1 files changed, 42 insertions, 0 deletions
diff --git a/src/test/ui-fulldeps/dropck-tarena-unsound-drop.rs b/src/test/ui-fulldeps/dropck-tarena-unsound-drop.rs
new file mode 100644
index 000000000..86485a988
--- /dev/null
+++ b/src/test/ui-fulldeps/dropck-tarena-unsound-drop.rs
@@ -0,0 +1,42 @@
+// Check that an arena (TypedArena) cannot carry elements whose drop
+// methods might access borrowed data of lifetime that does not
+// strictly outlive the arena itself.
+//
+// Compare against run-pass/dropck_tarena_sound_drop.rs, which shows a
+// similar setup, but loosens `f` so that the struct `C<'a>` can be
+// fed a lifetime longer than that of the arena.
+//
+// (Also compare against dropck_tarena_cycle_checked.rs, from which
+// this was reduced to better understand its error message.)
+
+#![feature(rustc_private)]
+
+extern crate rustc_arena;
+
+use rustc_arena::TypedArena;
+
+trait HasId { fn count(&self) -> usize; }
+
+struct CheckId<T:HasId> { v: T }
+
+// In the code below, the impl of HasId for `&'a usize` does not
+// actually access the borrowed data, but the point is that the
+// interface to CheckId does not (and cannot) know that, and therefore
+// when encountering a value V of type CheckId<S>, we must
+// conservatively force the type S to strictly outlive V.
+impl<T:HasId> Drop for CheckId<T> {
+    fn drop(&mut self) {
+        assert!(self.v.count() > 0);
+    }
+}
+
+struct C<'a> { v: CheckId<&'a usize>, }
+
+impl<'a> HasId for &'a usize { fn count(&self) -> usize { 1 } }
+
+fn f<'a>(_arena: &'a TypedArena<C<'a>>) {}
+
+fn main() {
+    let arena: TypedArena<C> = TypedArena::default();
+    f(&arena);
+} //~^ ERROR `arena` does not live long enough