serde-yaml | Strongly typed YAML library for Rust | YAML Processing library

Your problem is that serde_yaml::from_str(&s) does not return a Dependency struct directly as you expect, but a Result struct.

Result structs are rust's way of error handling. Results are either Ok(value) or an Err and you need to check which one it is. Typically in a match expression. In your case the parsed dependency is wrapped in Ok(project) if parsing the string is successful.

I could get your code to compile with the following match expression:

You can't use non-object-safe traits with dynamic dispatch; the object safety rules are specifically about the things that prevent dynamic dispatch.

There are sometimes workarounds for specific scenarios. They are usually complex. But for serde specifically, there's the erased_serde crate, because you're not the first one with this problem.