diff --git a/src/message_test.c b/src/message_test.c
index 014d8d9..85a29b4 100644
--- a/src/message_test.c
+++ b/src/message_test.c
@@ -127,7 +127,7 @@
     int		n;
     size_t	bsize;
     int		bsize_int;
-    char	*ptr = (char *)0x87654321;
+    void	*ptr = (void *)0x87654321;
 
     // Loop on various buffer sizes to make sure that truncation of
     // vim_snprintf() is correct.