1 files changed, 67 insertions, 0 deletions
diff --git a/src/test/ui/rfc-2361-dbg-macro/dbg-macro-expected-behavior.rs b/src/test/ui/rfc-2361-dbg-macro/dbg-macro-expected-behavior.rs
new file mode 100644
index 000000000..04d924a9a
--- /dev/null
+++ b/src/test/ui/rfc-2361-dbg-macro/dbg-macro-expected-behavior.rs
@@ -0,0 +1,67 @@
+// run-pass
+// check-run-results
+
+// Tests ensuring that `dbg!(expr)` has the expected run-time behavior.
+// as well as some compile time properties we expect.
+
+#[derive(Copy, Clone, Debug)]
+struct Unit;
+
+#[derive(Copy, Clone, Debug, PartialEq)]
+struct Point<T> {
+    x: T,
+    y: T,
+}
+
+#[derive(Debug, PartialEq)]
+struct NoCopy(usize);
+
+fn main() {
+    let a: Unit = dbg!(Unit);
+    let _: Unit = dbg!(a);
+    // We can move `a` because it's Copy.
+    drop(a);
+
+    // `Point<T>` will be faithfully formatted according to `{:#?}`.
+    let a = Point { x: 42, y: 24 };
+    let b: Point<u8> = dbg!(Point { x: 42, y: 24 }); // test stringify!(..)
+    let c: Point<u8> = dbg!(b);
+    // Identity conversion:
+    assert_eq!(a, b);
+    assert_eq!(a, c);
+    // We can move `b` because it's Copy.
+    drop(b);
+
+    // Without parameters works as expected.
+    let _: () = dbg!();
+
+    // Test that we can borrow and that successive applications is still identity.
+    let a = NoCopy(1337);
+    let b: &NoCopy = dbg!(dbg!(&a));
+    assert_eq!(&a, b);
+
+    // Test involving lifetimes of temporaries:
+    fn f<'a>(x: &'a u8) -> &'a u8 { x }
+    let a: &u8 = dbg!(f(&42));
+    assert_eq!(a, &42);
+
+    // Test side effects:
+    let mut foo = 41;
+    assert_eq!(7331, dbg!({
+        foo += 1;
+        eprintln!("before");
+        7331
+    }));
+    assert_eq!(foo, 42);
+
+    // Test trailing comma:
+    assert_eq!(("Yeah",), dbg!(("Yeah",)));
+
+    // Test multiple arguments:
+    assert_eq!((1u8, 2u32), dbg!(1,
+                                 2));
+
+    // Test multiple arguments + trailing comma:
+    assert_eq!((1u8, 2u32, "Yeah"), dbg!(1u8, 2u32,
+                                         "Yeah",));
+}