Auto merge of #30557 - sfackler:panic-propagate, r=aturon

See rust-lang/rfcs#1413.

r? @alexcrichton

2 files changed, 28 insertions, 1 deletions

diff --git a/src/libstd/panic.rs b/src/libstd/panic.rs
index 76d9c194b45..8c0a785a102 100644
--- a/src/libstd/panic.rs
+++ b/src/libstd/panic.rs
@@ -13,6 +13,8 @@
 #![unstable(feature = "std_panic", reason = "awaiting feedback",
             issue = "27719")]
 
+use any::Any;
+use boxed::Box;
 use cell::UnsafeCell;
 use ops::{Deref, DerefMut};
 use ptr::{Unique, Shared};
@@ -259,3 +261,28 @@ pub fn recover<F: FnOnce() -> R + RecoverSafe, R>(f: F) -> Result<R> {
     }
     Ok(result.unwrap())
 }
+
+/// Triggers a panic without invoking the panic handler.
+///
+/// This is designed to be used in conjunction with `recover` to, for example,
+/// carry a panic across a layer of C code.
+///
+/// # Examples
+///
+/// ```should_panic
+/// #![feature(std_panic, recover, panic_propagate)]
+///
+/// use std::panic;
+///
+/// let result = panic::recover(|| {
+///     panic!("oh no!");
+/// });
+///
+/// if let Err(err) = result {
+///     panic::propagate(err);
+/// }
+/// ```
+#[unstable(feature = "panic_propagate", reason = "awaiting feedback", issue = "30752")]
+pub fn propagate(payload: Box<Any + Send>) -> ! {
+    unwind::rust_panic(payload)
+}
diff --git a/src/libstd/sys/common/unwind/mod.rs b/src/libstd/sys/common/unwind/mod.rs
index 0f10e727461..666b2ed72ad 100644
--- a/src/libstd/sys/common/unwind/mod.rs
+++ b/src/libstd/sys/common/unwind/mod.rs
@@ -172,7 +172,7 @@ pub fn panicking() -> bool {
 #[inline(never)]
 #[no_mangle]
 #[allow(private_no_mangle_fns)]
-fn rust_panic(cause: Box<Any + Send + 'static>) -> ! {
+pub fn rust_panic(cause: Box<Any + Send + 'static>) -> ! {
     unsafe {
         imp::panic(cause)
     }