Whole method is rollbacked for specific assignment

Describe the bug Since the introduction of the block mutator it’s clear rollbacking assignment errors isn’t correct.

        public void SomeLinq()
        {
            var list = new List<List<double>>();
            var something = 1 + 3;
            int[] listProjected = list.Select(l => l.Count()).ToArray();
        }

In the above method all mutations are rollbacked. The linq select mutation (Count to Sum) changes the return value from double to int. So the assignment will fail.

[richardwerkman]

@dupdob sounds like a great idea! We could roll back block mutation first. Then statement mutations and if those didn’t help fall back to safe mode. I like this better than just turning off block mutations as a whole

[dupdob]

update: the work to do appears harder by the day. I think the two most complicated things are:

1. restoring rolledback mutations
2. tracking errors across mutant versions But, I just found out yesterday that my initial problem (excessive number of compile error) was due to the block mutator and not to the mutation identification strategy (upward vs downward). Initial count was close to 500. Integrating V 1.0.1 reduced it in half. So I still have 200 compile error due to block mutator.

I will look into to, but I am afraid I start to think that block mutation is not a good fit in its current form