Class: RuboCop::Cop::Lint::UselessNumericOperation

Inherits:
Base
  • Object
show all
Extended by:
AutoCorrector
Defined in:
lib/rubocop/cop/lint/useless_numeric_operation.rb

Overview

Certain numeric operations have no impact, being: Adding or subtracting 0, multiplying or dividing by 1 or raising to the power of 1. These are probably leftover from debugging, or are mistakes.

Examples:


# bad
x + 0
x - 0
x * 1
x / 1
x ** 1

# good
x

# bad
x += 0
x -= 0
x *= 1
x /= 1
x **= 1

# good
x = x

Constant Summary collapse

MSG = 
'Do not apply inconsequential numeric operations to variables.'
RESTRICT_ON_SEND = 
%i[+ - * / **].freeze

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_op_asgn(node) ⇒ Object 



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# File 'lib/rubocop/cop/lint/useless_numeric_operation.rb', line 54

def on_op_asgn(node)
  return unless useless_abbreviated_assignment?(node)

  variable, operation, number = useless_abbreviated_assignment?(node)
  return unless useless?(operation, number)

  add_offense(node) do |corrector|
    corrector.replace(node, "#{variable} = #{variable}")
  end
end

#on_send(node) ⇒ Object 



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# File 'lib/rubocop/cop/lint/useless_numeric_operation.rb', line 43

def on_send(node)
  return unless useless_operation?(node)

  variable, operation, number = useless_operation?(node)
  return unless useless?(operation, number)

  add_offense(node) do |corrector|
    corrector.replace(node, variable)
  end
end

#useless_abbreviated_assignment?(node) ⇒ Object 



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# File 'lib/rubocop/cop/lint/useless_numeric_operation.rb', line 41

def_node_matcher :useless_abbreviated_assignment?, '(op-asgn (lvasgn $_) $_ (int $_))'

#useless_operation?(node) ⇒ Object 



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# File 'lib/rubocop/cop/lint/useless_numeric_operation.rb', line 38

def_node_matcher :useless_operation?, '(send (send nil? $_) $_ (int $_))'