[PropertyAccessor] Throw exception on nonexistant "index" on read access

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | a kind of?
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | 7881
| License       | MIT
| Doc PR        | 

See discussion on issue #7881.