From 7e1cfc8893ecd220c517661a18eb0c94b9e342e3 Mon Sep 17 00:00:00 2001
From: Brendan Zabarauskas <bjzaba@yahoo.com.au>
Date: Fri, 7 Feb 2014 21:18:17 +1100
Subject: [PATCH] Add unimplemented! macro

---
 src/libstd/macros.rs                          |  7 +++++++
 src/test/run-fail/unimplemented-macro-fail.rs | 12 ++++++++++++
 2 files changed, 19 insertions(+)
 create mode 100644 src/test/run-fail/unimplemented-macro-fail.rs

diff --git a/src/libstd/macros.rs b/src/libstd/macros.rs
index cd81d6037e6..e67ac24fcd5 100644
--- a/src/libstd/macros.rs
+++ b/src/libstd/macros.rs
@@ -123,6 +123,13 @@ macro_rules! unreachable (() => (
     fail!("internal error: entered unreachable code");
 ))
 
+/// A standardised placeholder for marking unfinished code. It fails with the
+/// message `"not yet implemented"` when executed.
+#[macro_export]
+macro_rules! unimplemented(
+    () => (fail!("not yet implemented"))
+)
+
 #[macro_export]
 macro_rules! format(($($arg:tt)*) => (
     format_args!(::std::fmt::format, $($arg)*)
diff --git a/src/test/run-fail/unimplemented-macro-fail.rs b/src/test/run-fail/unimplemented-macro-fail.rs
new file mode 100644
index 00000000000..7eff1fee625
--- /dev/null
+++ b/src/test/run-fail/unimplemented-macro-fail.rs
@@ -0,0 +1,12 @@
+// Copyright 2014 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.
+
+// error-pattern:not yet implemented
+fn main() { unimplemented!() }