Index: Source/NSString.m
===================================================================
--- Source/NSString.m	(revision 33161)
+++ Source/NSString.m	(working copy)
@@ -1115,7 +1115,7 @@
 {
   va_list ap;
   va_start(ap, locale);
-  return [self initWithFormat: format locale: locale arguments: ap];
+  self = [self initWithFormat: format locale: locale arguments: ap];
   va_end(ap);
   return self;
 }