Add a regression test to catch future silliness in the index-building

area...

src/test/regress/expected/create_index.out

@@ -95,3 +95,10 @@ INSERT INTO func_index_heap VALUES('ABCD', 'EF');
 ERROR:  Cannot insert a duplicate key into unique index func_index_index
 -- but this shouldn't:
 INSERT INTO func_index_heap VALUES('QWERTY');
+--
+-- Also try building functional, expressional, and partial indexes on
+-- tables that already contain data.
+--
+create unique index hash_f8_index_1 on hash_f8_heap(abs(random));
+create unique index hash_f8_index_2 on hash_f8_heap((seqno + 1), random);
+create unique index hash_f8_index_3 on hash_f8_heap(random) where seqno > 1000;

src/test/regress/sql/create_index.sql

@@ -120,3 +120,11 @@ INSERT INTO func_index_heap VALUES('QWE','RTY');
 INSERT INTO func_index_heap VALUES('ABCD', 'EF');
 -- but this shouldn't:
 INSERT INTO func_index_heap VALUES('QWERTY');
+
+--
+-- Also try building functional, expressional, and partial indexes on
+-- tables that already contain data.
+--
+create unique index hash_f8_index_1 on hash_f8_heap(abs(random));
+create unique index hash_f8_index_2 on hash_f8_heap((seqno + 1), random);
+create unique index hash_f8_index_3 on hash_f8_heap(random) where seqno > 1000;