SELECT (CASE ... ) gives copyObject error in current CVS build.

I'm receiving the following error testing SELECT (CASE with
the recent cvs replication ( 29MAR99 , 8:30PM EST).

> Welcome to the POSTGRESQL interactive sql monitor:
> Please read the file COPYRIGHT for copyright terms of POSTGRESQL
>
> type \? for help on slash commands
> type \q to quit
> type \g or terminate with semicolon to execute query
> You are currently connected to the database: clark
>
> clark=> create table test (a text, b int4 );
> CREATE
> clark=> insert into test values ( 'one', 1);
> INSERT 18634 1
> clark=> insert into test values ( 'two', 2);
> INSERT 18635 1
> clark=> insert into test values ( null, null);
> INSERT 18636
> clark=> select ( case b when 1 then 'first' else 'other' end ) as xx from test;
> ERROR: copyObject: don't know how to copy 704
> clark=>
>