module RuboCop::Cop::CheckAssignment

def extract_rhs(node)
  if node.casgn_type?
    _scope, _lhs, rhs = *node
  elsif node.op_asgn_type?
    _lhs, _op, rhs = *node
  elsif Util::ASGN_NODES.include?(node.type)
    _lhs, rhs = *node
  elsif node.send_type?
    rhs = node.last_argument
  end
  rhs
end

def on_send(node)
  return unless node.setter_method?
  rhs = extract_rhs(node)
  return unless rhs
  check_assignment(node, rhs)
end