     /// Creates an instance that slices `base` at `_bounds`.
     @inlinable
     internal init(_ base: String.UTF8View, _bounds: Range<Index>) {
-      _slice = Slice(
-        base: String(base._guts).utf8,
-        bounds: _bounds)
+      _slice = Slice(base: base, bounds: _bounds)
     }
 
     @_alwaysEmitIntoClient @inline(__always)

  /// - Complexity: O(N), where N is the length of the resulting `String`'s
  ///   UTF-16.
  public init?(_ codeUnits: Substring.UTF8View) {
    let guts = codeUnits._slice._base._guts
    guard guts.isOnUnicodeScalarBoundary(codeUnits._slice.startIndex),
          guts.isOnUnicodeScalarBoundary(codeUnits._slice.endIndex) else {
      return nil
    }


  ///
  /// - Complexity: O(1)
  public init(_ content: UnicodeScalarView) {
      // No need to validate any indices.
    let slice = Slice(base: String(content._wholeGuts), bounds: content._bounds)
    self.init(_unchecked: slice)
  }
}

