Index an enum-value table bug

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

expected the value type of mapping when index

Actual Behaviour

got an unknown

Reproduction steps

---@enum(key) AttrName
local o = {
    ['hp_max'] = true,
}
local map = {
    ['hp_max'] = 114514,
}
---@param t table<AttrName, number>
local function test(t)
    --[[
        Usage 1: correct
    ]]
    local a = 'hp_max'
    local b = t[a]  -- expected: number, got: number
    print(b)

    --[[
        Usage 2: incorrect
    ]]
    local c = t['hp_max'] -- expected: number, got: unknown
    print(c)

    --[[
        Usage 3: correct
    ]]
    local d = "hp_grow"
    local e = t[d] -- expected: unknown, got: unknown
    print(e)
end
test(map)

Additional Notes

No response

Log File

No response

Reproduce the report in the LuaLS Visual Studio Code extension on Windows using the supplied Lua snippet and inspect the type-checking path for enum-key table indexing. Compare the diagnostics for the three usages, especially the literal 'hp_max' index. Done means the reported types match the expectations in the reproduction.