Const drop selection candidates

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

@@ -23,6 +23,57 @@ const fn b() -> u8 {
 
 const C: u8 = b();
 
+macro_rules! implements_const_drop {
+    ($($exp:expr),*$(,)?) => {
+        $(
+            const _: () = a($exp);
+        )*
+    }
+}
+
+#[allow(dead_code)]
+mod t {
+    pub struct Foo;
+    pub enum Bar { A }
+    pub fn foo() {}
+    pub struct ConstDrop;
+
+    impl const Drop for ConstDrop {
+        fn drop(&mut self) {}
+    }
+
+    pub struct HasConstDrop(pub ConstDrop);
+    pub struct TrivialFields(pub u8, pub i8, pub usize, pub isize);
+}
+
+use t::*;
+
+implements_const_drop! {
+    1u8,
+    2,
+    3.0,
+    Foo,
+    Bar::A,
+    foo,
+    ConstDrop,
+    HasConstDrop(ConstDrop),
+    TrivialFields(1, 2, 3, 4),
+    &1,
+    &1 as *const i32,
+}
+
 fn main() {
+    struct HasDropGlue(Box<u8>);
+    struct HasDropImpl;
+    impl Drop for HasDropImpl {
+        fn drop(&mut self) {
+            println!("not trivial drop");
+        }
+    }
+
+    // These types should pass because ~const in a non-const context should have no effect.
+    a(HasDropGlue(Box::new(0)));
+    a(HasDropImpl);
+
     assert_eq!(C, 2);
 }