Add passing test for Add on generic struct

src/test/ui/rfc-2632-const-trait-impl/generic-bound.rs

@@ -0,0 +1,32 @@
+// run-pass
+
+#![allow(incomplete_features)]
+#![feature(const_trait_impl)]
+#![feature(const_fn)]
+
+use std::marker::PhantomData;
+
+struct S<T>(PhantomData<T>);
+
+impl<T> Copy for S<T> {}
+impl<T> Clone for S<T> {
+    fn clone(&self) -> Self {
+        S(PhantomData)
+    }
+}
+
+impl<T> const std::ops::Add for S<T> {
+    type Output = Self;
+
+    fn add(self, _: Self) -> Self {
+        S(std::marker::PhantomData)
+    }
+}
+
+const fn twice<T: std::ops::Add>(arg: S<T>) -> S<T> {
+    arg + arg
+}
+
+fn main() {
+    let _ = twice(S(PhantomData::<i32>));
+}