ES-mechanism. Weird error message ("Integer overflow") when statement is concatenated from substrings containing `/**/` comment and is executed two times

[Pavel Zotov]

Cosider script:
======== start ========
set bail on;
set list on;
set autoterm on;
set keep_tran on;
set echo on;
shell if exist r:\temp\tmp4test.fdb del r:\temp\tmp4test.fdb;
create database 'localhost:r:\temp\tmp4test.fdb' user 'sysdba' password 'masterkey';
set autoddl off;
commit;

-- /********************
-- ##############
-- "static" code:
-- ##############
create LOCAL TEMPORARY table ltt_test(f01 int) on commit delete rows;
insert into ltt_test(f01) select i from generate_series(1, 1000) as s(i);
update ltt_test set f01 = -f01 where mod(f01,3) <= 2;
alter table ltt_test alter f01 type int128;
update ltt_test set f01 = 170141183460469231731687303715884105727 where mod(f01,3) = 0;
drop table ltt_test;

create LOCAL TEMPORARY table ltt_test(f01 int) on commit preserve rows;
insert into ltt_test(f01) select i from generate_series(1, 1000) as s(i);
update ltt_test set f01 = -f01 where mod(f01,3) <= 2; -------------------------- [ ! ]
alter table ltt_test alter f01 type int128;
update ltt_test set f01 = 170141183460469231731687303715884105727 where mod(f01,3) = 0;
drop table ltt_test;
exit;
-- *********************/


-- ###############
-- "dynamic" code:
-- ###############
create procedure sp_run_ddl_and_dml_via_es(a_table_name varchar(31), a_index_name varchar(31)) as
    declare i smallint;
    declare n smallint;
    declare v_commit_action varchar(8);
begin
    i = 1; --------------------- [ 1 ]
    n = 2; --------------------- [ 2 ]
    while (i <= n) do
    begin
        v_commit_action = iif(i = 1, 'DELETE', 'PRESERVE');
        execute statement 'create LOCAL TEMPORARY table ' || a_table_name || '(f01 int) on commit ' || v_commit_action || ' rows';
        -- execute statement 'create GLOBAL TEMPORARY table ' || a_table_name || '(f01 int) on commit ' || v_commit_action || ' rows';
        -- execute statement 'create table ' || a_table_name || '(f01 int)';
        execute statement 'insert into ' || a_table_name || '(f01) select i from generate_series(1, 1000) as s(i)';

        -- ###################
        -- ###   N O T E   ###
        -- ###################
        -- execute statement 'update /* ACHTUNG */ ' || a_table_name || ' set f01 = -f01 where mod(f01,3) <= 2';
        execute statement 'update /* ACHTUNG: ' || v_commit_action || ' rows */ ' || a_table_name || ' set f01 = -f01 where mod(f01,3) <= 2';

        execute statement 'alter table ' || a_table_name || ' alter f01 type int128';
        execute statement ('update ' || a_table_name || ' set f01 = ? where mod(f01,3) = ?') (170141183460469231731687303715884105727, 0);
        execute statement 'drop table ' || a_table_name;
        i = i + 1;
    end
end;
commit;

execute block as
begin
    execute procedure sp_run_ddl_and_dml_via_es('test_es_1', 'test_es_1_idx');
end
;
exit;
======== finish ========

If we UNcomment block marked as "static code" then script finished OK.
If we remain this block commented and run script as "dynamic" code (i.e. as it is shown) -- also no errors occur.

But if we UNcomment first statement under "###   N O T E   ###" and Comment out second then weird abend raises:
===============
Statement failed, SQLSTATE = 22003
arithmetic exception, numeric overflow, or string truncation
-Integer overflow.  The result of an integer operation caused the most significant bit of the result to carry.
-At procedure "PUBLIC"."SP_RUN_DDL_AND_DML_VIA_ES" line: 38, col: 9
===============

The difference between two statements:
execute statement 'update /* ACHTUNG */ ' || a_table_name || ' set f01 = -f01 where mod(f01,3) <= 2';
vs
execute statement 'update /* ACHTUNG: ' || v_commit_action || ' rows */ ' || a_table_name || ' set f01 = -f01 where mod(f01,3) <= 2';
-- relates only to additional detalization ('v_commit_action') that is "embedded" into the COMMENT that starts with '/* ACHTUNG'.
SAME outcome if we check GTT or permanent table.

Also note that this oddity occurs only when procedure sp_run_ddl_and_dml_via_es contains:
    i = 1; --------------------- [ 1 ]
    n = 2; --------------------- [ 2 ]
(and not i = 2 & n = 2 or i = 1 and n = 1 -- i.e. TWO iterations must be executed.)

Checked on 6.0.0.1999-c8bc46b.