[swift-evolution] An Alternative for Extensibility Modifiers

[Tino Heth]

Imho overall this is a good proposal, yet it saddens me to read this thread, because it's a good proof for the dogmatism I mentioned before: 
You address all issues of proposal 0117 in a more consistent way with less confusing keywords, even adding some features that are actually handy — but yet the tenor of the replies is pushback…

As a liberal, those discussions are a tough battle, because you accept other people's opinions and strive for compromise, while the other side keeps pushing their case as hard as possible to enforce their agenda:
- We need to have "sealed"!
- It has to be the default!
- There has to be no way out of it!

To add some more constructive thoughts:
Given the fact that we are talking about changing a situation where it's absolutely legitimate to override (it is the way Swift has been designed!), I really thing there is no need for an extra "unsafe"-keyword — a simple exclamation-mark would do.

Tino