check_match: Dereference ref x before comparing it and some other type

The arity of `ref x` is always 1, so it needs to be dereferenced before
being compared with some other type whose arity is not 1.

Fixes #23009.

src/test/compile-fail/match-ref-ice.rs

@@ -0,0 +1,24 @@
+// 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.
+
+// The arity of `ref x` is always 1. If the pattern is compared to some non-structural type whose
+// arity is always 0, an ICE occurs.
+//
+// Related issue: #23009
+
+fn main() {
+    let homura = [1, 2, 3];
+
+    match homura {
+        [1, ref madoka, 3] => (),
+        [1, 2, 3] => (), //~ ERROR unreachable pattern
+        [_, _, _] => (),
+    }
+}