Open Radar

 
Short version: Calling a chained method with trailing closure syntax as in the following example indents trailing closures properly ONLY if you use Xcode autocomplete:

array.filter { (element) in 
    return true
}.map { (element) -> OtherClass in
    return OtherClass.process(element)
}

BUT, if you type the filter call and then MANUALLY type ".map {", Xcode will auto-indent it with an extra level of indentation. I believe the Xcode dev team agrees that the autocomplete-provided trailing closure indentation is correct, but if not, you can read below for a philosophical explanation of why I think that it is: 



When I use multiple trailing closures in any configuration, for example array.filter { ... }.map { ... }, or Async.userInitiated { ... }.main { ... }, as is a common idiom in my Swift development so far, Xcode auto-indents the first trailing closure normally but then auto-indents the second trailing closure one tab ahead, which causes it to appear on a higher level than the rest of the line. Unfortunately, this detracts from the readability of synchronous closure-based code, and also presents an inconsistency with similar code in objective-C (e.g. calling [MagicalRecord saveWithBlock:^{ ... } completion:^{ ... }] would indent both blocks to the same indentation level in objC).

Steps to Reproduce:
1. Open a Swift file in Xcode
2. Enter the following line: let array: [Int?] = [1, 3, 5, nil]
3. Type "array.filter" and press enter twice to expand the trailing closure auto-complete; fill in the parentheses with "num", press tab and fill in the body of the closure with "return num != nil"
4. Move down a line to the closing brace from the filter call and type ".map {" -- WITHOUT PRESSING ENTER TO AUTOCOMPLETE.



Expected Results:
The line that I just typed on says "}.map {" and stays on the same level of indentation as the line containing its opening brace.

Actual Results:
The line that I just typed on says "}.map {" and indents an extra level past the level of indentation of the line containing its opening brace.