Use a wrapper struct to enable closures

1 files changed, 25 insertions, 0 deletions

diff --git a/tests/ui/example_opaque_vs_drop.rs b/tests/ui/example_opaque_vs_drop.rs
new file mode 100644
index 0000000..b2c1809
--- /dev/null
+++ b/tests/ui/example_opaque_vs_drop.rs
@@ -0,0 +1,25 @@
+//! Example of how `opaque!` prevents unsound `Drop`.
+//!
+//! NOTE: Also in trait `Opaque` documentation. Keep 'em in sync.
+
+use std::cell::Cell;
+use selfref::opaque;
+
+struct Foo<'a> {
+    foo: Cell<Option<&'a Foo<'a>>>,
+}
+
+impl<'a> Drop for Foo<'a> {
+    fn drop(&mut self) {
+    }
+}
+
+struct FooKey;
+opaque! {
+    impl Opaque for FooKey {
+        type Kind<'a> = Foo<'a>;
+    }
+}
+
+fn main() {
+}