- name: Effect of quotes in when conditions
  gather_facts: no
  hosts: localhost
  vars: 
    a: true
    b: false
    c: false
  tasks:

  - name: I'm skipped and that's ok
    debug:
      msg: I'm skipped and that's ok
    when: (a and b) or c

  - name: I'm skipped and that's ok
    debug:
      msg: I'm skipped and that's ok
    when: '(a and b) or c'

  - name: I'm skipped and that's ok
    debug:
      msg: I'm skipped and that's ok
    when: >-
      (a and b) or c

  - name: I should not be there!
    fail:
      msg: I should not be there!
    when: ('a and b') or 'c'