Cargo Features

diesel-citext has no features set by default.

[dependencies]
diesel-citext = { version = "0.3.0", features = ["with-actix-web"] }
with-actix-web = actix-web

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.

actix-web with-actix-web?

Enables actix-web ^0.7