   public init(stringLiteral: String) {
     guard let s = FilePath.Root(stringLiteral) else {
       // TODO: static assert
-      preconditionFailure("""
+      fatalError("""
         FilePath.Root must be created from a root
         """)
     }

    self.init(_platformString: platformString)
  }

  /// Calls the given closure with a pointer to the contents of the file path
  /// root, represented as a null-terminated platform string.
  ///

  ///   string.
  public init(platformString: UnsafePointer<CInterop.PlatformChar>) {
    self.init(_platformString: platformString)
  }

  /// Creates a file path by copying bytes from a null-terminated platform
  /// string.
  ///
  /// - Note It is a precondition that `platformString` must be null-terminated.
  /// The absence of a null byte will trigger a runtime error.
  ///
  /// - Parameter platformString: A null-terminated platform string.
  @inlinable
  @_alwaysEmitIntoClient
  public init(platformString: [CInterop.PlatformChar]) {
    guard let _ = platformString.firstIndex(of: 0) else {
      fatalError(
        "input of FilePath.init(platformString:) must be null-terminated"
      )
    }
    self = platformString.withUnsafeBufferPointer {
      FilePath(platformString: $0.baseAddress!)
    }
  }

  @inlinable
  @_alwaysEmitIntoClient
  @available(*, deprecated, message: "Use FilePath(_: String) to create a path from a String.")
  public init(platformString: inout CInterop.PlatformChar) {
    guard platformString == 0 else {
      fatalError(
        "input of FilePath.init(platformString:) must be null-terminated"
      )
    }
    self = FilePath()
  }

  @inlinable
  @_alwaysEmitIntoClient
  @available(*, deprecated, message: "Use FilePath(_: String) to create a path from a String.")
  public init(platformString: String) {
    if let nullLoc = platformString.firstIndex(of: "\0") {
      self = FilePath(String(platformString[..<nullLoc]))
    } else {
      self = FilePath(platformString)
    }
  }

  /// Calls the given closure with a pointer to the contents of the file path,
