Custom __pairs expects only 1 return value

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

I expected no warnings

Actual Behaviour

There is a redundant return value warning

Reproduction steps

Here's an example where string paths are transformed to their package.loaded value

local imports = {
    mod1 = "src.mod1",
    mod2 = "src.mod2"
}

return setmetatable({}, {
    __pairs = function(_)
        local iter = pairs(imports)

        local newiter = function (table, index) 
            local k, path = iter(table, index)

            return k, package.loaded[path]
        end

        --- LuaLS is wrong here
        ---@diagnostic disable-next-line:redundant-return-value
        return newiter, imports, nil
    end
})

Additional Notes

https://www.lua.org/pil/7.3.html

Log File

No response

在 Linux 上使用提供的 setmetatable 和 __pairs 示例，复现 LuaLS Visual Studio Code extension 中的警告。先从 __pairs 的类型检查处理入手，并将其与 issue 中链接的 Lua 7.3 参考资料进行比较。当该示例不再报告冗余返回值警告时，即表示完成。