[Feature Request] do comsub with builtins/functions in current env

[Akbarkhon Variskhanov]

I'd really like to see Bash not create a subshell for command
substitutions involving built-ins and functions.

Consider this situation:
> maxfd=$(ulimit -n)
or this:
> default_umask=$(umask)
Bash forks a new process just for those two. That doesn't really make
sense to me. Create another process, exec() another instance of bash
in it just to execute a built-in that was already known to the parent
bash anyway?
I believe ksh93 and mksh do this kind of "smart" branching, with the
latter also having the var=${ cmd; } form.

What do you think about incorporating such a feature into Bash?

Cheers,
Akbar.