Complete(?) the multiple trailing closure saga by allowing a label on the first

[xwu (Xiaodi Wu)]

I did the whole shebang.

Support use of an optional label for the first trailing closure

The core team has asked that discussion be spawned in a separate thread regarding support for use of an optional label for the first trailing closure. Therefore, later today, I'll be sharing a draft proposal here which addresses that topic. While it has been brought to mind by discussions on multiple trailing closures, the issue is entirely a separable one. Shortcomings related to our unlabeled trailing closure syntax have been known for years. Readers will note that the draft proposal is ampl…

[Proposal] Support use of an optional label for the first trailing closure

[Proof of concept] Support the use of optional labels for the first trailing closure