Canonical comparison does not handle reification of comparisons

[Wout4]

Flatten_constraint() allows nested output in the case of a reified comparison i.e (IV1 == IV2) == BV

This case is not handled by canonical comparison. Althought the example above does not give an error when using choco, the following does:

iv = intvar(-8,8, shape=5)
bv = boolvar(shape=3)
cons = [(((4 + iv[0]) == iv[1]) == bv[0])]
Model(cons).solve('choco')

[Dimosts]

Indeed. Opened a PR handling that

[IgnaceBleukx]

I think we were a bit fast in merging the pull request.
You would also want single-reified comparisons to be canonicalized:

a -> 4 + x >= y should also become a -> -1 * x + 1 * y <= 4

[Dimosts]

hmm, indeed. So we need to cover both rhs and lhs, or move canonical comparison after reify_rewrite. But as the plan is to move it before/in flatten at some point, we should just cover both cases.

[Dimosts]

This was solved with 2 PRs already merged