[Fix #359] Fix a false positive for Performance/RedundantEqualityComparisonBlock

Fixes #359.

This PR fixes a false positive for `Performance/RedundantEqualityComparisonBlock`
when the block variable is used on both sides of `==`.

Author: koic

changelog/fix_a_false_positive_for_performance_redundant_equality_comparison_block.md

@@ -0,0 +1 @@
+* [#359](https://github.com/rubocop/rubocop-performance/issues/359): Fix a false positive for `Performance/RedundantEqualityComparisonBlock` when the block variable is used on both sides of `==`. ([@koic][])

lib/rubocop/cop/performance/redundant_equality_comparison_block.rb

@@ -97,7 +97,7 @@ def same_block_argument_and_is_a_argument?(block_body, block_argument)
           elsif IS_A_METHODS.include?(block_body.method_name)
             block_argument.source == block_body.first_argument.source
           else
-            false
+            block_body.receiver.source == block_body.first_argument.receiver&.source
           end
         end
 

spec/rubocop/cop/performance/redundant_equality_comparison_block_spec.rb

@@ -102,6 +102,12 @@
       RUBY
     end
 
+    it 'does not register an offense when the block variable is used on both sides of `==`' do
+      expect_no_offenses(<<~RUBY)
+        items.all? { |item| item == item.do_something }
+      RUBY
+    end
+
     it 'does not register an offense when using not target methods with `===` comparison block' do
       expect_no_offenses(<<~RUBY)
         items.do_something { |item| item == other }