diff --git a/Source/String.m b/Source/String.m
index ae1e6c3ef..7d891072c 100644
--- a/Source/String.m
+++ b/Source/String.m
@@ -258,14 +258,14 @@
   return [self cStringCopyRange:((IndexRange){0, [self count]})];
 }
 
-- copy
+- copyWithZone: (NSZone*)z
 {
-  return [[[self class] alloc] initWithString:(NSString*)self];
+  return [[[self class] allocWithZone:z] initWithString:(NSString*)self];
 }
 
-- mutableCopy
+- mutableCopyWithZone: (NSZone*)z
 {
-  return [[MutableCString alloc] initWithString:(NSString*)self];
+  return [[MutableCString allocWithZone:z] initWithString:(NSString*)self];
 }
 
 // TESTING;