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//! 标准库中的 Panic 支持。

#![stable(feature = "core_panic_info", since = "1.41.0")]

mod location;
mod panic_info;
mod unwind_safe;

use crate::any::Any;

#[stable(feature = "panic_hooks", since = "1.10.0")]
pub use self::location::Location;
#[stable(feature = "panic_hooks", since = "1.10.0")]
pub use self::panic_info::PanicInfo;
#[stable(feature = "catch_unwind", since = "1.9.0")]
pub use self::unwind_safe::{AssertUnwindSafe, RefUnwindSafe, UnwindSafe};

#[doc(hidden)]
#[unstable(feature = "edition_panic", issue = "none", reason = "use panic!() instead")]
#[allow_internal_unstable(core_panic, const_format_args)]
#[rustc_diagnostic_item = "core_panic_2015_macro"]
#[rustc_macro_transparency = "semitransparent"]
pub macro panic_2015 {
    () => (
        $crate::panicking::panic("explicit panic")
    ),
    ($msg:literal $(,)?) => (
        $crate::panicking::panic($msg)
    ),
    // 对于 non_fmt_panic lint，使用 `panic_str` 而不是 `panic_display::<&str>`。
    ($msg:expr $(,)?) => ({
        $crate::panicking::panic_str($msg);
    }),
    // 特殊情况下 const_panic 的单个参数情况。
    ("{}", $arg:expr $(,)?) => ({
        $crate::panicking::panic_display(&$arg);
    }),
    ($fmt:expr, $($arg:tt)+) => ({
        // 分号，以防止在 panic_fmt 调用后调用者认为格式化机器内的临时对象还活着。
        //
        $crate::panicking::panic_fmt($crate::const_format_args!($fmt, $($arg)+));
    }),
}

#[doc(hidden)]
#[unstable(feature = "edition_panic", issue = "none", reason = "use panic!() instead")]
#[allow_internal_unstable(core_panic, const_format_args)]
#[rustc_diagnostic_item = "core_panic_2021_macro"]
#[rustc_macro_transparency = "semitransparent"]
pub macro panic_2021 {
    () => (
        $crate::panicking::panic("explicit panic")
    ),
    // 特殊情况下 const_panic 的单个参数情况。
    ("{}", $arg:expr $(,)?) => ({
        $crate::panicking::panic_display(&$arg);
    }),
    ($($t:tt)+) => ({
        // 分号，以防止在 panic_fmt 调用后调用者认为格式化机器内的临时对象还活着。
        //
        $crate::panicking::panic_fmt($crate::const_format_args!($($t)+));
    }),
}

#[doc(hidden)]
#[unstable(feature = "edition_panic", issue = "none", reason = "use unreachable!() instead")]
#[allow_internal_unstable(core_panic)]
#[rustc_diagnostic_item = "unreachable_2015_macro"]
#[rustc_macro_transparency = "semitransparent"]
pub macro unreachable_2015 {
    () => (
        $crate::panicking::panic("internal error: entered unreachable code")
    ),
    // 将 `unreachable_display` 用于 non_fmt_panic lint。
    // NOTE: 消息 (`内部错误...`) 直接嵌入到 unreachable_display
    ($msg:expr $(,)?) => ({
        $crate::panicking::unreachable_display(&$msg);
    }),
    ($fmt:expr, $($arg:tt)*) => (
        $crate::panic!($crate::concat!("internal error: entered unreachable code: ", $fmt), $($arg)*)
    ),
}

#[doc(hidden)]
#[unstable(feature = "edition_panic", issue = "none", reason = "use unreachable!() instead")]
#[allow_internal_unstable(core_panic)]
#[rustc_macro_transparency = "semitransparent"]
pub macro unreachable_2021 {
    () => (
        $crate::panicking::panic("internal error: entered unreachable code")
    ),
    ($($t:tt)+) => (
        $crate::panic!("internal error: entered unreachable code: {}", $crate::format_args!($($t)+))
    ),
}

/// std 使用内部 trait 将数据从 std 传递到 `panic_unwind` 和其他 panic 运行时。
/// 不打算在任何时候稳定下来，请勿使用。
///
#[unstable(feature = "std_internals", issue = "none")]
#[doc(hidden)]
pub unsafe trait BoxMeUp {
    /// 拥有内容的全部所有权。
    /// 返回类型实际上是 `Box<dyn Any + Send>`，但我们不能在核心中使用 `Box`。
    ///
    /// 调用此方法后，`self` 中仅保留一些虚拟默认值。
    /// 两次调用此方法，或在调用此方法后调用 `get`，都是错误的。
    ///
    /// 之所以借用该参数是因为 panic 运行时 (`__rust_start_panic`) 仅得到借用的 `dyn BoxMeUp`。
    ///
    fn take_box(&mut self) -> *mut (dyn Any + Send);

    /// 只是借用内容。
    fn get(&mut self) -> &(dyn Any + Send);
}