use thiserror_no_std::Error; pub use std::error::Error; #[test] fn test_unused_qualifications() { #![deny(unused_qualifications)] // Expansion of derive(Error) macro can't know whether something like // std::error::Error is already imported in the caller's scope so it must // suppress unused_qualifications. #[derive(Debug, Error)] #[error("...")] pub struct MyError; let _: MyError; }