class GraphQL::Upgrader::Member::FieldFinder

def add_location(send_node:,source_node:)
  receiver_node, method_name, *arg_nodes = *send_node
  # Implicit self and one of the recognized methods
  if receiver_node.nil? && DEFINITION_METHODS.include?(method_name)
    name = arg_nodes[0]
    # This field may have already been added because
    # we find `(block ...)` nodes _before_ we find `(send ...)` nodes.
    if @locations[method_name][name].nil?
      starting_idx = source_node.loc.expression.begin.begin_pos
      ending_idx = source_node.loc.expression.end.end_pos
      @locations[method_name][name] = [starting_idx, ending_idx]
    end
  end
end

def initialize
  # Pairs of `{ { method_name => { name => [start, end] } }`,
  # since fields/arguments are unique by name, within their category
  @locations = Hash.new { |h,k| h[k] = {} }
end

def on_block(node)
  send_node, _args_node, _body_node = *node
  add_location(send_node: send_node, source_node: node)
  super(node)
end

def on_send(node)
  add_location(send_node: node, source_node: node)
  super(node)
end