The 31f4d468b60eb27d768ef56d0a8b4982346465d9 commit on the devel branch, addressed this issue, but only partially:
bash-5.1$ ./bash --version |& head -n 1 GNU bash, version 5.2.9(6)-maint (x86_64-pc-linux-gnu) bash-5.1$ ./bash -c 'a () { local -; local -p; declare -p -; typeset -p -; local -p - ;}; a' local - declare -- - declare -- - local - `local -p -' no longer prints "declare -- -", but `declare -p -', and `typeset -p -' still do. emanuele6