Add tests for rust-lang#34784

Closes rust-lang#34784

src/test/compile-fail/issue-34784.rs

@@ -0,0 +1,20 @@
+// 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.
+
+const C: *const [u8; 4] = b"abcd";
+
+fn main() {
+    match C {
+        C => {}
+        //~^ ERROR this expression will panic at runtime
+        _ => {}
+    }
+}
+

src/test/run-pass/issue-34784.rs

@@ -0,0 +1,21 @@
+// 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.
+
+const C: *const u8 = &0;
+
+fn foo(x: *const u8) {
+    match x {
+        C => {}
+        _ => {}
+    }
+}
+
+fn main() {}
+