From 71187b7e187823f997ab0481a37c2a4b0ccafe7e Mon Sep 17 00:00:00 2001
From: Mazdak Farrokhzad <twingoow@gmail.com>
Date: Sun, 19 Aug 2018 18:49:31 +0200
Subject: [PATCH] Make core::convert::identity a const fn.

---
 src/libcore/convert.rs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/libcore/convert.rs b/src/libcore/convert.rs
index 67cb010c6b41..bfa1bd99bfe4 100644
--- a/src/libcore/convert.rs
+++ b/src/libcore/convert.rs
@@ -104,8 +104,9 @@
 /// assert_eq!(vec![1, 3], filtered);
 /// ```
 #[unstable(feature = "convert_id", issue = "0")]
+#[rustc_const_unstable(feature = "const_convert_id")]
 #[inline]
-pub fn identity<T>(x: T) -> T { x }
+pub const fn identity<T>(x: T) -> T { x }
 
 /// A cheap reference-to-reference conversion. Used to convert a value to a
 /// reference value within generic code.