-common/README.md

@@ -14,7 +14,7 @@ higher-level trait crates instead of this one.
 
 ## Minimum Supported Rust Version
 
-Rust **1.65** or higher.
+Rust **1.81** or higher.
 
 Minimum supported Rust version can be changed in the future, but it will be
 done with a minor version bump.
@@ -46,7 +46,7 @@ dual licensed as above, without any additional terms or conditions.
 [docs-image]: https://docs.rs/crypto-common/badge.svg
 [docs-link]: https://docs.rs/crypto-common/
 [license-image]: https://img.shields.io/badge/license-Apache2.0/MIT-blue.svg
-[rustc-image]: https://img.shields.io/badge/rustc-1.65+-blue.svg
+[rustc-image]: https://img.shields.io/badge/rustc-1.81+-blue.svg
 [chat-image]: https://img.shields.io/badge/zulip-join_chat-blue.svg
 [chat-link]: https://rustcrypto.zulipchat.com/#narrow/stream/260041-hashes
 [build-image]: https://github.com/RustCrypto/traits/workflows/crypto-common/badge.svg?branch=master&event=push

crypto-common/src/hazmat.rs

@@ -24,8 +24,7 @@ impl fmt::Display for DeserializeStateError {
     }
 }
 
-#[cfg(feature = "std")]
-impl std::error::Error for DeserializeStateError {}
+impl core::error::Error for DeserializeStateError {}
 
 /// Types which can serialize the internal state and be restored from it.
 ///

crypto-common/src/lib.rs

@@ -9,9 +9,6 @@
 #![forbid(unsafe_code)]
 #![warn(missing_docs, rust_2018_idioms, missing_debug_implementations)]
 
-#[cfg(feature = "std")]
-extern crate std;
-
 /// Hazardous materials.
 pub mod hazmat;
 
@@ -389,5 +386,4 @@ impl fmt::Display for InvalidLength {
     }
 }
 
-#[cfg(feature = "std")]
-impl std::error::Error for InvalidLength {}
+impl core::error::Error for InvalidLength {}