Ed Page ece031c338
More helpful error for invalid cargo-features = [] (#15781)
The error message for unknown values of `cargo-features` was unhelpful:

```text
Caused by:
  unknown cargo feature `build-dir`
```

I've made it more explanatory, and matching the style of the other
errors:

```text
Caused by:
  feature `build-dir` is not a valid unstable feature for Cargo.toml

  This feature can be enabled via -Zbuild-dir or the `[unstable]` section in config.toml.
  See https://doc.rust-lang.org/cargo/reference/unstable.html for more information.
```
2025-08-12 18:29:21 +00:00
..