Anouncements: rust-project.json changes

[matklad]

This is the issue to announce upcoming changes to rust-projec.json file format, you want to subscribe to it if you use rust-analyzer with non-cargo build system.

[benbrittain]

Thank you for doing this @matklad !

cc/ @dtolnay

[matklad]

#4860 makes sure that relative paths in project.json are interpereted relative to the config file, and not to the cwd of the binary.

[woody77]

Thanks!

[matklad]

#4864 adds target field to crates in rust-project.json

[matklad]

A bunch of changes mostly related to the new VFS impl

https://github.com/rust-analyzer/rust-analyzer/pull/5473/files#diff-157b45b85c30cb1df5929e3ac91ae86eR274-R329

[matklad]

#5884 adds a shortcut for defining sysroot.

[matklad]

#6297 adds an optional display_name to crates in project.json. It is used for UI purposes, but also in a nasty hack to make cfg_if work in stdlib.

[woody77]

Can you give some info on how it's used to make cfg_if work in stdlib (that didn't seem to jump out at me from reading through the changes).

[matklad]

Can you give some info on how it's used to make cfg_if work in stdlib

Oups, missed that one. If there's a crate anywhere in the crate graph with cfg_if name (not sure what's the right hyphen), then it'll be used as std dep.

For cargo, if any crates.io crate depend on (crates.io) cfg-if, that also gets used by sysroot.

[matklad]

#9752 adds support for analysis of proc-macro crates.

That is, even before #9752 it was possible to use proc macros by specifying proc_macro_dylib_path. #9752 is orthogonal to that -- it allows adding proc_macro dep from sysroot to proc macro crates themselves.