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use std::error::Error as StdError;
use std::io;
use thiserror::Error;
#[derive(Error, Debug)]
#[error("implicit source")]
pub struct ImplicitSource {
source: io::Error,
}
#[derive(Error, Debug)]
#[error("explicit source")]
pub struct ExplicitSource {
source: String,
#[source]
io: io::Error,
}
#[derive(Error, Debug)]
#[error("boxed source")]
pub struct BoxedSource {
#[source]
source: Box<dyn StdError + Send + 'static>,
}
#[test]
fn test_implicit_source() {
let io = io::Error::new(io::ErrorKind::Other, "oh no!");
let error = ImplicitSource { source: io };
error.source().unwrap().downcast_ref::<io::Error>().unwrap();
}
#[test]
fn test_explicit_source() {
let io = io::Error::new(io::ErrorKind::Other, "oh no!");
let error = ExplicitSource {
source: String::new(),
io,
};
error.source().unwrap().downcast_ref::<io::Error>().unwrap();
}
#[test]
fn test_boxed_source() {
let source = Box::new(io::Error::new(io::ErrorKind::Other, "oh no!"));
let error = BoxedSource { source };
error.source().unwrap().downcast_ref::<io::Error>().unwrap();
}
macro_rules! error_from_macro {
($($variants:tt)*) => {
#[derive(Error)]
#[derive(Debug)]
pub enum MacroSource {
$($variants)*
}
}
}
// Test that we generate impls with the proper hygiene
#[rustfmt::skip]
error_from_macro! {
#[error("Something")]
Variant(#[from] io::Error)
}