1 files changed, 69 insertions, 0 deletions
diff --git a/tests/ui/generator/drop-tracking-parent-expression.rs b/tests/ui/generator/drop-tracking-parent-expression.rs
new file mode 100644
index 00000000000..d40f1b8f64d
--- /dev/null
+++ b/tests/ui/generator/drop-tracking-parent-expression.rs
@@ -0,0 +1,69 @@
+// compile-flags: -Zdrop-tracking
+#![feature(generators, negative_impls, rustc_attrs)]
+
+macro_rules! type_combinations {
+    (
+        $( $name:ident => { $( $tt:tt )* } );* $(;)?
+    ) => { $(
+        mod $name {
+            $( $tt )*
+
+            impl !Sync for Client {}
+            impl !Send for Client {}
+        }
+
+        // Struct update syntax. This fails because the Client used in the update is considered
+        // dropped *after* the yield.
+        {
+            let g = move || match drop($name::Client { ..$name::Client::default() }) {
+            //~^ `significant_drop::Client` which is not `Send`
+            //~| `insignificant_dtor::Client` which is not `Send`
+            //~| `derived_drop::Client` which is not `Send`
+                _ => yield,
+            };
+            assert_send(g);
+            //~^ ERROR cannot be sent between threads
+            //~| ERROR cannot be sent between threads
+            //~| ERROR cannot be sent between threads
+        }
+
+        // Simple owned value. This works because the Client is considered moved into `drop`,
+        // even though the temporary expression doesn't end until after the yield.
+        {
+            let g = move || match drop($name::Client::default()) {
+                _ => yield,
+            };
+            assert_send(g);
+        }
+    )* }
+}
+
+fn assert_send<T: Send>(_thing: T) {}
+
+fn main() {
+    type_combinations!(
+        // OK
+        copy => { #[derive(Copy, Clone, Default)] pub struct Client; };
+        // NOT OK: MIR borrowck thinks that this is used after the yield, even though
+        // this has no `Drop` impl and only the drops of the fields are observable.
+        // FIXME: this should compile.
+        derived_drop => { #[derive(Default)] pub struct Client { pub nickname: String } };
+        // NOT OK
+        significant_drop => {
+            #[derive(Default)]
+            pub struct Client;
+            impl Drop for Client {
+                fn drop(&mut self) {}
+            }
+        };
+        // NOT OK (we need to agree with MIR borrowck)
+        insignificant_dtor => {
+            #[derive(Default)]
+            #[rustc_insignificant_dtor]
+            pub struct Client;
+            impl Drop for Client {
+                fn drop(&mut self) {}
+            }
+        };
+    );
+}