add test for rust-lang#23189

Fixes rust-lang#23189.

Author: euclio

Diff for: src/test/ui/issues/issue-23189.rs

@@ -0,0 +1,15 @@
+// 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.
+
+mod module {}
+
+fn main() {
+    let _ = module { x: 0 }; //~ERROR expected struct
+}

Diff for: src/test/ui/issues/issue-23189.stderr

@@ -0,0 +1,9 @@
+error[E0574]: expected struct, variant or union type, found module `module`
+  --> $DIR/issue-23189.rs:14:13
+   |
+LL |     let _ = module { x: 0 }; //~ERROR expected struct
+   |             ^^^^^^ not a struct, variant or union type
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0574`.