False compiler warning?

I am on rust 1.32.0 writing code for 2018 edition. I am bringing in custom derive macros from serde_yaml and using them to auto derive (Serialize and Deserialize). This works, however, I am getting an unused imports warning. Where does one file bugs such as these?

This would probably be a bug in the derive code and should be reported to serde presumably.

Serde_yaml doesn't provide any derive macros, those come from serde_derive or serde. What are you importing from serde_yaml?

my bad. I meant serde_derive::{Serialize, Deserialize}

I think it was a vscode bug. Went away with a rebuild of the project.