+// PR c++/90047
+// { dg-do compile { target c++11 } }
+
+template <int a> struct b { static constexpr int c = a; };
+template <typename> struct aa;
+template <typename...> struct d;
+template <typename e, typename f, typename g, typename... h>
+struct d<e, f, g, h...> : aa<e>::i {};
+template <typename> struct j;
+template <typename k, long l> struct j<k[l]> : b<true> {};
+struct m {
+ typedef b<0> i;
+};
+template <typename> struct n : m::i {};
+template <bool> struct o;
+template <typename p> struct aa { typedef p i; };
+template <bool ab> using ac = typename o<ab>::i; // { dg-error "incomplete" }
+class q {
+ template <typename k, typename> using ad = ac<d<n<k>, int, int>::c>;
+ template <typename k, typename = ad<k, void>> q(k &);
+};
+template <typename r> struct s {
+ s(r) { t; }
+ template <ac<!j<r>::c> *> void t();
+};
+class I {
+ friend char operator<<(char p1, I p2) { return p1 << p2; }
+ q ag;
+};
+int main() { s<char[10]> a = (char *)""; }