fix missing-fields diagnostic not warning about missing inherited fields

Also added tests for it

Author: SereneRuby12

script/core/diagnostics/missing-fields.lua

@@ -41,7 +41,8 @@ return function (uri, callback)
         for className, samedefs in pairs(sortedDefs) do
             local missedKeys = {}
             for _, def in ipairs(samedefs) do
-                if not def.fields or #def.fields == 0 then
+                local fields = vm.getFields(def)
+                if #fields == 0 then
                     goto continue
                 end
 
@@ -55,7 +56,7 @@ return function (uri, callback)
                     end
                 end
 
-                for _, field in ipairs(def.fields) do
+                for _, field in ipairs(fields) do
                     if  not field.optional
                     and not vm.compileNode(field):isNullable() then
                         local key = vm.getKeyName(field)

test/diagnostics/missing-fields.lua

@@ -352,4 +352,114 @@ TEST[[
 
 ---@type A
 local t = <!{x = 1}!>
-]]
+]]
+
+-- Inheritance
+
+TEST[[
+---@class A
+---@field x number
+
+---@class B: A
+
+---@type B
+local t = <!{}!>
+]]
+
+TEST[[
+---@class A
+---@field x number
+---@field y number
+
+---@class B: A
+
+---@type B
+local t = <!{y = 1}!>
+]]
+
+TEST[[
+---@class A
+---@field x number
+
+---@class B: A
+---@field y number
+
+---@type B
+local t = <!{y = 1}!>
+]]
+
+-- Inheritance + optional
+
+TEST[[
+---@class A
+---@field x? number
+
+---@class B: A
+
+---@type B
+local t = {}
+]]
+
+TEST[[
+---@class A
+---@field x? number
+---@field y number
+
+---@class B: A
+
+---@type B
+local t = {y = 1}
+]]
+
+TEST[[
+---@class A
+---@field x? number
+
+---@class B: A
+---@field y number
+
+---@type B
+local t = {y = 1}
+]]
+
+-- Inheritance + function call
+
+TEST[[
+---@class A
+---@field x number
+
+---@class B: A
+
+---@param b B
+local function f(b) end
+
+f <!{}!>
+]]
+
+TEST[[
+---@class A
+---@field x number
+---@field y number
+
+---@class B: A
+
+---@param b B
+local function f(b) end
+
+f <!{y = 1}!>
+]]
+
+TEST[[
+---@class A
+---@field x number
+
+---@class B: A
+---@field y number
+
+---@param b B
+local function f(b) end
+
+f <!{y = 1}!>
+]]
+
+--