class RuboCop::Cop::Style::RedundantSelfAssignment


foo.concat(ary)
# good
hash.merge!(other)
args += foo
args.concat(foo)
# good
hash = hash.merge!(other)
args = args.concat(ary)
# bad
@example
its receiver in place.
user defined methods having one of the expected names, but not modifying
This cop is unsafe, because it can produce false positives for
@safety
modification methods.
Checks for places where redundant assignments are made for in place

def correction_range(node) 

def correction_range(node)
  range_between(node.source_range.begin_pos, node.first_argument.source_range.begin_pos)
end

def method_returning_self?(method_name) 

def method_returning_self?(method_name)
  METHODS_RETURNING_SELF.include?(method_name)
end

def on_lvasgn(node)

rubocop:disable Metrics/AbcSize 
def on_lvasgn(node)
  return unless (rhs = node.rhs)
  return unless rhs.type?(:any_block, :call) && method_returning_self?(rhs.method_name)
  return unless (receiver = rhs.receiver)
  receiver_type = ASSIGNMENT_TYPE_TO_RECEIVER_TYPE[node.type]
  return unless receiver.type == receiver_type && receiver.children.first == node.lhs
  message = format(MSG, method_name: rhs.method_name)
  add_offense(node.loc.operator, message: message) do |corrector|
    corrector.replace(node, rhs.source)
  end
end

def on_send(node) 

def on_send(node)
  return unless node.assignment_method?
  return unless redundant_assignment?(node)
  message = format(MSG, method_name: node.first_argument.method_name)
  add_offense(node.loc.operator, message: message) do |corrector|
    corrector.remove(correction_range(node))
  end
end

def redundant_assignment?(node) 

def redundant_assignment?(node)
  receiver_name = node.method_name.to_s.delete_suffix('=').to_sym
  redundant_self_assignment?(node, node.receiver, receiver_name)
end