diff --git a/src/primitives.py b/src/primitives.py
index 3789d1a02ac107e12f12dd944b2a743c2af9fe71..14156de38d0bc106d1414da692f1a0c799c82092 100644
--- a/src/primitives.py
+++ b/src/primitives.py
@@ -250,7 +250,7 @@ class Lookup(AlgebraicLeaf):
 
     def __hash__(self):
         from pytools import hash_combine
-        return hash_combine(self.__class__, self.aggregate, self.index)
+        return hash_combine(self.__class__, self.aggregate, self.name)
 
     def get_mapper_method(self, mapper):
         return mapper.map_lookup