Is it ready that StrideTo and StrideThrough structs conform to RandomAccessCollection?

SusanCheng · March 19, 2020, 6:07am

The FIXME say that was due to the bug of SR-6474

apple/swift/blob/da61cc8cdf7aa2bfb3ab03200c52c4d371dc6751/stdlib/public/core/Stride.swift#L309


    return nil
  }
}


extension StrideTo: CustomReflectable {
  public var customMirror: Mirror {
    return Mirror(self, children: ["from": _start, "to": _end, "by": _stride])
  }
}


// FIXME(conditional-conformances): This does not yet compile (SR-6474).
#if false
extension StrideTo: RandomAccessCollection
where Element.Stride: BinaryInteger {
  public typealias Index = Int
  public typealias SubSequence = Slice<StrideTo<Element>>
  public typealias Indices = Range<Int>


  @inlinable
  public var startIndex: Index { return 0 }

and the bug was fixed in 2018.
https://bugs.swift.org/browse/SR-6474

glessard · March 19, 2020, 10:24am

If it works, which you could presumably find out by building a toolchain, it would be a change in api which would presumably require an evolution proposal.