diff --git a/age--1.4.0.sql b/age--1.4.0.sql
index 2049fb958..4d8c9f048 100644
--- a/age--1.4.0.sql
+++ b/age--1.4.0.sql
@@ -149,7 +149,7 @@ CREATE TYPE graphid;
 CREATE FUNCTION ag_catalog.graphid_in(cstring)
 RETURNS graphid
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -157,7 +157,7 @@ AS 'MODULE_PATHNAME';
 CREATE FUNCTION ag_catalog.graphid_out(graphid)
 RETURNS cstring
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -253,7 +253,7 @@ CREATE OPERATOR < (
 CREATE FUNCTION ag_catalog.graphid_gt(graphid, graphid)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -271,7 +271,7 @@ CREATE OPERATOR > (
 CREATE FUNCTION ag_catalog.graphid_le(graphid, graphid)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -289,7 +289,7 @@ CREATE OPERATOR <= (
 CREATE FUNCTION ag_catalog.graphid_ge(graphid, graphid)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -312,7 +312,7 @@ CREATE OPERATOR >= (
 CREATE FUNCTION ag_catalog.graphid_btree_cmp(graphid, graphid)
 RETURNS int
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -321,7 +321,7 @@ AS 'MODULE_PATHNAME';
 CREATE FUNCTION ag_catalog.graphid_btree_sort(internal)
 RETURNS void
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -388,7 +388,7 @@ CREATE TYPE agtype;
 CREATE FUNCTION ag_catalog.agtype_in(cstring)
 RETURNS agtype
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -396,7 +396,7 @@ AS 'MODULE_PATHNAME';
 CREATE FUNCTION ag_catalog.agtype_out(agtype)
 RETURNS cstring
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -1428,7 +1428,7 @@ CREATE OPERATOR CLASS graphid_ops_hash
 CREATE FUNCTION ag_catalog.agtype_eq(agtype, agtype)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -1447,7 +1447,7 @@ CREATE OPERATOR = (
 CREATE FUNCTION ag_catalog.agtype_any_eq(agtype, smallint)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -1465,7 +1465,7 @@ CREATE OPERATOR = (
 CREATE FUNCTION ag_catalog.agtype_any_eq(smallint, agtype)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -1483,7 +1483,7 @@ CREATE OPERATOR = (
 CREATE FUNCTION ag_catalog.agtype_any_eq(agtype, integer)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -1501,7 +1501,7 @@ CREATE OPERATOR = (
 CREATE FUNCTION ag_catalog.agtype_any_eq(integer, agtype)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -1519,7 +1519,7 @@ CREATE OPERATOR = (
 CREATE FUNCTION ag_catalog.agtype_any_eq(agtype, bigint)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -1537,7 +1537,7 @@ CREATE OPERATOR = (
 CREATE FUNCTION ag_catalog.agtype_any_eq(bigint, agtype)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -1555,7 +1555,7 @@ CREATE OPERATOR = (
 CREATE FUNCTION ag_catalog.agtype_any_eq(agtype, real)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -1573,7 +1573,7 @@ CREATE OPERATOR = (
 CREATE FUNCTION ag_catalog.agtype_any_eq(real, agtype)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -1591,7 +1591,7 @@ CREATE OPERATOR = (
 CREATE FUNCTION ag_catalog.agtype_any_eq(agtype, double precision)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -1609,7 +1609,7 @@ CREATE OPERATOR = (
 CREATE FUNCTION ag_catalog.agtype_any_eq(double precision, agtype)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -1627,7 +1627,7 @@ CREATE OPERATOR = (
 CREATE FUNCTION ag_catalog.agtype_any_eq(agtype, numeric)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -1645,7 +1645,7 @@ CREATE OPERATOR = (
 CREATE FUNCTION ag_catalog.agtype_any_eq(numeric, agtype)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -1663,7 +1663,7 @@ CREATE OPERATOR = (
 CREATE FUNCTION ag_catalog.agtype_ne(agtype, agtype)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -1681,7 +1681,7 @@ CREATE OPERATOR <> (
 CREATE FUNCTION ag_catalog.agtype_any_ne(agtype, smallint)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -1699,7 +1699,7 @@ CREATE OPERATOR <> (
 CREATE FUNCTION ag_catalog.agtype_any_ne(smallint, agtype)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -1717,7 +1717,7 @@ CREATE OPERATOR <> (
 CREATE FUNCTION ag_catalog.agtype_any_ne(agtype, integer)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -1735,7 +1735,7 @@ CREATE OPERATOR <> (
 CREATE FUNCTION ag_catalog.agtype_any_ne(integer, agtype)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -1753,7 +1753,7 @@ CREATE OPERATOR <> (
 CREATE FUNCTION ag_catalog.agtype_any_ne(agtype, bigint)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -1771,7 +1771,7 @@ CREATE OPERATOR <> (
 CREATE FUNCTION ag_catalog.agtype_any_ne(bigint, agtype)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -1789,7 +1789,7 @@ CREATE OPERATOR <> (
 CREATE FUNCTION ag_catalog.agtype_any_ne(agtype, real)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -1807,7 +1807,7 @@ CREATE OPERATOR <> (
 CREATE FUNCTION ag_catalog.agtype_any_ne(real, agtype)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -1825,7 +1825,7 @@ CREATE OPERATOR <> (
 CREATE FUNCTION ag_catalog.agtype_any_ne(agtype, double precision)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -1843,7 +1843,7 @@ CREATE OPERATOR <> (
 CREATE FUNCTION ag_catalog.agtype_any_ne(double precision, agtype)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -1861,7 +1861,7 @@ CREATE OPERATOR <> (
 CREATE FUNCTION ag_catalog.agtype_any_ne(agtype, numeric)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -1879,7 +1879,7 @@ CREATE OPERATOR <> (
 CREATE FUNCTION ag_catalog.agtype_any_ne(numeric, agtype)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -1897,7 +1897,7 @@ CREATE OPERATOR <> (
 CREATE FUNCTION ag_catalog.agtype_lt(agtype, agtype)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -1915,7 +1915,7 @@ CREATE OPERATOR < (
 CREATE FUNCTION ag_catalog.agtype_any_lt(agtype, smallint)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -1933,7 +1933,7 @@ CREATE OPERATOR < (
 CREATE FUNCTION ag_catalog.agtype_any_lt(smallint, agtype)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -1951,7 +1951,7 @@ CREATE OPERATOR < (
 CREATE FUNCTION ag_catalog.agtype_any_lt(agtype, integer)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -1969,7 +1969,7 @@ CREATE OPERATOR < (
 CREATE FUNCTION ag_catalog.agtype_any_lt(integer, agtype)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -1987,7 +1987,7 @@ CREATE OPERATOR < (
 CREATE FUNCTION ag_catalog.agtype_any_lt(agtype, bigint)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -2005,7 +2005,7 @@ CREATE OPERATOR < (
 CREATE FUNCTION ag_catalog.agtype_any_lt(bigint, agtype)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -2023,7 +2023,7 @@ CREATE OPERATOR < (
 CREATE FUNCTION ag_catalog.agtype_any_lt(agtype, real)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -2041,7 +2041,7 @@ CREATE OPERATOR < (
 CREATE FUNCTION ag_catalog.agtype_any_lt(real, agtype)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -2059,7 +2059,7 @@ CREATE OPERATOR < (
 CREATE FUNCTION ag_catalog.agtype_any_lt(agtype, double precision)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -2077,7 +2077,7 @@ CREATE OPERATOR < (
 CREATE FUNCTION ag_catalog.agtype_any_lt(double precision, agtype)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -2095,7 +2095,7 @@ CREATE OPERATOR < (
 CREATE FUNCTION ag_catalog.agtype_any_lt(agtype, numeric)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -2113,7 +2113,7 @@ CREATE OPERATOR < (
 CREATE FUNCTION ag_catalog.agtype_any_lt(numeric, agtype)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -2131,7 +2131,7 @@ CREATE OPERATOR < (
 CREATE FUNCTION ag_catalog.agtype_gt(agtype, agtype)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -2149,7 +2149,7 @@ CREATE OPERATOR > (
 CREATE FUNCTION ag_catalog.agtype_any_gt(agtype, smallint)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -2167,7 +2167,7 @@ CREATE OPERATOR > (
 CREATE FUNCTION ag_catalog.agtype_any_gt(smallint, agtype)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -2185,7 +2185,7 @@ CREATE OPERATOR > (
 CREATE FUNCTION ag_catalog.agtype_any_gt(agtype, integer)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -2203,7 +2203,7 @@ CREATE OPERATOR > (
 CREATE FUNCTION ag_catalog.agtype_any_gt(integer, agtype)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -2221,7 +2221,7 @@ CREATE OPERATOR > (
 CREATE FUNCTION ag_catalog.agtype_any_gt(agtype, bigint)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -2239,7 +2239,7 @@ CREATE OPERATOR > (
 CREATE FUNCTION ag_catalog.agtype_any_gt(bigint, agtype)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -2257,7 +2257,7 @@ CREATE OPERATOR > (
 CREATE FUNCTION ag_catalog.agtype_any_gt(agtype, real)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -2275,7 +2275,7 @@ CREATE OPERATOR > (
 CREATE FUNCTION ag_catalog.agtype_any_gt(real, agtype)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -2293,7 +2293,7 @@ CREATE OPERATOR > (
 CREATE FUNCTION ag_catalog.agtype_any_gt(agtype, double precision)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -2311,7 +2311,7 @@ CREATE OPERATOR > (
 CREATE FUNCTION ag_catalog.agtype_any_gt(double precision, agtype)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -2329,7 +2329,7 @@ CREATE OPERATOR > (
 CREATE FUNCTION ag_catalog.agtype_any_gt(agtype, numeric)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -2347,7 +2347,7 @@ CREATE OPERATOR > (
 CREATE FUNCTION ag_catalog.agtype_any_gt(numeric, agtype)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -2365,7 +2365,7 @@ CREATE OPERATOR > (
 CREATE FUNCTION ag_catalog.agtype_le(agtype, agtype)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -2383,7 +2383,7 @@ CREATE OPERATOR <= (
 CREATE FUNCTION ag_catalog.agtype_any_le(agtype, smallint)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -2401,7 +2401,7 @@ CREATE OPERATOR <= (
 CREATE FUNCTION ag_catalog.agtype_any_le(smallint, agtype)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -2419,7 +2419,7 @@ CREATE OPERATOR <= (
 CREATE FUNCTION ag_catalog.agtype_any_le(agtype, integer)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -2437,7 +2437,7 @@ CREATE OPERATOR <= (
 CREATE FUNCTION ag_catalog.agtype_any_le(integer, agtype)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -2455,7 +2455,7 @@ CREATE OPERATOR <= (
 CREATE FUNCTION ag_catalog.agtype_any_le(agtype, bigint)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -2473,7 +2473,7 @@ CREATE OPERATOR <= (
 CREATE FUNCTION ag_catalog.agtype_any_le(bigint, agtype)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -2491,7 +2491,7 @@ CREATE OPERATOR <= (
 CREATE FUNCTION ag_catalog.agtype_any_le(agtype, real)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -2509,7 +2509,7 @@ CREATE OPERATOR <= (
 CREATE FUNCTION ag_catalog.agtype_any_le(real, agtype)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -2527,7 +2527,7 @@ CREATE OPERATOR <= (
 CREATE FUNCTION ag_catalog.agtype_any_le(agtype, double precision)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -2545,7 +2545,7 @@ CREATE OPERATOR <= (
 CREATE FUNCTION ag_catalog.agtype_any_le(double precision, agtype)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -2563,7 +2563,7 @@ CREATE OPERATOR <= (
 CREATE FUNCTION ag_catalog.agtype_any_le(agtype, numeric)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -2581,7 +2581,7 @@ CREATE OPERATOR <= (
 CREATE FUNCTION ag_catalog.agtype_any_le(numeric, agtype)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -2599,7 +2599,7 @@ CREATE OPERATOR <= (
 CREATE FUNCTION ag_catalog.agtype_ge(agtype, agtype)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -2617,7 +2617,7 @@ CREATE OPERATOR >= (
 CREATE FUNCTION ag_catalog.agtype_any_ge(agtype, smallint)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -2635,7 +2635,7 @@ CREATE OPERATOR >= (
 CREATE FUNCTION ag_catalog.agtype_any_ge(smallint, agtype)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -2653,7 +2653,7 @@ CREATE OPERATOR >= (
 CREATE FUNCTION ag_catalog.agtype_any_ge(agtype, integer)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -2671,7 +2671,7 @@ CREATE OPERATOR >= (
 CREATE FUNCTION ag_catalog.agtype_any_ge(integer, agtype)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -2689,7 +2689,7 @@ CREATE OPERATOR >= (
 CREATE FUNCTION ag_catalog.agtype_any_ge(agtype, bigint)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -2707,7 +2707,7 @@ CREATE OPERATOR >= (
 CREATE FUNCTION ag_catalog.agtype_any_ge(bigint, agtype)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -2725,7 +2725,7 @@ CREATE OPERATOR >= (
 CREATE FUNCTION ag_catalog.agtype_any_ge(agtype, real)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -2743,7 +2743,7 @@ CREATE OPERATOR >= (
 CREATE FUNCTION ag_catalog.agtype_any_ge(real, agtype)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -2761,7 +2761,7 @@ CREATE OPERATOR >= (
 CREATE FUNCTION ag_catalog.agtype_any_ge(agtype, double precision)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -2779,7 +2779,7 @@ CREATE OPERATOR >= (
 CREATE FUNCTION ag_catalog.agtype_any_ge(double precision, agtype)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -2797,7 +2797,7 @@ CREATE OPERATOR >= (
 CREATE FUNCTION ag_catalog.agtype_any_ge(agtype, numeric)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -2815,7 +2815,7 @@ CREATE OPERATOR >= (
 CREATE FUNCTION ag_catalog.agtype_any_ge(numeric, agtype)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -2833,7 +2833,7 @@ CREATE OPERATOR >= (
 CREATE FUNCTION ag_catalog.agtype_btree_cmp(agtype, agtype)
 RETURNS INTEGER
 LANGUAGE c
-STABLE
+IMMUTABLE
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
 
@@ -2962,7 +2962,7 @@ CREATE OPERATOR #>> (
 CREATE FUNCTION ag_catalog.agtype_contains(agtype, agtype)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -2979,7 +2979,7 @@ CREATE OPERATOR @> (
 CREATE FUNCTION ag_catalog.agtype_contained_by(agtype, agtype)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -3162,7 +3162,7 @@ STORAGE text;
 CREATE FUNCTION ag_catalog.graphid_to_agtype(graphid)
 RETURNS agtype
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -3173,7 +3173,7 @@ WITH FUNCTION ag_catalog.graphid_to_agtype(graphid);
 CREATE FUNCTION ag_catalog.agtype_to_graphid(agtype)
 RETURNS graphid
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -3188,7 +3188,7 @@ AS IMPLICIT;
 CREATE FUNCTION ag_catalog._agtype_build_path(VARIADIC "any")
 RETURNS agtype
 LANGUAGE c
-STABLE
+IMMUTABLE
 CALLED ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -3230,7 +3230,7 @@ as 'MODULE_PATHNAME';
 CREATE FUNCTION ag_catalog.agtype_build_map(VARIADIC "any")
 RETURNS agtype
 LANGUAGE c
-STABLE
+IMMUTABLE
 CALLED ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -3238,7 +3238,7 @@ AS 'MODULE_PATHNAME';
 CREATE FUNCTION ag_catalog.agtype_build_map()
 RETURNS agtype
 LANGUAGE c
-STABLE
+IMMUTABLE
 CALLED ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME', 'agtype_build_map_noargs';
@@ -3246,7 +3246,7 @@ AS 'MODULE_PATHNAME', 'agtype_build_map_noargs';
 CREATE FUNCTION ag_catalog.agtype_build_map_nonull(VARIADIC "any")
 RETURNS agtype
 LANGUAGE c
-STABLE
+IMMUTABLE
 CALLED ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -3272,7 +3272,7 @@ AS 'MODULE_PATHNAME';
 CREATE FUNCTION ag_catalog.agtype_build_list(VARIADIC "any")
 RETURNS agtype
 LANGUAGE c
-STABLE
+IMMUTABLE
 CALLED ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -3280,7 +3280,7 @@ AS 'MODULE_PATHNAME';
 CREATE FUNCTION ag_catalog.agtype_build_list()
 RETURNS agtype
 LANGUAGE c
-STABLE
+IMMUTABLE
 CALLED ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME', 'agtype_build_list_noargs';
@@ -3292,7 +3292,7 @@ AS 'MODULE_PATHNAME', 'agtype_build_list_noargs';
 CREATE FUNCTION ag_catalog.agtype_to_text(agtype)
 RETURNS text
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -3304,7 +3304,7 @@ WITH FUNCTION ag_catalog.agtype_to_text(agtype);
 CREATE FUNCTION ag_catalog.agtype_to_bool(agtype)
 RETURNS boolean
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -3317,7 +3317,7 @@ AS IMPLICIT;
 CREATE FUNCTION ag_catalog.bool_to_agtype(boolean)
 RETURNS agtype
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -3329,7 +3329,7 @@ WITH FUNCTION ag_catalog.bool_to_agtype(boolean);
 CREATE FUNCTION ag_catalog.float8_to_agtype(float8)
 RETURNS agtype
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -3341,7 +3341,7 @@ WITH FUNCTION ag_catalog.float8_to_agtype(float8);
 CREATE FUNCTION ag_catalog.agtype_to_float8(agtype)
 RETURNS float8
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -3353,7 +3353,7 @@ WITH FUNCTION ag_catalog.agtype_to_float8(agtype);
 CREATE FUNCTION ag_catalog.int8_to_agtype(int8)
 RETURNS agtype
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -3365,7 +3365,7 @@ WITH FUNCTION ag_catalog.int8_to_agtype(int8);
 CREATE FUNCTION ag_catalog.agtype_to_int8(variadic "any")
 RETURNS bigint
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -3378,7 +3378,7 @@ AS ASSIGNMENT;
 CREATE FUNCTION ag_catalog.agtype_to_int4(variadic "any")
 RETURNS int
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -3390,7 +3390,7 @@ WITH FUNCTION ag_catalog.agtype_to_int4(variadic "any");
 CREATE FUNCTION ag_catalog.agtype_to_int2(variadic "any")
 RETURNS smallint
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -3402,7 +3402,7 @@ WITH FUNCTION ag_catalog.agtype_to_int2(variadic "any");
 CREATE FUNCTION ag_catalog.agtype_to_int4_array(variadic "any")
     RETURNS int[]
     LANGUAGE c
-    STABLE
+    IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -3425,14 +3425,14 @@ AS 'MODULE_PATHNAME';
 CREATE FUNCTION ag_catalog.agtype_access_slice(agtype, agtype, agtype)
 RETURNS agtype
 LANGUAGE c
-STABLE
+IMMUTABLE
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
 
 CREATE FUNCTION ag_catalog.agtype_in_operator(agtype, agtype)
 RETURNS agtype
 LANGUAGE c
-STABLE
+IMMUTABLE
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
 
@@ -3459,7 +3459,7 @@ AS 'MODULE_PATHNAME';
 CREATE FUNCTION ag_catalog.agtype_string_match_contains(agtype, agtype)
 RETURNS agtype
 LANGUAGE c
-STABLE
+IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -3872,21 +3872,21 @@ AS 'MODULE_PATHNAME';
 CREATE FUNCTION ag_catalog.age_abs(variadic "any")
 RETURNS agtype
 LANGUAGE c
-STABLE
+IMMUTABLE
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
 
 CREATE FUNCTION ag_catalog.age_sign(variadic "any")
 RETURNS agtype
 LANGUAGE c
-STABLE
+IMMUTABLE
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
 
 CREATE FUNCTION ag_catalog.age_log(variadic "any")
 RETURNS agtype
 LANGUAGE c
-STABLE
+IMMUTABLE
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
 
@@ -4217,7 +4217,7 @@ AS 'MODULE_PATHNAME';
 CREATE FUNCTION ag_catalog.age_build_vle_match_edge(agtype, agtype)
 RETURNS agtype
 LANGUAGE C
-STABLE
+IMMUTABLE
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
 
diff --git a/src/backend/parser/cypher_clause.c b/src/backend/parser/cypher_clause.c
index 0fac1ec93..af51b729b 100644
--- a/src/backend/parser/cypher_clause.c
+++ b/src/backend/parser/cypher_clause.c
@@ -4244,11 +4244,12 @@ transform_match_create_path_variable(cypher_parsestate *cpstate,
                                      cypher_path *path, List *entities)
 {
     ParseState *pstate = (ParseState *)cpstate;
-    Oid build_path_oid;
-    FuncExpr *fexpr;
-    int resno;
+    Oid build_path_oid = InvalidOid;
+    Expr *expr = NULL;
+    int resno = -1;
     List *entity_exprs = NIL;
-    ListCell *lc;
+    ListCell *lc = NULL;
+    bool null_path_entity = false;
 
     if (list_length(entities) < 1)
     {
@@ -4258,28 +4259,51 @@ transform_match_create_path_variable(cypher_parsestate *cpstate,
                  parser_errposition(pstate, path->location)));
     }
 
-    // extract the expr for each entity
+    /* extract the expr for each entity */
     foreach (lc, entities)
     {
         transform_entity *entity = lfirst(lc);
 
         if (entity->expr != NULL)
         {
+            /*
+             * Is it a NULL constant, meaning there was an invalid label?
+             * If so, flag it for later
+             */
+            if (IsA(entity->expr, Const) &&
+                ((Const*)(entity->expr))->constisnull)
+            {
+                null_path_entity = true;
+            }
+
             entity_exprs = lappend(entity_exprs, entity->expr);
         }
     }
 
-    // get the oid for the path creation function
+    /* get the oid for the path creation function */
     build_path_oid = get_ag_func_oid("_agtype_build_path", 1, ANYOID);
 
-    // build the expr node for the function
-    fexpr = makeFuncExpr(build_path_oid, AGTYPEOID, entity_exprs, InvalidOid,
-                         InvalidOid, COERCE_EXPLICIT_CALL);
+    /*
+     * If we have a NULL in the path, there is an invalid label, so there aren't
+     * any paths to be selected - the path variable will be NULL. In this case
+     * we need to return a NULL constant instead.
+     */
+    if (null_path_entity)
+    {
+        expr = (Expr*)makeNullConst(AGTYPEOID, -1, InvalidOid);
+    }
+    /* otherwise, build the expr node for the function */
+    else
+    {
+        expr = (Expr*)makeFuncExpr(build_path_oid, AGTYPEOID, entity_exprs,
+                                   InvalidOid, InvalidOid,
+                                   COERCE_EXPLICIT_CALL);
+    }
 
     resno = cpstate->pstate.p_next_resno++;
 
-    // create the target entry
-    return makeTargetEntry((Expr *)fexpr, resno, path->var_name, false);
+    /* create the target entry */
+    return makeTargetEntry(expr, resno, path->var_name, false);
 }
 
 /*
diff --git a/src/backend/parser/cypher_expr.c b/src/backend/parser/cypher_expr.c
index cf4ec6295..92f0134cd 100644
--- a/src/backend/parser/cypher_expr.c
+++ b/src/backend/parser/cypher_expr.c
@@ -97,6 +97,8 @@ static Node *transform_FuncCall(cypher_parsestate *cpstate, FuncCall *fn);
 static Node *transform_WholeRowRef(ParseState *pstate, ParseNamespaceItem *pnsi,
                                    int location, int sublevels_up);
 static ArrayExpr *make_agtype_array_expr(List *args);
+static Node *transform_column_ref_for_indirection(cypher_parsestate *cpstate,
+                                                  ColumnRef *cr);
 
 /* transform a cypher expression */
 Node *transform_cypher_expr(cypher_parsestate *cpstate, Node *expr,
@@ -796,6 +798,52 @@ static ArrayExpr *make_agtype_array_expr(List *args)
     return newa;
 }
 
+/*
+ * Transform a ColumnRef for indirection. Try to find the rte that the ColumnRef
+ * references and pass the properties of that rte as what the ColumnRef is
+ * referencing. Otherwise, reference the Var.
+ */
+static Node *transform_column_ref_for_indirection(cypher_parsestate *cpstate,
+                                                  ColumnRef *cr)
+{
+    ParseState *pstate = (ParseState *)cpstate;
+    ParseNamespaceItem *pnsi = NULL;
+    Node *field1 = linitial(cr->fields);
+    char *relname = NULL;
+    Node *node = NULL;
+    int levels_up = 0;
+
+    Assert(IsA(field1, String));
+    relname = strVal(field1);
+
+    /* locate the referenced RTE (used to be find_rte(cpstate, relname)) */
+    pnsi = refnameNamespaceItem(pstate, NULL, relname, cr->location,
+                                &levels_up);
+
+    /* if we didn't find anything, return NULL */
+    if (!pnsi)
+    {
+        return NULL;
+    }
+
+    /* find the properties column of the NSI and return a var for it */
+    node = scanNSItemForColumn(pstate, pnsi, 0, "properties", cr->location);
+
+    /*
+     * Error out if we couldn't find it.
+     *
+     * TODO: Should we error out or return NULL for further processing?
+     *       For now, just error out.
+     */
+    if (!node)
+    {
+        ereport(ERROR, (errcode(ERRCODE_UNDEFINED_OBJECT),
+                        errmsg("could not find properties for %s", relname)));
+    }
+
+    return node;
+}
+
 static Node *transform_A_Indirection(cypher_parsestate *cpstate,
                                      A_Indirection *a_ind)
 {
@@ -817,8 +865,25 @@ static Node *transform_A_Indirection(cypher_parsestate *cpstate,
     func_slice_oid = get_ag_func_oid("agtype_access_slice", 3, AGTYPEOID,
                                      AGTYPEOID, AGTYPEOID);
 
-    /* transform indirection argument expression */
-    ind_arg_expr = transform_cypher_expr_recurse(cpstate, a_ind->arg);
+    /*
+     * If the indirection argument is a ColumnRef, we want to pull out the
+     * properties, as a var node, if possible.
+     */
+    if (IsA(a_ind->arg, ColumnRef))
+    {
+        ColumnRef *cr = (ColumnRef *)a_ind->arg;
+
+        ind_arg_expr = transform_column_ref_for_indirection(cpstate, cr);
+    }
+
+    /*
+     * If we didn't get the properties from a ColumnRef, just transform the
+     * indirection argument.
+     */
+    if (ind_arg_expr == NULL)
+    {
+        ind_arg_expr = transform_cypher_expr_recurse(cpstate, a_ind->arg);
+    }
 
     /* get the location of the expression */
     location = exprLocation(ind_arg_expr);
diff --git a/src/backend/utils/adt/agtype_ops.c b/src/backend/utils/adt/agtype_ops.c
index 715b72660..b1e8f666f 100644
--- a/src/backend/utils/adt/agtype_ops.c
+++ b/src/backend/utils/adt/agtype_ops.c
@@ -1165,8 +1165,10 @@ PG_FUNCTION_INFO_V1(agtype_contains);
  */
 Datum agtype_contains(PG_FUNCTION_ARGS)
 {
-    agtype_iterator *constraint_it, *property_it;
-    agtype *properties, *constraints;
+    agtype_iterator *constraint_it = NULL;
+    agtype_iterator *property_it = NULL;
+    agtype *properties = NULL;
+    agtype *constraints = NULL;
 
     if (PG_ARGISNULL(0) || PG_ARGISNULL(1))
     {
@@ -1176,8 +1178,13 @@ Datum agtype_contains(PG_FUNCTION_ARGS)
     properties = AG_GET_ARG_AGTYPE_P(0);
     constraints = AG_GET_ARG_AGTYPE_P(1);
 
-    constraint_it = agtype_iterator_init(&constraints->root);
+    if (AGT_ROOT_IS_OBJECT(properties) != AGT_ROOT_IS_OBJECT(constraints))
+    {
+        PG_RETURN_BOOL(false);
+    }
+
     property_it = agtype_iterator_init(&properties->root);
+    constraint_it = agtype_iterator_init(&constraints->root);
 
     PG_RETURN_BOOL(agtype_deep_contains(&property_it, &constraint_it));
 }