Using LuaJIT's nil-coalescing extension does not narrow the type correctly

How are you using the lua-language-server?

Other

Which OS are you using?

Linux

What is the issue affecting?

Type Checking

Expected Behaviour

Using the nil-coalescing operator should narrow an expressions type. For example, in this sample code, the type of b should be narrowed to integer:

---@type integer?
local foo = 1
local bar = foo ?? 2

Actual Behaviour

Instead of the type being narrowed, the type of foo is copied instead, and the type of bar is thought to be integer? instead of integer.

Reproduction steps

1. Insert the following sample code in a project:

---@type integer?
local foo = 1
local bar = foo ?? 2

2. Check the type of b

Additional Notes

This seems to work fine using the classic Lua approach with or:

---@type integer?
local foo = 1
local bar = foo or 2

The type of bar is integer here, as expected.

Log File

No response

Comienza reproduciendo el problema en el comprobador de tipos de lua-language-server con el ejemplo ?? proporcionado y, a continuación, compara su tipo inferido con el de la expresión or equivalente. Traza cómo la expresión nil-coalescing gestiona los operandos nullable; el trabajo está terminado cuando bar se infiere como integer y el comportamiento existente sigue siendo correcto para el caso de comparación.