A union type should not merge class fields

[CarterLi]

How are you using the lua-language-server?

Visual Studio Code Extension (sumneko.lua)

Which OS are you using?

MacOS

What is the issue affecting?

Annotations

Expected Behaviour

---@class (exact) TypeA
---@field type 'A'
---@field commonField number
---@field specificFieldA number

---@class (exact) TypeB
---@field type 'B'
---@field commonField string
---@field specificFieldB string

---@alias Type_Either_A_Or_B_But_Not_Both TypeA|TypeB

---@type Type_Either_A_Or_B_But_Not_Both
local testA = {
    type = 'A', --- Indicates that this should be of TypeA
    commonField = 'test', --- Should be an error. TypeA.commonField should be a number
    specificFieldA = 123, --- OK
    specificFieldB = 'Hello' --- Should be an error. TypeA.specificFieldB doesn't exist
}

---@type Type_Either_A_Or_B_But_Not_Both
local testB = {
    type = 'B', --- Indicates that this should be of TypeB
    commonField = 'test', --- OK
    specificFieldA = 123, --- Should be an error. TypeB.specificFieldA doesn't exist
    specificFieldB = 'Hello' --- OK
}

Actual Behaviour

TypeA|TypeB is merged, so none of the mismatched fields/types are reported as errors.

local testA: TypeA|TypeB {
    commonField: string|number,
    specificFieldA: number,
    specificFieldB: string,
    type: 'A'|'B',
}

Reproduction steps

Paste the code into vscode

Additional Notes

No response

Log File

No response