In fact, it doesn't reach top priority since we can do without for now (we have bitfields.) The issue with slicing is more a question of design: does slicing need to be constant expression or should we authorize more expression power (and then how could we implement that and how could we check it … )

Anyway, I'm looking for a clever way to define values accessed in a none uniform ways.

Integer as bit array was the simplest idea to test (and seems useful to me.) Now the compiler has almost everything I need to implement easily that kind of syntactic sugars.