22781

src/22781.rs

@@ -0,0 +1,11 @@
+use std::collections::HashMap;
+use std::collections::hash_map::Entry::Vacant;
+
+pub fn main() {
+    type F = Box<Fn(&()) + 'static>;
+    let mut map: HashMap<(), F> = HashMap::new();
+    let x: &mut F = match map.entry(()) {
+        Vacant(_) => unimplemented!(),
+        _ => unimplemented!()
+    };
+}