Incorrectly computed view field size when concatenating string literals

[sim1984]

set names UTF8;
connect 'inet4://localhost:3053/test' user SYSDBA password 'masterkey';
Database: 'inet4://localhost:3053/test', User: SYSDBA

CREATE OR ALTER VIEW VW_TB3(
     RENT)
 AS
 select
   'ab '||' ab '||' abcd'
from $RDB$DATABASE;

show view VW_TB3;

RENT                            VARCHAR(2) Expression <-- Error
View Source:
==== ======
select
'ab '||' ab '||' abcd'
from rdb$database

Expected VARCHAR (12), actual VARCHAR (2)

Reproduced in Firebird 3.0.7, 4.0.0 and 5.0