Proc macro span API redesign: Replace proc_macro::SourceFile by Span::{file, local_file}

[m-ou-se]

Simplification/redesign of the unstable proc macro span API, tracked in #54725:

Before:

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:

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.)

[m-ou-se]

r? @dtolnay

[Veykril]

For rust-analyzer's proc-macro server those two functions can be just stubbed out with None / String::new(), they aren't implementable right now

[dtolnay]

Thank you! This is great.

[dtolnay]

@bors r+

[bors]

📌 Commit 5113f5e has been approved by dtolnay

It is now in the queue for this repository.

[jhpratt]

@bors r-

likely cause of #139761 (comment)

[m-ou-se]

@rust-lang/rust-analyzer One of the rust-analyzer tests is panicking. See logs. Please advise.

[m-ou-se]

Looks like

./x.py test src/tools/rust-analyzer --stage=2

works fine, but

./x.py test src/tools/rust-analyzer --stage=1

fails, resulting in those panics.

It looks like --stage=1 rust-analyzer uses the proc_macro client from the checkout, but the proc_macro server from beta (stage 0). 😬

I don't think we can properly support stage 1 r-a, unless we assume that proc_macro never changes its unstable private interface..

[m-ou-se]

I've disabled two r-a tests in stage 1 with #[cfg(not(bootstrap))]. This needs a proper fix though. Perhaps we should not support --stage=1 r-a at all.

[m-ou-se]

@bors r=dtolnay

[bors]

📌 Commit 1f3199c has been approved by dtolnay

It is now in the queue for this repository.