 }
 
 SubstringTests.test("UTF8View") {
-  var t = s.utf8.dropFirst(2)
-  var u = t.dropFirst(2)
+  let s = "abcdefg"
+  let t = s.utf8.dropFirst(2)
+  let u = t.dropFirst(2)
   
   checkMatch(s.utf8, t, t.startIndex)
   checkMatch(s.utf8, t, t.index(after: t.startIndex))

SubstringTests.test("UnicodeScalars")
  .xfail(.always("UnicodeScalarsView slices don't share indices"))
  .code {
  var t = s.unicodeScalars.dropFirst(2)
  var u = t.dropFirst(2)
  

  expectEqual(x[i], y[i])
}

SubstringTests.test("String") {
  let s = "abcdefg"
  let s1 = s[s.index(s.startIndex, offsetBy: 2) ..<
    s.index(s.startIndex, offsetBy: 4)]
  let s2 = s1[s1.startIndex..<s1.endIndex]
