Remove unneeded copy

Xaeroxe · web-flow · commit 0e2427cd3c52 · 2017-09-05T15:32:02.000-06:00
diff --git a/src/liballoc/vec.rs b/src/liballoc/vec.rs
@@ -2691,7 +2691,8 @@ impl<'a, T, F> Iterator for DrainFilter<'a, T, F>
                     self.del += 1;
                     return Some(ptr::read(&v[i]));
                 } else if self.del > 0 {
-                    v.swap(i - self.del, i);
+                    let del = self.del;
+                    ptr::copy_nonoverlapping(self.vec.as_ptr().offset(i), self.vec.as_mut_ptr().offset(i - del), 1);
                 }
             }
             None

Original file line number	Diff line number	Diff line change
`@@ -2691,7 +2691,8 @@ impl<'a, T, F> Iterator for DrainFilter<'a, T, F>`
`2691`	`2691`	`self.del += 1;`
`2692`	`2692`	`return Some(ptr::read(&v[i]));`
`2693`	`2693`	`} else if self.del > 0 {`
`2694`		`- v.swap(i - self.del, i);`
	`2694`	`+ let del = self.del;`
	`2695`	`+ ptr::copy_nonoverlapping(self.vec.as_ptr().offset(i), self.vec.as_mut_ptr().offset(i - del), 1);`
`2695`	`2696`	`}`
`2696`	`2697`	`}`
`2697`	`2698`	`None`