Dart - request_document_symbols does not return complete range of symbol definitions

Today I've been working with the new Dart parser, I really appreciate the community getting this added in just as I encountered a project that required it.

However, it seems like the language server only returns the selection range of each symbol, not the full range of each symbol's definition. Whereas with any other parser I've used (Java, Python, TS/JS), I can get the selection range of the symbol (ie: the name of a function) as well as the range of the complete symbol definition (ie: a function body).

For my own case I have added a very crude workaround where I try to construct the missing range based on the given range of the symbol's definition, however it isn't perfect and definitely isnt ideal when every other language server in multilspy supports this functionality out of the box.

I tried to dig around the code for the Dart implementation, and the Dart parser itself, but haven't been able to identify the source of this discrepancy in functionality, or how to reliably fix it.

Start by tracing request_document_symbols through the Dart parser and language-server integration, then compare its returned ranges with the Java, Python, and TypeScript/JavaScript implementations mentioned in the issue. Confirm whether the Dart parser or server omits the full definition range; done means each symbol includes both its selection range and complete definition range.