Cargo Features

option-lock = { version = "0.3.1", default-features = false, features = ["std", "alloc", "bench"] }
default = std

The std feature is set by default whenever option-lock is added without default-features = false somewhere in the dependency tree.

std default = alloc
alloc std
bench = criterion

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.

criterion bench?

Enables criterion ^0.3

should be a dev-dependency, but we only want it when running benches slows down builds the rest of the time