1 files changed, 20 insertions, 0 deletions
diff --git a/tests/ui/borrowck/borrowck-borrow-mut-object-twice.rs b/tests/ui/borrowck/borrowck-borrow-mut-object-twice.rs
new file mode 100644
index 000000000..b4d85b60c
--- /dev/null
+++ b/tests/ui/borrowck/borrowck-borrow-mut-object-twice.rs
@@ -0,0 +1,20 @@
+// Check that `&mut` objects cannot be borrowed twice, just like
+// other `&mut` pointers.
+
+
+
+trait Foo {
+    fn f1(&mut self) -> &();
+    fn f2(&mut self);
+}
+
+fn test(x: &mut dyn Foo) {
+    let y = x.f1();
+    x.f2(); //~ ERROR cannot borrow `*x` as mutable
+    y.use_ref();
+}
+
+fn main() {}
+
+trait Fake { fn use_mut(&mut self) { } fn use_ref(&self) { }  }
+impl<T> Fake for T { }