   public typealias CodeUnit = UInt8
   
   public // @testable
-  func _parseNonASCII() -> (valid: Bool, length: UInt8) {
+  func _parseNonASCII() -> (isValid: Bool, length: UInt8) {
     _sanityCheck(buffer._storage & 0x80 != 0) // this case handled elsewhere
     
     if buffer._storage & 0b0__1100_0000__1110_0000



public protocol _UTF8Decoder : UnicodeDecoder {
  func _parseNonASCII() -> (valid: Bool, length: UInt8)
  var buffer: Buffer { get set }
}


  }
  
  public // @testable
  func _parseNonASCII() -> (isValid: Bool, length: UInt8) {
    _sanityCheck(buffer._storage & 0x80 != 0) // this case handled elsewhere
    if buffer._storage                & 0b0__1110_0000__1100_0000
                                     == 0b0__1100_0000__1000_0000 {
