bug in prepared statements, alter table <8.3

postgres=# create table abc (a int, b int);
CREATE TABLE
Time: 492.417 ms
postgres=# insert into abc values (1,2);
INSERT 0 1
Time: 16.602 ms
postgres=# prepare ins_abc as insert into abc values(1,2);
PREPARE
Time: 0.248 ms
postgres=# alter table abc alter a type numeric;
ALTER TABLE
Time: 254.847 ms
postgres=# EXECUTE ins_abc;
INSERT 0 1
Time: 0.452 ms
postgres=# select * from abc;
ERROR:  invalid memory alloc request size 18446744073709551610

:-)

h/t to rhodium toad.

merlin