Naming of proc_macro::Span::local_file()

[m-ou-se]

This is about #54725's open question on the name of local_file:

The unstable API is now:

impl Span {
    /// The path to the source file in which this span occurs, for display purposes.
    ///
    /// This might not correspond to a valid file system path.
    /// 
    /// It might be remapped (e.g. `/src/lib.rs`) , or might be an artificial path (e.g. `"<command line>"`).
    pub fn file(&self) -> String;

    /// The path to the source file in which this span occurs on the local file system.
    ///
    /// This is unaffected by path remapping.
    ///
    /// This path should not be embedded in the output of the macro; prefer `file()` instead.
    pub fn local_file(&self) -> Option<PathBuf>;
}

The question is: What should we name local_file?

Keeping it as local_file is an option, but maybe we can think of something better.

[m-ou-se]

FWIW, rustc internally uses "LocalPath" for this:

rust/compiler/rustc_span/src/lib.rs

Line 196 in 9857284

local_path: Option<PathBuf>,

[m-ou-se]

I personally think local_file is good enough.

[m-ou-se]

@rust-lang/libs-api If you have an opinion/ideas, please speak up!

[BurntSushi]

I weakly prefer path/local_path, but I don't feel strongly.

[m-ou-se]

We discussed this last week in the libs-api meeting. We didn't have any better ideas than local_file.

I'll make a PR to stabilize it under that name and propose an FCP.