FEAT: Update nodrop for stable needs_drop

.travis.yml

@@ -8,6 +8,7 @@ matrix:
     - rust: stable
       env:
         - NODEFAULT=1
+        - NODROP_FEATURES='use_needs_drop'
     - rust: beta
     - rust: nightly
       env:

nodrop/README.rst

@@ -0,0 +1,50 @@
+
+nodrop
+======
+
+Recent Changes (nodrop)
+-----------------------
+
+-
+
+  - Update for stable ``needs_drop`` (Rust 1.21, was nightly only)
+
+- 0.1.9
+
+  - Fix issue in recent nightly where ``repr(u8)`` did not work. Use
+    a better way to get rid of the enum layout optimization.
+
+- 0.1.8
+  
+  - Add crate feature ``use_union`` that uses untagged unions to implement NoDrop.
+    Finally we have an implementation without hacks, without a runtime flag,
+    and without an actual ``Drop`` impl (which was needed to suppress drop).
+    The crate feature requires nightly and is unstable.
+
+- 0.1.7
+
+  - Remove crate feature ``no_drop_flag``, because it doesn't compile on nightly
+    anymore. Drop flags are gone anyway!
+
+- 0.1.6
+
+  - Add feature std, which you can opt out of to use ``no_std``.
+
+- 0.1.5
+
+  - Added crate feature ``use_needs_drop`` which is a nightly-only
+    optimization, which skips overwriting if the inner value does not need
+    drop.
+
+License
+=======
+
+Dual-licensed to be compatible with the Rust project.
+
+Licensed under the Apache License, Version 2.0
+http://www.apache.org/licenses/LICENSE-2.0 or the MIT license
+http://opensource.org/licenses/MIT, at your
+option. This file may not be copied, modified, or distributed
+except according to those terms.
+
+

nodrop/src/lib.rs

@@ -3,11 +3,10 @@
 //!
 //! - `std`
 //!   - Optional, enabled by default
-//!   - Requires Rust 1.6 *to disable*
 //!   - Use libstd
 //! - `use_needs_drop`
 //!   - Optional
-//!   - Requires nightly channel.
+//!   - Requires Rust 1.21
 //!   - Use `needs_drop` to skip overwriting if not necessary
 //! - `use_union`
 //!   - Optional
@@ -16,8 +15,6 @@
 //!     for example the fact that `NoDrop<T>` never has a destructor anymore.
 //!
 
-#![cfg_attr(feature="use_needs_drop", feature(core_intrinsics))]
-
 #![cfg_attr(not(any(test, feature="std")), no_std)]
 #[cfg(not(any(test, feature="std")))]
 extern crate core as std;
@@ -81,7 +78,7 @@ mod imp {
     #[inline]
     fn needs_drop<T>() -> bool {
         unsafe {
-            ::std::intrinsics::needs_drop::<T>()
+            ::std::mem::needs_drop::<T>()
         }
     }