TypeGuards no longer seem to work

[NyakoFox]

---@class MyClass
---@class MyInheritedClass : MyClass
---@field test fun(): void


---@return TypeGuard<MyInheritedClass>
function typeguard(instance)
    return true
end

---@type MyClass
local instance = {}

if typeguard(instance) then
    instance:test() -- this is MyClass still, this is a warning! Undefined field `test`.

    ---@cast instance MyInheritedClass
    instance:test()
end

Tested on the latest update, and also #1017, both have this issue

[xuhuanzy]

This behavior is correct: MyInheritedClass is broader in scope than MyClass, so it cannot be converted.

[NyakoFox]

I am not sure I understand. A very desirable thing to do is:

---@param instance VeryGenericClass
function test(instance)
    if IsSpecializedClass(instance) then
        instance:doSpecializedThing()
    end
end

the same way instanceof would be used in Java. If you have a "wide" class, and you want to access more "specialized" behavior on the child, you want to type check, and then run it.

Is this not a good use of TypeGuard? is there anything else which allows this? It is a very common pattern.