This reminds me of a similar idea I'd like to see. A smart tracer that keeps track of function call args and results and possibly local variables in a cache.

This reminds me of a similar idea I'd like to see. A smart tracer that keeps track of function call args and results and possibly local variables in a cache. Then when your program crashes, it can show you not just the backtrace but also recently called functions that may have influenced the crash. With such a tool you may be able to debug some crashes without a debugger at all.