No completions for function aliases

[musjj]

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

Global function aliases are typechecked.

Actual Behaviour

Global function aliases are not typechecked.

Reproduction steps

---@class foo
foo = {}

---@alias foo.bar fun(baz: number)

foo.bar = function(baz) -- (parameter) baz: any

end

function foo.bar(baz) -- (parameter) baz: any
 
end

The field bar and argument baz should be inferred, but it's not.

Additional Notes

I'm not sure what's supposed to be the correct behavior here. But this is how they're defined in the https://github.com/LuaCATS/love2d plugin:

-- version: 11.5
---
---[Open in Browser](https://love2d.org/wiki/love)
---
---@class love
love = {}

---
---Callback function used to update the state of the game every frame.
---
---@alias love.update fun(dt: number)

And this breaks all completions for these functions: LuaCATS/love2d#10.

Was there a breaking change somewhere?

Log File

No response

[CppCXY]

bad usage，should use @param instead alias

[tomlau10]

You are using the annotation incorrectly.

• @alias is for creating a type name with the specified type (and a type name can contains a .)
• by writing ---@alias foo.bar fun(baz: number), you essentially created a type name foo.bar for you to use in @type
• it doesn't mean that any foo.bar expression will be inferred as fun(baz: number), it's just a type name

---@class foo
foo = {}

---@alias foo.bar fun(baz: number)

---@type foo.bar
function foo.bar(baz) -- (parameter) baz: number
end

I believe this is how those @alias love.* is supposed to be used:
=> when you define your callback, you have to use the corresponding @type above your defintion.

---

I see that you have replied to #1779 (comment) as well, and with my PR #2859 (which can resolve #2158 I believe), I think now the love2d plugin can just use standard function + @param style to define all those callbacks 🤔 no more @alias or @type is needed.

• for example:

---
---Callback function used to update the state of the game every frame.
---
---@param dt number
function love.update(dt) end

• and then in user code:

local love = require "love"

function love.update(dt) --> (parameter) dt: number
end

• result
  

But I am not a user of the love2d library, so this has to be decided by the community and maintainer of that plugin.

[musjj]

Thank you for the detailed explanation! I will consider opening a PR for the Love2D plugin.