wasm_memory_access_error_repro.rs

// When compiled in debug mode with rustc 1.25.0-nightly (97520ccb1 2018-01-21),
// calling test from JS results in a `memory access out of bounds` error
// Note the dependency on the [email protected] crate

extern crate futures;

use futures::Stream;

#[no_mangle]
pub fn test() -> usize {
    let (tx, rx) = futures::sync::mpsc::unbounded::<usize>();

    // These lines exist just to confirm that the channels aren't getting optimized away when
    // compiled in release mode. They are *not* required to reproduce the `memory access out of
    // bounds` error in debug mode
    tx.unbounded_send(42).unwrap();
    rx.wait().next().unwrap().unwrap()
}