// RUN: not %target-swift-frontend %s -typecheck | |
struct S : Sequence { | |
struct Iterator : IteratorProtocol { | |
mutating func next() -> Int? { | |
fatalError() | |
} | |
} | |
func makeIterator() -> Iterator { | |
fatalError() | |
} | |
} | |
extension S : Collection { | |
typealias Index = Int | |
var startIndex: Int { return 0 } | |
var endIndex: Int { return 1 } | |
} |