Dot vs. array notation (foo.bar / foo['bar']) in variables

[MarkusTeufelberger]

See: https://docs.ansible.com/ansible/latest/reference_appendices/faq.html#ansible-allows-dot-notation-and-array-notation-for-variables-which-notation-should-i-use

The dot notation comes from Jinja and works fine for variables without special characters. If your variable contains dots (.), colons (:), or dashes (-), if a key begins and ends with two underscores, or if a key uses any of the known public attributes, it is safer to use the array notation. See Using Variables for a list of the known public attributes.

Ansible-lint should at the very least detect risky usages and maybe even (optionally?) disallow dot notation alltogether.