Unexpected typechecking (with classes only?)

How are you using the lua-language-server?

Visual Studio Code Extension (sumneko.lua)

Which OS are you using?

MacOS

What is the issue affecting?

Type Checking

Expected Behaviour

---@param a string
---@return string
local function expandHeader(a) return a end

---@class baz
---@field header string?

---@type baz
local foo = {}
local bar = foo.header
expandHeader(foo.header) -- param-type-mismatch
expandHeader(bar) -- param-type-mismatch

Actual Behaviour

---@param a string
---@return string
local function expandHeader(a) return a end

---@class baz
---@field header string?

---@type baz
local foo = {}
local bar = foo.header
expandHeader(foo.header) -- NO WARNING
expandHeader(bar) -- param-type-mismatch

Reproduction steps

See actual behavior

Additional Notes

No response

Log File

No response

從 issue 中的 Lua 重現開始，檢查帶註解類別的 nullable 欄位之型別檢查路徑。確認 expandHeader(foo.header) 和 expandHeader(bar) 的行為；當兩次呼叫都回報預期的參數型別不相符時即表示完成。