Fix no_std build

.travis.yml

@@ -64,17 +64,26 @@ matrix:
       script:
         - cargo build --manifest-path futures/Cargo.toml --features io-compat
 
-    # Allow build fail until #1396 is fixed.
     - name: cargo build --target=thumbv6m-none-eabi
       rust: nightly
-      env: ALLOW_FAILURES=true
       install:
         - rustup target add thumbv6m-none-eabi
       script:
+        - cargo run --manifest-path ci/remove-dev-dependencies/Cargo.toml */Cargo.toml
         - cargo build --manifest-path futures/Cargo.toml
             --target thumbv6m-none-eabi
             --no-default-features
-            --features nightly
+            --features nightly,cfg-target-has-atomic
+
+    - name: cargo build --target=thumbv7m-none-eabi
+      rust: nightly
+      install:
+        - rustup target add thumbv7m-none-eabi
+      script:
+        - cargo run --manifest-path ci/remove-dev-dependencies/Cargo.toml */Cargo.toml
+        - cargo build --manifest-path futures/Cargo.toml
+            --target thumbv7m-none-eabi
+            --no-default-features
 
     - name: cargo doc
       rust: nightly
@@ -102,10 +111,6 @@ matrix:
         - git commit -m "Add API docs for $TRAVIS_TAG"
         - git push origin master
 
-  allow_failures:
-    - rust: nightly
-      env: ALLOW_FAILURES=true
-
 script:
   - cargo test --all --all-features
   - cargo test --all --all-features --release

ci/remove-dev-dependencies/Cargo.toml

@@ -0,0 +1,11 @@
+[package]
+name = "remove-dev-dependencies"
+version = "0.1.0"
+authors = ["Wim Looman <wim@nemo157.com>"]
+edition = "2018"
+publish = false
+
+[workspace]
+
+[dependencies]
+toml_edit = "0.1.3"

ci/remove-dev-dependencies/src/main.rs

@@ -0,0 +1,12 @@
+use std::{env, error::Error, fs};
+
+fn main() -> Result<(), Box<dyn Error>> {
+    for file in env::args().skip(1) {
+        let content = fs::read_to_string(&file)?;
+        let mut doc: toml_edit::Document = content.parse()?;
+        doc.as_table_mut().remove("dev-dependencies");
+        fs::write(file, doc.to_string())?;
+    }
+
+    Ok(())
+}

futures-util/src/lib.rs

@@ -1,8 +1,8 @@
 //! Combinators and utilities for working with `Future`s, `Stream`s, `Sink`s,
 //! and the `AsyncRead` and `AsyncWrite` traits.
 
-#![feature(futures_api, box_into_pin)]
-#![cfg_attr(feature = "std", feature(async_await, await_macro))]
+#![feature(futures_api)]
+#![cfg_attr(feature = "std", feature(async_await, await_macro, box_into_pin))]
 #![cfg_attr(feature = "cfg-target-has-atomic", feature(cfg_target_has_atomic))]
 
 #![cfg_attr(not(feature = "std"), no_std)]

futures-util/src/task/mod.rs

@@ -6,7 +6,9 @@ mod arc_wake;
 pub use self::arc_wake::ArcWake;
 
 mod noop_waker;
-pub use self::noop_waker::{noop_waker, noop_waker_ref};
+pub use self::noop_waker::noop_waker;
+#[cfg(feature = "std")]
+pub use self::noop_waker::noop_waker_ref;
 
 mod spawn;
 pub use self::spawn::{SpawnExt, LocalSpawnExt};

futures-util/src/task/noop_waker.rs

@@ -1,6 +1,7 @@
 //! Utilities for creating zero-cost wakers that don't do anything.
 use futures_core::task::{RawWaker, RawWakerVTable, Waker};
 use core::ptr::null;
+#[cfg(feature = "std")]
 use core::cell::UnsafeCell;
 
 unsafe fn noop_clone(_data: *const()) -> RawWaker {
@@ -52,6 +53,7 @@ pub fn noop_waker() -> Waker {
 /// lw.wake();
 /// ```
 #[inline]
+#[cfg(feature = "std")]
 pub fn noop_waker_ref() -> &'static Waker {
     thread_local! {
         static NOOP_WAKER_INSTANCE: UnsafeCell<Waker> =

futures/src/lib.rs

@@ -207,6 +207,10 @@ pub mod future {
         AndThen, ErrInto, FlattenSink, IntoFuture, MapErr, MapOk, OrElse,
         UnwrapOrElse,
         TryJoin, TryJoin3, TryJoin4, TryJoin5,
+    };
+
+    #[cfg(feature = "std")]
+    pub use futures_util::try_future::{
         try_join_all, TryJoinAll,
     };
 }
@@ -364,18 +368,17 @@ pub mod task {
         Waker, RawWaker, RawWakerVTable
     };
 
+    pub use futures_util::task::noop_waker;
+
     #[cfg(feature = "std")]
     pub use futures_util::task::{
         WakerRef, waker_ref, ArcWake,
         SpawnExt, LocalSpawnExt,
-    };
-
-    pub use futures_util::task::{
-        noop_waker, noop_waker_ref,
+        noop_waker_ref,
     };
 
     #[cfg_attr(
-        feature = "target-has-atomic",
+        feature = "cfg-target-has-atomic",
         cfg(all(target_has_atomic = "cas", target_has_atomic = "ptr"))
     )]
     pub use futures_util::task::AtomicWaker;