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// RUN: %target-run-simple-swift
// REQUIRES: executable_test
struct X: BidirectionalCollection {
var startIndex: Int { return 0 }
var endIndex: Int { return 10 }
subscript(position: Int) -> String { return "element" }
subscript(range: Range<Int>) -> X { return X() }
func index(after i: Int) -> Int { return i + 1 }
func index(before i: Int) -> Int { return i - 1 }
}
struct A<C: Collection>: Collection {
let c: C
var startIndex: C.Index { return c.startIndex }
var endIndex: C.Index { return c.endIndex }
subscript(position: C.Index) -> C.Element { return c[position] }
subscript(range: Range<C.Index>) -> A<C.SubSequence> {
return A<C.SubSequence>(c: c[range])
}
func index(after i: C.Index) -> C.Index { return c.index(after: i) }
}
extension A: BidirectionalCollection where C: BidirectionalCollection {
func index(before i: C.Index) -> C.Index { return c.index(before: i) }
}
// https://github.com/apple/swift/issues/50555
do {
var c = A(c: X())
_ = c.popLast()
_ = c.removeLast()
c.removeLast(2)
_ = c.dropLast(2)
_ = c.suffix(2)
}
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