1 files changed, 39 insertions, 0 deletions
diff --git a/tests/ui/impl-trait/auto-trait-leak2.rs b/tests/ui/impl-trait/auto-trait-leak2.rs
new file mode 100644
index 000000000..09450089a
--- /dev/null
+++ b/tests/ui/impl-trait/auto-trait-leak2.rs
@@ -0,0 +1,39 @@
+use std::cell::Cell;
+use std::rc::Rc;
+
+// Fast path, main can see the concrete type returned.
+fn before() -> impl Fn(i32) {
+//~^ NOTE within this `impl Fn
+//~| NOTE within the type `impl Fn
+//~| NOTE expansion of desugaring
+    let p = Rc::new(Cell::new(0));
+    move |x| p.set(x) //~ NOTE used within this closure
+}
+
+fn send<T: Send>(_: T) {}
+//~^ NOTE required by a bound
+//~| NOTE required by a bound
+//~| NOTE required by this bound
+//~| NOTE required by this bound
+
+fn main() {
+    send(before());
+    //~^ ERROR `Rc<Cell<i32>>` cannot be sent between threads safely
+    //~| NOTE `Rc<Cell<i32>>` cannot be sent between threads safely
+    //~| NOTE required by a bound
+
+    send(after());
+    //~^ ERROR `Rc<Cell<i32>>` cannot be sent between threads safely
+    //~| NOTE `Rc<Cell<i32>>` cannot be sent between threads safely
+    //~| NOTE required by a bound
+}
+
+// Deferred path, main has to wait until typeck finishes,
+// to check if the return type of after is Send.
+fn after() -> impl Fn(i32) {
+//~^ NOTE within this `impl Fn(i32)`
+//~| NOTE in this expansion
+//~| NOTE appears within the type
+    let p = Rc::new(Cell::new(0));
+    move |x| p.set(x) //~ NOTE used within this closure
+}