When eliminating configurations, also remove any configurations that can subsequently not be satisfied.
When eliminating configurations, also remove any configurations that can subsequently not be satisfied.

WIP: this could remove wrong configurations because the stored configuration indices might not be up to date anymore after the recursion returns.

grogancolin/dub,gedaiu/dub,rjframe/dub,Flamaros/dub,Geod24/dub,D-Programming-Language/dub