Compile error with crossbeam-channel

[Caleb Bassi]

Minimal reproducible example:

// main.rs
#![feature(async_await)]

use std::time::Duration;

use crossbeam_channel::{select, tick};

async fn foo() {}

#[runtime::main]
async fn main() {
    let ticker1 = tick(Duration::from_secs(1));
    let ticker2 = tick(Duration::from_secs(1));

    select! {
        recv(ticker1) -> _ => {
            foo().await;
        }
        recv(ticker2) -> _ => {
        }
    }
}

// Cargo.toml
[package]
name = "foo"
version = "0.1.0"
edition = "2018"

[dependencies]
crossbeam-channel = "0.3"
runtime = "0.3.0-alpha.6"

Both recv statements are required. The .await in either recv is required. Doesn't error when using #[tokio::main] instead from tokio master branch. Also errors when doing #[runtime::main(runtime_tokio::Tokio)].

Using rustc 1.38.0-nightly (95b1fe560 2019-07-20)
Running: rustup run nightly cargo run

Results in:

error[E0277]: `*const u8` cannot be sent between threads safely
 --> src/main.rs:9:1
  |
9 | #[runtime::main]
  | ^^^^^^^^^^^^^^^^ `*const u8` cannot be sent between threads safely
  |
  = help: within `impl std::future::Future`, the trait `std::marker::Send` is not implemented for `*const u8`
  = note: required because it appears within the type `crossbeam_channel::select::SelectedOperation<'_>`
  = note: required because it appears within the type `for<'r, 's, 't0, 't1, 't2, 't3> {crossbeam_channel::channel::Receiver<std::time::Instant>, crossbeam_channel::select::Select<'r>, &'s crossbeam_channel::channel::Receiver<std::time::Instant>, &'t0 crossbeam_channel::channel::Receiver<std::time::Instant>, &'t1 crossbeam_channel::channel::Receiver<std::time::Instant>, &'t2 crossbeam_channel::channel::Receiver<std::time::Instant>, crossbeam_channel::select::SelectedOperation<'t3>, bool, std::result::Result<std::time::Instant, crossbeam_channel::err::RecvError>, impl std::future::Future, ()}`
  = note: required because it appears within the type `[static generator@src/main.rs:9:1: 9:17 for<'r, 's, 't0, 't1, 't2, 't3> {crossbeam_channel::channel::Receiver<std::time::Instant>, crossbeam_channel::select::Select<'r>, &'s crossbeam_channel::channel::Receiver<std::time::Instant>, &'t0 crossbeam_channel::channel::Receiver<std::time::Instant>, &'t1 crossbeam_channel::channel::Receiver<std::time::Instant>, &'t2 crossbeam_channel::channel::Receiver<std::time::Instant>, crossbeam_channel::select::SelectedOperation<'t3>, bool, std::result::Result<std::time::Instant, crossbeam_channel::err::RecvError>, impl std::future::Future, ()}]`
  = note: required because it appears within the type `std::future::GenFuture<[static generator@src/main.rs:9:1: 9:17 for<'r, 's, 't0, 't1, 't2, 't3> {crossbeam_channel::channel::Receiver<std::time::Instant>, crossbeam_channel::select::Select<'r>, &'s crossbeam_channel::channel::Receiver<std::time::Instant>, &'t0 crossbeam_channel::channel::Receiver<std::time::Instant>, &'t1 crossbeam_channel::channel::Receiver<std::time::Instant>, &'t2 crossbeam_channel::channel::Receiver<std::time::Instant>, crossbeam_channel::select::SelectedOperation<'t3>, bool, std::result::Result<std::time::Instant, crossbeam_channel::err::RecvError>, impl std::future::Future, ()}]>`
  = note: required because it appears within the type `impl std::future::Future`
  = note: required because it appears within the type `impl std::future::Future`
  = note: required because it appears within the type `{impl std::future::Future, ()}`
  = note: required because it appears within the type `[static generator@src/main.rs:9:1: 9:17 {impl std::future::Future, ()}]`
  = note: required because it appears within the type `std::future::GenFuture<[static generator@src/main.rs:9:1: 9:17 {impl std::future::Future, ()}]>`
  = note: required because it appears within the type `impl std::future::Future`
  = note: required by `runtime_raw::enter`

error: aborting due to previous error

For more information about this error, try `rustc --explain E0277`.
error: Could not compile `foo`.

To learn more, run the command again with --verbose.

[Yosh]

cc/ @stjepang