1 files changed, 44 insertions, 0 deletions
diff --git a/tests/ui/async-await/multiple-lifetimes/ret-ref.rs b/tests/ui/async-await/multiple-lifetimes/ret-ref.rs
new file mode 100644
index 00000000000..149c020f9cb
--- /dev/null
+++ b/tests/ui/async-await/multiple-lifetimes/ret-ref.rs
@@ -0,0 +1,44 @@
+// edition:2018
+
+// Test that we get the expected borrow check errors when an async
+// function (which takes multiple lifetimes) only returns data from
+// one of them.
+
+async fn multiple_named_lifetimes<'a, 'b>(a: &'a u8, _: &'b u8) -> &'a u8 {
+    a
+}
+
+// Both are borrowed whilst the future is live.
+async fn future_live() {
+    let mut a = 22;
+    let mut b = 44;
+    let future = multiple_named_lifetimes(&a, &b);
+    a += 1; //~ ERROR cannot assign
+    b += 1; //~ ERROR cannot assign
+    let p = future.await;
+    drop(p);
+}
+
+// Just the return value is live after future is awaited.
+async fn just_return_live() {
+    let mut a = 22;
+    let mut b = 44;
+    let future = multiple_named_lifetimes(&a, &b);
+    let p = future.await;
+    a += 1; //~ ERROR cannot assign
+    b += 1;
+    drop(p);
+}
+
+// Once `p` is dead, both `a` and `b` are unborrowed.
+async fn after_both_dead() {
+    let mut a = 22;
+    let mut b = 44;
+    let future = multiple_named_lifetimes(&a, &b);
+    let p = future.await;
+    drop(p);
+    a += 1;
+    b += 1;
+}
+
+fn main() { }