This code has some pretty specific knowledge of the internals of the `ace` library. I think we want a bit more encapsulation here. I would suggest that this code gets the current `AceEditor`, and calls a method on it like `navigateToDeclaration()`. That would be an empty implementation in the parent AceEditor class, and have a custom implementation in the `DartEditor` subclass.

That `DartEditor` class can have knowledge of the session/file/current char offset and know how to resolve things and perform navigation.

When you do call `declaration.getFile(...)`, you'll want to pass in the project of the file for the DartEditor. That will ensure that the project is non-null, and that the correct project is used to resolve the file uuid reference.

If the `file.project` _is_ null, you should bail out before performing any hyperlink resolution. That will mean that the file is a top-level file, doesn't have a project, and we won't have the context to do any analysis for it...