You're wrong. I've actually had to maintain the big C++ projects. That have Zillion of classes, fully different, but each one has more Read(), Write() functions. Some are virtual, some are not. Some have two parameters, some have three, some four. And they even do fully different stuff! Which Read() will be called depends on anything and everything. I claim you just can't figure out what some piece of code does in any other way than by actually single-stepping through the debug build. Any time the debug build pieces of code don't reflect the source, you're fully lost. Note that Linus usage scenario is "read the chunk of code outside of the whole source base" and you argumenting "if I use some hypotetical very clever tool the tool would maybe able to show me what some line in the chunk of code actually does." I've actually made some "very clever tools" since some twenty years ago. And I wouldn't want to have to use them on the really big projects.