Firebird WI-T0.9.4.41 Firebird Test1 on NT and
Firebird LI-T0.9.4.34 (p1) Firebird Test1 on Linux.

There might be a small bug:
Using dialect 1 cast(integer <any operation except multiplying> integer as
varchar(... returns a floating point or double precision value:
SQL> select cast(1 + 1 as varchar(9)) from rdb$database;
=========
2.000000

It's cute that multiplying works ok.

Dialect 3 works as expected:
SQL> select cast(1 + 1 as varchar(9)) from rdb$database;
=========
2

Veli-Matti Hurskainen