Swift Regret: Tuples and Argument Lists

Part of the Swift Regrets series.

I already wrote this up on the Swift forums, so why is it on the list at all? Because we have never recovered from that initial mistake. There are still compiler PRs trying to separate tuples and argument lists, five years after that blog post. (Thank you for fighting the good fight!)

It’s not an inherently bad idea, but it was always wrong for Swift. We’ve gone through multiple evolution proposals trying to deal with this (SE-0021, SE-0029, SE-0066, SE-0110, SE-0111). Check out the forum post for this one, that’s the fun part.