Accessing deeply nested variable at 'if' statemet cause type collision

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

Type checking does not breaks after accessing variable at 'if' statement.

Actual Behaviour

2nd nested variable type became '<type> | unknown' so accessing variable or function which not exists in this class does not cause warning.

Reproduction steps

---@class DemoD
---@field c integer 
local DemoD = {}
DemoD.c = 0

---@class DemoC
local DemoC = {}
DemoC.D = DemoD

---@class DemoB
local DemoB = {}
DemoB.C = DemoC

---@class DemoA
local DemoA = {}
DemoA.B = DemoB

---@class DemoRoot
DemoRoot = {}
DemoRoot.A = DemoA

local d = DemoRoot.A.B.C.D

-- if d.c > 1 then end -- if we replace 'DemoRoot.A.B.C.D' with 'd' then F is undefined in all 4 cases
if DemoRoot.A.B.C.D.c > 1 then end

DemoRoot.F() -- warning: F is undefined
DemoRoot.A.F() -- warning: F  is undefined
DemoRoot.A.B.F() -- no warning
DemoRoot.A.B.C.F() -- no warning

Additional Notes

No response

Log File

No response

首先，使用 issue 中的 Lua 代码片段重现所报告的行为，并比较 Visual Studio Code 扩展使用的类型检查器中的直接形式和局部变量形式。当 DemoRoot.A.B.F() 和 DemoRoot.A.B.C.F() 等无效成员产生未定义成员警告，同时不破坏有效的嵌套访问时，修复才算完成。