Class: RuboCop::Cop::Style::RedundantSelfAssignment

Inherits:
Base
  • Object
show all
Extended by:
AutoCorrector
Includes:
RangeHelp
Defined in:
lib/rubocop/cop/style/redundant_self_assignment.rb

Overview

Checks for places where redundant assignments are made for in place modification methods.

Examples:

# bad
args = args.concat(ary)
hash = hash.merge!(other)

# good
args.concat(foo)
args += foo
hash.merge!(other)

# bad
self.foo = foo.concat(ary)

# good
foo.concat(ary)
self.foo += ary

Constant Summary collapse

MSG = 
'Redundant self assignment detected. ' \
'Method `%<method_name>s` modifies its receiver in place.'
METHODS_RETURNING_SELF = 
%i[
  append clear collect! compare_by_identity concat delete_if
  fill initialize_copy insert keep_if map! merge! prepend push
  rehash replace reverse! rotate! shuffle! sort! sort_by!
  transform_keys! transform_values! unshift update
].to_set.freeze
ASSIGNMENT_TYPE_TO_RECEIVER_TYPE = 
{
  lvasgn: :lvar,
  ivasgn: :ivar,
  cvasgn: :cvar,
  gvasgn: :gvar
}.freeze

Constants inherited from Base

Base::RESTRICT_ON_SEND

Instance Attribute Summary

Attributes inherited from Base

#config, #processed_source

Instance Method Summary collapse

Methods included from AutoCorrector

support_autocorrect?

Methods inherited from Base

#active_support_extensions_enabled?, #add_global_offense, #add_offense, #always_autocorrect?, autocorrect_incompatible_with, badge, #begin_investigation, #callbacks_needed, callbacks_needed, #config_to_allow_offenses, #config_to_allow_offenses=, #contextual_autocorrect?, #cop_config, cop_name, #cop_name, department, documentation_url, exclude_from_registry, #excluded_file?, #external_dependency_checksum, inherited, #initialize, #inspect, joining_forces, lint?, match?, #message, #offenses, #on_investigation_end, #on_new_investigation, #on_other_file, #parse, #parser_engine, #ready, #relevant_file?, requires_gem, #string_literals_frozen_by_default?, support_autocorrect?, support_multiple_source?, #target_rails_version, #target_ruby_version

Methods included from ExcludeLimit

#exclude_limit

Methods included from AutocorrectLogic

#autocorrect?, #autocorrect_enabled?, #autocorrect_requested?, #autocorrect_with_disable_uncorrectable?, #correctable?, #disable_uncorrectable?, #safe_autocorrect?

Methods included from IgnoredNode

#ignore_node, #ignored_node?, #part_of_ignored_node?

Methods included from Util

silence_warnings

Constructor Details

This class inherits a constructor from RuboCop::Cop::Base

Instance Method Details

#on_lvasgn(node) ⇒ Object Also known as: on_ivasgn, on_cvasgn, on_gvasgn 



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# File 'lib/rubocop/cop/style/redundant_self_assignment.rb', line 52

def on_lvasgn(node)
  lhs, rhs = *node
  receiver, method_name, = *rhs
  return unless receiver && method_returning_self?(method_name)

  receiver_type = ASSIGNMENT_TYPE_TO_RECEIVER_TYPE[node.type]
  return unless receiver.type == receiver_type && receiver.children.first == lhs

  message = format(MSG, method_name: method_name)
  add_offense(node.loc.operator, message: message) do |corrector|
    corrector.replace(node, rhs.source)
  end
end

#on_send(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/redundant_self_assignment.rb', line 69

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