ErrorKind = enum
  RawTypeMismatchError, ExpressionCannotBeCalled, CustomError,
  WrongNumberOfArguments, AmbiguousCall

proc errorSubNode(n: PNode): PNode {....raises: [], tags: [].}

proc errorToString(config: ConfigRef; n: PNode): string {.
    ...raises: [ValueError, Exception, KeyError, OSError],
    tags: [RootEffect, ReadDirEffect].}

proc newError(wrongNode: PNode; k: ErrorKind; args: varargs[PNode]): PNode {.
    ...raises: [], tags: [].}

proc newError(wrongNode: PNode; msg: string): PNode {....raises: [], tags: [].}