If an InternalAsserFalse is guarded by an expression that is `AlwaysSat`, we can statically throw an error

I think at this point (now that we've done reaching definition analysis) we have everything in place such that we can statically identify conflicting assignmnments by finding `InternalAsserFalse` guards that are `AlwaysSat` i.e. tautologically true.

Start by locating the implementations of InternalAsserFalse and AlwaysSat, then read how reaching-definition analysis represents guards and conflicting assignments. Done means an InternalAsserFalse guarded by a tautologically true expression is detected and reported as a static error.

Written by the indexing model from the issue text.