Rollup merge of #110958 - compiler-errors:stdlib-refinement, r=cuviper

Make sure that some stdlib method signatures aren't accidental refinements

In the process of implementing https://rust-lang.github.io/rfcs/3245-refined-impls.html, I found a bunch of stdlib implementations that accidentally "refined" their method signatures by dropping  (unnecessary) bounds.

This isn't currently a problem, but may become one if/when method  signature refining is stabilized in the future. Shouldn't hurt to make these signatures a bit more accurate anyways.

NOTE (just to be clear lol): This does not affect behavior at all, since we don't actually take advantage of refined implementations yet!

library/alloc/src/collections/btree/map.rs

@@ -1543,11 +1543,17 @@ impl<'a, K: 'a, V: 'a> Iterator for Iter<'a, K, V> {
         self.next_back()
     }
 
-    fn min(mut self) -> Option<(&'a K, &'a V)> {
+    fn min(mut self) -> Option<(&'a K, &'a V)>
+    where
+        (&'a K, &'a V): Ord,
+    {
         self.next()
     }
 
-    fn max(mut self) -> Option<(&'a K, &'a V)> {
+    fn max(mut self) -> Option<(&'a K, &'a V)>
+    where
+        (&'a K, &'a V): Ord,
+    {
         self.next_back()
     }
 }
@@ -1612,11 +1618,17 @@ impl<'a, K, V> Iterator for IterMut<'a, K, V> {
         self.next_back()
     }
 
-    fn min(mut self) -> Option<(&'a K, &'a mut V)> {
+    fn min(mut self) -> Option<(&'a K, &'a mut V)>
+    where
+        (&'a K, &'a mut V): Ord,
+    {
         self.next()
     }
 
-    fn max(mut self) -> Option<(&'a K, &'a mut V)> {
+    fn max(mut self) -> Option<(&'a K, &'a mut V)>
+    where
+        (&'a K, &'a mut V): Ord,
+    {
         self.next_back()
     }
 }
@@ -1779,11 +1791,17 @@ impl<'a, K, V> Iterator for Keys<'a, K, V> {
         self.next_back()
     }
 
-    fn min(mut self) -> Option<&'a K> {
+    fn min(mut self) -> Option<&'a K>
+    where
+        &'a K: Ord,
+    {
         self.next()
     }
 
-    fn max(mut self) -> Option<&'a K> {
+    fn max(mut self) -> Option<&'a K>
+    where
+        &'a K: Ord,
+    {
         self.next_back()
     }
 }
@@ -2008,11 +2026,17 @@ impl<'a, K, V> Iterator for Range<'a, K, V> {
         self.next_back()
     }
 
-    fn min(mut self) -> Option<(&'a K, &'a V)> {
+    fn min(mut self) -> Option<(&'a K, &'a V)>
+    where
+        (&'a K, &'a V): Ord,
+    {
         self.next()
     }
 
-    fn max(mut self) -> Option<(&'a K, &'a V)> {
+    fn max(mut self) -> Option<(&'a K, &'a V)>
+    where
+        (&'a K, &'a V): Ord,
+    {
         self.next_back()
     }
 }
@@ -2081,11 +2105,17 @@ impl<K, V, A: Allocator + Clone> Iterator for IntoKeys<K, V, A> {
         self.next_back()
     }
 
-    fn min(mut self) -> Option<K> {
+    fn min(mut self) -> Option<K>
+    where
+        K: Ord,
+    {
         self.next()
     }
 
-    fn max(mut self) -> Option<K> {
+    fn max(mut self) -> Option<K>
+    where
+        K: Ord,
+    {
         self.next_back()
     }
 }
@@ -2204,11 +2234,17 @@ impl<'a, K, V> Iterator for RangeMut<'a, K, V> {
         self.next_back()
     }
 
-    fn min(mut self) -> Option<(&'a K, &'a mut V)> {
+    fn min(mut self) -> Option<(&'a K, &'a mut V)>
+    where
+        (&'a K, &'a mut V): Ord,
+    {
         self.next()
     }
 
-    fn max(mut self) -> Option<(&'a K, &'a mut V)> {
+    fn max(mut self) -> Option<(&'a K, &'a mut V)>
+    where
+        (&'a K, &'a mut V): Ord,
+    {
         self.next_back()
     }
 }

library/alloc/src/collections/btree/set.rs

@@ -1501,11 +1501,17 @@ impl<'a, T> Iterator for Iter<'a, T> {
         self.next_back()
     }
 
-    fn min(mut self) -> Option<&'a T> {
+    fn min(mut self) -> Option<&'a T>
+    where
+        &'a T: Ord,
+    {
         self.next()
     }
 
-    fn max(mut self) -> Option<&'a T> {
+    fn max(mut self) -> Option<&'a T>
+    where
+        &'a T: Ord,
+    {
         self.next_back()
     }
 }
@@ -1604,11 +1610,17 @@ impl<'a, T> Iterator for Range<'a, T> {
         self.next_back()
     }
 
-    fn min(mut self) -> Option<&'a T> {
+    fn min(mut self) -> Option<&'a T>
+    where
+        &'a T: Ord,
+    {
         self.next()
     }
 
-    fn max(mut self) -> Option<&'a T> {
+    fn max(mut self) -> Option<&'a T>
+    where
+        &'a T: Ord,
+    {
         self.next_back()
     }
 }

library/alloc/src/collections/vec_deque/mod.rs

@@ -2815,7 +2815,7 @@ impl<'a, T: 'a + Copy, A: Allocator> Extend<&'a T> for VecDeque<T, A> {
     }
 
     #[inline]
-    fn extend_one(&mut self, &elem: &T) {
+    fn extend_one(&mut self, &elem: &'a T) {
         self.push_back(elem);
     }
 

library/core/src/array/mod.rs

@@ -248,7 +248,7 @@ where
 impl<'a, T, const N: usize> TryFrom<&'a [T]> for &'a [T; N] {
     type Error = TryFromSliceError;
 
-    fn try_from(slice: &[T]) -> Result<&[T; N], TryFromSliceError> {
+    fn try_from(slice: &'a [T]) -> Result<&'a [T; N], TryFromSliceError> {
         if slice.len() == N {
             let ptr = slice.as_ptr() as *const [T; N];
             // SAFETY: ok because we just checked that the length fits
@@ -275,7 +275,7 @@ impl<'a, T, const N: usize> TryFrom<&'a [T]> for &'a [T; N] {
 impl<'a, T, const N: usize> TryFrom<&'a mut [T]> for &'a mut [T; N] {
     type Error = TryFromSliceError;
 
-    fn try_from(slice: &mut [T]) -> Result<&mut [T; N], TryFromSliceError> {
+    fn try_from(slice: &'a mut [T]) -> Result<&'a mut [T; N], TryFromSliceError> {
         if slice.len() == N {
             let ptr = slice.as_mut_ptr() as *mut [T; N];
             // SAFETY: ok because we just checked that the length fits

library/core/src/iter/range.rs

@@ -732,12 +732,18 @@ impl<A: Step> Iterator for ops::Range<A> {
     }
 
     #[inline]
-    fn min(mut self) -> Option<A> {
+    fn min(mut self) -> Option<A>
+    where
+        A: Ord,
+    {
         self.next()
     }
 
     #[inline]
-    fn max(mut self) -> Option<A> {
+    fn max(mut self) -> Option<A>
+    where
+        A: Ord,
+    {
         self.next_back()
     }
 
@@ -1158,12 +1164,18 @@ impl<A: Step> Iterator for ops::RangeInclusive<A> {
     }
 
     #[inline]
-    fn min(mut self) -> Option<A> {
+    fn min(mut self) -> Option<A>
+    where
+        A: Ord,
+    {
         self.next()
     }
 
     #[inline]
-    fn max(mut self) -> Option<A> {
+    fn max(mut self) -> Option<A>
+    where
+        A: Ord,
+    {
         self.next_back()
     }
 

library/portable-simd/crates/core_simd/src/ops/deref.rs

@@ -71,7 +71,7 @@ macro_rules! deref_ops {
 
                 #[inline]
                 #[must_use = "operator returns a new vector without mutating the inputs"]
-                fn $call(self, rhs: &$simd) -> Self::Output {
+                fn $call(self, rhs: &'rhs $simd) -> Self::Output {
                     (*self).$call(*rhs)
                 }
             }