False negative: Warnings missing for table length mismatch

How are you using the lua-language-server?

NeoVim

Which OS are you using?

Linux

What is the issue affecting?

Type Checking, Diagnostics/Syntax Checking

Expected Behaviour

In the reproduction code below, f({0}) and f({0, 0, 0}) should issue warnings because they do not match the annotation [integer, integer], which requires a two-element table (tuple).

Actual Behaviour

There are no warnings issued for tables that have an invalid length.

I can see other warnings (e.g., for f("string")), so Neovim and other diagnostics are working correctly.

Reproduction steps

Open a text editor with lua-ls enabled and copy/paste this code.

---@alias Cursor [integer, integer]

---@param c Cursor
local function f(c) end

f("string")

f({ 0 })
f({ 0, 0, 0 })

Additional Notes

I tested with lua-language-server 3.9.1 and 3.13.2 and both have this problem.

Log File

I checked ~/.local/state/nvim/lsp.log since :LspInfo indicates it is the log file, but it was empty.

Start with the reproduction snippet and the lua-language-server type-checking and diagnostics path for table aliases. Compare the existing warning for f("string") with the missing warnings for f({ 0 }) and f({ 0, 0, 0 }). Done means tuple annotations report a diagnostic when the table length differs from the required two elements.