diff --git a/src/libexpr/eval-cache.cc b/src/libexpr/eval-cache.cc
index d77b25898..dbfd8e70b 100644
--- a/src/libexpr/eval-cache.cc
+++ b/src/libexpr/eval-cache.cc
@@ -282,7 +282,7 @@ struct AttrDb
         auto queryAttribute(state->queryAttribute.use()(key.first)(symbols[key.second]));
         if (!queryAttribute.next()) return {};
 
-        auto rowId = (AttrType) queryAttribute.getInt(0);
+        auto rowId = (AttrId) queryAttribute.getInt(0);
         auto type = (AttrType) queryAttribute.getInt(1);
 
         switch (type) {