Transitively resolving a crate dependency when its features are required

[mlalic]

Given the following section of a Cargo.toml file:

[dependencies.openssl]
version = "*"
features = ["tlsv1_2", "npn"]
optional = true

[features]
tls = ["openssl/tlsv1_2", "openssl/npn"]

Previously (i.e. in the beta and stable channels), when attempting to build the project with

$ cargo build --features="tls"

it would correctly compile and automatically include the openssl crate (along with the two requested features, of course) as a dependency.

In the nightly channel (cargo 0.4.0-nightly (553b363 2015-08-03) (built 2015-08-02)), however, this isn't the case... It seems that a dependency isn't included as an --extern flag to rustc when its features are requested, without specifying the crate too, which leads to a compilation error once the extern crate openssl is encountered in the source.

Explicitly adding the crate to the feature's dependencies (i.e. tls = ["openssl", "openssl/tlsv1_2", "openssl/npn"]) fixes the issue, but this seems to be a regression, rather than expected behavior?

For an example of a crate affected by this, see this Travis build.