     else {
       let b = UnsafeBufferPointer(start: c.startUTF16, count: c.count)
       var i = b.makeIterator()
-      result = _parseASCII(codeUnits: &i, radix: r)
+      result = _parseASCIIOutlined(codeUnits: &i, radix: r)
     }
     guard _fastPath(result != nil) else { return nil }
     self = result!

    let result: Self?
    if _slowPath(c._baseAddress == nil) {
      var i = s.utf16.makeIterator()
      result = _parseASCII(codeUnits: &i, radix: r)
    }
    else if _fastPath(c.elementWidth == 1), let a = c.asciiBuffer {
      var i = a.makeIterator()

  }
}

@inline(never)
internal func _parseASCIIOutlined<
  CodeUnits : IteratorProtocol, Result: FixedWidthInteger
>(
  codeUnits: inout CodeUnits, radix: Result
) -> Result?
where CodeUnits.Element : UnsignedInteger {
  return _parseASCII(codeUnits: &codeUnits, radix: radix)
}

extension FixedWidthInteger {
  /// Creates a new integer value from the given string and radix.
  ///
