Does not reproduce in 6.9.1

Repro steps:
1. Use HDRP or Universal project of 7.0.1 or later
2. Create a subgraph
3. Open the subgraph
4. Drag the subgraph into its own graph and connect it to the output
5. Save the subgraph

Expected result: the fact that the subgraph detects a recursion (which it does) should preventing it from attempting to compile (it does in 6.9.1)
Actual result: the subgraph attempts to compile and the process never ends, leaving Unity inoperable and forcing you to shut it down via the task manager. Upon loading unity back up, the subgraph will be corrupted, forcing you to open up Window's file explorer and delete it from there (you can not delete it from Unity).