johnu, on 2021-October-25, 15:27, said:
I don't know if 4♣ by North after the 2♠ by responder should have been a splinter, but it should be because 3♣ if forcing. That should discourage responder from making any slam tries.
As it was, 4♣ denied a spade control (ace?) so I think North cue bid 4♦ to imply the ♠A, notwithstanding the explanation.
Who are you and what have you done with johnu?
GIB bids the same way with Jxxx QJxxx AKxx -, so nope, doesn't show anything at all in spades.
Also (ignoring South's hand) bids it with Jxxx KQJxx Axxx -, where it doesn't have spades *or* the extra diamond.
Incidentally the 3
♦ bid also denies a void in clubs, since GIB treats ace and a void the same way.
Both 3
♦ and 4
♦ mean I have some points and no idea how cuebidding works.