Issue when using tables/class with generics?

How are you using the lua-language-server?

Visual Studio Code Extension (sumneko.lua)

Which OS are you using?

Windows

What is the issue affecting?

Type Checking

Expected Behaviour

In the following code:

---@class TestClass
---@field test string
---@field test2 string

---@param test TestClass
local function test_function(test)
	for k, v in pairs(test) do end

	---@type {test: string, test2: string}
	local test_table

	for k, v in pairs(test_table) do end

	---@type {test: string, test2: string}
	local test_table2 = {
		test = "test",
		test2 = "test2",
	}

	for k, v in pairs(test_table2) do end
end

I would hope that the inferred type of k and v would work the same in each instance where k is inferred to be a string and v is inferred to be a string.

Actual Behaviour

In the following code:

---@class TestClass
---@field test string
---@field test2 string

---@param test TestClass
local function test_function(test)
	for k, v in pairs(test) do end

	---@type {test: string, test2: string}
	local test_table

	for k, v in pairs(test_table) do end

	---@type {test: string, test2: string}
	local test_table2 = {
		test = "test",
		test2 = "test2",
	}

	for k, v in pairs(test_table2) do end
end

the k and in line: for k, v in pairs(test) do end and the k in line for k, v in pairs(test_table) do end get the error can not infer type and are typed as unknown.

I assume there is some issue here with generics as the pairs definition uses them heavily

---@generic T: table, K, V
---@param t T
---@return fun(table: table<K, V>, index?: K):K, V
---@return T

but this is only a guess.

Reproduction steps

1. Copy this code:

---@class TestClass
---@field test string
---@field test2 string

---@param test TestClass
local function test_function(test)
	for k, v in pairs(test) do end

	---@type {test: string, test2: string}
	local test_table

	for k, v in pairs(test_table) do end

	---@type {test: string, test2: string}
	local test_table2 = {
		test = "test",
		test2 = "test2",
	}

	for k, v in pairs(test_table2) do end
end

2. See errors

Additional Notes

No response

Log File

No response

Comienza reproduciendo el fragmento proporcionado en la extensión de Visual Studio Code y, después, inspecciona la definición de pairs y sus tipos de retorno genéricos. La corrección estará completa cuando k y v se infieran como string para los casos de TestClass, tabla no inicializada y tabla inicializada, sin errores can not infer type.