1 files changed, 32 insertions, 0 deletions
diff --git a/src/test/ui/functional-struct-update/functional-struct-update-respects-privacy.rs b/src/test/ui/functional-struct-update/functional-struct-update-respects-privacy.rs
new file mode 100644
index 000000000..500633edf
--- /dev/null
+++ b/src/test/ui/functional-struct-update/functional-struct-update-respects-privacy.rs
@@ -0,0 +1,32 @@
+// RFC 736 (and Issue 21407): functional struct update should respect privacy.
+
+// The `foo` module attempts to maintains an invariant that each `S`
+// has a unique `u64` id.
+use self::foo::S;
+mod foo {
+    use std::cell::{UnsafeCell};
+
+    static mut COUNT : UnsafeCell<u64> = UnsafeCell::new(1);
+
+    pub struct S { pub a: u8, pub b: String, secret_uid: u64 }
+
+    pub fn make_secrets(a: u8, b: String) -> S {
+        let val = unsafe { let p = COUNT.get(); let val = *p; *p = val + 1; val };
+        println!("creating {}, uid {}", b, val);
+        S { a: a, b: b, secret_uid: val }
+    }
+
+    impl Drop for S {
+        fn drop(&mut self) {
+            println!("dropping {}, uid {}", self.b, self.secret_uid);
+        }
+    }
+}
+
+fn main() {
+    let s_1 = foo::make_secrets(3, format!("ess one"));
+    let s_2 = foo::S { b: format!("ess two"), ..s_1 }; // FRU ...
+    //~^ ERROR field `secret_uid` of struct `S` is private
+    println!("main forged an S named: {}", s_2.b);
+    // at end of scope, ... both s_1 *and* s_2 get dropped.  Boom!
+}