That's yet another source of nil, but it can be fixed with modules like strict.lua, or simply setmetatable(_G or _ENV, {__index = error}) -- `error` fo

That's yet another source of nil, but it can be fixed with modules like strict.lua, or simply setmetatable(_G or _ENV, {__index = error}) -- `error` for the example, you can write a function that prints a better error message.