Support Range#member? method for Performance/RangeInclude cop

CHANGELOG.md

@@ -4,6 +4,8 @@
 
 ### New features
 
+* [#125](https://github.com/rubocop-hq/rubocop-performance/pull/125): Support `Range#member?` method for `Performance/RangeInclude` cop. ([@fatkodima][])
+
 * [#115](https://github.com/rubocop-hq/rubocop-performance/issues/115): Support `String#sub` and `String#sub!` methods for `Performance/DeletePrefix` and `Performance/DeleteSuffix` cops. ([@fatkodima][])
 
 ### Bug fixes

config/default.yml

@@ -135,10 +135,11 @@ Performance/OpenStruct:
   Safe: false
 
 Performance/RangeInclude:
-  Description: 'Use `Range#cover?` instead of `Range#include?`.'
+  Description: 'Use `Range#cover?` instead of `Range#include?` (or `Range#member?`).'
   Reference: 'https://github.com/JuanitoFatas/fast-ruby#cover-vs-include-code'
   Enabled: true
   VersionAdded: '0.36'
+  VersionChanged: '1.7'
   Safe: false
 
 Performance/RedundantBlockCall:

docs/modules/ROOT/pages/cops_performance.adoc

@@ -727,16 +727,16 @@ end
 | No
 | Yes (Unsafe)
 | 0.36
-| -
+| 1.7
 |===
 
-This cop identifies uses of `Range#include?`, which iterates over each
+This cop identifies uses of `Range#include?` and `Range#member?`, which iterates over each
 item in a `Range` to see if a specified item is there. In contrast,
 `Range#cover?` simply compares the target item with the beginning and
 end points of the `Range`. In a great majority of cases, this is what
 is wanted.
 
-This cop is `Safe: false` by default because `Range#include?` and
+This cop is `Safe: false` by default because `Range#include?` (or `Range#member?`) and
 `Range#cover?` are not equivalent behaviour.
 
 === Examples
@@ -745,6 +745,7 @@ This cop is `Safe: false` by default because `Range#include?` and
 ----
 # bad
 ('a'..'z').include?('b') # => true
+('a'..'z').member?('b')  # => true
 
 # good
 ('a'..'z').cover?('b') # => true

lib/rubocop/cop/performance/range_include.rb

@@ -3,18 +3,19 @@
 module RuboCop
   module Cop
     module Performance
-      # This cop identifies uses of `Range#include?`, which iterates over each
+      # This cop identifies uses of `Range#include?` and `Range#member?`, which iterates over each
       # item in a `Range` to see if a specified item is there. In contrast,
       # `Range#cover?` simply compares the target item with the beginning and
       # end points of the `Range`. In a great majority of cases, this is what
       # is wanted.
       #
-      # This cop is `Safe: false` by default because `Range#include?` and
+      # This cop is `Safe: false` by default because `Range#include?` (or `Range#member?`) and
       # `Range#cover?` are not equivalent behaviour.
       #
       # @example
       #   # bad
       #   ('a'..'z').include?('b') # => true
+      #   ('a'..'z').member?('b')  # => true
       #
       #   # good
       #   ('a'..'z').cover?('b') # => true
@@ -24,21 +25,22 @@ module Performance
       #
       #   ('a'..'z').cover?('yellow') # => true
       class RangeInclude < Cop
-        MSG = 'Use `Range#cover?` instead of `Range#include?`.'
+        MSG = 'Use `Range#cover?` instead of `Range#%<bad_method>s`.'
 
         # TODO: If we traced out assignments of variables to their uses, we
         # might pick up on a few more instances of this issue
         # Right now, we only detect direct calls on a Range literal
         # (We don't even catch it if the Range is in double parens)
 
         def_node_matcher :range_include, <<~PATTERN
-          (send {irange erange (begin {irange erange})} :include? ...)
+          (send {irange erange (begin {irange erange})} ${:include? :member?} ...)
         PATTERN
 
         def on_send(node)
-          return unless range_include(node)
-
-          add_offense(node, location: :selector)
+          range_include(node) do |bad_method|
+            message = format(MSG, bad_method: bad_method)
+            add_offense(node, location: :selector, message: message)
+          end
         end
 
         def autocorrect(node)

spec/rubocop/cop/performance/range_include_spec.rb

@@ -3,24 +3,26 @@
 RSpec.describe RuboCop::Cop::Performance::RangeInclude do
   subject(:cop) { described_class.new }
 
-  it 'autocorrects (a..b).include? without parens' do
-    new_source = autocorrect_source('(a..b).include? 1')
-    expect(new_source).to eq '(a..b).cover? 1'
-  end
+  %i[include? member?].each do |method|
+    it "autocorrects (a..b).#{method} without parens" do
+      new_source = autocorrect_source("(a..b).#{method} 1")
+      expect(new_source).to eq '(a..b).cover? 1'
+    end
 
-  it 'autocorrects (a...b).include? without parens' do
-    new_source = autocorrect_source('(a...b).include? 1')
-    expect(new_source).to eq '(a...b).cover? 1'
-  end
+    it "autocorrects (a...b).#{method} without parens" do
+      new_source = autocorrect_source("(a...b).#{method} 1")
+      expect(new_source).to eq '(a...b).cover? 1'
+    end
 
-  it 'autocorrects (a..b).include? with parens' do
-    new_source = autocorrect_source('(a..b).include?(1)')
-    expect(new_source).to eq '(a..b).cover?(1)'
-  end
+    it "autocorrects (a..b).#{method} with parens" do
+      new_source = autocorrect_source("(a..b).#{method}(1)")
+      expect(new_source).to eq '(a..b).cover?(1)'
+    end
 
-  it 'autocorrects (a...b).include? with parens' do
-    new_source = autocorrect_source('(a...b).include?(1)')
-    expect(new_source).to eq '(a...b).cover?(1)'
+    it "autocorrects (a...b).#{method} with parens" do
+      new_source = autocorrect_source("(a...b).#{method}(1)")
+      expect(new_source).to eq '(a...b).cover?(1)'
+    end
   end
 
   it 'formats the error message correctly for (a..b).include? 1' do
@@ -29,4 +31,11 @@
              ^^^^^^^^ Use `Range#cover?` instead of `Range#include?`.
     RUBY
   end
+
+  it 'formats the error message correctly for (a..b).member? 1' do
+    expect_offense(<<~RUBY)
+      (a..b).member? 1
+             ^^^^^^^ Use `Range#cover?` instead of `Range#member?`.
+    RUBY
+  end
 end