Add regression tests

Author: oli-obk

tests/ui/any/try_as_dyn_generic_impl.rs

@@ -0,0 +1,34 @@
+#![feature(try_as_dyn)]
+//@ check-pass
+
+use std::any::try_as_dyn;
+
+struct Thing<T>(T);
+trait Trait {}
+impl<T> Trait for Thing<T> {}
+
+const _: () = {
+    let thing = Thing(1);
+    assert!(try_as_dyn::<_, dyn Trait>(&thing).is_none());
+};
+
+struct Thing2<T>(T);
+impl<T: std::fmt::Debug> Trait for Thing2<T> {}
+
+const _: () = {
+    let thing = Thing2(1);
+    assert!(try_as_dyn::<_, dyn Trait>(&thing).is_none());
+};
+
+trait Trait2 {}
+impl<'a, 'b> Trait2 for &'a &'b () {}
+
+struct Thing3<T>(T);
+impl<T: Trait2> Trait for Thing3<T> {}
+
+const _: () = {
+    let thing = Thing3(&&());
+    assert!(try_as_dyn::<_, dyn Trait2>(&thing).is_none());
+};
+
+fn main() {}