Class: RuboCop::Cop::Style::SlicingWithRange

Inherits:
Base
  • Object
show all
Extended by:
AutoCorrector, TargetRubyVersion
Defined in:
lib/rubocop/cop/style/slicing_with_range.rb

Overview

Checks that arrays are sliced with endless ranges instead of ary[start..-1] on Ruby 2.6+.

Examples:

# bad
items[1..-1]

# good
items[1..]

Cop Safety Information:

  • This cop is unsafe because x..-1 and x.. are only guaranteed to be equivalent for Array#[], String#[], and the cop cannot determine what class the receiver is.

    For example:

    sum = proc { |ary| ary.sum }
sum[-3..-1] # => -6
sum[-3..] # Hangs forever

Constant Summary collapse

MSG = 
'Prefer ary[n..] over ary[n..-1].'
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 included from TargetRubyVersion

minimum_target_ruby_version, required_minimum_ruby_version, support_target_ruby_version?

Methods inherited from Base

#active_support_extensions_enabled?, #add_global_offense, #add_offense, autocorrect_incompatible_with, badge, #begin_investigation, 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, #inspect, 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?, #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_send(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/slicing_with_range.rb', line 40

def on_send(node)
  return unless node.arguments.count == 1
  return unless range_till_minus_one?(node.arguments.first)

  add_offense(node.first_argument) do |corrector|
    corrector.remove(node.first_argument.end)
  end
end

#range_till_minus_one?(node) ⇒ Object 



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# File 'lib/rubocop/cop/style/slicing_with_range.rb', line 38

def_node_matcher :range_till_minus_one?, '(irange !nil? (int -1))'