How do I fix 'W001 Unknown Global *blank*' Errors?

Hello, I was starting to learn how to script in my Roblox game and after fixing all the syntax errors I got onto trying to fix the Unknown global errors but cannot figure out how to fix them.

local ModuleScript = {}
mt = getrawmetatable(game)
make_writeable(mt)
local old = mt.__namecall

mt.__namecall = newcclosure(function (self,...)
	local args  = {...}

^^^ Thats all the code that has caused this error.

Usually, the error leads to unknown variable names or function calls the script doesn't recognize. Take these examples:

variable typo

local food = 100 --full hunger!!

if fod == 100 then --fod is not defined and so it leads to the W001 unknown global error
	print("not hungry.")
end

function call typo

local function Eat()
	food += 15
end

script.Parent.Activated:Connect(function()
	if food == 100 then
		return false
	elseif food > 100 then
		food = 100
		return false
	elseif food < 100 then
		Et() --Et() isn't defined so it leads to the W001 unknown global error
	end
end)

Make sure to look through your scripts for typos, but also incorrect function calls. In this case you've probably typed in a function that is incorrect.

Here is a Roblox Dev Hub page upon Metatables.

https://developer.roblox.com/en-us/articles/Metatables

Hope this helped!