1 files changed, 40 insertions, 0 deletions
diff --git a/tests/ui/nll/issue-30104.rs b/tests/ui/nll/issue-30104.rs
new file mode 100644
index 000000000..38850cd3f
--- /dev/null
+++ b/tests/ui/nll/issue-30104.rs
@@ -0,0 +1,40 @@
+// Regression test for #30104
+
+// check-pass
+
+use std::ops::{Deref, DerefMut};
+
+fn box_two_field(v: &mut Box<(i32, i32)>) {
+    let _a = &mut v.0;
+    let _b = &mut v.1;
+}
+
+fn box_destructure(v: &mut Box<(i32, i32)>) {
+    let (ref mut _head, ref mut _tail) = **v;
+}
+
+struct Wrap<T>(T);
+
+impl<T> Deref for Wrap<T> {
+    type Target = T;
+    fn deref(&self) -> &T {
+        &self.0
+    }
+}
+
+impl<T> DerefMut for Wrap<T> {
+    fn deref_mut(&mut self) -> &mut T {
+        &mut self.0
+    }
+}
+
+fn smart_two_field(v: &mut Wrap<(i32, i32)>) {
+    let _a = &mut v.0;
+    let _b = &mut v.1;
+}
+
+fn smart_destructure(v: &mut Wrap<(i32, i32)>) {
+    let (ref mut _head, ref mut _tail) = **v;
+}
+
+fn main() {}