Ansible: Using multiple arguments in with_items

roles--x--tasks--main.yml

---
- name: Echo some things!
  command: echo {{ item.foo }} {{ item.bar }}
  with_items: echo_arguments

roles--x--vars--main.yml

---
echo_arguments:
  - { foo: 'Hello',   bar: 'World!' }
  - { foo: 'Goodbye', bar: 'Caroline!' }
  - { foo: 'Hello',   bar: 'Ava!' }