remove trivial bounds

Author: lcnr

library/core/src/iter/adapters/step_by.rs

@@ -515,9 +515,7 @@ macro_rules! spec_int_ranges_r {
         unsafe impl StepByBackImpl<Range<$t>> for StepBy<Range<$t>> {
 
             #[inline]
-            fn spec_next_back(&mut self) -> Option<Self::Item>
-                where Range<$t>: DoubleEndedIterator + ExactSizeIterator,
-            {
+            fn spec_next_back(&mut self) -> Option<Self::Item> {
                 let step = self.original_step().get() as $t;
                 let remaining = self.iter.end;
                 if remaining > 0 {
@@ -533,9 +531,7 @@ macro_rules! spec_int_ranges_r {
             // We have to repeat them here so that the specialization overrides the StepByImplBack defaults
 
             #[inline]
-            fn spec_nth_back(&mut self, n: usize) -> Option<Self::Item>
-                where Self: DoubleEndedIterator,
-            {
+            fn spec_nth_back(&mut self, n: usize) -> Option<Self::Item> {
                 if self.advance_back_by(n).is_err() {
                     return None;
                 }
@@ -544,10 +540,9 @@ macro_rules! spec_int_ranges_r {
 
             #[inline]
             fn spec_try_rfold<Acc, F, R>(&mut self, init: Acc, mut f: F) -> R
-                where
-                    Self: DoubleEndedIterator,
-                    F: FnMut(Acc, Self::Item) -> R,
-                    R: Try<Output = Acc>
+            where
+                F: FnMut(Acc, Self::Item) -> R,
+                R: Try<Output = Acc>
             {
                 let mut accum = init;
                 while let Some(x) = self.next_back() {
@@ -558,9 +553,8 @@ macro_rules! spec_int_ranges_r {
 
             #[inline]
             fn spec_rfold<Acc, F>(mut self, init: Acc, mut f: F) -> Acc
-                where
-                    Self: DoubleEndedIterator,
-                    F: FnMut(Acc, Self::Item) -> Acc
+            where
+                F: FnMut(Acc, Self::Item) -> Acc
             {
                 let mut accum = init;
                 while let Some(x) = self.next_back() {