I don't know how common it is in the wild, but deserializing to a function-local type is routinely used by Serde's documentation for examples e.g. https://serde

I don't know how common it is in the wild, but deserializing to a function-local type is routinely used by Serde's documentation for examples e.g. https://serde.rs/deserialize-struct.html https://serde.rs/deserialize-struct.html