Cargo Features

RangeMap has no features set by default.

[dependencies]
rangemap = { version = "1.5.1", features = ["serde1", "nightly", "const_fn"] }
serde1 = serde
nightly

So we can run doc tests from "README.md".

const_fn

Enables RangeMap::new(), RangeInclusiveMap::new(), RangeSet::new(), and RangeInclusiveSet::new() to be const functions. Requires a nightly compiler because const_btree_new is an unstable feature, but is soon to be stabilized: https://github.com/rust-lang/rust/issues/71835

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.

serde serde1?