unused_variable false positive when mutating over the return value of a function

[Kampfkarren]

local runServicePrototype = getmetatable(habitat.game:GetService("RunService")).class.prototype
function runServicePrototype.IsServer()
	return true
end

throws:

warning[unused_variable]: runServicePrototype is assigned a value, but never used

    ┌── Tests/tests.lua:88:7 ───
    │
 88 │ local runServicePrototype = getmetatable(habitat.game:GetService("RunService")).class.prototype
    │       ^^^^^^^^^^^^^^^^^^^
    │

This does not happen when the code is:

runServicePrototype.IsServer = function()
	return true
end