I didn't know SillyMUD. But I did read the paper about an interpretation based memory checking tool many years ago. Unfortunately, I forgot the name. I believe the interpretation based memory checking tool assigns each pointer a type. So the idea is not new.

ASAN is great because of its compatibility with existing libraries, as you have pointed out, is available in both gcc/clang. Valgrind is in the same league. Both are fantastic tools even though they might miss some errors.