make &mut !Unpin not dereferenceable

[rust.git] / src / tools / miri / tests / pass / stacked-borrows / stacked-borrows.rs

diff --git a/src/tools/miri/tests/pass/stacked-borrows/stacked-borrows.rs b/src/tools/miri/tests/pass/stacked-borrows/stacked-borrows.rs
index ef6eb346c17b12804cb9c92dd5caaa424d35dbec..8e78efa73c751578c9c3b7849553bb62fcd32e31 100644 (file)
--- a/src/tools/miri/tests/pass/stacked-borrows/stacked-borrows.rs
+++ b/src/tools/miri/tests/pass/stacked-borrows/stacked-borrows.rs
@@ -19,6 +19,7 @@ fn main() {
     array_casts();
     mut_below_shr();
     wide_raw_ptr_in_tuple();
+    not_unpin_not_protected();
 }
 
 // Make sure that reading from an `&mut` does, like reborrowing to `&`,
@@ -219,3 +220,22 @@ fn wide_raw_ptr_in_tuple() {
     // Make sure the fn ptr part of the vtable is still fine.
     r.type_id();
 }
+
+fn not_unpin_not_protected() {
+    // `&mut !Unpin`, at least for now, does not get `noalias` nor `dereferenceable`, so we also
+    // don't add protectors. (We could, but until we have a better idea for where we want to go with
+    // the self-referntial-generator situation, it does not seem worth the potential trouble.)
+    use std::marker::PhantomPinned;
+
+    pub struct NotUnpin(i32, PhantomPinned);
+
+    fn inner(x: &mut NotUnpin, f: fn(&mut NotUnpin)) {
+        // `f` may mutate, but it may not deallocate!
+        f(x)
+    }
+
+    inner(Box::leak(Box::new(NotUnpin(0, PhantomPinned))), |x| {
+        let raw = x as *mut _;
+        drop(unsafe { Box::from_raw(raw) });
+    });
+}