Postgresql – How to execute a trigger procedure with an expression as an argument

How can I pass an expression as an argument when calling a trigger function?

create trigger my_trigger
after insert on my_table
for each row
execute function trigger_job(
    'job_name',
    (json_build_object(
       'foo', current_setting('foo', true),
       'bar', current_setting('bar', true)
    ))
);

I know how to call a "normal" function with an expression as an argument, but I can't get it to work calling a function from the trigger. I also know how to read the passed arguments from TG_ARGV[] in the trigger function, but that's beyond this question.

I also tried something simple like:

create trigger my_trigger
after insert on my_table
for each row
execute function trigger_job(
    'job_name',
    (true)
);

But I still get the error:

ERROR: syntax error at or near "("

LINE 6: (true)

^

Update: I am now using an intermediate function. The trigger calls the intermediate function with the single text parameter. That intermediate function builds the second argument and calls the final trigger_job function with both arguments. Simple.