--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/g++.dg/warn/Winit-list2.C	Thu Oct 25 07:37:49 2018 +0900
@@ -0,0 +1,32 @@
+// { dg-do compile { target c++11 } }
+
+#include <initializer_list>
+
+extern "C" int printf (const char *, ...);
+
+using size_t = decltype(sizeof(0));
+
+template <typename T> class ArrayRef {
+public:
+  using size_type = size_t;
+
+private:
+  /// The start of the array, in an external buffer.
+  const T *Data = nullptr;
+
+  /// The number of elements.
+  size_type Length = 0;
+
+public:
+  /// Construct an ArrayRef from a std::initializer_list.
+  /*implicit*/ ArrayRef(const std::initializer_list<T> &Vec)
+      : Data(Vec.begin() == Vec.end() ? (T *)nullptr : Vec.begin()), // { dg-warning initializer_list }
+        Length(Vec.size()) {}
+
+  const T &operator[](size_t Index) const { return Data[Index]; }
+};
+
+int main() {
+  const ArrayRef<int> Foo = {42};
+  printf ("Foo %d\n", Foo[0]);
+}