Separate cfg-target-has-atomic feature

Author: Nemo157

futures-core/Cargo.toml

@@ -18,6 +18,7 @@ name = "futures_core"
 default = ["std"]
 std = ["either/use_std"]
 nightly = []
+cfg-target-has-atomic = []
 
 [dependencies]
 either = { version = "1.4", default-features = false, optional = true }

futures-core/src/lib.rs

@@ -1,14 +1,17 @@
 //! Core traits and types for asynchronous operations in Rust.
 
 #![feature(futures_api)]
-#![cfg_attr(feature = "nightly", feature(cfg_target_has_atomic))]
+#![cfg_attr(feature = "cfg-target-has-atomic", feature(cfg_target_has_atomic))]
 
 #![cfg_attr(not(feature = "std"), no_std)]
 
 #![warn(missing_docs, missing_debug_implementations, rust_2018_idioms)]
 
 #![doc(html_root_url = "https://rust-lang-nursery.github.io/futures-api-docs/0.3.0-alpha.12/futures_core")]
 
+#[cfg(all(feature = "cfg-target-has-atomic", not(feature = "nightly")))]
+compile_error!("The `cfg-target-has-atomic` feature requires the `nightly` feature as an explicit opt-in to unstable features");
+
 pub mod future;
 #[doc(hidden)] pub use self::future::{Future, FusedFuture, TryFuture};
 

futures-core/src/task/__internal/mod.rs

@@ -1,10 +1,10 @@
 #[cfg_attr(
-    feature = "nightly",
+    feature = "cfg-target-has-atomic",
     cfg(all(target_has_atomic = "cas", target_has_atomic = "ptr"))
 )]
 mod atomic_waker;
 #[cfg_attr(
-    feature = "nightly",
+    feature = "cfg-target-has-atomic",
     cfg(all(target_has_atomic = "cas", target_has_atomic = "ptr"))
 )]
 pub use self::atomic_waker::AtomicWaker;

futures-util/Cargo.toml

@@ -21,6 +21,7 @@ compat = ["std", "futures_01"]
 io-compat = ["compat", "tokio-io"]
 bench = []
 nightly = []
+cfg-target-has-atomic = []
 
 [dependencies]
 futures-core-preview = { path = "../futures-core", version = "=0.3.0-alpha.12", default-features = false }

futures-util/src/lib.rs

@@ -3,13 +3,16 @@
 
 #![feature(futures_api, box_into_pin)]
 #![cfg_attr(feature = "std", feature(async_await, await_macro))]
-#![cfg_attr(feature = "nightly", feature(cfg_target_has_atomic))]
+#![cfg_attr(feature = "cfg-target-has-atomic", feature(cfg_target_has_atomic))]
 
 #![cfg_attr(not(feature = "std"), no_std)]
 #![warn(missing_docs, missing_debug_implementations, rust_2018_idioms)]
 
 #![doc(html_root_url = "https://rust-lang-nursery.github.io/futures-api-docs/0.3.0-alpha.12/futures_util")]
 
+#[cfg(all(feature = "cfg-target-has-atomic", not(feature = "nightly")))]
+compile_error!("The `cfg-target-has-atomic` feature requires the `nightly` feature as an explicit opt-in to unstable features");
+
 #[macro_use]
 mod macros;
 

futures-util/src/task/mod.rs

@@ -12,7 +12,7 @@ mod local_waker_ref;
 pub use self::local_waker_ref::{local_waker_ref, local_waker_ref_from_nonlocal, LocalWakerRef};
 
 #[cfg_attr(
-    feature = "nightly",
+    feature = "cfg-target-has-atomic",
     cfg(all(target_has_atomic = "cas", target_has_atomic = "ptr"))
 )]
 pub use futures_core::task::__internal::AtomicWaker;

futures/Cargo.toml

@@ -41,3 +41,4 @@ std = ["futures-core-preview/std", "futures-executor-preview/std", "futures-io-p
 default = ["std"]
 compat = ["std", "futures-util-preview/compat"]
 io-compat = ["compat", "futures-util-preview/io-compat"]
+cfg-target-has-atomic = ["futures-core-preview/cfg-target-has-atomic", "futures-util-preview/cfg-target-has-atomic"]

futures/src/lib.rs

@@ -29,8 +29,6 @@
 
 #![doc(html_root_url = "https://rust-lang-nursery.github.io/futures-api-docs/0.3.0-alpha.12/futures")]
 
-#![cfg_attr(feature = "nightly", feature(cfg_target_has_atomic))]
-
 #[doc(hidden)] pub use futures_util::core_reexport;
 
 #[doc(hidden)] pub use futures_core::future::Future;