@tarunon ↓ですからねぇ・・・ public typealias UnboundedRange = (UnboundedRange_)->() https://github.com/apple/swift/commit/4dee6ead#diff-ef421a80a004f996d47697e4c2074790R939 (edited)

[stdlib] Provisional c[...] syntax while we await language features · apple/swift@4dee6ea