Warning message does tell me which cache does not exist

[antazoey]

I am getting a warning:

Path Validation Error: Path(s) specified in the action for caching do(es) not exist, hence no cache is being saved.

I am using several caches, I know most of them work, but it is not clear to me which cache is not valid.

Request: Mention the cache key in the warning message so I know where to look!