more advanced reference queries

[oriongonza]

This would be an LSP extension, of course.

Rustdoc allows for really nice queries, like -> MyTy that returns all functions that return that type.
I'd love to have that in my editor, I could configure it so that I can see all functions that return this type with a click.

Likewise for all functions that take this as an argument, etc.

Rustdoc seems to have a DSL for this, could r-a have a similar thing?