Move static_assert! into librustc_data_structures.

This means it can be used by more crates.

src/librustc/macros.rs

@@ -62,16 +62,6 @@ macro_rules! span_bug {
     })
 }
 
-#[macro_export]
-macro_rules! static_assert {
-    ($name:ident: $test:expr) => {
-        // Use the bool to access an array such that if the bool is false, the access
-        // is out-of-bounds.
-        #[allow(dead_code)]
-        static $name: () = [()][!$test as usize];
-    }
-}
-
 #[macro_export]
 macro_rules! __impl_stable_hash_field {
     ($field:ident, $ctx:expr, $hasher:expr) => ($field.hash_stable($ctx, $hasher));

src/librustc_data_structures/lib.rs

@@ -57,6 +57,7 @@ extern crate rustc_cratesio_shim;
 
 pub use rustc_serialize::hex::ToHex;
 
+pub mod macros;
 pub mod svh;
 pub mod base_n;
 pub mod bit_set;

src/librustc_data_structures/macros.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.
+
+/// A simple static assertion macro. The first argument should be a unique
+/// ALL_CAPS identifier that describes the condition.
+#[macro_export]
+macro_rules! static_assert {
+    ($name:ident: $test:expr) => {
+        // Use the bool to access an array such that if the bool is false, the access
+        // is out-of-bounds.
+        #[allow(dead_code)]
+        static $name: () = [()][!$test as usize];
+    }
+}