rust-analyzer does not see the path of a Span's source_file

[sadeli413]

I'd like rust-analyzer to be able to detect the source-file's path of a span.

I have a proc-macro that simply panics and shows the caller's source path:

#![feature(proc_macro_span)]
use proc_macro::{Span, TokenStream};

#[proc_macro]
pub fn file_test(_input: TokenStream) -> TokenStream {
    let span = Span::call_site();
    let path = span.source_file().path();
    panic!("test: `{}`", path.display());
}

rustc sees that the filename is src/main.rs just fine, but rust-analyzer thinks the filename is blank.

use macro_hell::file_test;

fn main() {
    // rustc: test: `src/main.rs`
    // rust-analyzer: test: ``
    let _ = file_test!();
}

[ChayimFriedman2]

Generally we don't properly support the span APIs, and doing it will be difficult for us. Although maybe the file name is not that problematic.

[Veykril]

#15950