Adding upstream version 1.64.0+dfsg1.upstream/1.64.0+dfsg1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 35 insertions, 0 deletions

diff --git a/src/test/ui/moves/moves-based-on-type-no-recursive-stack-closure.rs b/src/test/ui/moves/moves-based-on-type-no-recursive-stack-closure.rs
new file mode 100644
index 000000000..86fd37e78
--- /dev/null
+++ b/src/test/ui/moves/moves-based-on-type-no-recursive-stack-closure.rs
@@ -0,0 +1,35 @@
+// Tests correct kind-checking of the reason stack closures without the :Copy
+// bound must be noncopyable. For details see
+// https://smallcultfollowing.com/babysteps/blog/2013/04/30/the-case-of-the-recurring-closure/
+
+struct R<'a> {
+    // This struct is needed to create the
+    // otherwise infinite type of a fn that
+    // accepts itself as argument:
+    c: Box<dyn FnMut(&mut R, bool) + 'a>
+}
+
+fn innocent_looking_victim() {
+    let mut x = Some("hello".to_string());
+    conspirator(|f, writer| {
+        if writer {
+            x = None;
+        } else {
+            match x {
+                Some(ref msg) => {
+                    (f.c)(f, true);
+                    //~^ ERROR: cannot borrow `*f` as mutable more than once at a time
+                    println!("{}", msg);
+                },
+                None => panic!("oops"),
+            }
+        }
+    })
+}
+
+fn conspirator<F>(mut f: F) where F: FnMut(&mut R, bool) {
+    let mut r = R {c: Box::new(f)};
+    f(&mut r, false) //~ ERROR borrow of moved value
+}
+
+fn main() { innocent_looking_victim() }