1 files changed, 16 insertions, 0 deletions
diff --git a/src/test/ui/reassign-ref-mut.rs b/src/test/ui/reassign-ref-mut.rs
new file mode 100644
index 000000000..d6d41e959
--- /dev/null
+++ b/src/test/ui/reassign-ref-mut.rs
@@ -0,0 +1,16 @@
+// Tests how we behave when the user attempts to mutate an immutable
+// binding that was introduced by either `ref` or `ref mut`
+// patterns.
+//
+// Such bindings cannot be made mutable via the mere addition of the
+// `mut` keyword, and thus we want to check that the compiler does not
+// suggest doing so.
+
+fn main() {
+    let (mut one_two, mut three_four) = ((1, 2), (3, 4));
+    let &mut (ref a, ref mut b) = &mut one_two;
+    a = &three_four.0;
+    //~^ ERROR cannot assign twice to immutable variable `a` [E0384]
+    b = &mut three_four.1;
+    //~^ ERROR cannot assign twice to immutable variable `b` [E0384]
+}