From 3f671bc94450aff38d7fcd9243327a20cb553ee0 Mon Sep 17 00:00:00 2001
From: Ohad Ravid <ohad.rv@gmail.com>
Date: Mon, 16 Nov 2020 15:38:22 +0200
Subject: [PATCH 1/3] Added `impl Div<NonZeroU{0}> for u{0}` which cannot panic

---
 library/core/src/num/nonzero.rs | 30 +++++++++++++++++++++++++++++-
 library/core/tests/nonzero.rs   |  8 ++++++++
 2 files changed, 37 insertions(+), 1 deletion(-)

diff --git a/library/core/src/num/nonzero.rs b/library/core/src/num/nonzero.rs
index 716b4a90e5ec2..3355fb64ecfd1 100644
--- a/library/core/src/num/nonzero.rs
+++ b/library/core/src/num/nonzero.rs
@@ -1,7 +1,7 @@
 //! Definitions of integer that is known not to equal zero.
 
 use crate::fmt;
-use crate::ops::{BitOr, BitOrAssign};
+use crate::ops::{BitOr, BitOrAssign, Div};
 use crate::str::FromStr;
 
 use super::from_str_radix;
@@ -263,3 +263,31 @@ nonzero_leading_trailing_zeros! {
     NonZeroI128(u128), -1i128;
     NonZeroIsize(usize), -1isize;
 }
+
+macro_rules! nonzero_integers_div {
+    ( $( $Ty: ident($Int: ty); )+ ) => {
+        $(
+            #[stable(feature = "nonzero_div", since = "1.50.0")]
+            impl Div<$Ty> for $Int {
+                type Output = $Int;
+                /// This operation rounds towards zero,
+                /// truncating any fractional part of the exact result, and cannot panic.
+                #[inline]
+                fn div(self, other: $Ty) -> $Int {
+                    // SAFETY: div by zero is checked because `other` is a nonzero,
+                    // and MIN/-1 is checked because `self` is an unsigned int.
+                    unsafe { crate::intrinsics::unchecked_div(self, other.get()) }
+                }
+            }
+        )+
+    }
+}
+
+nonzero_integers_div! {
+    NonZeroU8(u8);
+    NonZeroU16(u16);
+    NonZeroU32(u32);
+    NonZeroU64(u64);
+    NonZeroU128(u128);
+    NonZeroUsize(usize);
+}
diff --git a/library/core/tests/nonzero.rs b/library/core/tests/nonzero.rs
index b66c482c5e5e3..6ec3a04adc080 100644
--- a/library/core/tests/nonzero.rs
+++ b/library/core/tests/nonzero.rs
@@ -312,3 +312,11 @@ fn nonzero_trailing_zeros() {
     const TRAILING_ZEROS: u32 = NonZeroU16::new(1 << 2).unwrap().trailing_zeros();
     assert_eq!(TRAILING_ZEROS, 2);
 }
+
+#[test]
+fn test_nonzero_uint_div() {
+    let nz = NonZeroU32::new(1).unwrap();
+
+    let x: u32 = 42u32 / nz;
+    assert_eq!(x, 42u32);
+}

From 1e9e30dc404edaec5bf5ef9c1d88157a883da374 Mon Sep 17 00:00:00 2001
From: Ohad Ravid <ohad.rv@gmail.com>
Date: Wed, 18 Nov 2020 07:48:03 +0200
Subject: [PATCH 2/3] Added `impl Rem<NonZeroU{0}> for u{0}` which cannot panic

---
 library/core/src/num/nonzero.rs | 14 +++++++++++++-
 library/core/tests/nonzero.rs   |  8 ++++++++
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/library/core/src/num/nonzero.rs b/library/core/src/num/nonzero.rs
index 3355fb64ecfd1..e139facb6ea49 100644
--- a/library/core/src/num/nonzero.rs
+++ b/library/core/src/num/nonzero.rs
@@ -1,7 +1,7 @@
 //! Definitions of integer that is known not to equal zero.
 
 use crate::fmt;
-use crate::ops::{BitOr, BitOrAssign, Div};
+use crate::ops::{BitOr, BitOrAssign, Div, Rem};
 use crate::str::FromStr;
 
 use super::from_str_radix;
@@ -279,6 +279,18 @@ macro_rules! nonzero_integers_div {
                     unsafe { crate::intrinsics::unchecked_div(self, other.get()) }
                 }
             }
+
+            #[stable(feature = "nonzero_div", since = "1.50.0")]
+            impl Rem<$Ty> for $Int {
+                type Output = $Int;
+                /// This operation satisfies `n % d == n - (n / d) * d`, and cannot panic.
+                #[inline]
+                fn rem(self, other: $Ty) -> $Int {
+                    // SAFETY: rem by zero is checked because `other` is a nonzero,
+                    // and MIN/-1 is checked because `self` is an unsigned int.
+                    unsafe { crate::intrinsics::unchecked_rem(self, other.get()) }
+                }
+            }
         )+
     }
 }
diff --git a/library/core/tests/nonzero.rs b/library/core/tests/nonzero.rs
index 6ec3a04adc080..c2c08522d0cae 100644
--- a/library/core/tests/nonzero.rs
+++ b/library/core/tests/nonzero.rs
@@ -320,3 +320,11 @@ fn test_nonzero_uint_div() {
     let x: u32 = 42u32 / nz;
     assert_eq!(x, 42u32);
 }
+
+#[test]
+fn test_nonzero_uint_rem() {
+    let nz = NonZeroU32::new(10).unwrap();
+
+    let x: u32 = 42u32 % nz;
+    assert_eq!(x, 2u32);
+}

From 95866439125c1f81e9eb7a242d7e9f99e6d921b6 Mon Sep 17 00:00:00 2001
From: David Tolnay <dtolnay@gmail.com>
Date: Sun, 27 Dec 2020 03:17:30 -0800
Subject: [PATCH 3/3] Bump nonzero_div feature to Rust 1.51

---
 library/core/src/num/nonzero.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/library/core/src/num/nonzero.rs b/library/core/src/num/nonzero.rs
index e139facb6ea49..5eb70026d7e77 100644
--- a/library/core/src/num/nonzero.rs
+++ b/library/core/src/num/nonzero.rs
@@ -267,7 +267,7 @@ nonzero_leading_trailing_zeros! {
 macro_rules! nonzero_integers_div {
     ( $( $Ty: ident($Int: ty); )+ ) => {
         $(
-            #[stable(feature = "nonzero_div", since = "1.50.0")]
+            #[stable(feature = "nonzero_div", since = "1.51.0")]
             impl Div<$Ty> for $Int {
                 type Output = $Int;
                 /// This operation rounds towards zero,
@@ -280,7 +280,7 @@ macro_rules! nonzero_integers_div {
                 }
             }
 
-            #[stable(feature = "nonzero_div", since = "1.50.0")]
+            #[stable(feature = "nonzero_div", since = "1.51.0")]
             impl Rem<$Ty> for $Int {
                 type Output = $Int;
                 /// This operation satisfies `n % d == n - (n / d) * d`, and cannot panic.