1 files changed, 74 insertions, 0 deletions
diff --git a/tests/ui/async-await/async-fn-nonsend.rs b/tests/ui/async-await/async-fn-nonsend.rs
new file mode 100644
index 00000000000..d7f8d7ac546
--- /dev/null
+++ b/tests/ui/async-await/async-fn-nonsend.rs
@@ -0,0 +1,74 @@
+// edition:2018
+// compile-flags: --crate-type lib -Zdrop-tracking
+
+use std::{cell::RefCell, fmt::Debug, rc::Rc};
+
+fn non_sync() -> impl Debug {
+    RefCell::new(())
+}
+
+fn non_send() -> impl Debug {
+    Rc::new(())
+}
+
+fn take_ref<T>(_: &T) {}
+
+async fn fut() {}
+
+async fn fut_arg<T>(_: T) {}
+
+async fn local_dropped_before_await() {
+    // this is okay now because of the drop
+    let x = non_send();
+    drop(x);
+    fut().await;
+}
+
+async fn non_send_temporary_in_match() {
+    // We could theoretically make this work as well (produce a `Send` future)
+    // for scrutinees / temporaries that can or will
+    // be dropped prior to the match body
+    // (e.g. `Copy` types).
+    match Some(non_send()) {
+        Some(_) => fut().await,
+        None => {}
+    }
+}
+
+fn get_formatter() -> std::fmt::Formatter<'static> {
+    panic!()
+}
+
+async fn non_sync_with_method_call() {
+    let f: &mut std::fmt::Formatter = &mut get_formatter();
+    // It would by nice for this to work.
+    if non_sync().fmt(f).unwrap() == () {
+        fut().await;
+    }
+}
+
+async fn non_sync_with_method_call_panic() {
+    let f: &mut std::fmt::Formatter = panic!();
+    if non_sync().fmt(f).unwrap() == () {
+        fut().await;
+    }
+}
+
+async fn non_sync_with_method_call_infinite_loop() {
+    let f: &mut std::fmt::Formatter = loop {};
+    if non_sync().fmt(f).unwrap() == () {
+        fut().await;
+    }
+}
+
+fn assert_send(_: impl Send) {}
+
+pub fn pass_assert() {
+    assert_send(local_dropped_before_await());
+    assert_send(non_send_temporary_in_match());
+    //~^ ERROR future cannot be sent between threads safely
+    assert_send(non_sync_with_method_call());
+    //~^ ERROR future cannot be sent between threads safely
+    assert_send(non_sync_with_method_call_panic());
+    assert_send(non_sync_with_method_call_infinite_loop());
+}