Merging upstream version 1.68.2+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 41 insertions, 0 deletions

diff --git a/tests/ui/dropck/issue-28498-ugeh-with-trait-bound.rs b/tests/ui/dropck/issue-28498-ugeh-with-trait-bound.rs
new file mode 100644
index 000000000..61d11cf38
--- /dev/null
+++ b/tests/ui/dropck/issue-28498-ugeh-with-trait-bound.rs
@@ -0,0 +1,41 @@
+// run-pass
+
+// Demonstrate the use of the unguarded escape hatch with a trait bound
+// to assert that destructor will not access any dead data.
+//
+// Compare with ui/span/issue28498-reject-trait-bound.rs
+
+#![feature(dropck_eyepatch)]
+
+use std::fmt;
+
+#[derive(Debug)]
+struct ScribbleOnDrop(String);
+
+impl Drop for ScribbleOnDrop {
+    fn drop(&mut self) {
+        self.0 = format!("DROPPED");
+    }
+}
+
+struct Foo<T: fmt::Debug>(u32, T);
+
+unsafe impl<#[may_dangle] T: fmt::Debug> Drop for Foo<T> {
+    fn drop(&mut self) {
+        // Use of `may_dangle` is sound, because destructor never accesses
+        // the `Debug::fmt` method of `T`, despite having it available.
+        println!("Dropping Foo({}, _)", self.0);
+    }
+}
+
+fn main() {
+    let (last_dropped, foo0);
+    let (foo1, first_dropped);
+
+    last_dropped = ScribbleOnDrop(format!("last"));
+    first_dropped = ScribbleOnDrop(format!("first"));
+    foo0 = Foo(0, &last_dropped);
+    foo1 = Foo(1, &first_dropped);
+
+    println!("foo0.1: {:?} foo1.1: {:?}", foo0.1, foo1.1);
+}