Do not perform superfluous bounds checks on drop

Shnatsel · Shnatsel · commit ebb6b5fe6d74 · 2019-10-27T10:58:49.000+01:00
diff --git a/crossbeam-epoch/src/internal.rs b/crossbeam-epoch/src/internal.rs
@@ -133,10 +133,10 @@ impl Default for Bag {
 impl Drop for Bag {
     fn drop(&mut self) {
         // Call all deferred functions.
-        for i in 0..self.len {
+        for deferred in &mut self.deferreds[..self.len] {
             let no_op = Deferred::new(no_op_func);
-            let deferred = mem::replace(&mut self.deferreds[i], no_op);
-            deferred.call();
+            let owned_deferred = mem::replace(deferred, no_op);
+            owned_deferred.call();
         }
     }
 }

Original file line number	Diff line number	Diff line change
`@@ -133,10 +133,10 @@ impl Default for Bag {`
`133`	`133`	`impl Drop for Bag {`
`134`	`134`	`fn drop(&mut self) {`
`135`	`135`	`// Call all deferred functions.`
`136`		`- for i in 0..self.len {`
	`136`	`+ for deferred in &mut self.deferreds[..self.len] {`
`137`	`137`	`let no_op = Deferred::new(no_op_func);`
`138`		`- let deferred = mem::replace(&mut self.deferreds[i], no_op);`
`139`		`- deferred.call();`
	`138`	`+ let owned_deferred = mem::replace(deferred, no_op);`
	`139`	`+ owned_deferred.call();`
`140`	`140`	`}`
`141`	`141`	`}`
`142`	`142`	`}`