Exact Class with `__index` Assignment Result in Loss of All Class Methods

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?

Completion, Hover

Expected Behaviour

Method :method and :method2 is shown.

Actual Behaviour

No method is shown.

Reproduction steps

Test code:

---@class (exact) Foo
local Foo = {}
Foo.__index = Foo ---@diagnostic disable-line inject-field

function Foo:method()
end

function Foo:method2(value)
end

---@return Foo
local function foo()
end

local b = foo()

Variable b has type of Foo. However typing b: won't show method and method2. The self variable inside Foo:nethod and Foo:method2 will also have same issue if used.

Removing the (exact) make it work works as expected. Removing the __index assignment also make it works as expected. However, silencing the __index inject field with ---@field __index Foo instead of using ---@diagnostic still result in same issue.

Hovering to b also won't show any of the methods. However hovering to Foo works.

Additional Notes

Typing the method name manually (e.g. :method2) will show completion normally and will make b show method2 after it's used once. But only method2 in that specific case. method still not be shown.

Log File

file_d%3A_Data_Development_love-11.3-win64_luals-report.log

Reproduce the provided Lua snippet and inspect the completion and hover behavior for exact classes with a __index assignment. Use the reported difference between exact and non-exact classes as the starting comparison. Done means Foo methods appear for b and self in completion and hover, without requiring the method name to be typed first.