[Fix #436] Fix a false positive for Rails/ContentTag

Fixes #436.

This PR fixes a false positive for `Rails/ContentTag`
when the first argument is a splat argument.

CHANGELOG.md

@@ -1,5 +1,9 @@
 # Change log
 
+### Bug fixes
+
+* [#436](https://github.com/rubocop-hq/rubocop-rails/issues/436): Fix a false positive for `Rails/ContentTag` when the first argument is a splat argument. ([@koic][])
+
 ## master (unreleased)
 
 ### Bug fixes

lib/rubocop/cop/rails/content_tag.rb

@@ -30,9 +30,7 @@ class ContentTag < Base
 
  def on_send(node)
  first_argument = node.first_argument
- return unless first_argument
-
- return if first_argument.variable? || first_argument.send_type? || first_argument.const_type?
+ return if !first_argument || allowed_type?(first_argument)
 
  add_offense(node) do |corrector|
  autocorrect(corrector, node)
@@ -41,6 +39,10 @@ def on_send(node)
 
  private
 
+ def allowed_type?(argument)
+ argument.variable? || argument.send_type? || argument.const_type? || argument.splat_type?
+ end
+
  def autocorrect(corrector, node)
  if method_name?(node.first_argument)
  range = correction_range(node)

spec/rubocop/cop/rails/content_tag_spec.rb

@@ -165,6 +165,12 @@
  content_tag($name, "Hello world!", class: ["strong", "highlight"])
  RUBY
  end
+
+ it 'does not register an offence when the first argument is a splat argument' do
+ expect_no_offenses(<<~RUBY)
+ content_tag(*args, &block)
+ RUBY
+ end
  end
 
  context 'when the first argument is a method' do