Class: RuboCop::Cop::Style::DoubleNegation

Inherits:
Cop
  • Object
show all
Defined in:
lib/rubocop/cop/style/double_negation.rb

Overview

This cop checks for uses of double negation (!!) to convert something to a boolean value. As this is both cryptic and usually redundant, it should be avoided.

Please, note that when something is a boolean value !!something and !something.nil? are not the same thing. As you're unlikely to write code that can accept values of any type this is rarely a problem in practice.

Examples:


# bad
!!something

# good
!something.nil?

Constant Summary collapse

MSG = 
'Avoid the use of double negation (`!!`).'

Constants included from Util

Util::ASGN_NODES, Util::EQUALS_ASGN_NODES, Util::OPERATOR_METHODS, Util::PROC_NEW_NODE, Util::SHORTHAND_ASGN_NODES

Instance Attribute Summary

Attributes inherited from Cop

#config, #corrections, #offenses, #processed_source

Instance Method Summary collapse

Methods inherited from Cop

#add_offense, all, #autocorrect?, #config_to_allow_offenses, #config_to_allow_offenses=, #cop_config, #cop_name, cop_name, cop_name_with_namespace, cop_type, #debug?, #display_cop_names?, inherited, #initialize, #join_force?, lint?, #message, non_rails, qualified_cop_name, rails?, #relevant_file?, #support_autocorrect?

Methods included from IgnoredNode

#ignore_node, #ignored_node?, #part_of_ignored_node?

Methods included from Util

begins_its_line?, block_length, command?, comment_line?, const_name, first_part_of_call_chain, lambda?, lambda_or_proc?, line_range, numeric_range_size, on_node, operator?, parentheses?, proc?, range_with_surrounding_space, source_range, strip_quotes, within_node?

Methods included from PathUtil

issue_deprecation_warning, match_path?, relative_path

Constructor Details

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

Instance Method Details

#on_send(node) ⇒ Object 



25
26
27
28
29
30
31
 
# File 'lib/rubocop/cop/style/double_negation.rb', line 25

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

  receiver, _method_name, *_args = *node

  add_offense(node, :selector) if not_node?(receiver)
end