1 files changed, 21 insertions, 0 deletions
diff --git a/src/test/ui/mut-function-arguments.rs b/src/test/ui/mut-function-arguments.rs
new file mode 100644
index 00000000000..620d00edbbc
--- /dev/null
+++ b/src/test/ui/mut-function-arguments.rs
@@ -0,0 +1,21 @@
+// run-pass
+
+#![feature(box_syntax)]
+
+fn f(mut y: Box<isize>) {
+    *y = 5;
+    assert_eq!(*y, 5);
+}
+
+fn g() {
+    let frob = |mut q: Box<isize>| { *q = 2; assert_eq!(*q, 2); };
+    let w = box 37;
+    frob(w);
+
+}
+
+pub fn main() {
+    let z = box 17;
+    f(z);
+    g();
+}