SE-110 Fallout… I’m Confused

I was going to put this in a comment on the bug, but it really belongs on swift-evolution, but I left that a year or more ago now… so I’ll just put it here, I suppose:

I’m confused how this change also requires removing destructuring of tuple elements in these closures?

let a : ((Int, Int, Int)) -> Int = { x in return x.0 + x.1 + x.2 }

That makes sense that x is of type (Int, Int, Int), but it makes no sense that I cannot write this:

let a : ((Int, Int, Int)) -> Int = { (x, y, z) in return x + y + z }

The proposal also completely glosses over these changes by referring to them as “minor changes to user code may be required if this proposal is accepted.”

It’s further even more confusing to me why this syntax (note the (x) vs. x):

let a : ((Int, Int, Int)) -> Int = { (x) in return x.0 + x.1 + x.2 }

Would even be allowed to be the same as the entire change is about clarifying tuple vs. non-tuple arguments. Further, allowing this syntax creates yet-another-breaking-change if the destructuring convenience is brought back in the future.


SE-110 Fallout… I’m Confused