Merge pull request rubocop#12997 from Earlopain/error-for-unmodified-…

…reduce-acc

Fix an error for `Lint/UnmodifiedReduceAccumulator` when the block is empty

changelog/fix_error_for_lint_unmodified_reduce_accumulator.md

@@ -0,0 +1 @@
+* [#12997](https://github.com/rubocop/rubocop/pull/12997): Fix an error for `Lint/UnmodifiedReduceAccumulator` when the block is empty. ([@earlopain][])

lib/rubocop/cop/lint/unmodified_reduce_accumulator.rb

@@ -113,6 +113,7 @@ class UnmodifiedReduceAccumulator < Base
         PATTERN
 
         def on_block(node)
+          return unless node.body
           return unless reduce_with_block?(node)
           return unless node.argument_list.length >= 2
 

spec/rubocop/cop/lint/unmodified_reduce_accumulator_spec.rb

@@ -16,6 +16,12 @@
       RUBY
     end
 
+    it "does not affect #{method} called with an empty block" do
+      expect_no_offenses(<<~RUBY)
+        values.#{method}(:+) { |result, value| }
+      RUBY
+    end
+
     context "given a #{method} block" do
       it 'does not register an offense when returning a literal' do
         expect_no_offenses(<<~RUBY)