Index: src/runtime/category.m
==================================================================
--- src/runtime/category.m
+++ src/runtime/category.m
@@ -114,11 +114,11 @@
 	return (struct objc_category**)objc_hashtable_get(categories,
 	    cls->name);
 }
 
 void
-objc_free_all_categories(void)
+objc_unregister_all_categories(void)
 {
 	uint32_t i;
 
 	if (categories == NULL)
 		return;

Index: src/runtime/class.m
==================================================================
--- src/runtime/class.m
+++ src/runtime/class.m
@@ -312,11 +312,11 @@
 		return;
 
 	if ((superclass = ((struct objc_abi_class*)cls)->superclass) != NULL) {
 		Class super = objc_classname_to_class(superclass, false);
 
-		if (super == nil)
+		if (super == Nil)
 			return;
 
 		setup_class(super);
 
 		if (!(super->info & OBJC_CLASS_INFO_SETUP))
@@ -655,11 +655,11 @@
 
 	objc_update_dtable(cls);
 
 	objc_global_mutex_unlock();
 
-	return (IMP)nil;
+	return NULL;
 }
 
 Class
 object_getClass(id obj_)
 {
@@ -684,12 +684,12 @@
 object_getClassName(id obj)
 {
 	return object_getClass(obj)->name;
 }
 
-void
-objc_free_class(Class rcls)
+static void
+unregister_class(Class rcls)
 {
 	struct objc_abi_class *cls = (struct objc_abi_class*)rcls;
 
 	if (rcls->subclass_list != NULL) {
 		free(rcls->subclass_list);
@@ -704,10 +704,17 @@
 	if (rcls->superclass != Nil)
 		cls->superclass = rcls->superclass->name;
 
 	objc_hashtable_set(classes, cls->name, NULL);
 }
+
+void
+objc_unregister_class(Class cls)
+{
+	unregister_class(cls);
+	unregister_class(cls->isa);
+}
 
 static void
 free_sparsearray(struct sparsearray *sa, size_t depth)
 {
 	uint_fast16_t i;
@@ -720,11 +727,11 @@
 
 	free(sa);
 }
 
 void
-objc_free_all_classes(void)
+objc_unregister_all_classes(void)
 {
 	uint_fast32_t i;
 
 	if (classes == NULL)
 		return;
@@ -734,12 +741,11 @@
 			Class cls = (Class)classes->data[i]->obj;
 
 			if (cls == Nil || (uintptr_t)cls & 1)
 				continue;
 
-			objc_free_class(cls);
-			objc_free_class(cls->isa);
+			objc_unregister_class(cls);
 		}
 	}
 
 	if (empty_dtable != NULL) {
 		objc_sparsearray_free(empty_dtable);

Index: src/runtime/init.m
==================================================================
--- src/runtime/init.m
+++ src/runtime/init.m
@@ -35,13 +35,14 @@
 void
 objc_exit(void)
 {
 	objc_global_mutex_lock();
 
-	objc_free_all_categories();
-	objc_free_all_classes();
-	objc_free_all_selectors();
+	objc_unregister_all_categories();
+	objc_unregister_all_classes();
+	objc_unregister_all_selectors();
+	objc_forget_pending_static_instances();
 	objc_sparsearray_cleanup();
 
 	objc_global_mutex_unlock();
 	objc_global_mutex_free();
 }

Index: src/runtime/runtime-private.h
==================================================================
--- src/runtime/runtime-private.h
+++ src/runtime/runtime-private.h
@@ -120,34 +120,35 @@
 };
 #endif
 
 extern void objc_register_all_categories(struct objc_abi_symtab*);
 extern struct objc_category** objc_categories_for_class(Class);
-extern void objc_free_all_categories(void);
+extern void objc_unregister_all_categories(void);
 extern void objc_initialize_class(Class);
 extern void objc_update_dtable(Class);
 extern void objc_register_all_classes(struct objc_abi_symtab*);
 extern Class objc_classname_to_class(const char*, bool);
-extern void objc_free_class(Class);
-extern void objc_free_all_classes(void);
+extern void objc_unregister_class(Class);
+extern void objc_unregister_all_classes(void);
 extern uint32_t objc_hash_string(const char*);
 extern struct objc_hashtable* objc_hashtable_new(uint32_t);
 extern void objc_hashtable_set(struct objc_hashtable*, const char*,
     const void*);
 extern void* objc_hashtable_get(struct objc_hashtable*, const char*);
 extern void objc_hashtable_free(struct objc_hashtable *h);
 extern void objc_register_selector(struct objc_abi_selector*);
 extern void objc_register_all_selectors(struct objc_abi_symtab*);
-extern void objc_free_all_selectors(void);
+extern void objc_unregister_all_selectors(void);
 extern struct objc_sparsearray* objc_sparsearray_new(void);
 extern void objc_sparsearray_copy(struct objc_sparsearray*,
     struct objc_sparsearray*);
 extern void objc_sparsearray_set(struct objc_sparsearray*, uint32_t,
     const void*);
 extern void objc_sparsearray_free(struct objc_sparsearray*);
 extern void objc_sparsearray_cleanup(void);
 extern void objc_init_static_instances(struct objc_abi_symtab*);
+extern void objc_forget_pending_static_instances(void);
 extern void __objc_exec_class(struct objc_abi_module*);
 #ifdef OF_HAVE_THREADS
 extern void objc_global_mutex_lock(void);
 extern void objc_global_mutex_unlock(void);
 extern void objc_global_mutex_free(void);

Index: src/runtime/runtime.h
==================================================================
--- src/runtime/runtime.h
+++ src/runtime/runtime.h
@@ -14,10 +14,11 @@
  * file.
  */
 
 #ifndef __OBJFW_RUNTIME_H__
 #define __OBJFW_RUNTIME_H__
+
 #include <stdint.h>
 #include <stdbool.h>
 
 #ifndef __has_feature
 # define __has_feature(x) 0

Index: src/runtime/selector.m
==================================================================
--- src/runtime/selector.m
+++ src/runtime/selector.m
@@ -126,11 +126,11 @@
 {
 	return (sel1->uid == sel2->uid);
 }
 
 void
-objc_free_all_selectors(void)
+objc_unregister_all_selectors(void)
 {
 	objc_hashtable_free(selectors);
 	objc_sparsearray_free(selector_names);
 
 	if (free_list != NULL) {

Index: src/runtime/static-instances.m
==================================================================
--- src/runtime/static-instances.m
+++ src/runtime/static-instances.m
@@ -89,5 +89,13 @@
 
 			static_instances[static_instances_cnt++] = *si;
 		}
 	}
 }
+
+void
+objc_forget_pending_static_instances()
+{
+	free(static_instances);
+	static_instances = NULL;
+	static_instances_cnt = 0;
+}

Index: tests/plugin/TestPlugin.m
==================================================================
--- tests/plugin/TestPlugin.m
+++ tests/plugin/TestPlugin.m
@@ -22,15 +22,11 @@
 # import "runtime-private.h"
 
 static void __attribute__((destructor))
 unload(void)
 {
-	Class class = objc_getClass("TestPlugin");
-	Class metaclass = object_getClass(class);
-
-	objc_free_class(class);
-	objc_free_class(metaclass);
+	objc_unregister_class(objc_getClass("TestPlugin"));
 }
 #endif
 
 @implementation TestPlugin
 - (int)test: (int)num