This is not so much about Lua, it's more about ToLua, the tool that generates the Lua bindings from C++ headers. There isn't much documentation about it, other than its homepage: http://www.codenix.com/~tolua/

The main point here is that it sometimes generates the wrong bindings, especially where references are used. You might want to check the generated `src/Bindings/Bindings.cpp` file before and after this change, to see if any of the bindings have changed; they shouldn't.