Allow const assignment for int saturating_sub() for #58030

1 files changed, 44 insertions, 10 deletions

diff --git a/src/libcore/num/mod.rs b/src/libcore/num/mod.rs
index 55de04db028..104b124bad4 100644
--- a/src/libcore/num/mod.rs
+++ b/src/libcore/num/mod.rs
@@ -932,17 +932,35 @@ $EndFeature, "
 ```"),
             #[stable(feature = "rust1", since = "1.0.0")]
             #[inline]
+            #[cfg(stage0)]
             pub fn saturating_sub(self, rhs: Self) -> Self {
-                #[cfg(stage0)]
                 match self.checked_sub(rhs) {
                     Some(x) => x,
                     None if rhs >= 0 => Self::min_value(),
                     None => Self::max_value(),
                 }
-                #[cfg(not(stage0))]
-                {
-                    intrinsics::saturating_sub(self, rhs)
-                }
+            }
+        }
+
+        doc_comment! {
+            concat!("Saturating integer subtraction. Computes `self - rhs`, saturating at the
+numeric bounds instead of overflowing.
+
+# Examples
+
+Basic usage:
+
+```
+", $Feature, "assert_eq!(100", stringify!($SelfT), ".saturating_sub(127), -27);
+assert_eq!(", stringify!($SelfT), "::min_value().saturating_sub(100), ", stringify!($SelfT),
+"::min_value());",
+$EndFeature, "
+```"),
+            #[stable(feature = "rust1", since = "1.0.0")]
+            #[inline]
+            #[cfg(not(stage0))]
+            pub const fn saturating_sub(self, rhs: Self) -> Self {
+                intrinsics::saturating_sub(self, rhs)
             }
         }
 
@@ -2817,16 +2835,32 @@ assert_eq!(13", stringify!($SelfT), ".saturating_sub(127), 0);", $EndFeature, "
 ```"),
             #[stable(feature = "rust1", since = "1.0.0")]
             #[inline]
+            #[cfg(stage0)]
             pub fn saturating_sub(self, rhs: Self) -> Self {
-                #[cfg(stage0)]
                 match self.checked_sub(rhs) {
                     Some(x) => x,
                     None => Self::min_value(),
                 }
-                #[cfg(not(stage0))]
-                {
-                    intrinsics::saturating_sub(self, rhs)
-                }
+            }
+        }
+
+        doc_comment! {
+            concat!("Saturating integer subtraction. Computes `self - rhs`, saturating
+at the numeric bounds instead of overflowing.
+
+# Examples
+
+Basic usage:
+
+```
+", $Feature, "assert_eq!(100", stringify!($SelfT), ".saturating_sub(27), 73);
+assert_eq!(13", stringify!($SelfT), ".saturating_sub(127), 0);", $EndFeature, "
+```"),
+            #[stable(feature = "rust1", since = "1.0.0")]
+            #[inline]
+            #[cfg(not(stage0))]
+            pub const fn saturating_sub(self, rhs: Self) -> Self {
+                intrinsics::saturating_sub(self, rhs)
             }
         }