I have a more modest request:<p>Could debuggers please store the code paths and variable values, over the last 50 executions or perhaps the test suite (deterministic)? This is particularly useful for understanding someone else's code.<p>[edit: a context-free version of reverse debugging]<p>I've recently been enjoying using IntelliJ for Scala, because it can show me types, and jump to type declarations, and usages.<p>However, I still have to do a bunch of print debugging when trying to understand someone else's code, because I want to understand what values certain variables take. This is a pain using a compiler as slow as Scala.<p>Something that captured relevant information, so that it would be easier + faster to do print debugging against previous code runs or the test suite, would be awesome.