should be it

external/duckdb/test/sql/upsert/upsert_default_expressions.test

@@ -0,0 +1,42 @@
+# name: test/sql/upsert/upsert_default_expressions.test
+# group: [upsert]
+
+statement ok
+pragma enable_verification;
+
+statement ok
+create or replace table tbl (
+	a integer primary key default 4,
+	b integer DEFAULT 3
+);
+
+statement ok
+insert into tbl VALUES (2,3), (4,5)
+
+query II
+select * from tbl;
+----
+2	3
+4	5
+
+# DEFAULT in set expression
+statement ok
+insert into tbl VALUES (DEFAULT, 6) ON CONFLICT (a) DO UPDATE SET b = DEFAULT
+
+query II
+select * from tbl;
+----
+2	3
+4	3
+
+# DEFAULT in ON CONFLICT (..) WHERE <expr>
+statement error
+insert into tbl VALUES (4,8) ON CONFLICT (a) DO UPDATE SET b = excluded.b WHERE a = DEFAULT;
+----
+WHERE clause cannot contain DEFAULT clause
+
+# DEFAULT in DO UPDATE SET .. WHERE <expr>
+statement error
+insert into tbl VALUES (4,3) ON CONFLICT (a) DO UPDATE SET b = excluded.b WHERE excluded.b = DEFAULT * 2;
+----
+WHERE clause cannot contain DEFAULT clause