diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h
index 9008eab..a9f7947 100644
--- a/include/linux/compiler-gcc.h
+++ b/include/linux/compiler-gcc.h
@@ -22,6 +22,9 @@
     __asm__ ("" : "=r"(__ptr) : "0"(ptr));		\
     (typeof(ptr)) (__ptr + (off)); })
 
+/* &a[0] degrades to a pointer: a different type from an array */
+#define __must_be_array(a) \
+  BUILD_BUG_ON_ZERO(__builtin_types_compatible_p(typeof(a), typeof(&a[0])))
 
 #define inline		inline		__attribute__((always_inline))
 #define __inline__	__inline__	__attribute__((always_inline))