1 files changed, 31 insertions, 0 deletions
diff --git a/src/test/ui/generator/ref-upvar-not-send.rs b/src/test/ui/generator/ref-upvar-not-send.rs
new file mode 100644
index 00000000000..eb9ef63ecfc
--- /dev/null
+++ b/src/test/ui/generator/ref-upvar-not-send.rs
@@ -0,0 +1,31 @@
+// For `Send` generators, suggest a `T: Sync` requirement for `&T` upvars,
+// and suggest a `T: Send` requirement for `&mut T` upvars.
+
+#![feature(generators)]
+
+fn assert_send<T: Send>(_: T) {}
+//~^ NOTE required by a bound in `assert_send`
+//~| NOTE required by this bound in `assert_send`
+//~| NOTE required by a bound in `assert_send`
+//~| NOTE required by this bound in `assert_send`
+
+fn main() {
+    let x: &*mut () = &std::ptr::null_mut();
+    let y: &mut *mut () = &mut std::ptr::null_mut();
+    assert_send(move || {
+        //~^ ERROR generator cannot be sent between threads safely
+        //~| NOTE generator is not `Send`
+        yield;
+        let _x = x;
+    });
+    //~^^ NOTE captured value is not `Send` because `&` references cannot be sent unless their referent is `Sync`
+    //~| NOTE has type `&*mut ()` which is not `Send`, because `*mut ()` is not `Sync`
+    assert_send(move || {
+        //~^ ERROR generator cannot be sent between threads safely
+        //~| NOTE generator is not `Send`
+        yield;
+        let _y = y;
+    });
+    //~^^ NOTE captured value is not `Send` because `&mut` references cannot be sent unless their referent is `Send`
+    //~| NOTE has type `&mut *mut ()` which is not `Send`, because `*mut ()` is not `Send`
+}