1 files changed, 30 insertions, 0 deletions
diff --git a/tests/ui/logging-only-prints-once.rs b/tests/ui/logging-only-prints-once.rs
new file mode 100644
index 000000000..6d16819ce
--- /dev/null
+++ b/tests/ui/logging-only-prints-once.rs
@@ -0,0 +1,30 @@
+// run-pass
+// ignore-windows
+// ignore-emscripten no threads support
+
+use std::cell::Cell;
+use std::fmt;
+use std::thread;
+
+struct Foo(Cell<isize>);
+
+impl fmt::Debug for Foo {
+    fn fmt(&self, _fmt: &mut fmt::Formatter) -> fmt::Result {
+        let Foo(ref f) = *self;
+        assert_eq!(f.get(), 0);
+        f.set(1);
+        Ok(())
+    }
+}
+
+pub fn main() {
+    thread::spawn(move || {
+        let mut f = Foo(Cell::new(0));
+        println!("{:?}", f);
+        let Foo(ref mut f) = f;
+        assert_eq!(f.get(), 1);
+    })
+    .join()
+    .ok()
+    .unwrap();
+}