Hi Stéphane, hi all!
Was that enough time for seeing what it's worth? ;-) I use the #rememberProvenance utility from time to time and cannot see any harm, because when disabled as by default, the total overhead makes up tiny 12 byte code steps (for comparison, the bounds initialization costs 13 steps). If you still feel worried about this, we could also lower the overhead to 2 steps by inlining the class variable access. I'd love to see this in Trunk soon, IMHO it also makes the new Objectland example projects which will be ready soon much better explorable.
Best,
Christoph