diff --git a/src/test/regress/expected/for_portion_of.out b/src/test/regress/expected/for_portion_of.out
index 31f772c7..b862e5d4 100644
--- a/src/test/regress/expected/for_portion_of.out
+++ b/src/test/regress/expected/for_portion_of.out
@@ -2097,4 +2097,26 @@ SELECT * FROM temporal_partitioned_5 ORDER BY id, valid_at;
 (4 rows)
 
 DROP TABLE temporal_partitioned;
+-- Test: FOR PORTION OF should be rejected on views with INSTEAD OF triggers
+CREATE TABLE fpo_instead_base (id int, valid_at daterange, val int);
+INSERT INTO fpo_instead_base VALUES (1, '[2024-01-01,2024-12-31)', 100);
+CREATE VIEW fpo_instead_view AS SELECT * FROM fpo_instead_base;
+CREATE FUNCTION fpo_instead_trig_fn() RETURNS trigger LANGUAGE plpgsql AS $$
+BEGIN
+    RETURN NEW;
+END;
+$$;
+CREATE TRIGGER fpo_instead_trig INSTEAD OF UPDATE ON fpo_instead_view
+    FOR EACH ROW EXECUTE FUNCTION fpo_instead_trig_fn();
+CREATE TRIGGER fpo_instead_del_trig INSTEAD OF DELETE ON fpo_instead_view
+    FOR EACH ROW EXECUTE FUNCTION fpo_instead_trig_fn();
+-- These should produce clean error messages, not crash the server
+UPDATE fpo_instead_view FOR PORTION OF valid_at FROM '2024-04-01' TO '2024-08-01'
+    SET val = 999 WHERE id = 1;  -- error
+ERROR:  FOR PORTION OF is not supported on views with INSTEAD OF triggers
+DELETE FROM fpo_instead_view FOR PORTION OF valid_at FROM '2024-04-01' TO '2024-08-01'
+    WHERE id = 1;  -- error
+ERROR:  FOR PORTION OF is not supported on views with INSTEAD OF triggers
+DROP VIEW fpo_instead_view;
+DROP TABLE fpo_instead_base;
 RESET datestyle;
diff --git a/src/test/regress/sql/for_portion_of.sql b/src/test/regress/sql/for_portion_of.sql
index d4062acf..77610e5f 100644
--- a/src/test/regress/sql/for_portion_of.sql
+++ b/src/test/regress/sql/for_portion_of.sql
@@ -1365,4 +1365,25 @@ SELECT * FROM temporal_partitioned_5 ORDER BY id, valid_at;
 
 DROP TABLE temporal_partitioned;
 
+-- Test: FOR PORTION OF should be rejected on views with INSTEAD OF triggers
+CREATE TABLE fpo_instead_base (id int, valid_at daterange, val int);
+INSERT INTO fpo_instead_base VALUES (1, '[2024-01-01,2024-12-31)', 100);
+CREATE VIEW fpo_instead_view AS SELECT * FROM fpo_instead_base;
+CREATE FUNCTION fpo_instead_trig_fn() RETURNS trigger LANGUAGE plpgsql AS $$
+BEGIN
+    RETURN NEW;
+END;
+$$;
+CREATE TRIGGER fpo_instead_trig INSTEAD OF UPDATE ON fpo_instead_view
+    FOR EACH ROW EXECUTE FUNCTION fpo_instead_trig_fn();
+CREATE TRIGGER fpo_instead_del_trig INSTEAD OF DELETE ON fpo_instead_view
+    FOR EACH ROW EXECUTE FUNCTION fpo_instead_trig_fn();
+-- These should produce clean error messages, not crash the server
+UPDATE fpo_instead_view FOR PORTION OF valid_at FROM '2024-04-01' TO '2024-08-01'
+    SET val = 999 WHERE id = 1;  -- error
+DELETE FROM fpo_instead_view FOR PORTION OF valid_at FROM '2024-04-01' TO '2024-08-01'
+    WHERE id = 1;  -- error
+DROP VIEW fpo_instead_view;
+DROP TABLE fpo_instead_base;
+
 RESET datestyle;