busybox/shell/ash_test/ash-vars/readonly1.tests

readonly bla=123
# Bare "eval bla=123" should abort ("eval" is a special builtin):
(eval bla=123 2>/dev/null; echo BUG)
echo Fail:$?
# "command BLTIN" disables "special-ness", should not abort:
command eval bla=123 2>/dev/null
echo Fail:$?