lib/rubocop/cop/lint/redundant_with_object.rb
# frozen_string_literal: true
module RuboCop
module Cop
module Lint
# Checks for redundant `with_object`.
#
# @example
# # bad
# ary.each_with_object([]) do |v|
# v
# end
#
# # good
# ary.each do |v|
# v
# end
#
# # bad
# ary.each.with_object([]) do |v|
# v
# end
#
# # good
# ary.each do |v|
# v
# end
#
class RedundantWithObject < Base
include RangeHelp
extend AutoCorrector
MSG_EACH_WITH_OBJECT = 'Use `each` instead of `each_with_object`.'
MSG_WITH_OBJECT = 'Remove redundant `with_object`.'
def on_block(node)
return unless (send = redundant_with_object?(node))
range = with_object_range(send)
add_offense(range, message: message(send)) do |corrector|
if send.method?(:each_with_object)
corrector.replace(range, 'each')
else
corrector.remove(range)
corrector.remove(send.loc.dot)
end
end
end
alias on_numblock on_block
private
# @!method redundant_with_object?(node)
def_node_matcher :redundant_with_object?, <<~PATTERN
{
(block
$(call _ {:each_with_object :with_object} _) (args (arg _)) ...)
(numblock
$(call _ {:each_with_object :with_object} _) 1 ...)
}
PATTERN
def message(node)
if node.method?(:each_with_object)
MSG_EACH_WITH_OBJECT
else
MSG_WITH_OBJECT
end
end
def with_object_range(send)
range_between(send.loc.selector.begin_pos, send.source_range.end_pos)
end
end
end
end
end