diff --git a/core/class.c b/core/class.c
index 7d305dd..0967330 100644
--- a/core/class.c
+++ b/core/class.c
@@ -47,16 +47,18 @@ b_result b_class_instantiate(
 	out->c_magic = B_CLASS_MAGIC;
 	out->c_type = type;
 
-	b_queue_iterator q_it;
-	b_queue_foreach (&q_it, &type->r_class_hierarchy) {
+	struct b_queue_entry *entry = b_queue_first(&type->r_class_hierarchy);
+	while (entry) {
 		struct b_type_component *comp
-			= b_unbox(struct b_type_component, q_it.entry, c_entry);
+			= b_unbox(struct b_type_component, entry, c_entry);
 		const struct b_type_info *class_info = comp->c_type->r_info;
 		void *class_data = (char *)out + comp->c_class_data_offset;
 
 		if (class_info->t_class_init) {
 			class_info->t_class_init(out, class_data);
 		}
+
+		entry = b_queue_next(entry);
 	}
 
 	*out_class = out;
diff --git a/core/object.c b/core/object.c
index 513242a..20e5cca 100644
--- a/core/object.c
+++ b/core/object.c
@@ -33,10 +33,10 @@ b_result b_object_instantiate(
 	out->obj_type = type;
 	out->obj_ref = 1;
 
-	b_queue_iterator q_it;
-	b_queue_foreach (&q_it, &type->r_class_hierarchy) {
+	struct b_queue_entry *entry = b_queue_first(&type->r_class_hierarchy);
+	while (entry) {
 		struct b_type_component *comp
-			= b_unbox(struct b_type_component, q_it.entry, c_entry);
+			= b_unbox(struct b_type_component, entry, c_entry);
 		const struct b_type_info *class_info = comp->c_type->r_info;
 		void *private_data
 			= (char *)out + comp->c_instance_private_data_offset;
@@ -49,6 +49,8 @@ b_result b_object_instantiate(
 			out->obj_main_priv_offset
 				= comp->c_instance_private_data_offset;
 		}
+
+		entry = b_queue_next(entry);
 	}
 
 	*out_object = out;
diff --git a/core/type.c b/core/type.c
index 23e594a..818080c 100644
--- a/core/type.c
+++ b/core/type.c
@@ -233,21 +233,23 @@ static b_result find_type_components(struct b_type_registration *reg)
 		current_id = &dep_class->r_info->t_parent_id;
 	}
 
-	b_queue_iterator q_it;
-	b_queue_foreach (&q_it, &reg->r_class_hierarchy) {
-		comp = b_unbox(struct b_type_component, q_it.entry, c_entry);
+	b_queue_entry *entry = b_queue_first(&reg->r_class_hierarchy);
+	while (entry) {
+		comp = b_unbox(struct b_type_component, entry, c_entry);
 		initialise_type_component(comp, comp->c_type->r_info, &init_ctx);
+		entry = b_queue_next(entry);
 	}
 
-	b_btree_iterator t_it;
-	b_btree_foreach (&t_it, &reg->r_components) {
-		comp = b_unbox(struct b_type_component, t_it.node, c_node);
+	b_btree_node *node = b_btree_first(&reg->r_components);
+	while (node) {
+		comp = b_unbox(struct b_type_component, node, c_node);
 		if (comp->c_type->r_category == B_TYPE_CLASS) {
 			/* this component was already initialised above */
 			continue;
 		}
 
 		initialise_type_component(comp, comp->c_type->r_info, &init_ctx);
+		node = b_btree_next(node);
 	}
 
 skip_class_hierarchy:
diff --git a/core/type.h b/core/type.h
index c5b46b8..c728bdb 100644
--- a/core/type.h
+++ b/core/type.h
@@ -2,6 +2,7 @@
 #define _TYPE_H_
 
 #include <blue/core/btree.h>
+#include <blue/core/queue.h>
 #include <blue/core/type.h>
 #include <stddef.h>