New unsoundness bug in z3str3 after recent pushes

[numairmansur]

Hi @mtrberzi
I have an example where z3str3 gives an unsound result. The following file is satisfiable but z3str3 gives unsat.

9.smt2

I think this bug was introduced after the recent changes in z3str3. It does not exist in commit 321bad2 .

The bug was found on the following commit:

commit 0146259
Author: Murphy Berzish murphy.berzish@gmail.com
Date: Wed Feb 12 13:46:27 2020 -0500

[mtrberzi]

This was an interesting one. The bug ended up being exposed as a result of the commit you identified, but had been around for a while previous to that commit. Thanks for the report!

Opened #2997