Support core::error in Rust 1.81

.cirrus.yml

@@ -100,20 +100,20 @@ stable_no_std_test_task:
     - cargo build --no-default-features --target thumbv6m-none-eabi
   before_cache_script: rm -rf $CARGO_HOME/registry/index
 
-nightly_no_std_test_task:
-  name: "Rust Nightly (no_std)"
+rust_1_81_no_std_test_task:
+  name: "Rust 1.81 (no_std)"
   container:
-    image: rustlang/rust:nightly
+    image: rust:latest
     cpu: 1
     memory: 2Gi
   cargo_cache:
     folder: $CARGO_HOME/registry
     fingerprint_script: cat Cargo.toml
   setup_script:
-    - rustup target add thumbv6m-none-eabi --toolchain nightly
+    - rustup target add thumbv6m-none-eabi
   core_error_test_script:
     - rustc --version
-    - cargo +nightly build --no-default-features --features=unstable-core-error --target thumbv6m-none-eabi
+    - cargo build --no-default-features --features=rust_1_81 --target thumbv6m-none-eabi
   before_cache_script: rm -rf $CARGO_HOME/registry/index
 
 nightly_test_task:

Cargo.toml

@@ -43,6 +43,9 @@ rust_1_61 = ["snafu-derive/rust_1_61"]
 # `Backtrace` was stabilized
 rust_1_65 = ["rust_1_61"]
 
+# `core::error` was stabilized
+rust_1_81 = ["rust_1_65"]
+
 # The backtrace type becomes `backtrace::Backtrace`
 backtraces-impl-backtrace-crate = ["backtrace"]
 

src/guide/compatibility.md

@@ -46,3 +46,20 @@ the standard library is available and no other backtrace provider is
 selected.
 
 [`Backtrace`]: std::backtrace::Backtrace
+
+## `rust_1_81`
+
+<dl class="snafu-ff-meta">
+<dt>Default</dt>
+<dd>disabled</dd>
+<dt>Implies</dt>
+<dd>
+
+[`rust_1_65`](#rust_1_65)
+
+</dd>
+</dl>
+
+When enabled, SNAFU will assume that it's safe to target features
+available in Rust 1.81. Notably, the [`core::error::Error`][] trait is
+used instead of [`std::error::Error`][].

src/lib.rs

@@ -338,25 +338,41 @@ generate_guide! {
     }
 }
 
-#[cfg(feature = "unstable-core-error")]
+#[cfg(any(feature = "rust_1_81", feature = "unstable-core-error"))]
 #[doc(hidden)]
 pub use core::error;
 
-#[cfg(feature = "unstable-core-error")]
+#[cfg(any(feature = "rust_1_81", feature = "unstable-core-error"))]
 #[doc(hidden)]
 pub use core::error::Error;
 
-#[cfg(all(not(feature = "unstable-core-error"), any(feature = "std", test)))]
+#[cfg(all(
+    not(any(feature = "rust_1_81", feature = "unstable-core-error")),
+    any(feature = "std", test)
+))]
 #[doc(hidden)]
 pub use std::error;
 
-#[cfg(all(not(feature = "unstable-core-error"), any(feature = "std", test)))]
+#[cfg(all(
+    not(any(feature = "rust_1_81", feature = "unstable-core-error")),
+    any(feature = "std", test)
+))]
 #[doc(hidden)]
 pub use std::error::Error;
 
-#[cfg(not(any(feature = "unstable-core-error", feature = "std", test)))]
+#[cfg(not(any(
+    feature = "rust_1_81",
+    feature = "unstable-core-error",
+    feature = "std",
+    test
+)))]
 mod no_std_error;
-#[cfg(not(any(feature = "unstable-core-error", feature = "std", test)))]
+#[cfg(not(any(
+    feature = "rust_1_81",
+    feature = "unstable-core-error",
+    feature = "std",
+    test
+)))]
 #[doc(hidden)]
 pub use no_std_error::Error;