Get "required-features" for target and set them

[little-arhat]

Since it's currently impossible to define additional dependencies for a binary, some projects use workaround with required-features (link). To build such target one need to provide these required features:

cargo build --bin pwm
error: target `pwm` in package `proving_ground` requires the features: `with_device`
Consider enabling them by passing e.g. `--features="with_device"`

flycheck-rust should extract required-features and configure rust-cargo checker to use it.
rust-cargo will have to be extended as well to support --features flag, I guess?

[fmdkdd]

flycheck-rust should extract required-features and configure rust-cargo checker to use it.
rust-cargo will have to be extended as well to support --features flag, I guess?

That how we should handle it, yes.

Please notify us when the required-features is added to nightly.

[little-arhat]

rust-lang/cargo#5902 (comment) -- pull request adding required-features to cargo metadata output has been merged.

[fmdkdd]

That was quick! Do you want to make the PR that extracts the required-features field as well?

[little-arhat]

@fmdkdd here is my attempt: #69. Not sure it's the best solution (I had to fix all the tests), so feel free to fix, abandon or suggest a better way %)