1 files changed, 31 insertions, 0 deletions
diff --git a/src/test/ui/type-alias-impl-trait/constrain_inputs_unsound.rs b/src/test/ui/type-alias-impl-trait/constrain_inputs_unsound.rs
new file mode 100644
index 000000000..3bae0f173
--- /dev/null
+++ b/src/test/ui/type-alias-impl-trait/constrain_inputs_unsound.rs
@@ -0,0 +1,31 @@
+#![feature(type_alias_impl_trait)]
+
+trait Static: 'static {}
+impl Static for () {}
+
+type Gal<T> = impl Static;
+fn _defining<T>() -> Gal<T> {}
+
+trait Callable<Arg> { type Output; }
+
+/// We can infer `<C as Callable<Arg>>::Output: 'static`,
+/// because we know `C: 'static` and `Arg: 'static`,
+fn box_str<C, Arg>(s: C::Output) -> Box<dyn AsRef<str> + 'static>
+where
+    Arg: Static,
+    C: ?Sized + Callable<Arg> + 'static,
+    C::Output: AsRef<str>,
+{
+    Box::new(s)
+}
+
+fn extend_lifetime(s: &str) -> Box<dyn AsRef<str> + 'static> {
+    type MalformedTy = dyn for<'a> Callable<Gal<&'a ()>, Output = &'a str>;
+    //~^ ERROR binding for associated type `Output` references lifetime `'a`
+    box_str::<MalformedTy, _>(s)
+}
+
+fn main() {
+    let extended = extend_lifetime(&String::from("hello"));
+    println!("{}", extended.as_ref().as_ref());
+}