use std::fs::read_to_string;
use error_stack::{IntoReport, ResultExt};
use error_stack_derive::ErrorStack;
#[derive(ErrorStack, Debug)]
#[error_message(&format!("Error occured with foo ({}, {})", self.bar, self.baz))]
struct FooError {
bar: u8,
baz: u8,
}
fn main() {
let foo = read_to_string("foo.txt")
.report()
.change_context(FooError { bar: 0, baz: 1 });
assert!(foo.is_err());
let err = foo.err().unwrap();
println!("{:?}\n{:?}", err, err.downcast_ref::<FooError>().unwrap())
}