Auto merge of #52314 - varkor:issue-52023, r=oli-obk

Fix ICE when using a pointer cast as array size

Fixes #52023. I'm not sure if the comment https://github.com/rust-lang/rust/issues/52023#issuecomment-402402392 suggested we also emit `E0080`, but just emitting `E0018` seems reasonable for now.

r? @oli-obk

src/test/ui/issue-52023-array-size-pointer-cast.rs

@@ -0,0 +1,13 @@
+// Copyright 2018 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() {
+    let _ = [0; (&0 as *const i32) as usize]; //~ ERROR raw pointers cannot be cast
+}

src/test/ui/issue-52023-array-size-pointer-cast.stderr

@@ -0,0 +1,9 @@
+error[E0018]: raw pointers cannot be cast to integers in constants
+  --> $DIR/issue-52023-array-size-pointer-cast.rs:12:17
+   |
+LL |     let _ = [0; (&0 as *const i32) as usize]; //~ ERROR raw pointers cannot be cast
+   |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0018`.