Fix clippy issue for benches crate (#6806)

# Objective

- https://github.com/bevyengine/bevy/pull/3505 marked `S-Adopt-Me` , this pr is to continue his work.

## Solution

- run `cargo clippy --workspace --all-targets --all-features -- -Aclippy::type_complexity -Wclippy::doc_markdown -Wclippy::redundant_else -Wclippy::match_same_arms -Wclippy::semicolon_if_nothing_returned -Wclippy::explicit_iter_loop -Wclippy::map_flatten -Dwarnings` under benches dir.
- fix issue according to suggestion.

benches/benches/bevy_ecs/components/archetype_updates.rs

@@ -109,7 +109,7 @@ pub fn added_archetypes(criterion: &mut Criterion) {
                         stage.run(&mut world);
                     },
                     criterion::BatchSize::LargeInput,
-                )
+                );
             },
         );
     }

benches/benches/bevy_ecs/scheduling/schedule.rs

@@ -110,11 +110,11 @@ pub fn build_schedule(criterion: &mut Criterion) {
                 // Not particularly realistic but this can be refined later.
                 for i in 0..graph_size {
                     let mut sys = empty_system.label(labels[i]).before(DummyLabel);
-                    for a in 0..i {
-                        sys = sys.after(labels[a]);
+                    for label in labels.iter().take(i) {
+                        sys = sys.after(*label);
                     }
-                    for b in i + 1..graph_size {
-                        sys = sys.before(labels[b]);
+                    for label in &labels[i + 1..graph_size] {
+                        sys = sys.before(*label);
                     }
                     app.add_system(sys);
                 }

benches/benches/bevy_ecs/scheduling/stages.rs

@@ -58,7 +58,7 @@ pub fn empty_systems(criterion: &mut Criterion) {
             });
         });
     }
-    group.finish()
+    group.finish();
 }
 
 pub fn busy_systems(criterion: &mut Criterion) {
@@ -107,7 +107,7 @@ pub fn busy_systems(criterion: &mut Criterion) {
             );
         }
     }
-    group.finish()
+    group.finish();
 }
 
 pub fn contrived(criterion: &mut Criterion) {
@@ -158,5 +158,5 @@ pub fn contrived(criterion: &mut Criterion) {
             );
         }
     }
-    group.finish()
+    group.finish();
 }

benches/benches/bevy_ecs/world/commands.rs

@@ -61,7 +61,6 @@ pub fn spawn_commands(criterion: &mut Criterion) {
                         entity.despawn();
                     }
                 }
-                drop(commands);
                 command_queue.apply(&mut world);
             });
         });
@@ -82,7 +81,7 @@ pub fn insert_commands(criterion: &mut Criterion) {
     group.measurement_time(std::time::Duration::from_secs(4));
 
     let entity_count = 10_000;
-    group.bench_function(format!("insert"), |bencher| {
+    group.bench_function("insert", |bencher| {
         let mut world = World::default();
         let mut command_queue = CommandQueue::default();
         let mut entities = Vec::new();
@@ -97,11 +96,10 @@ pub fn insert_commands(criterion: &mut Criterion) {
                     .entity(*entity)
                     .insert((Matrix::default(), Vec3::default()));
             }
-            drop(commands);
             command_queue.apply(&mut world);
         });
     });
-    group.bench_function(format!("insert_batch"), |bencher| {
+    group.bench_function("insert_batch", |bencher| {
         let mut world = World::default();
         let mut command_queue = CommandQueue::default();
         let mut entities = Vec::new();
@@ -116,7 +114,6 @@ pub fn insert_commands(criterion: &mut Criterion) {
                 values.push((*entity, (Matrix::default(), Vec3::default())));
             }
             commands.insert_or_spawn_batch(values);
-            drop(commands);
             command_queue.apply(&mut world);
         });
     });
@@ -160,7 +157,6 @@ pub fn fake_commands(criterion: &mut Criterion) {
                         commands.add(FakeCommandB(0));
                     }
                 }
-                drop(commands);
                 command_queue.apply(&mut world);
             });
         });
@@ -203,7 +199,6 @@ pub fn sized_commands_impl<T: Default + Command>(criterion: &mut Criterion) {
                 for _ in 0..command_count {
                     commands.add(T::default());
                 }
-                drop(commands);
                 command_queue.apply(&mut world);
             });
         });

benches/benches/bevy_ecs/world/world_get.rs

@@ -273,7 +273,7 @@ pub fn query_get_component_simple(criterion: &mut Criterion) {
 
         bencher.iter(|| {
             for _x in 0..100000 {
-                let mut a = unsafe { query.get_unchecked(&mut world, entity).unwrap() };
+                let mut a = unsafe { query.get_unchecked(&world, entity).unwrap() };
                 a.0 += 1.0;
             }
         });

benches/benches/bevy_reflect/list.rs

@@ -44,7 +44,7 @@ fn list_apply<M, LBase, LPatch, F1, F2, F3>(
                 let f_base = f_base(size);
                 let patch = f_patch(size);
                 bencher.iter_batched(
-                    || f_base(),
+                    f_base,
                     |mut base| base.apply(black_box(&patch)),
                     BatchSize::SmallInput,
                 );
@@ -58,7 +58,7 @@ fn concrete_list_apply(criterion: &mut Criterion) {
     group.warm_up_time(WARM_UP_TIME);
     group.measurement_time(MEASUREMENT_TIME);
 
-    let empty_base = |_: usize| || Vec::<u64>::new();
+    let empty_base = |_: usize| Vec::<u64>::new;
     let full_base = |size: usize| move || iter::repeat(0).take(size).collect::<Vec<u64>>();
     let patch = |size: usize| iter::repeat(1).take(size).collect::<Vec<u64>>();
 

benches/benches/bevy_reflect/map.rs

@@ -60,7 +60,7 @@ fn concrete_map_apply(criterion: &mut Criterion) {
     group.warm_up_time(WARM_UP_TIME);
     group.measurement_time(MEASUREMENT_TIME);
 
-    let empty_base = |_: usize| || HashMap::<u64, u64>::default();
+    let empty_base = |_: usize| HashMap::<u64, u64>::default;
 
     let key_range_base = |size: usize| {
         move || {
@@ -136,7 +136,7 @@ fn dynamic_map_apply(criterion: &mut Criterion) {
     group.warm_up_time(WARM_UP_TIME);
     group.measurement_time(MEASUREMENT_TIME);
 
-    let empty_base = |_: usize| || DynamicMap::default();
+    let empty_base = |_: usize| DynamicMap::default;
 
     let key_range_base = |size: usize| {
         move || {
@@ -240,8 +240,8 @@ fn dynamic_map_get(criterion: &mut Criterion) {
                 }
 
                 bencher.iter(|| {
-                    for i in 0..size {
-                        let key = black_box(&keys[i]);
+                    for key in keys.iter().take(size) {
+                        let key = black_box(key);
                         assert!(map.get(key).is_some());
                     }
                 });
@@ -262,7 +262,7 @@ fn dynamic_map_insert(criterion: &mut Criterion) {
             &size,
             |bencher, &size| {
                 bencher.iter_batched(
-                    || DynamicMap::default(),
+                    DynamicMap::default,
                     |mut map| {
                         for i in 0..size as u64 {
                             let key = black_box(i);

benches/benches/bevy_tasks/iter.rs

@@ -28,7 +28,7 @@ fn bench_overhead(c: &mut Criterion) {
     c.bench_function("overhead_iter", |b| {
         b.iter(|| {
             v.iter_mut().for_each(noop);
-        })
+        });
     });
 
     let mut v = (0..10000).collect::<Vec<usize>>();
@@ -41,7 +41,7 @@ fn bench_overhead(c: &mut Criterion) {
             |b, _| {
                 b.iter(|| {
                     ParChunksMut(v.chunks_mut(100)).for_each(&pool, noop);
-                })
+                });
             },
         );
     }
@@ -63,7 +63,7 @@ fn bench_for_each(c: &mut Criterion) {
                 busy_work(10000);
                 *x *= *x;
             });
-        })
+        });
     });
 
     let mut v = (0..10000).collect::<Vec<usize>>();
@@ -79,7 +79,7 @@ fn bench_for_each(c: &mut Criterion) {
                         busy_work(10000);
                         *x *= *x;
                     });
-                })
+                });
             },
         );
     }
@@ -109,7 +109,7 @@ fn bench_many_maps(c: &mut Criterion) {
                 .map(|x| busy_doubles(x, 1000))
                 .map(|x| busy_doubles(x, 1000))
                 .for_each(drop);
-        })
+        });
     });
 
     let v = (0..10000).collect::<Vec<usize>>();
@@ -133,7 +133,7 @@ fn bench_many_maps(c: &mut Criterion) {
                         .map(|x| busy_doubles(x, 1000))
                         .map(|x| busy_doubles(x, 1000))
                         .for_each(&pool, drop);
-                })
+                });
             },
         );
     }