`---@cast` annotation doesn't respect scope rules

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

The ---@cast annotation should respect Lua scoping rules.

Actual Behaviour

Let's consider:

--- @class foo
--- @field a number

--- @class bar
--- @field b string

--- @type { [integer]: foo|bar }
local array = {}

for i, instance in ipairs(array) do
	if instance.a then
                -- First if block
		--- @cast instance foo
	end

	if instance.b then
                -- Second if block
	end
end

In the first if block, we cast the instance to the foo type. When hovering over the instance variable in the second if block we can see its type is foo. It would be expected for its type to be bar since the ---@cast happened in different scope.

Reproduction steps

1. Copy-paste the given example code into your text editor.
2. Hover over the instance variable in the second if block.
3. See the error in the popup.

Additional Notes

No response

Log File

No response

まず、Visual Studio Code 拡張機能で提供されている Lua の例を使って問題を再現し、型チェックが 2 つの if ブロックのスコープをどのように扱うかを調べます。完了条件は、foo へのキャストが最初のブロック内でのみ適用され、2 番目のブロックのインスタンスが foo ではなく適切な推論型を保持することです。