use std::env;
use std::process::Command;
use std::str;
fn main() {
    let compiler = match rustc_version() {
        Some(compiler) => compiler,
        None => return,
    };
    if compiler.nightly {
        println!("cargo:rustc-cfg=backtrace");
    }
}
struct Compiler {
    nightly: bool,
}
fn rustc_version() -> Option<Compiler> {
    let rustc = match env::var_os("RUSTC") {
        Some(rustc) => rustc,
        None => return None,
    };
    let output = match Command::new(rustc).arg("--version").output() {
        Ok(output) => output,
        Err(_) => return None,
    };
    let version = match str::from_utf8(&output.stdout) {
        Ok(version) => version,
        Err(_) => return None,
    };
    Some(Compiler {
        nightly: version.contains("nightly") || version.contains("dev"),
    })
}

use std::backtrace::Backtrace;

use crate::Error;

use crate::Error;

#[cfg(backtrace)]
use std::backtrace::Backtrace;

    #[cfg(backtrace)]

    #[cfg(backtrace)]

use std::backtrace::{Backtrace, BacktraceStatus};

#[cfg(backtrace)]
use std::backtrace::{Backtrace, BacktraceStatus};

        #[cfg(backtrace)]

                #[cfg(backtrace)]

    ///
    /// Backtraces are only available on the nightly channel. Tracking issue:
    /// [rust-lang/rust#53487][tracking].
    ///
    /// [tracking]: https://github.com/rust-lang/rust/issues/53487
    #[cfg(backtrace)]

        let backtrace = self.backtrace();
        match backtrace.status() {
            BacktraceStatus::Captured => {
                writeln!(f, "\n{}", backtrace)?;
            }
            BacktraceStatus::Disabled => {
                writeln!(
                    f,
                    "\nbacktrace disabled; run with RUST_LIB_BACKTRACE=1 environment variable to display a backtrace"
                )?;

        #[cfg(backtrace)]
        {
            let backtrace = self.backtrace();
            match backtrace.status() {
                BacktraceStatus::Captured => {
                    writeln!(f, "\n{}", backtrace)?;
                }
                BacktraceStatus::Disabled => {
                    writeln!(
                        f,
                        "\nbacktrace disabled; run with RUST_LIB_BACKTRACE=1 environment variable to display a backtrace"
                    )?;
                }
                _ => {}

            _ => {}

    #[cfg(backtrace)]

#![feature(backtrace)]

#![cfg_attr(backtrace, feature(backtrace))]