diff --git a/activerecord/test/cases/relations_test.rb b/activerecord/test/cases/relations_test.rb
index 0cd838c0b0..4f6116203e 100644
--- a/activerecord/test/cases/relations_test.rb
+++ b/activerecord/test/cases/relations_test.rb
@@ -745,6 +745,11 @@ class RelationTest < ActiveRecord::TestCase
     end
   end
 
+  def test_relation_to_sql
+    sql = Post.first.comments.to_sql
+    assert_no_match(/\?/, sql)
+  end
+
   def test_count
     posts = Post.all