Impl From<NonZero<T>> for T

src/libcore/num/mod.rs

@@ -93,6 +93,13 @@ assert_eq!(size_of::<Option<std::num::", stringify!($Ty), ">>(), size_of::<", st
 
             }
 
+            #[stable(feature = "nonzero", since = "1.28.0")]
+            impl From<$Ty> for $Int {
+                fn from(nonzero: $Ty) -> Self {
+                    nonzero.0 .0
+                }
+            }
+
             impl_nonzero_fmt! {
                 (Debug, Display, Binary, Octal, LowerHex, UpperHex) for $Ty
             }

src/test/run-pass/nonzero.rs

@@ -0,0 +1,16 @@
+// 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.
+
+fn main() {
+    use std::num::NonZeroU32;
+    let nz = NonZeroU32::new(5).unwrap();
+    let num: u32 = nz.into();
+}
+