Method not found in 'Span' after release.

[adama789]

error[E0599]: no method named source_file found for struct proc_macro2::Span in the current scope

let source_path = proc_macro2::Span::call_site().source_file().path();
| ^^^^^^^^^^^ method not found in Span

[VictorArcium]

This was fixed in 1.0.95.

[joshka]

I saw this still be triggered in 1.0.95 when running cargo-docsrs with cargo 1.88.0-nightly (a6c604d1b 2025-03-26), but updating nightly makes it goes away. cargo 1.88.0-nightly (d811228b1 2025-04-15), so something changed in those versions that affects this.

error[E0599]: no method named `file` found for reference `&proc_macro::Span` in the current scope
   --> /Users/joshka/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/proc-macro2-1.0.95/src/wrapper.rs:465:36
    |
465 |             Span::Compiler(s) => s.file(),
    |                                    ^^^^ method not found in `&Span`

error[E0599]: no method named `local_file` found for reference `&proc_macro::Span` in the current scope
   --> /Users/joshka/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/proc-macro2-1.0.95/src/wrapper.rs:473:36
    |
473 |             Span::Compiler(s) => s.local_file(),
    |                                    ^^^^^^^^^^ method not found in `&Span`

[mrchantey]

Im getting this again in 1.0.95 with nightly 2025-05-22 even after a cargo clean, haven't yet pinned down the cause.

Edit: found it

# .cargo/config.toml
[target.'cfg(all())']
rustflags = ["--cfg", "procmacro2_semver_exempt"]

let file = tokens.span().file();

Edit 2: I ended up in a rabbit hole of cfgs trying to get it to compile for wasm so instead opted for passing around the vanilla file():

fn source_file(tokens: &proc_macro::TokenStream) -> String {
  tokens
    .clone()
    .into_iter()
    .next()
    .map(|token| token.span().file()).unwrap()