re PR c++/87523 (ICE: Closures apparently fail to capture constexpr)

	PR c++/87523
	* g++.dg/cpp1y/lambda-generic-87523.C: New test.

From-SVN: r266714

gcc/testsuite/ChangeLog

@@ -40,6 +40,9 @@
 	PR c++/79629
 	* g++.dg/other/error35.C: New test.
 
+	PR c++/87523
+	* g++.dg/cpp1y/lambda-generic-87523.C: New test.
+
 2018-12-01  Jeff Law  <law@redhat.com>
 
 	* gcc.dg/predict-22.c: Update expected output.

gcc/testsuite/g++.dg/cpp1y/lambda-generic-87523.C

+// PR c++/87523
+// { dg-do compile { target c++14 } }
+
+template <typename T, T v>
+struct my_integer_constant {
+    constexpr my_integer_constant() {}
+    constexpr operator T() const { return v; }
+    constexpr T operator()() const { return v; }
+};
+
+template <typename T, T... u>
+struct constant_call {
+    template <typename Callback>
+    static void call(T v, Callback f) {
+        char dummy[sizeof...(u)] = { ( (v == u) ? (f(my_integer_constant<T, u>{}), static_cast<char>(0)) : static_cast<char>(0))... };
+        (void)dummy;
+    }
+};
+
+void f(bool reverse_in, bool other_bool_in) {
+    auto helper = [&] (auto reverse_t) {
+        bool constexpr reverse_v = reverse_t;
+        (void)reverse_v;
+        constant_call<bool, true, false>::call(other_bool_in,
+                                               [&] (auto newb) {
+                                                   bool reverse_v_dyn = reverse_v;
+                                               });
+    };
+    constant_call<bool, true, false>::call(reverse_in, [&] (auto reverse_t) {
+            helper(reverse_t);
+        });
+}