class RuboCop::Cop::Style::ArrayJoin

array literal or the second is a string literal.
types, so we consider only cases when the first argument is an
Not all cases can reliably checked, due to Ruby’s dynamic
This cop checks for uses of “*” as a substitute for join.

def autocorrect(node) 

def autocorrect(node)
  receiver_node, _method_name, *arg_nodes = *node
  array = receiver_node.source
  join_arg = arg_nodes[0].source
  lambda do |corrector|
    corrector.replace(node.source_range, "#{array}.join(#{join_arg})")
  end
end

def on_send(node) 

def on_send(node)
  receiver_node, method_name, *arg_nodes = *node
  return unless receiver_node && receiver_node.type == :array &&
                method_name == :* && arg_nodes[0].type == :str
  add_offense(node, :selector)
end