Class: RuboCop::Cop::Style::NilLambda

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

Overview

This cop checks for lambdas and procs that always return nil, which can be replaced with an empty lambda or proc instead.

Examples:

# bad
-> { nil }

lambda do
  next nil
end

proc { nil }

Proc.new do
  break nil
end

# good
-> {}

lambda do
end

-> (x) { nil if x }

proc {}

Proc.new { nil if x }

Constant Summary collapse

MSG = 
'Use an empty %<type>s instead of always returning nil.'

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

#add_global_offense, #add_offense, autocorrect_incompatible_with, badge, #callbacks_needed, callbacks_needed, #config_to_allow_offenses, #config_to_allow_offenses=, #cop_config, #cop_name, cop_name, department, documentation_url, exclude_from_registry, #excluded_file?, #external_dependency_checksum, inherited, #initialize, joining_forces, lint?, match?, #message, #offenses, #on_investigation_end, #on_new_investigation, #on_other_file, #parse, #ready, #relevant_file?, 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?, #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

#nil_return?(node) ⇒ Object 


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# File 'lib/rubocop/cop/style/nil_lambda.rb', line 42

def_node_matcher :nil_return?, <<~PATTERN
  { ({return next break} nil) (nil) }
PATTERN

#on_block(node) ⇒ Object 


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# File 'lib/rubocop/cop/style/nil_lambda.rb', line 46

def on_block(node)
  return unless node.lambda? || node.proc?
  return unless nil_return?(node.body)

  message = format(MSG, type: node.lambda? ? 'lambda' : 'proc')
  add_offense(node, message: message) do |corrector|
    autocorrect(corrector, node)
  end
end