[swift-evolution] Allow trailing comma in guard, if-let, et al

[Ben Rimmington]

> On 18 Aug 2016, at 00:13, Rick Mann wrote:
> 
> Is there any reason Swift can't allow a trailing comma in constructs like this:
> 
> guard
>    let a = ...,
>    let b = ...,
>    let c = ...,
> else
> {
> }
> 
> doing so makes it a bit easier to rearrange lines, and is similar to the trailing comma allowed inside array and dictionary definitions:
> 
> let a = [ 1, 2, 3, ]

A similar proposal was rejected:

<https://lists.swift.org/pipermail/swift-evolution-announce/2016-May/000171.html>

-- Ben