One of my side-projects is named Atelier and is a Rust implementation of the AWS Smithy IDL framework. AWS Smithy is a framework around a language and runtime neutral IDL for service definition. It consists of a semantic model, a native IDL representation, and a mapping to JSON.
The goal of Atelier is to replicate these core components of Smithy in Rust but also to experiment in alternate integrations such as the representation of the semantic model in RDF. This could provide the basis for Rust code generation from a Smithy model and other tooling opportunities. This has been a major effort for myself as well as another ex-Amazon PE with full support from the awesome Smithy team.
So far Atelier has been used internally for some experimental tooling; hopefully, something we can also open up on Github some day.