`---@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

Start by reproducing the issue with the supplied Lua example in the Visual Studio Code extension and inspect how type checking handles the two if-block scopes. Done means the cast to foo applies only within the first block, while the instance in the second block retains the appropriate inferred type instead of foo.