[Fix rubocop#794] Fix an error for Rails/RedundantReceiverInWithOptions

Fixes rubocop#794.

This PR fixes an error for `Rails/RedundantReceiverInWithOptions`
when calling a method with a receiver in `with_options` without block arguments

Author: koic

changelog/fix_an_error_for_rails_redundant_receiver_in_with_option.md

@@ -0,0 +1 @@
+* [#794](https://github.com/rubocop/rubocop-rails/issues/794): Fix an error for `Rails/RedundantReceiverInWithOptions` when calling a method with a receiver in `with_options` without block arguments. ([@koic][])

lib/rubocop/cop/rails/redundant_receiver_in_with_options.rb

@@ -98,6 +98,8 @@ def redundant_receiver?(send_nodes, node)
           proc = if node.numblock_type?
                    ->(n) { n.receiver.lvar_type? && n.receiver.source == '_1' }
                  else
+                   return false if node.arguments.empty?
+
                    arg = node.arguments.first
                    ->(n) { same_value?(arg, n.receiver) }
                  end

spec/rubocop/cop/rails/redundant_receiver_in_with_options_spec.rb

@@ -108,6 +108,14 @@ class Account < ApplicationRecord
     RUBY
   end
 
+  it 'does not register an offense when calling a method with a receiver in `with_options` without block arguments' do
+    expect_no_offenses(<<~RUBY)
+      with_options do
+        obj.do_something
+      end
+    RUBY
+  end
+
   it 'does not register an offense when empty' do
     expect_no_offenses(<<~RUBY)
       with_options options: false do |merger|