Blowback from text conversion changes

This seems odd. It's not deciding that it's ambiguous or coming from another
datatype for which no implicit cast exists. It knows perfectly well that it
wants to convert to text but fails?


postgres=# select 'a'||b from (select 'b' as b) as x;
ERROR:  failed to find conversion function from unknown to text


--  Gregory Stark EnterpriseDB          http://www.enterprisedb.com