Test returning Vec by value from C to Rust
diff --git a/tests/ffi/tests.cc b/tests/ffi/tests.cc
index 8503ac7..7867bf0 100644
--- a/tests/ffi/tests.cc
+++ b/tests/ffi/tests.cc
@@ -93,6 +93,10 @@
   return c.get_v();
 }
 
+rust::Vec<uint8_t> c_return_rust_vec() {
+  throw std::runtime_error("unimplemented");
+}
+
 void c_take_primitive(size_t n) {
   if (n == 2020) {
     cxx_test_suite_set_correct();