Optimistic would be a good term for this type of student. Optimistic is often regarded as a trait that assumes only good things will occur, which can be contributed to an extremely unrealistic outlook. However, in its true nature, optimism is simply the ability to push past setbacks using the mindset that bad things happen but they should not be assigned a heavier meaning than necessary. An optimistic student would intelligently explore a setback by trying to understand why it happened and how to prevent it in the future. That way, the lesson offers advice and additional insight that the student wouldn't have had otherwise.