Question mark optional syntax not supported in fun() declarations

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

Optional value to actually be optional

Actual Behaviour

It's not optional.

This code block should show as Human? and throw warnings for not checking nil. If I manually annotate with ---@param man Human? this works as expected.

The class in question:

---@class Command
---@field info string What the command does.
---@field usage string? How to use the command.
---@field alias string[]? Aliases of the command.
---@field canCall (fun(player: Player): boolean)? Function which checks whether a player can call this command.
---@field call fun(player: Player, human: Human?, args: string[]) Calls the command.
---@field autoComplete fun(args: string[])? Function which manipulates arguments when pressing tab in the terminal.
---@field cooldownTime number? How many seconds a player has to wait before using the command again.

I have also tried with human?: Human and human?: Human? but neither way works.

Reproduction steps

1. Create class with a field with a short form function declaration with an optional value parameter
2. Attempt to create object of class with that field,
3. Parameter correctly types, except as not optional.

Additional Notes

No response

Log File

No response

まず Visual Studio Code extension のクラスフィールドの例を再現し、nullable な Human パラメーターを持つ短縮形式の関数宣言に焦点を当てます。手動で注釈を付けた ---@param man Human? のケースと比較します。パラメーターが optional として推論され、説明どおりに nil チェックの警告が表示されれば完了です。