1 files changed, 46 insertions, 0 deletions
diff --git a/src/test/ui/dropck/issue-28498-ugeh-with-passed-to-fn.rs b/src/test/ui/dropck/issue-28498-ugeh-with-passed-to-fn.rs
new file mode 100644
index 000000000..04d0d3203
--- /dev/null
+++ b/src/test/ui/dropck/issue-28498-ugeh-with-passed-to-fn.rs
@@ -0,0 +1,46 @@
+// run-pass
+
+// Demonstrate the use of the unguarded escape hatch with a type param in negative position
+// to assert that destructor will not access any dead data.
+//
+// Compare with ui/span/issue28498-reject-lifetime-param.rs
+
+// Demonstrate that a type param in negative position causes dropck to reject code
+// that might indirectly access previously dropped value.
+//
+// Compare with run-pass/issue28498-ugeh-with-passed-to-fn.rs
+
+#![feature(dropck_eyepatch)]
+
+#[derive(Debug)]
+struct ScribbleOnDrop(String);
+
+impl Drop for ScribbleOnDrop {
+    fn drop(&mut self) {
+        self.0 = format!("DROPPED");
+    }
+}
+
+struct Foo<T>(u32, T, #[allow(unused_tuple_struct_fields)] Box<for <'r> fn(&'r T) -> String>);
+
+unsafe impl<#[may_dangle] T> Drop for Foo<T> {
+    fn drop(&mut self) {
+        // Use of `may_dangle` is sound, because destructor never passes a `self.1`
+        // to the callback (in `self.2`) despite having it available.
+        println!("Dropping Foo({}, _)", self.0);
+    }
+}
+
+fn callback(s: & &ScribbleOnDrop) -> String { format!("{:?}", s) }
+
+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, Box::new(callback));
+    foo1 = Foo(1, &first_dropped, Box::new(callback));
+
+    println!("foo0.1: {:?} foo1.1: {:?}", foo0.1, foo1.1);
+}