impl TryFrom<{integer}> for NonZero{integer}

src/libcore/num/mod.rs

@@ -4,7 +4,7 @@
 
 #![stable(feature = "rust1", since = "1.0.0")]
 
-use crate::convert::Infallible;
+use crate::convert::{Infallible, TryFrom};
 use crate::fmt;
 use crate::intrinsics;
 use crate::mem;
@@ -100,6 +100,20 @@ assert_eq!(size_of::<Option<core::num::", stringify!($Ty), ">>(), size_of::<", s
                 }
             }
 
+            #[stable(feature = "try_from_nonzero", since = "1.43.0")]
+            impl TryFrom<$Int> for $Ty {
+                type Error = ();
+                doc_comment! {
+                    concat!(
+"Converts a `", stringify!($Int), "` into an `", stringify!($Ty),
+"` if it is non-zero"),
+                    fn try_from(int: $Int) -> Result<Self, ()> {
+                        Self::new(int).ok_or(())
+                    }
+                }
+
+            }
+
             impl_nonzero_fmt! {
                 #[$stability] (Debug, Display, Binary, Octal, LowerHex, UpperHex) for $Ty
             }

src/test/ui/numeric/numeric-cast-3.rs

@@ -0,0 +1,10 @@
+// make sure that TryInto is implemented for NonZero{integer}
+//
+// check-pass
+use std::num::NonZeroUsize;
+use std::convert::TryInto;
+
+fn main() {
+    let a: NonZeroUsize = 1_usize.try_into().unwrap();
+    let b: NonZeroUsize = 0_usize.try_into().unwrap();
+}