From 2c3c8822e057c4ed972d0ce736b089c11afeaac3 Mon Sep 17 00:00:00 2001
From: Michael Bradshaw <mjbshaw@google.com>
Date: Wed, 26 Sep 2018 14:46:14 -0700
Subject: [PATCH] Gate const core::mem::needs_drop behind const_needs_drop

---
 src/libcore/mem.rs                    | 1 +
 src/test/run-pass/const-needs_drop.rs | 2 ++
 2 files changed, 3 insertions(+)

diff --git a/src/libcore/mem.rs b/src/libcore/mem.rs
index 13c0b89f5df..dd3775bff5e 100644
--- a/src/libcore/mem.rs
+++ b/src/libcore/mem.rs
@@ -483,6 +483,7 @@ pub fn align_of_val<T: ?Sized>(val: &T) -> usize {
 /// ```
 #[inline]
 #[stable(feature = "needs_drop", since = "1.21.0")]
+#[rustc_const_unstable(feature = "const_needs_drop")]
 #[cfg(not(stage0))]
 pub const fn needs_drop<T>() -> bool {
     intrinsics::needs_drop::<T>()
diff --git a/src/test/run-pass/const-needs_drop.rs b/src/test/run-pass/const-needs_drop.rs
index 2e381593b77..edf3a6b3dcd 100644
--- a/src/test/run-pass/const-needs_drop.rs
+++ b/src/test/run-pass/const-needs_drop.rs
@@ -8,6 +8,8 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+#![feature(const_needs_drop)]
+
 use std::mem;
 
 struct Trivial(u8, f32);