> JIT optimizations like devirtualization JIT devirt can be nitpicky, PGO has improved the situation greatly but until around 6.0 or 7.0 devirt was easy to 'br

> JIT optimizations like devirtualization JIT devirt can be nitpicky, PGO has improved the situation greatly but until around 6.0 or 7.0 devirt was easy to 'break' in a lot of common scenarios. Heck, tying into the generic composition bit, ironically static generics still have issues right around devirts. Go figure.