Most coursebooks teach mixed conditionals, but few look at just how mixed the conditionals can be.
It is possible to mix the first and the third conditional:
If she is such a good doctor, she should have diagnosed the disease.
Here, the problem that makes me doubt her ability is in the past, but my doubts are present. If I use a more certain modal verb, the sentence changes:
If she was\were such a good doctor, she would have diagnosed the disease.
Here, her failure to diagnose is clear, so I do not believe in her ability.
Most mixed conditionals are taught along the lines of starting in the third conditional (past action) and finishing with the second (present\future result:
If he hadn't broken his leg, he would be playing in the match.
However, there are more complex conditionals where past result affects the current situation.