LuaLS / LuaLS/lua-language-server

[Feature Request] Automatically overload with `__call` metamethod.

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#2,920 10 comments 4 reactions 0 assignees View on GitHub

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Dominant language
Lua
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Description

There is already custom behavior when __index is defined in a metatable, why not __call? You can manually define the overload, but then you have to define the signature twice.

---@overload fun(a: string, b: number): boolean
local foo = setmetatable({}, {
    ---@param a string
    ---@param b number
    ---@return boolean
    __call = function(a, b)
        return true;
    end
});

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First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by tracing the existing automatic behavior for metatables with __index, then compare it with the __call example in the issue. Done means a callable metatable's function signature is inferred without repeating an @overload declaration, with coverage for the string-and-number example.

Written by the indexing model from the issue text.

Assessment

Tech stack
lua
Domain
devtools
Issue type
Feature
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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