When using alias values as its keys, Dictionary types don't give completion when defining an instance of that dictionary

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?

Completion

Expected Behaviour

When trying to define a table annotated with ---@type {[an_alias]: a_type}, beginning to type a key in the table brings up an_alias's values for automatic completion.

Actual Behaviour

When trying to define a table annotated with ---@type {[an_alias]: a_type}, beginning to type a key in the table will not bring up an_alias's values.

Reproduction steps

Enter the following:

---@alias Flavor
---| "sweet"
---| "spicy"
---| "tangy"
---| "juicy"
---| "tough"
---| "gummy"


---@type {[Flavor]: number}
local test = {

}

Try typing "s" into the empty line in the test table, and it should be able to tell that you'd like to type sweet or spicy because those are members of the Flavor alias, but it does not. It recognizes those words as words found elsewhere in the document and will display them in the autocompletion dropdown as such (below other words found elsewhere in the document that also start with "s"), as shown in this screenshot of a larger file:

This might not be the best of examples because there are no other words that start with "s" in the code, but hopefully the issue is still clear. Adding other things (defining variables, using strings, what not) that start with "s" into the example code will give a result like my screenshot.

Additional Notes

I've tried to make this work with the ---@class annotation, and it behaves how I'd expect (the autocompletion dropdown's first results are field names on that class), but it brings up another issue: I'm trying to iterate through an instance of the class, and I don't get the correct return types when using functions like pairs. That makes sense to me - an object is probably not meant to be iterated through, because it likely has fields of different types.

I'm running into this issue because I'm trying to define a dictionary, i.e. a collection of fields that do have the same type. I know all of the names of the fields beforehand, and I define them in an alias. It seems to me that the language server should be able to recognize when I begin typing one of the alias's values in a table that's being defined as a dictionary with that alias as its keys.

Log File

No response

Start by reproducing the completion behavior with the Flavor alias and ---@type {[Flavor]: number} table shown in the issue. Trace the completion entry point for keys in annotated dictionary tables and compare it with class-field completion; done means alias values such as sweet and spicy are prioritized when typing a key.