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use error::Error;
#[cfg(target_arch = "wasm32")]
mod exit {
pub const SUCCESS: i32 = 0;
pub const FAILURE: i32 = 1;
}
#[cfg(not(target_arch = "wasm32"))]
mod exit {
use libc;
pub const SUCCESS: i32 = libc::EXIT_SUCCESS;
pub const FAILURE: i32 = libc::EXIT_FAILURE;
}
#[cfg_attr(not(test), lang = "termination")]
#[unstable(feature = "termination_trait", issue = "43301")]
#[rustc_on_unimplemented =
"`main` can only return types that implement {Termination}, not `{Self}`"]
pub trait Termination {
fn report(self) -> i32;
}
#[unstable(feature = "termination_trait", issue = "43301")]
impl Termination for () {
fn report(self) -> i32 { exit::SUCCESS }
}
#[unstable(feature = "termination_trait", issue = "43301")]
impl<T: Termination, E: Error> Termination for Result<T, E> {
fn report(self) -> i32 {
match self {
Ok(val) => val.report(),
Err(err) => {
print_error(err);
exit::FAILURE
}
}
}
}
#[unstable(feature = "termination_trait", issue = "43301")]
fn print_error<E: Error>(err: E) {
eprintln!("Error: {}", err.description());
if let Some(ref err) = err.cause() {
eprintln!("Caused by: {}", err.description());
}
}
#[unstable(feature = "termination_trait", issue = "43301")]
impl Termination for ! {
fn report(self) -> i32 { unreachable!(); }
}
#[unstable(feature = "termination_trait", issue = "43301")]
impl Termination for bool {
fn report(self) -> i32 {
if self { exit::SUCCESS } else { exit::FAILURE }
}
}
#[unstable(feature = "termination_trait", issue = "43301")]
impl Termination for i32 {
fn report(self) -> i32 {
self
}
}