signed strict division: just use normal division

Author: RalfJung

library/core/src/num/imp/overflow_panic.rs

@@ -20,12 +20,6 @@ pub(in crate::num) const fn mul() -> ! {
     panic!("attempt to multiply with overflow")
 }
 
-#[cold]
-#[track_caller]
-pub(in crate::num) const fn div() -> ! {
-    panic!("attempt to divide with overflow")
-}
-
 #[cold]
 #[track_caller]
 pub(in crate::num) const fn rem() -> ! {

library/core/src/num/int_macros.rs

@@ -983,9 +983,12 @@ macro_rules! int_impl {
         /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
         ///
         /// The only case where such an overflow can occur is when one divides `MIN / -1` on a signed type (where
-        /// `MIN` is the negative minimal value for the type); this is equivalent to `-MIN`, a positive value
+        /// `MIN` is the negative minimal value for the type): the result of this is `-MIN`, a positive value
         /// that is too large to represent in the type.
         ///
+        /// Note that this is equivalent to normal division: `MIN / -1` will also panic both in
+        /// debug and release builds.
+        ///
         /// # Examples
         ///
         /// ```
@@ -1010,8 +1013,8 @@ macro_rules! int_impl {
         #[inline]
         #[track_caller]
         pub const fn strict_div(self, rhs: Self) -> Self {
-            let (a, b) = self.overflowing_div(rhs);
-            if b { imp::overflow_panic::div() } else { a }
+            // Normal division already checks for "div-by-minus-1".
+            self / rhs
         }
 
         /// Checked Euclidean division. Computes `self.div_euclid(rhs)`,
@@ -1050,9 +1053,12 @@ macro_rules! int_impl {
         /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
         ///
         /// The only case where such an overflow can occur is when one divides `MIN / -1` on a signed type (where
-        /// `MIN` is the negative minimal value for the type); this is equivalent to `-MIN`, a positive value
+        /// `MIN` is the negative minimal value for the type); the result of this is `-MIN`, a positive value
         /// that is too large to represent in the type.
         ///
+        /// Note that this is equivalent to `div_euclid`: `MIN.div_euclid(-1)` will also panic both
+        /// in debug and release builds.
+        ///
         /// # Examples
         ///
         /// ```
@@ -1077,8 +1083,8 @@ macro_rules! int_impl {
         #[inline]
         #[track_caller]
         pub const fn strict_div_euclid(self, rhs: Self) -> Self {
-            let (a, b) = self.overflowing_div_euclid(rhs);
-            if b { imp::overflow_panic::div() } else { a }
+            // Normal `div_euclid` already checks for "div-by-minus-1".
+            self.div_euclid(rhs)
         }
 
         /// Checked integer division without remainder. Computes `self / rhs`,