// RUN: %target-typecheck-verify-swift

// SR-5726
protocol Foo
{
  associatedtype Bar
  var bar: Bar { get }
}

extension Foo where Self: Collection, Bar: Collection, Self.SubSequence == Bar.SubSequence, /*redundant: */Self.Index == Bar.Index
{
  subscript(_ bounds: Range<Index>) -> SubSequence
  {
    return bar[bounds]
  }
}