Cargo Features

rings-derive has no features set by default.

[dependencies]
rings-derive = { version = "0.7.0", features = ["core_crate", "wasm"] }
core_crate
wasm = wasm-bindgen-macro-support

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.

wasm-bindgen-macro-support wasm?