diff --git a/loopy/kernel/__init__.py b/loopy/kernel/__init__.py
index 0c9e4d3d1d6ccfab769cf53abe32fccc4be15086..0ec62012be503ee6378cd996273797a876fbeef3 100644
--- a/loopy/kernel/__init__.py
+++ b/loopy/kernel/__init__.py
@@ -589,7 +589,7 @@ class LoopKernel(RecordWithoutPickling):
 
         all_inames = set()
         all_params = set()
-        for dom in self.domains:
+        for dom in domains:
             all_inames.update(dom.get_var_names(dim_type.set))
             all_params.update(dom.get_var_names(dim_type.param))