diff --git a/src/test_module.cpp b/src/test_module.cpp
index c5da4c9..ebccf73 100644
--- a/src/test_module.cpp
+++ b/src/test_module.cpp
@@ -34,6 +34,11 @@ class TestBaseType
     int mdarray[2][3][5];
     std::function<int (int)> func_member;
 
+    void set_string_val(std::string &t_str)
+    {
+      t_str = "42";
+    }
+
   private:
     TestBaseType &operator=(const TestBaseType &) = delete;
 };
@@ -52,6 +57,7 @@ class Type2
       return m_bt.val;
     }
 
+
     const char *get_str() const
     {
       return m_str.c_str();
@@ -171,6 +177,7 @@ CHAISCRIPT_MODULE_EXPORT  chaiscript::ModulePtr create_chaiscript_module_test_mo
   m->add(chaiscript::fun(&TestBaseType::val), "val");
   m->add(chaiscript::fun(&TestBaseType::const_val), "const_val");
   m->add(chaiscript::fun(&TestBaseType::base_only_func), "base_only_func");
+  m->add(chaiscript::fun(&TestBaseType::set_string_val), "set_string_val");
 
 #ifndef CHAISCRIPT_MSVC_12
   // we cannot support these in MSVC_12 because of a bug in the implementation of
diff --git a/unittests/non_const_param.chai b/unittests/non_const_param.chai
new file mode 100644
index 0000000..fa385db
--- /dev/null
+++ b/unittests/non_const_param.chai
@@ -0,0 +1,8 @@
+load_module("test_module")
+
+var t2 = TestBaseType();
+
+var s = "5";
+t2.set_string_val(s);
+assert_equal(s, "42")
+