1 files changed, 45 insertions, 0 deletions
diff --git a/tests/ui/async-await/generator-not-future.rs b/tests/ui/async-await/generator-not-future.rs
new file mode 100644
index 00000000000..37d7cfa6fb7
--- /dev/null
+++ b/tests/ui/async-await/generator-not-future.rs
@@ -0,0 +1,45 @@
+// edition:2018
+#![feature(generators, generator_trait)]
+
+use std::future::Future;
+use std::ops::Generator;
+
+async fn async_fn() {}
+fn returns_async_block() -> impl Future<Output = ()> {
+    async {}
+}
+fn returns_generator() -> impl Generator<(), Yield = (), Return = ()> {
+    || {
+        let _: () = yield ();
+    }
+}
+
+fn takes_future(_f: impl Future<Output = ()>) {}
+fn takes_generator<ResumeTy>(_g: impl Generator<ResumeTy, Yield = (), Return = ()>) {}
+
+fn main() {
+    // okay:
+    takes_future(async_fn());
+    takes_future(returns_async_block());
+    takes_future(async {});
+    takes_generator(returns_generator());
+    takes_generator(|| {
+        let _: () = yield ();
+    });
+
+    // async futures are not generators:
+    takes_generator(async_fn());
+    //~^ ERROR the trait bound
+    takes_generator(returns_async_block());
+    //~^ ERROR the trait bound
+    takes_generator(async {});
+    //~^ ERROR the trait bound
+
+    // generators are not futures:
+    takes_future(returns_generator());
+    //~^ ERROR is not a future
+    takes_future(|ctx| {
+        //~^ ERROR is not a future
+        ctx = yield ();
+    });
+}