Enable the nightly-error-messages feature unconditionally for nightly compilers

Author: weiznich

axum-core/Cargo.toml

@@ -21,12 +21,12 @@ mime = "0.3.16"
 tower-layer = "0.3"
 tower-service = "0.3"
 
+[build-dependencies]
+rustversion = "1.0.9"
+
 [dev-dependencies]
 axum = { path = "../axum", version = "0.6.0-rc.2" }
 futures-util = "0.3"
 hyper = "0.14"
 tokio = { version = "1.0", features = ["macros"] }
 tower-http = { version = "0.3.4", features = ["limit"] }
-
-[features]
-nightly-error-messages = []

axum-core/build.rs

@@ -0,0 +1,7 @@
+#[rustversion::nightly]
+fn main() {
+    println!("cargo:rustc-cfg=nightly_error_messages");
+}
+
+#[rustversion::not(nightly)]
+fn main() {}

axum-core/src/extract/mod.rs

@@ -40,7 +40,7 @@ mod private {
 /// [`axum::extract`]: https://docs.rs/axum/0.6.0-rc.2/axum/extract/index.html
 #[async_trait]
 #[cfg_attr(
-    feature = "nightly-error-messages",
+    nightly_error_messages,
     rustc_on_unimplemented(
         on(
             _Self = "axum::http::Request<axum::body::Body>",

axum-core/src/lib.rs

@@ -1,4 +1,4 @@
-#![cfg_attr(feature = "nightly-error-messages", feature(rustc_attrs))]
+#![cfg_attr(nightly_error_messages, feature(rustc_attrs))]
 //! Core types and traits for [`axum`].
 //!
 //! Libraries authors that want to provide [`FromRequest`] or [`IntoResponse`] implementations

axum/Cargo.toml

@@ -25,7 +25,6 @@ query = ["dep:serde_urlencoded"]
 tokio = ["dep:tokio", "hyper/server", "hyper/tcp", "tower/make"]
 tower-log = ["tower/log"]
 ws = ["tokio", "dep:tokio-tungstenite", "dep:sha-1", "dep:base64"]
-nightly-error-messages = ["axum-core/nightly-error-messages"]
 
 # Required for intra-doc links to resolve correctly
 __private_docs = ["tower/full", "tower-http/full"]
@@ -64,6 +63,9 @@ sha-1 = { version = "0.10", optional = true }
 tokio = { package = "tokio", version = "1.21", features = ["time"], optional = true }
 tokio-tungstenite = { version = "0.17.2", optional = true }
 
+[build-dependencies]
+rustversion = "1.0.9"
+
 [dev-dependencies]
 anyhow = "1.0"
 futures = "0.3"

axum/build.rs

@@ -0,0 +1,7 @@
+#[rustversion::nightly]
+fn main() {
+    println!("cargo:rustc-cfg=nightly_error_messages");
+}
+
+#[rustversion::not(nightly)]
+fn main() {}

axum/src/handler/mod.rs

@@ -100,7 +100,7 @@ pub(crate) use self::{
 /// ```
 #[doc = include_str!("../docs/debugging_handler_type_errors.md")]
 #[cfg_attr(
-    feature = "nightly-error-messages",
+    nightly_error_messages,
     rustc_on_unimplemented(
         note = "Consider using `#[axum_macros::debug_handler]` to improve the error message"
     )

axum/src/lib.rs

@@ -1,4 +1,4 @@
-#![cfg_attr(feature = "nightly-error-messages", feature(rustc_attrs))]
+#![cfg_attr(nightly_error_messages, feature(rustc_attrs))]
 //! axum is a web application framework that focuses on ergonomics and modularity.
 //!
 //! # Table of contents