BUG #19064: Trigger allows creation with invalid column references but fails at runtime

The following bug has been logged on the website:

Bug reference: 19064
Logged by: Ketan Bhatiya
Email address: ketan(dot)bhatiya(at)lenditt(dot)com
PostgreSQL version: Unsupported/Unknown
Operating system: Windows
Description:

Example Function & Trigger

CREATE OR REPLACE FUNCTION update_order_total()
RETURNS TRIGGER AS $$
BEGIN
-- Wrong column reference: "wrong_column" does not exist in "Orders"
UPDATE Orders
SET total = NEW.wrong_column
WHERE id = NEW.id;
RETURN NULL;
END;
$$ LANGUAGE plpgsql;

CREATE OR REPLACE TRIGGER trg_update_order_total
AFTER UPDATE ON Orders
FOR EACH ROW
EXECUTE FUNCTION update_order_total();

Steps to Reproduce

Run the above function and trigger creation.
✅ They are created successfully.

Update a row in Orders.

Expected Result
If the trigger contains a reference to a non-existing column, PostgreSQL
should throw an error at creation time.

Actual Result

The function and trigger creation succeed.

❌ At runtime, when an update happens, it fails with:

ERROR: record "new" has no field "wrong_column"

Suggestion / Proposed Improvement
PostgreSQL should validate column references at trigger creation time, not
just at runtime.
If a column does not exist in the target table (Orders in this example),
trigger creation should fail immediately with a clear error message.