1 files changed, 50 insertions, 0 deletions
diff --git a/tests/ui/macros/format-args-temporaries-in-write.rs b/tests/ui/macros/format-args-temporaries-in-write.rs
new file mode 100644
index 00000000000..339ccbc33ac
--- /dev/null
+++ b/tests/ui/macros/format-args-temporaries-in-write.rs
@@ -0,0 +1,50 @@
+// check-fail
+
+use std::fmt::{self, Display};
+
+struct Mutex;
+
+impl Mutex {
+    fn lock(&self) -> MutexGuard {
+        MutexGuard(self)
+    }
+}
+
+struct MutexGuard<'a>(&'a Mutex);
+
+impl<'a> Drop for MutexGuard<'a> {
+    fn drop(&mut self) {
+        // Empty but this is a necessary part of the repro. Otherwise borrow
+        // checker is fine with 'a dangling at the time that MutexGuard goes out
+        // of scope.
+    }
+}
+
+struct Out;
+
+impl Out {
+    fn write_fmt(&self, _args: fmt::Arguments) {}
+}
+
+impl<'a> Display for MutexGuard<'a> {
+    fn fmt(&self, _formatter: &mut fmt::Formatter) -> fmt::Result {
+        Ok(())
+    }
+}
+
+fn main() {
+    // FIXME(dtolnay): We actually want both of these to work. I think it's
+    // sadly unimplementable today though.
+
+    let _write = {
+        let mutex = Mutex;
+        write!(Out, "{}", mutex.lock()) /* no semicolon */
+        //~^ ERROR `mutex` does not live long enough
+    };
+
+    let _writeln = {
+        let mutex = Mutex;
+        writeln!(Out, "{}", mutex.lock()) /* no semicolon */
+        //~^ ERROR `mutex` does not live long enough
+    };
+}