rust/tests/ui/macros/panic-temporaries-2018.rs

56 lines
1.4 KiB
Rust

// check-pass
// edition:2018
#![allow(non_fmt_panics, unreachable_code)]
use std::fmt::{self, Display};
use std::marker::PhantomData;
struct NotSend {
marker: PhantomData<*const u8>,
}
const NOT_SEND: NotSend = NotSend { marker: PhantomData };
impl Display for NotSend {
fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
formatter.write_str("this value does not implement Send")
}
}
async fn f(_: u8) {}
// Exercises this matcher in panic_2015:
// ($fmt:expr, $($arg:tt)+) => $crate::panicking::panic_fmt(...)
async fn panic_fmt() {
// Panic returns `!`, so the await is never reached, and in particular the
// temporaries inside the formatting machinery are not still alive at the
// await point.
let todo = "...";
f(panic!("not yet implemented: {}", todo)).await;
}
// Exercises ("{}", $arg:expr) => $crate::panicking::panic_display(&$arg)
async fn panic_display() {
f(panic!("{}", NOT_SEND)).await;
}
// Exercises ($msg:expr) => $crate::panicking::panic_str($msg)
async fn panic_str() {
f(panic!((NOT_SEND, "...").1)).await;
}
// Exercises ($msg:expr) => $crate::panicking::unreachable_display(&$msg)
async fn unreachable_display() {
f(unreachable!(NOT_SEND)).await;
}
fn require_send(_: impl Send) {}
fn main() {
require_send(panic_fmt());
require_send(panic_display());
require_send(panic_str());
require_send(unreachable_display());
}