use failure::{Error, Fail};
use std::any::Any;
use std::fmt;
use std::sync::Mutex;

struct SyncBoxedAny(Mutex<Box<dyn Any + Send>>);

impl SyncBoxedAny {
    pub fn new(inner: Box<dyn Any + Send>) -> Self {
        SyncBoxedAny(Mutex::new(inner))
    }
}

impl fmt::Display for SyncBoxedAny {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        let inner = self.0.lock().unwrap();

        if let Some(x) = inner.downcast_ref::<&str>() {
            x.fmt(f)?;
        } else if let Some(x) = inner.downcast_ref::<String>() {
            x.fmt(f)?;
        }

        Ok(())
    }
}

impl fmt::Debug for SyncBoxedAny {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        let inner = self.0.lock().unwrap();

        if let Some(x) = inner.downcast_ref::<&str>() {
            x.fmt(f)?;
        } else if let Some(x) = inner.downcast_ref::<String>() {
            x.fmt(f)?;
        }

        Ok(())
    }
}

impl Fail for SyncBoxedAny {}

fn main() -> Result<(), Error> {
    let t = std::thread::spawn(|| panic!("message"));

    t.join().map_err(SyncBoxedAny::new)?;

    Ok(())
}