diff --git a/lib/searchkick/model.rb b/lib/searchkick/model.rb
index 8f29fe1..90ad8f5 100644
--- a/lib/searchkick/model.rb
+++ b/lib/searchkick/model.rb
@@ -41,6 +41,8 @@ module Searchkick
 
         class << self
           def searchkick_search(term = "*", **options, &block)
+            # TODO same for Mongoid
+            Searchkick.warn("calling search on a relation is deprecated") if respond_to?(:current_scope) && !current_scope.nil?
             Searchkick.search(term, model: self, **options, &block)
           end
           alias_method Searchkick.search_method_name, :searchkick_search if Searchkick.search_method_name
diff --git a/test/match_test.rb b/test/match_test.rb
index 89e149e..8fffd1b 100644
--- a/test/match_test.rb
+++ b/test/match_test.rb
@@ -301,4 +301,17 @@ class MatchTest < Minitest::Test
     store_names ["Ice Cream Cake"]
     assert_search "🍨🍰", ["Ice Cream Cake"], emoji: true
   end
+
+  # TODO find better place
+
+  def test_search_relation
+    skip unless defined?(ActiveRecord)
+
+    assert_nil Product.current_scope
+    _, stderr = capture_io { Product.search("*") }
+    assert_equal "", stderr
+    assert Product.where(name: nil).current_scope
+    _, stderr = capture_io { Product.where(name: nil).search("*") }
+    assert_match "WARNING", stderr
+  end
 end
--
libgit2 0.21.0