diff --git a/src/main.rs b/src/main.rs
index 6c78fb6b..d8eeb9f1 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -161,7 +161,7 @@ impl GraphicsData {
 		//the models received here are supposed to be tightly packed, i.e. no code needs to check if two models are using the same groups.
 		let indexed_models_len=indexed_models.models.len();
 		let mut unique_texture_models=Vec::with_capacity(indexed_models_len);
-		for mut model in indexed_models.models.drain(..){
+		for mut model in indexed_models.models.into_iter(){
 			//convert ModelInstance into ModelGraphicsInstance
 			let instances:Vec<ModelGraphicsInstance>=model.instances.iter().map(|instance|{
 				ModelGraphicsInstance{
@@ -200,7 +200,7 @@ impl GraphicsData {
 		}
 		//de-index models
 		let mut models=Vec::with_capacity(unique_texture_models.len());
-		for model in unique_texture_models.drain(..){
+		for model in unique_texture_models.into_iter(){
 			let mut vertices = Vec::new();
 			let mut index_from_vertex = std::collections::HashMap::new();//::<IndexedVertex,usize>
 			let mut entities = Vec::new();
@@ -243,7 +243,7 @@ impl GraphicsData {
 		let uniform_buffer_binding_size=<GraphicsData as framework::Example>::required_limits().max_uniform_buffer_binding_size as usize;
 		let chunk_size=uniform_buffer_binding_size/MODEL_BUFFER_SIZE_BYTES;
 		self.models.reserve(models.len());
-		for model in models.drain(..) {
+		for model in models.into_iter() {
 			instance_count+=model.instances.len();
 			for instances_chunk in model.instances.rchunks(chunk_size){
 				model_count+=1;
diff --git a/src/primitives.rs b/src/primitives.rs
index bdda6cbc..6f0e607c 100644
--- a/src/primitives.rs
+++ b/src/primitives.rs
@@ -206,7 +206,7 @@ pub fn generate_partial_unit_cube(face_descriptions:CubeFaceDescription)->crate:
 	let mut groups=Vec::new();
 	let mut transforms=Vec::new();
 	//note that on a cube every vertex is guaranteed to be unique, so there's no need to hash them against existing vertices.
-	for (face,face_description) in face_descriptions.iter(){
+	for (face,face_description) in face_descriptions.into_iter(){
 		//assume that scanning short lists is faster than hashing.
 		let transform_index=if let Some(transform_index)=transforms.iter().position(|&transform|transform==face_description.transform){
 			transform_index
@@ -321,7 +321,7 @@ pub fn generate_partial_unit_wedge(face_descriptions:WedgeFaceDescription)->crat
 	let mut groups=Vec::new();
 	let mut transforms=Vec::new();
 	//note that on a cube every vertex is guaranteed to be unique, so there's no need to hash them against existing vertices.
-	for (face,face_description) in face_descriptions.iter(){
+	for (face,face_description) in face_descriptions.into_iter(){
 		//assume that scanning short lists is faster than hashing.
 		let transform_index=if let Some(transform_index)=transforms.iter().position(|&transform|transform==face_description.transform){
 			transform_index
@@ -433,7 +433,7 @@ pub fn generate_partial_unit_cornerwedge(face_descriptions:CornerWedgeFaceDescri
 	let mut groups=Vec::new();
 	let mut transforms=Vec::new();
 	//note that on a cube every vertex is guaranteed to be unique, so there's no need to hash them against existing vertices.
-	for (face,face_description) in face_descriptions.iter(){
+	for (face,face_description) in face_descriptions.into_iter(){
 		//assume that scanning short lists is faster than hashing.
 		let transform_index=if let Some(transform_index)=transforms.iter().position(|&transform|transform==face_description.transform){
 			transform_index