Add regression test for #24446

Closes #24446.

src/test/compile-fail/issue-24446.rs

@@ -0,0 +1,20 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+fn main() {
+    static foo: Fn() -> u32 = || -> u32 {
+        //~^ ERROR: mismatched types:
+        //~| expected `core::ops::Fn() -> u32`,
+        //~| found closure
+        //~| (expected trait core::ops::Fn,
+        //~| found closure)
+        0
+    };
+}