1 files changed, 28 insertions, 0 deletions
diff --git a/tests/ui/impl-trait/alias-liveness/tait-hidden-erased-unsoundness.rs b/tests/ui/impl-trait/alias-liveness/tait-hidden-erased-unsoundness.rs
new file mode 100644
index 000000000..40efd941e
--- /dev/null
+++ b/tests/ui/impl-trait/alias-liveness/tait-hidden-erased-unsoundness.rs
@@ -0,0 +1,28 @@
+// This test should never pass!
+
+#![feature(type_alias_impl_trait)]
+
+trait Captures<'a> {}
+impl<T> Captures<'_> for T {}
+
+struct MyTy<'a, 'b>(Option<*mut &'a &'b ()>);
+unsafe impl Send for MyTy<'_, 'static> {}
+
+fn step1<'a, 'b: 'a>() -> impl Sized + Captures<'b> + 'a {
+    MyTy::<'a, 'b>(None)
+}
+
+mod tait {
+    type Tait<'a> = impl Sized + 'a;
+    pub(super) fn step2<'a, 'b: 'a>() -> Tait<'a> {
+        super::step1::<'a, 'b>()
+        //~^ ERROR hidden type for `Tait<'a>` captures lifetime that does not appear in bounds
+    }
+}
+
+fn step3<'a, 'b: 'a>() -> impl Send + 'a {
+    tait::step2::<'a, 'b>()
+    // This should not be Send unless `'b: 'static`
+}
+
+fn main() {}