Merge pull request #385 from dtolnay/docnostd

Update documentation on no-std error type conversions

README.md

@@ -136,10 +136,10 @@ Cargo.toml. A global allocator is required.
 anyhow = { version = "1.0", default-features = false }
 ```
 
-Since the `?`-based error conversions would normally rely on the
-`std::error::Error` trait which is only available through std, no_std mode will
-require an explicit `.map_err(Error::msg)` when working with a non-Anyhow error
-type inside a function that returns Anyhow's error type.
+With versions of Rust older than 1.81, no_std mode may require an additional
+`.map_err(Error::msg)` when working with a non-Anyhow error type inside a
+function that returns Anyhow's error type, as the trait that `?`-based error
+conversions are defined by is only available in std in those old versions.
 
 <br>
 

src/lib.rs

@@ -201,10 +201,10 @@
 //! anyhow = { version = "1.0", default-features = false }
 //! ```
 //!
-//! Since the `?`-based error conversions would normally rely on the
-//! `std::error::Error` trait which is only available through std, no_std mode
-//! will require an explicit `.map_err(Error::msg)` when working with a
-//! non-Anyhow error type inside a function that returns Anyhow's error type.
+//! With versions of Rust older than 1.81, no_std mode may require an additional
+//! `.map_err(Error::msg)` when working with a non-Anyhow error type inside a
+//! function that returns Anyhow's error type, as the trait that `?`-based error
+//! conversions are defined by is only available in std in those old versions.
 
 #![doc(html_root_url = "https://docs.rs/anyhow/1.0.87")]
 #![cfg_attr(error_generic_member_access, feature(error_generic_member_access))]