feat: support type inference for @field and @type function declarations in method overrides

changelog.md

@@ -2,6 +2,7 @@
 
 ## Unreleased
 <!-- Add all new changes here. They will be moved under a version at release -->
+* `NEW` Support type inference for `@field` and `@type` function declarations in method overrides [#3367](https://github.com/LuaLS/lua-language-server/issues/3367)
 * `CHG` Modified the `ResolveRequire` function to pass the source URI as a third argument.
 
 ## 3.17.1

script/vm/compiler.lua

@@ -1460,7 +1460,9 @@ local function compileFunctionParam(func, source)
                         end
                         vm.getClassFields(suri, extClass, key, function (field, _isMark)
                             for n in vm.compileNode(field):eachObject() do
-                                if n.type == 'function' and n.args[aindex] then
+                                if (n.type == 'function' or n.type == 'doc.type.function')
+                                and n.args[aindex]
+                                then
                                     local argNode = vm.compileNode(n.args[aindex])
                                     for an in argNode:eachObject() do
                                         if an.type ~= 'doc.generic.name' then

test/type_inference/field_override.lua

@@ -0,0 +1,68 @@
+
+-- Test @type field declaration with method override
+TEST 'Buff' [[
+---@class Buff
+local mt = {}
+---@type (fun(self: Buff, target: Buff): boolean)?
+mt.on_cover = nil
+
+---@class Buff.CommandAura : Buff
+local tpl = {}
+function tpl:on_cover(<?target?>)
+    return true
+end
+]]
+
+-- Test @field declaration with method override
+TEST 'Animal' [[
+---@class Animal
+---@field can_eat (fun(self: Animal, other: Animal): boolean)?
+local base = {}
+
+---@class Dog : Animal
+local dog = {}
+function dog:can_eat(<?other?>)
+    return true
+end
+]]
+
+-- Test optional method with @type
+TEST 'string' [[
+---@class Base
+local base = {}
+---@type (fun(self: Base, x: string): number)?
+base.callback = nil
+
+---@class Child : Base
+local child = {}
+function child:callback(<?x?>)
+    return 1
+end
+]]
+
+-- Test non-optional @field
+TEST 'number' [[
+---@class Handler
+---@field process fun(self: Handler, value: number): string
+local handler = {}
+
+---@class CustomHandler : Handler
+local custom = {}
+function custom:process(<?value?>)
+    return tostring(value)
+end
+]]
+
+-- Test multiple parameters with @type
+TEST 'string' [[
+---@class Processor
+local proc = {}
+---@type fun(self: Processor, a: number, b: string): boolean
+proc.handle = nil
+
+---@class MyProcessor : Processor
+local my = {}
+function my:handle(a, <?b?>)
+    return true
+end
+]]

test/type_inference/init.lua

@@ -46,3 +46,4 @@ end
 
 require 'type_inference.common'
 require 'type_inference.param_match'
+require 'type_inference.field_override'