Doesn't that come with sublime by default?

It would be hard to ship a full compiler and still be a lightweight text editor... :)

"Go to definition" is the first choice you get when you right-click a word.

There is "go to definition" feature that based on syntax highlighting files rather than on real language parsing. It works fine if you jump only across the project and have "vendor" folders excluded.

Not to mention refactorings such as rename, extract method, etc.