Matthias Krüger
fe5403f517
Rollup merge of #130236 - yaahc:unstable-feature-usage, r=estebank
unstable feature usage metrics
example output
```
test-lib on master [?] is 📦 v0.1.0 via 🦀 v1.80.1
❯ cat src/lib.rs
───────┬───────────────────────────────────────────────────────
│ File: src/lib.rs
───────┼───────────────────────────────────────────────────────
1 │ #![feature(unix_set_mark)]
2 │ pub fn add(left: u64, right: u64) -> u64 {
3 │ left + right
4 │ }
5 │
6 │ #[cfg(test)]
7 │ mod tests {
8 │ use super::*;
9 │
10 │ #[test]
11 │ fn it_works() {
12 │ let result = add(2, 2);
13 │ assert_eq!(result, 4);
14 │ }
15 │ }
───────┴───────────────────────────────────────────────────────
test-lib on master [?] is 📦 v0.1.0 via 🦀 v1.80.1
❯ cargo +stage1 rustc -- -Zmetrics-dir=$PWD/metrics
Compiling test-lib v0.1.0 (/home/yaahc/tmp/test-lib)
Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.08s
test-lib on master [?] is 📦 v0.1.0 via 🦀 v1.80.1
❯ cat metrics/unstable_feature_usage.json
───────┬─────────────────────────────────────────────────────────────────────
│ File: metrics/unstable_feature_usage.json
───────┼─────────────────────────────────────────────────────────────────────
1 │ {"lib_features":[{"symbol":"unix_set_mark"}],"lang_features":[]}
```
related to https://github.com/rust-lang/rust/issues/129485