Yes, language servers provide that feature, too, and all language server clients replace „xref“ with their own implementation. „lsp-mode“ even provide some gui extensions to Emacs so it can display a hover window when there are several possible matches for your definition (e.g. all overridden methods in your inheritance tree). That’s quite cool.

But the disadvantage is you now need to run a static analyzer in the background parsing half of your code base to find definitions. On very large code based this can create slow downs.

Furthermore, finding definitions by means of static analysis cannot always work, especially so in dynamically typed languages or in languages employing generic variables.