1 files changed, 10 insertions, 0 deletions
diff --git a/tests/ui/fmt/send-sync.rs b/tests/ui/fmt/send-sync.rs
new file mode 100644
index 000000000..95ec68d1d
--- /dev/null
+++ b/tests/ui/fmt/send-sync.rs
@@ -0,0 +1,10 @@
+fn send<T: Send>(_: T) {}
+fn sync<T: Sync>(_: T) {}
+
+fn main() {
+    // `Cell` is not `Sync`, so `&Cell` is neither `Sync` nor `Send`,
+    // `std::fmt::Arguments` used to forget this...
+    let c = std::cell::Cell::new(42);
+    send(format_args!("{:?}", c)); //~ ERROR E0277
+    sync(format_args!("{:?}", c)); //~ ERROR E0277
+}