Enum created with `@alias` breaks when unioned with table

How are you using the lua-language-server?

Visual Studio Code Extension (sumneko.lua)

Which OS are you using?

Linux

What is the issue affecting?

Type Checking

Expected Behaviour

it should allow either the enum or a table

Actual Behaviour

Cannot assign `integer` to parameter ``BAR`|`FOO`|any[]`.
- `integer` cannot match ``BAR`|`FOO`|any[]`
- Type `integer` cannot match `any[]`
- Type `number` cannot match `any[]`

Reproduction steps

FOO = 1
BAR = 2

--- @alias WAT `FOO` | `BAR`
--- @param a WAT | any[]
local function aa(a) end

aa(FOO)

Additional Notes

Bonus: If you change the type to WAT | WAT[] the error message is

Cannot assign `integer` to parameter ``BAR`|`BAR`|`FOO`[]|`FOO``.
- `integer` cannot match ``BAR`|`BAR`|`FOO`[]|`FOO``
- Type `integer` cannot match ``BAR`|`FOO`[]`
- Type `number` cannot match ``BAR`|`FOO`[]`

which looks very visually confusing

Log File

No response

Visual Studio Code拡張機能で報告されたLuaコードを再現し、ユニオンおよびテーブルと組み合わせたエイリアスの型チェック経路を調査します。aa(FOO) が WAT | any[] に対して受け入れられ、WAT | WAT[] のケースで結果として生成される型診断がもはや分かりにくくなければ完了です。