Lib.rs

Cargo Features

[dependencies]
parity-bn = { version = "0.4.4", default-features = false, features = ["rustc-serialize"] }

default = rustc-serialize

The rustc-serialize feature is set by default whenever parity-bn is added without default-features = false somewhere in the dependency tree.

Features from optional dependencies

In crates that don't use the dep: syntax, optional dependencies automatically become Cargo features. These features may have been created by mistake, and this functionality [may be removed in the future](https://rust-lang.github.io/rfcs/3491-remove-implicit-features.html).

rustc-serialize default