Can not infer basic assignments in nested loop.

Discussed in https://github.com/LuaLS/lua-language-server/discussions/2471

^{Originally posted by Luke100000 January 8, 2024}
Why can it not infer the type here? How would I rewrite this to be type conform, without spamming type annotations?

local y = 0

for i = 1, 2 do
    y = y + 1 -- here, y is inferred as an integer correctly

    for j = 1, 2 do
        y = y + 1 -- can not infer type
    end

    -- sometimes a bit more complexity is required to trigger the issue, so lets add another loop
    for j = 1, 2 do
        y = y + 1 -- can not infer type
    end
end

print(y)

Start by reproducing the nested-loop example from the issue and read discussion 2471 for the existing analysis. Trace how the language server infers y across the loop assignments. Done means the shown assignments retain the inferred integer type without requiring repeated type annotations.