a() {
	(exit 2)
	echo a:$?
	(kill -s USR1 $$; echo b:$?; exit 3)
	echo c:$?	# does not execute
	(exit 4)
}

trap "echo Trap; return" USR1
a

echo d:$?
# It's debatable what is the correct value above.
# Does 'return' in trap see $? == 2 or $? == 3?
# IOW: after (kill..), does shell first wait for its completion
# and sets $?, then checks pending signals and runs a trap handler,
# or does it first check pending signals and runs handler?
# hush does the former, and prints 3.