Fix error for Performance/RedundantEqualityComparisonBlock when block is empty

changelog/fix_error_for_redundant_equality_comparison_block.md

@@ -0,0 +1 @@
+* [#452](https://github.com/rubocop/rubocop-performance/pull/452): Fix an error for `Performance/RedundantEqualityComparisonBlock` when the block is empty. ([@earlopain][])

lib/rubocop/cop/performance/redundant_equality_comparison_block.rb

@@ -64,7 +64,7 @@ def on_block(node)
           return unless one_block_argument?(node.arguments)
 
           block_argument = node.first_argument
-          block_body = node.body
+          return unless (block_body = node.body)
           return unless use_equality_comparison_block?(block_body)
           return if same_block_argument_and_is_a_argument?(block_body, block_argument)
           return unless (new_argument = new_argument(block_argument, block_body))

spec/rubocop/cop/performance/redundant_equality_comparison_block_spec.rb

@@ -181,4 +181,16 @@
       items.any? { |item| do_something[0..item] == item }
     RUBY
   end
+
+  it 'does not register an offense when the block is empty' do
+    expect_no_offenses(<<~RUBY)
+      items.any? { |item| }
+    RUBY
+  end
+
+  it 'does not register an offense when the block takes no argument' do
+    expect_no_offenses(<<~RUBY)
+      items.any? { }
+    RUBY
+  end
 end