Earlier quoted context omitted.
I use Clion for C/C++ and Rust (with the rust plugin) and indexing seems fine. PHP, Python, Ruby and Go have been generally miserable for me.
I use Rust in IntelliJ, and the indexing is usually fine once the IDE is up . But for some reason, whenever I reopen a project, it needs to reindex it. Even when I open the same project every day, not having changed anything in between. I understand from a friend it doesn't do that with Java projects.
Sometimes it does. I have no idea what causes it.