Cargo Features

codespan has no features set by default.

[dependencies]
codespan = { version = "0.11.1", features = ["serialization"] }
serialization = serde

Enables serialization of codespan-reporting

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 serialization?