use std::fmt::Debug; use thiserror_no_std::Error; #[derive(Error, Debug)] #[error("error")] struct Error<'a>(#[from] Inner<'a>); #[derive(Error, Debug)] #[error("{0}")] struct Inner<'a>(&'a str); #[derive(Error, Debug)] enum Enum<'a> { #[error("error")] Foo(#[from] Generic<&'a str>), } #[derive(Error, Debug)] #[error("{0:?}")] struct Generic(T); fn main() -> Result<(), Error<'static>> { Err(Error(Inner("some text"))) }