added test for issue #31

tests/compile-fail/box_vec.rs

@@ -7,6 +7,11 @@ pub fn test(foo: Box<Vec<bool>>) { //~ ERROR You seem to be trying to use Box<Ve
     println!("{:?}", foo.get(0))
 }
 
+pub fn test2(foo: Box<Fn(Vec<u32>)>) { // pass if #31 is fixed
+	foo(vec![1, 2, 3])
+}
+
 fn main(){
     test(Box::new(Vec::new()));
-}
+    test2(Box::new(|v| println!("{:?}", v)));
+}