[Fix rubocop#556] Fix a false positive for Rails/ContentTag

Fixes rubocop#556.

This PR fixes a false positive for `Rails/ContentTag`
when using using the `tag` method with 3 or more arguments.

changelog/fix_a_false_positive_for_rails_content_tag.md

@@ -0,0 +1 @@
+* [#556](https://github.com/rubocop/rubocop-rails/issues/556): Fix a false positive for `Rails/ContentTag` when using using the `tag` method with 3 or more arguments. ([@koic][])

lib/rubocop/cop/rails/content_tag.rb

@@ -34,6 +34,7 @@ def on_new_investigation
 
         def on_send(node)
           return unless node.receiver.nil?
+          return if node.arguments.count >= 3
 
           first_argument = node.first_argument
           return if !first_argument ||

spec/rubocop/cop/rails/content_tag_spec.rb

@@ -75,14 +75,19 @@
       RUBY
     end
 
-    it 'corrects an offense with all arguments' do
-      expect_offense(<<~RUBY)
+    # Prevents `ArgumentError` reported by https://github.com/rubocop/rubocop-rails/issues/556.
+    # See: https://api.rubyonrails.org/v6.1.4/classes/ActionView/Helpers/TagHelper.html#method-i-tag-label-Legacy+syntax
+    it 'does not register an offense with all arguments' do
+      expect_no_offenses(<<~RUBY)
         tag(:br, {class: ["strong", "highlight"]}, true, false)
-        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Use `tag.br` instead of `tag(:br)`.
       RUBY
+    end
 
-      expect_correction(<<~RUBY)
-        tag.br({class: ["strong", "highlight"]}, true, false)
+    # Prevents `ArgumentError` reported by https://github.com/rubocop/rubocop-rails/issues/556.
+    # See: https://api.rubyonrails.org/v6.1.4/classes/ActionView/Helpers/TagHelper.html#method-i-tag-label-Legacy+syntax
+    it 'does not register an offense with three arguments' do
+      expect_no_offenses(<<~RUBY)
+        tag(:br, {class: ["strong", "highlight"]}, true)
       RUBY
     end