   }
 
   do {
-    var (s, unused) = { ()->(String, Int) in
+    var (s, _) = { ()->(String, Int) in
       let (s0, unused) = stringWithUnusedCapacity()
       return (s0[s0.index(_nth: 5)..<s0.endIndex], unused)
     }()

    }
    expectEqual(!base._core.hasCocoaBuffer, startedNative)
    
    var originalBuffer = base.bufferID
    let startedUnique = startedNative && base._core._owner != nil
      && isKnownUniquelyReferenced(&base._core._owner!)
    

  }

  do {
    var (s, _) = { ()->(Substring, Int) in
      let (s0, unused) = stringWithUnusedCapacity()
      return (s0[s0.index(_nth: 5)..<s0.endIndex], unused)
    }()
