By using the AST? Do you really not know how languages work? I mean seriously, this is incredibly basic stuff. You don’t need to know the type to jump to the ast node location. Do you think that formatters for dynamic languages need to know the type in order to format them properly? Then why in the world would you need it to know where to jump to in a type definition!?!

Edit: also in the case of Ruby, the entire thing runs on a VM which used to be YARV but I think might have changed recently. So there’s literally bytecode providing all the information needed to run it. I highly recommend reading a book about how the Ruby internals work since you seem to think you understand but it’s quite clear you don’t, or for some reason think “jump to” is this magical thing that requires types.