Commented by: @pavel-zotov

Perhaps, this problem relates not only domain definition:

SQL> recreate table test(n bigint default -9223372036854775807);
SQL> alter table test add n2 bigint default -9223372036854775808;
Statement failed, SQLSTATE = 22003
unsuccessful metadata update
-ALTER TABLE TEST failed
-Dynamic SQL Error
-SQL error code = -104
-arithmetic exception, numeric overflow, or string truncation
-numeric value is out of range
SQL>

As temp. workaround one may use hex literal 0x8000000000000000 which equal to min_bigint:

SQL> set heading off;
SQL> recreate table test(n bigint default 0x8000000000000000);
SQL> insert into test default values;
SQL> select * from test;

-9223372036854775808

SQL> create domain dm_test bigint default 0x8000000000000000;
SQL> create table test2( d dm_test );
SQL> insert into test2 default values;
SQL> select * from test2;

-9223372036854775808

Commented by: @pavel-zotov

Some examples still fail. Checked on WI-T4.0.0.1954 Firebird 4.0 Beta 2:

create domain dom06_13 as numeric(20,2) default -9999999999999999991; -- this is from CORE6294; it failed before, now it runs OK

create domain dm_bigint_absolute_max as bigint default 9223372036854775807;

create domain dm_bigint_near_abs_min as bigint default -9223372036854775807;

create domain dm_bigint_absolute_min as bigint default -9223372036854775808;
Statement failed, SQLSTATE = 22003
unsuccessful metadata update
-CREATE DOMAIN DM_BIGINT_ABSOLUTE_MIN failed
-Dynamic SQL Error
-SQL error code = -104
-arithmetic exception, numeric overflow, or string truncation
-numeric value is out of range

create table test1(n bigint default -9223372036854775808);
Statement failed, SQLSTATE = 22003
unsuccessful metadata update
-CREATE TABLE TEST1 failed
-Dynamic SQL Error
-SQL error code = -104
-arithmetic exception, numeric overflow, or string truncation
-numeric value is out of range