Am I misunderstanding what is meant by semantic code search? I thought the idea was that you run something like a parser on the repo to extract function/class/variable names and then allow searching on a more rich set of data, rather than tokenizing it like English.

I know github kind of added this but their version falls apart still even in common languages like C++. It's not unusual for it to just completely miss cross references, even in smaller repos. A proper compiler's eye view of symbolic data would be super useful, and Github's halfway attempt can be frustratingly daft about it.