1 files changed, 20 insertions, 0 deletions
diff --git a/src/tools/clippy/tests/ui/let_underscore_future.rs b/src/tools/clippy/tests/ui/let_underscore_future.rs
new file mode 100644
index 000000000..d8f54cdca
--- /dev/null
+++ b/src/tools/clippy/tests/ui/let_underscore_future.rs
@@ -0,0 +1,20 @@
+use std::future::Future;
+
+async fn some_async_fn() {}
+
+fn sync_side_effects() {}
+fn custom() -> impl Future<Output = ()> {
+    sync_side_effects();
+    async {}
+}
+
+fn do_something_to_future(future: &mut impl Future<Output = ()>) {}
+
+fn main() {
+    let _ = some_async_fn();
+    let _ = custom();
+
+    let mut future = some_async_fn();
+    do_something_to_future(&mut future);
+    let _ = future;
+}