Strict POSIX mode

[FlyingWombat]

I know this is bash-language-server, but I'm wondering it would be in-scope to add a strict POSIX mode to check script compatibility with shells like dash and regular sh.

As the name suggests, this mode would flag any deviations from the POSIX shell standard.

This would pretty much be solved by #104, since shellcheck already has a mode for linting strict POSIX shell, with its --shell option.
Another useful tool for this might be checkbashisms from the Debian DevScripts repo. (Arch package for reference)

[skovhus]

@mads-hartmann do you know if the tree-sitter-bash would support this?

[mads-hartmann]

Given that shellcheck already has support for this and has a great VSCode extension I think it's outside the scope of this project to check for POSIX compliance 🙂