mangling include_role path

I’ve set up a playbook that includes another playbook located under ‘a/b/c’ subdirectory. From that included playbook I do ‘include_role’ which fails since role is located at top level and not the sub-playbook level. What are the most common ways of mitigating this?

sample (that doesn’t work):

main.yml

my current workaround is to stash top-level playbook’s directory and use “include_tasks” instead of “include_role”:

main.yml