diff --git a/contrib/hstore/hstore--1.1--1.2.sql b/contrib/hstore/hstore--1.1--1.2.sql
index 99b8a168fa3..9c127d44033 100644
--- a/contrib/hstore/hstore--1.1--1.2.sql
+++ b/contrib/hstore/hstore--1.1--1.2.sql
@@ -18,6 +18,7 @@ BEGIN
    FROM pg_proc p
        JOIN  pg_depend d
           ON p.proname = 'hstore_to_json_loose'
+            AND d.classid = 'pg_proc'::regclass
             AND d.objid = p.oid
             AND d.refclassid = 'pg_extension'::regclass
        JOIN pg_extension x