Proc macro span API redesign: Replace proc_macro::SourceFile by Span::{file, local_file} Simplification/redesign of the unstable proc macro span API, tracked in https://github.com/rust-lang/rust/issues/54725: Before: ```rust impl Span { pub fn line(&self) -> usize; pub fn column(&self) -> usize; pub fn source_file(&self) -> SourceFile; } #[derive(Clone, Debug, PartialEq, Eq)] pub struct SourceFile { .. } impl !Send for SourceFile {} impl !Sync for SourceFile {} impl SourceFile { pub fn path(&self) -> PathBuf; pub fn is_real(&self) -> bool; } ``` After: ```rust impl Span { pub fn line(&self) -> usize; pub fn column(&self) -> usize; pub fn file(&self) -> String; // Mapped file name, for display purposes. pub fn local_file(&self) -> Option<PathBuf>; // Real file name as it exists on disk. } ``` This resolves the last blocker for stabilizing these methods. (Stabilizing will be a separate PR with FCP.)