Thanks for sharing this request.

This has been asked for a few times in the lifespan of the product, but we decided not to go down this road for the following reasons:
- UI complexity: Having an additional or half state on coverage markers makes the UI harder to interpret
- Performance: A structure like this would change a single dimensional data structure (one state for a single line of code) to a multi-dimensional one (multiple states per line). This would greatly increase the memory and CPU requirements of the engine to be able to handle the more complex data structures, thus significantly slowing the engine.
- Engineering: It's actually really hard to do. The algorithm that handles code coverage merging is massive and very tightly constrained. Right now it performs well enough to keep up with merging for a 100+ thread grid without needing more than a single thread. Adding multiple coverage status values per line would likely make the system unmaintainable.