===================================================================
@@ -0,0 +1,37 @@
+// PR c++/54323
+// { dg-do compile { target c++11 } }
+
+template<bool, typename T = void>
+struct enable_if { };
+
+template<typename T>
+struct enable_if<true, T>
+{ typedef T type; };
+
+template<template<typename> class CRTP, typename T>
+class Base
+{
+public:
+ template<template<typename> class CRTP0, typename T0, class>
+ friend int func(const Base<CRTP0, T0>& rhs);
+
+protected:
+ int n;
+};
+
+template<template<typename> class CRTP0, typename T0,
+ class = typename enable_if<true>::type>
+int func(const Base<CRTP0, T0>& rhs)
+{
+ return rhs.n;
+}
+
+template<typename T>
+class Derived : public Base<Derived, T> {};
+
+int main()
+{
+ Derived<int> x;
+ func(x);
+ return 0;
+}