Disallow ? on values

How are you using the lua-language-server?

Visual Studio Code Extension (sumneko.lua)

Which OS are you using?

Windows

What is the issue affecting?

Type Checking

Expected Behaviour

? is not a type, and should only be used when marking fields as optional. If nil is explicitly allowed as a value, | nil should be used. This is in line with TypeScript.

Actual Behaviour

? does not add | nil to the value type, and the second option should be disallowed.

Reproduction steps

---@class Foo
---@field foo? string
---@field bar string?
---@field baz string | nil
local test = {};

function Foo()
    return test.foo, test.bar, test.baz
end;

Additional Notes

No response

Log File

No response

首先，使用 issue 中的 Lua 程式碼片段重現 Visual Studio Code Extension (sumneko.lua) 中的型別檢查行為。完成的標準是：不允許使用 string?，foo? string 仍然是選用欄位形式，且 string | nil 明確允許 nil。