[swift-evolution] Proposal: Introduce User-defined "Dynamic Member Lookup" Types

[Thorsten Seitz]

> Am 03.12.2017 um 20:08 schrieb Magnus Ahltorp <map at kth.se>:
> 
>> 4 Dec. 2017 03:54 Thorsten Seitz via swift-evolution <swift-evolution at swift.org> wrote:
>> 
>> The difference is that IUOs are marked by a "!“ whereas dynamic member lookups look just like normal member lookups but unlike them can fail.
> 
> IUOs are not marked with an "!" by the caller, that's what makes them implicit. They *are* marked at the declaration, but so would dynamic member lookups be.

You are right, my mistake. 

-Thorsten