excutor: fix Send unsoundness with `-> impl Future` tasks.

1 files changed, 41 insertions, 0 deletions

diff --git a/embassy-executor/tests/ui/spawn_nonsend.stderr b/embassy-executor/tests/ui/spawn_nonsend.stderr
new file mode 100644
index 000000000..2a06c8b94
--- /dev/null
+++ b/embassy-executor/tests/ui/spawn_nonsend.stderr
@@ -0,0 +1,41 @@
+warning: unused import: `core::future::Future`
+ --> tests/ui/spawn_nonsend.rs:3:5
+  |
+3 | use core::future::Future;
+  |     ^^^^^^^^^^^^^^^^^^^^
+  |
+  = note: `#[warn(unused_imports)]` on by default
+
+error[E0277]: `*mut ()` cannot be sent between threads safely
+  --> tests/ui/spawn_nonsend.rs:13:13
+   |
+7  | #[embassy_executor::task]
+   | ------------------------- within this `impl Sized`
+...
+13 |     s.spawn(task(core::ptr::null_mut())).unwrap();
+   |       ----- ^^^^^^^^^^^^^^^^^^^^^^^^^^^ `*mut ()` cannot be sent between threads safely
+   |       |
+   |       required by a bound introduced by this call
+   |
+   = help: within `impl Sized`, the trait `Send` is not implemented for `*mut ()`
+note: required because it's used within this closure
+  --> tests/ui/spawn_nonsend.rs:7:1
+   |
+7  | #[embassy_executor::task]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^
+note: required because it appears within the type `impl Sized`
+  --> src/raw/mod.rs
+   |
+   |     pub unsafe fn _spawn_async_fn<FutFn>(&'static self, future: FutFn) -> SpawnToken<impl Sized>
+   |                                                                                      ^^^^^^^^^^
+note: required because it appears within the type `impl Sized`
+  --> tests/ui/spawn_nonsend.rs:7:1
+   |
+7  | #[embassy_executor::task]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^
+note: required by a bound in `SendSpawner::spawn`
+  --> src/spawner.rs
+   |
+   |     pub fn spawn<S: Send>(&self, token: SpawnToken<S>) -> Result<(), SpawnError> {
+   |                     ^^^^ required by this bound in `SendSpawner::spawn`
+   = note: this error originates in the attribute macro `embassy_executor::task` (in Nightly builds, run with -Z macro-backtrace for more info)