Function Prototype Narrowing with nils about lua-language-server HOT 2 OPEN

---@param baz string|number
---@param qux string|number
---@return string
---@overload fun(text: string|number, title?: nil):nil ### add `?` to `title`
---@overload fun(text?: nil, title: string|number):nil ### add `?` to `text`
---@overload fun(text?: nil, title?: nil):nil ### add `?` to both `text` and `title`
function Foo.Bar(baz, qux)
    if not baz or not qux then
        return nil
    end
    return 'SomeString'
end

local a = Foo.Bar('Baz', 'Qux') -- **string** => it's corrects now
local a = Foo.Bar('Baz', nil) -- nil
local a = Foo.Bar('Baz') -- nil
local a = Foo.Bar(nil, 'Qux') -- nil
local a = Foo.Bar(nil, nil) -- nil
local a = Foo.Bar() -- nil