For example in this position:
Whatever move Black makes white will move the queen to a2 for checkmate.
this has been suggested before. I agree but in that diagram position its easy to conditional-move both lines; the feature would be more useful in positions like this.
I agree, such a feature would be great.
Erik seemed to be in favour of it ... 3 years ago ...
and made encouraging noises when this was raised 2 years ago ...
(This was an interesting discussion ... conditional-moves9).