"Go to Declaration" does not work when the type was asserted to a different type

[sonnguyen9800]

Problem

When using the Luau Language Server (johnymorgan) with VSCode, I cannot use the "Go to Declaration" functionality for functions defined on tables with metatables and type annotations. This occurs in cases where functions are defined for a table using a type that employs setmetatable for object-like behavior.

Reproduction

Here’s an example:

type AccountImpl = {
    __index: AccountImpl,
    new: (name: string, balance: number) -> AccountType,
    deposit: (self: AccountType, credit: number) -> (),
    withdraw: (self: AccountType, debit: number) -> (),
}

type AccountType = typeof(setmetatable({} :: { name: string, balance: number }, {} :: AccountImpl))

local MyAccount: AccountImpl = {} :: AccountImpl
MyAccount.__index = MyAccount

function MyAccount.new(name: string, balance: number): AccountType
    local self = {}
    self.name = name
    self.balance = balance
    return setmetatable(self, MyAccount)
end

function MyAccount:deposit(credit: number)
    self.balance += credit
end

function MyAccount:withdraw(debit: number)
    self.balance -= debit
end

local account = MyAccount.new("Alexander", 500)
account:withdraw(100) -- cannot go to declaration

Expected Behavior

When right-clicking account:withdraw(100) or MyAccount.new(...) and selecting "Go to Declaration," the LSP should navigate to the respective function definitions (MyAccount:withdraw or MyAccount.new).

Observed Behavior

"Go to Declaration" does not work for either the method (withdraw) or the function (new).

Additional Information

Luau Language Server version: 1.32.4
VSCode version: 1.93.1
Reproduction environment: Window

P/S

• I have tried adding explicit type annotations, but the issue persists.
• If I use Nightrains's Roblox-LSP then the issue no longer persist

Update

• I also cannot find "references" & "go to definitions".

Update #2

So basically I cannot find "references" or "go to definition" if tables assigned to any custom type

The code below is working

local Sample = {}
Sample.__index = Sample

function Sample.HelloWorld(): () 
    print("LOL")
end

Sample.HelloWorld() -- Can go to the definition
return Sample

While the other is not

local Sample = {} :: ACustomType
Sample.__index = Sample

function Sample.HelloWorld(): () 
    print("LOL")
end

Sample.HelloWorld() -- Can't go to the definition
return Sample

[JohnnyMorganz]

We rely on Luau's type tracking for function definitions and go to declaration.

When you apply a type assertion, then the Luau type checker doesn't ever care / track your definition of Sample.HelloWorld anymore when you call the function. It is going to try and find the definition of HelloWorld inside of ACustomType.

I don't think there is much we can do here to solve this, because really it is working as intended