Fix incorrect_dependent_option checker for broken associations

lib/active_record_doctor/detectors/incorrect_dependent_option.rb

@@ -77,8 +77,8 @@ def detect
                   associated_models: [through_association.klass.name],
                   associated_models_type: "join"
                 )
-                next
               end
+              next
             end
 
             associated_models, associated_models_type =

test/active_record_doctor/detectors/incorrect_dependent_option_test.rb

@@ -405,6 +405,25 @@ def test_has_through_associations_when_join_model_incomplete
     OUTPUT
   end
 
+  def test_has_through_associations_with_bad_source
+    Context.create_table(:users).define_model do
+      has_many :posts
+      has_many :comments, through: :posts, source: :non_existent
+    end
+
+    Context.create_table(:posts) do |t|
+      t.references :users
+    end.define_model do
+      has_many :comments
+    end
+
+    Context.create_table(:comments) do |t|
+      t.references :posts
+    end.define_model
+
+    refute_problems
+  end
+
   def test_destroy_async_and_foreign_key_exists
     Context.create_table(:companies) do
     end.define_model do