experiment with partial solution based constraint solving cache

[redianthus]

see https://dl.acm.org/doi/abs/10.1145/3660817

(cc @filipeom, I guess it'll be interesting for you :-)

[filipeom]

Thanks! Very interesting. We tried doing something similar following https://dl.acm.org/doi/10.1145/2393596.2393665. But it was never merged https://github.com/formalsec/smtml/tree/caching, experimental results weren't great.

It would be interesting to have a proper go at it again at some point

[redianthus]

cc @felixL-K