Improve type infer of table.unpack and unpack

Author: sumneko

changelog.md

@@ -2,8 +2,9 @@
 
 ## Unreleased
 <!-- Add all new changes here. They will be moved under a version at release -->
-* `FIX` missing-fields diagnostic now warns about missing inherited fields
 * `CHG` Update Love2d version
+* `CHG` Improve type infer of `table.unpack` and `unpack`
+* `FIX` missing-fields diagnostic now warns about missing inherited fields
 
 ## 3.13.2
 `2024-11-21`

meta/template/basic.lua

@@ -332,11 +332,22 @@ function xpcall(f, msgh, arg1, ...) end
 
 ---@version 5.1
 ---#DES 'unpack'
----@generic T
----@param list T[]
+---@generic T1, T2, T3, T4, T5, T6, T7, T8, T9, T10
+---@param list {
+--- [1]?: T1,
+--- [2]?: T2,
+--- [3]?: T3,
+--- [4]?: T4,
+--- [5]?: T5,
+--- [6]?: T6,
+--- [7]?: T7,
+--- [8]?: T8,
+--- [9]?: T9,
+--- [10]?: T10,
+---}
 ---@param i?   integer
 ---@param j?   integer
----@return T   ...
+---@return T1, T2, T3, T4, T5, T6, T7, T8, T9, T10
 ---@nodiscard
 function unpack(list, i, j) end
 

meta/template/table.lua

@@ -57,11 +57,22 @@ function table.sort(list, comp) end
 
 ---@version >5.2, JIT
 ---#DES 'table.unpack'
----@generic T
----@param list T[]
+---@generic T1, T2, T3, T4, T5, T6, T7, T8, T9, T10
+---@param list {
+--- [1]?: T1,
+--- [2]?: T2,
+--- [3]?: T3,
+--- [4]?: T4,
+--- [5]?: T5,
+--- [6]?: T6,
+--- [7]?: T7,
+--- [8]?: T8,
+--- [9]?: T9,
+--- [10]?: T10,
+---}
 ---@param i?   integer
 ---@param j?   integer
----@return T   ...
+---@return T1, T2, T3, T4, T5, T6, T7, T8, T9, T10
 ---@nodiscard
 function table.unpack(list, i, j) end
 

test/type_inference/common.lua

@@ -4673,3 +4673,75 @@ local function F(...)
     end
 end
 ]]
+
+TEST '1' [[
+---@type [1, 2, 3]
+local t
+
+---@generic T1, T2, T3, T4, T5, T6, T7, T8, T9, T10
+---@param arr {
+--- [1]?: T1,
+--- [2]?: T2,
+--- [3]?: T3,
+--- [4]?: T4,
+--- [5]?: T5,
+--- [6]?: T6,
+--- [7]?: T7,
+--- [8]?: T8,
+--- [9]?: T9,
+--- [10]?: T10,
+---}
+---@return T1, T2, T3, T4, T5, T6, T7, T8, T9, T10
+local function unpack(arr)
+end
+
+local <?a?>, b, c, d = unpack(t)
+]]
+
+TEST '2' [[
+---@type [1, 2, 3]
+local t
+
+---@generic T1, T2, T3, T4, T5, T6, T7, T8, T9, T10
+---@param arr {
+--- [1]?: T1,
+--- [2]?: T2,
+--- [3]?: T3,
+--- [4]?: T4,
+--- [5]?: T5,
+--- [6]?: T6,
+--- [7]?: T7,
+--- [8]?: T8,
+--- [9]?: T9,
+--- [10]?: T10,
+---}
+---@return T1, T2, T3, T4, T5, T6, T7, T8, T9, T10
+local function unpack(arr)
+end
+
+local a, <?b?>, c, d = unpack(t)
+]]
+
+TEST '3' [[
+---@type [1, 2, 3]
+local t
+
+---@generic T1, T2, T3, T4, T5, T6, T7, T8, T9, T10
+---@param arr {
+--- [1]?: T1,
+--- [2]?: T2,
+--- [3]?: T3,
+--- [4]?: T4,
+--- [5]?: T5,
+--- [6]?: T6,
+--- [7]?: T7,
+--- [8]?: T8,
+--- [9]?: T9,
+--- [10]?: T10,
+---}
+---@return T1, T2, T3, T4, T5, T6, T7, T8, T9, T10
+local function unpack(arr)
+end
+
+local a, b, <?c?>, d = unpack(t)
+]]