diff --git a/MagickCore/cache-private.h b/MagickCore/cache-private.h
index 71d6768..2fc090e 100644
--- a/MagickCore/cache-private.h
+++ b/MagickCore/cache-private.h
@@ -24,6 +24,7 @@
 
 #include <time.h>
 #include "MagickCore/cache.h"
+#include "MagickCore/pixel.h"
 #include "MagickCore/random_.h"
 #include "MagickCore/thread-private.h"
 #include "MagickCore/semaphore.h"
@@ -110,8 +111,10 @@
   ColorspaceType
     colorspace;
 
+  PixelTrait
+    alpha_trait;
+
   MagickBooleanType
-    matte,
     mask;
 
   size_t