@@ -295,12 +295,13 @@
 	return self;
 }
 
 + (OFString *)className
 {
-	return [OFString stringWithCString: class_getName(self)
-				  encoding: OF_STRING_ENCODING_ASCII];
+	return [OFString
+	    stringWithCString: (const char *)class_getName(self)
+		     encoding: OF_STRING_ENCODING_ASCII];
 }
 
 + (bool)isSubclassOfClass: (Class)class
 {
 	for (Class iter = self; iter != Nil; iter = class_getSuperclass(iter))
@@ -357,13 +358,13 @@
 	IMP method = [class methodForSelector: selector];
 
 	if (method == NULL)
 		@throw [OFInvalidArgumentException exception];
 
-	return class_replaceMethod(object_getClass(self), selector,
-	    (IMP _Nonnull)method,
-	    typeEncodingForSelector(object_getClass(class), selector));
+	return class_replaceMethod((Class)object_getClass(self), selector,
+	    (IMP)method, typeEncodingForSelector(object_getClass(class),
+	    selector));
 }
 
 + (IMP)replaceInstanceMethod: (SEL)selector
 	 withMethodFromClass: (Class)class
 {
@@ -370,11 +371,11 @@
 	IMP method = [class instanceMethodForSelector: selector];
 
 	if (method == NULL)
 		@throw [OFInvalidArgumentException exception];
 
-	return class_replaceMethod(self, selector, (IMP _Nonnull)method,
+	return class_replaceMethod(self, selector, (IMP)method,
 	    typeEncodingForSelector(class, selector));
 }
 
 + (void)inheritMethodsFromClass: (Class)class
 {
@@ -483,22 +484,23 @@
 	return self;
 }
 
 - (Class)class
 {
-	return (Class _Nonnull)object_getClass(self);
+	return (Class)object_getClass(self);
 }
 
 - (Class)superclass
 {
 	return class_getSuperclass(object_getClass(self));
 }
 
 - (OFString *)className
 {
-	return [OFString stringWithCString: object_getClassName(self)
-				  encoding: OF_STRING_ENCODING_ASCII];
+	return [OFString
+	    stringWithCString: (const char *)object_getClassName(self)
+		     encoding: OF_STRING_ENCODING_ASCII];
 }
 
 - (bool)isKindOfClass: (Class)class
 {
 	for (Class iter = object_getClass(self); iter != Nil;
@@ -1026,11 +1028,11 @@
 {
 	void *pointer;
 	struct pre_mem *preMem;
 
 	if OF_UNLIKELY (size == 0)
-		return (void *_Nonnull)NULL;
+		return NULL;
 
 	if OF_UNLIKELY (size > SIZE_MAX - PRE_IVARS_ALIGN)
 		@throw [OFOutOfRangeException exception];
 
 	if OF_UNLIKELY ((pointer = malloc(PRE_MEM_ALIGN + size)) == NULL)