Submitted by: @pavel-zotov

Following query should NOT be allowed (nested aggregation):

with
rf as (
select 1 as p from rdb$database union all
select 3 from rdb$database union all
select 5 from rdb$database union all
select 7 from rdb$database
)
,dual as (
select 1 x from rdb$database
)

select
count(
sum (
(select sum(rf.p) from rf)
)
)
from dual;

But:
1) it returns "internal Firebird consistency check (EVL_expr: invalid operation (232), file: evl.cpp line: 1220)" on WI-V2.5.9.27111
2) it runs without any error on WI-V3.0.4.32988 and WI-T4.0.0.1008 Firebird (and returns: 0 - which is also wrong because argument of COUNT is NOT-null value :)).

PS.
I've opened this separate ticket after discuss with dimitr, related to CORE5563