Here's a strange bug. I don't know if this is legitimate or not, but it seems like there is some sort of overflow.

Given the following code:

  data = """
  def function(*, foot):
    print(foot)
  """
  from ast import parse
  import tracemalloc
  tracemalloc.start()
  node = parse(data)
  tracemalloc.stop()
  arg = node.body[0].args.kwonlyargs[0]
  print(arg.lineno, arg.col_offset)

it yields on a freshly build the following, which is obviously wrong. It should have printed `1 1`.

  <_ast.arg object at 0x80103bcf8>
  1681660160 -2124152704

Also, there is no need to call tracemalloc.start, it has the same behaviour just by importing it.