Auto merge of #1494 - RalfJung:stack-unwind-top, r=RalfJung

test unwinding past topmost frame of a stack

This tests https://github.com/rust-lang/rust/pull/74984

rust-version

@@ -1 +1 @@
-21867225a74d3b07c2b65e32c67f45197db36896
+dfe1e3b641abbede6230e3931d14f0d43e5b8e54

tests/compile-fail/concurrency/unwind_top_of_stack.rs

@@ -0,0 +1,24 @@
+// ignore-windows: Concurrency on Windows is not supported yet.
+// error-pattern: unwinding past the topmost frame of the stack
+
+//! Unwinding past the top frame of a stack is Undefined Behavior.
+
+#![feature(rustc_private)]
+
+extern crate libc;
+
+use std::{mem, ptr};
+
+extern "C" fn thread_start(_null: *mut libc::c_void) -> *mut libc::c_void {
+    panic!()
+}
+
+fn main() {
+    unsafe {
+        let mut native: libc::pthread_t = mem::zeroed();
+        let attr: libc::pthread_attr_t = mem::zeroed();
+        // assert_eq!(libc::pthread_attr_init(&mut attr), 0); FIXME: this function is not yet implemented.
+        assert_eq!(libc::pthread_create(&mut native, &attr, thread_start, ptr::null_mut()), 0);
+        assert_eq!(libc::pthread_join(native, ptr::null_mut()), 0);
+    }
+}

tests/run-pass/linked-list.rs

@@ -1,4 +1,4 @@
-#![feature(linked_list_extras)]
+#![feature(linked_list_cursors)]
 use std::collections::LinkedList;
 
 fn list_from<T: Clone>(v: &[T]) -> LinkedList<T> {
@@ -9,25 +9,27 @@ fn main() {
     let mut m = list_from(&[0, 2, 4, 6, 8]);
     let len = m.len();
     {
-        let mut it = m.iter_mut();
-        it.insert_next(-2);
+        let mut it = m.cursor_front_mut();
+        it.insert_before(-2);
         loop {
-            match it.next() {
+            match it.current().copied() {
                 None => break,
                 Some(elt) => {
-                    it.insert_next(*elt + 1);
                     match it.peek_next() {
-                        Some(x) => assert_eq!(*x, *elt + 2),
-                        None => assert_eq!(8, *elt),
+                        Some(x) => assert_eq!(*x, elt + 2),
+                        None => assert_eq!(8, elt),
                     }
+                    it.insert_after(elt + 1);
+                    it.move_next(); // Move by 2 to skip the one we inserted.
+                    it.move_next();
                 }
             }
         }
-        it.insert_next(0);
-        it.insert_next(1);
+        it.insert_before(99);
+        it.insert_after(-10);
     }
 
     assert_eq!(m.len(), 3 + len * 2);
     assert_eq!(m.into_iter().collect::<Vec<_>>(),
-               [-2, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1]);
+               [-10, -2, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 99]);
 }