// RUN: rm -rf %t ; mkdir -p %t
// RUN: %target-build-swift %s -o %t/a.out3 -swift-version 3 && %target-run %t/a.out3
// RUN: %target-build-swift %s -o %t/a.out4 -swift-version 4 && %target-run %t/a.out4

import StdlibUnittest

#if swift(>=4)

public typealias ExpectedSubstring = Substring

#else

public typealias ExpectedSubstring = String

#endif

var Tests = TestSuite("SubstringCompatibility")

Tests.test("Range/Subscript/ExpectedType") {
  var s = "hello world"
  var sub = s[s.startIndex ..< s.endIndex]
  var subsub = sub[s.startIndex ..< s.endIndex]

  expectType(String.self, &s)
  expectType(ExpectedSubstring.self, &sub)
  expectType(ExpectedSubstring.self, &subsub)
}

Tests.test("ClosedRange/Subsript/ExpectedType") {
  var s = "hello world"
  let lastIndex = s.index(before:s.endIndex)
  var sub = s[s.startIndex ... lastIndex]
  var subsub = sub[s.startIndex ... lastIndex]

  expectType(String.self, &s)
  expectType(ExpectedSubstring.self, &sub)
  expectType(ExpectedSubstring.self, &subsub)
}

Tests.test("String.init(_:String)/default type") {
  var s = String("")
  expectType(String.self, &s)
}

Tests.test("LosslessStringConvertible/generic") {
  func f<T : LosslessStringConvertible>(_ x: T.Type) {
    _ = T("")! // unwrapping optional should work in generic context
  }
  f(String.self)
}

Tests.test("LosslessStringConvertible/concrete") {
  _ = String("") as String?
}

#if swift(>=4)
#else
Tests.test("LosslessStringConvertible/force unwrap") {
  // Force unwrap should still work in Swift 3 mode
  _ = String("")!
}
#endif


runAllTests()