Hover preview incorrectly narrows union of literal and type

How are you using the lua-language-server?

Visual Studio Code Extension (sumneko.lua)

Which OS are you using?

Linux

What is the issue affecting?

Hover

Expected Behaviour

---@alias inttype -1 | 0 | integer
---@type inttype
local intvar = 1
---@alias stringtype "a" | "b" | string
---@type stringtype
local stringvar = "x"

I expect the hover previews for inttype, intvar, stringtype, and stringvar to show the full expansion of the intttype and stringtype aliases, something like

inttype:
    | -1
    | 0
    | integer

and

stringtype:
    | "a"
    | "b"
    | string

Actual Behaviour

The rendered preview of the type aliases omits the overall type:

inttype:
    | -1
    | 0

and

stringtype:
    | "a"
    | "b"

This is especially weird because if those were the actual type definitions then the two assignments in the example would be type errors, which they are not.

Reproduction steps

Put the code above into a Lua file in vscode with the language server extension running. Hover over the type aliases and the variables. The problem happens with just one literal in each union, two aren't required but I thought they illustrated the preview problem better.

Additional Notes

The reason I want to make "useless" union types like this is for hinting to humans that those specific values are special in some way.

Log File

No response

Riproduci il problema in un file Lua aperto nell’estensione Visual Studio Code passando con il cursore sugli alias e sulle variabili mostrati nel report. Segui il percorso di rendering dei tipi al passaggio del mouse per le union che combinano valori letterali con integer o string e verifica che le anteprime mantengano il tipo complessivo insieme ai membri letterali.