[swift-evolution] Proposal - Allow properties in Extensions

[Tino Heth]

+1/-1:

When the extension is in the same module, it's nice to be able to group all aspects of an extension in one place instead of being forced to declare properties in the definition.
But I guess the most important use case is to extend types that aren't in the same module, and I wouldn't like to see that hacking the runtime becomes a common thing to do.

Tino