fixed bug

Author: michirakara

library/core/src/iter/range.rs

@@ -262,7 +262,7 @@ macro_rules! step_integer_impls {
                 fn steps_between(start: &Self, end: &Self) -> (usize, Option<usize>) {
                     if *start <= *end {
                         // This relies on $u_narrower <= usize
-                        let steps = (*end - *start) as usize
+                        let steps = (*end - *start) as usize;
                         (steps, Some(steps))
                     } else {
                         (0, None)
@@ -788,7 +788,7 @@ impl<T: TrustedStep> RangeIteratorImpl for ops::Range<T> {
     #[inline]
     fn spec_advance_by(&mut self, n: usize) -> Result<(), NonZero<usize>> {
         let steps = Step::steps_between(&self.start, &self.end);
-        let available = steps.1.unwrap_or(step.0);
+        let available = steps.1.unwrap_or(steps.0);
 
         let taken = available.min(n);
 
@@ -851,7 +851,11 @@ impl<A: Step> Iterator for ops::Range<A> {
 
     #[inline]
     fn size_hint(&self) -> (usize, Option<usize>) {
-        Step::steps_between(&self.start, &self.end)
+        if self.start < self.end {
+            Step::steps_between(&self.start, &self.end)
+        } else {
+            (0, Some(0))
+        }
     }
 
     #[inline]