--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/g++.dg/cpp1y/auto-fn50.C	Thu Oct 25 07:37:49 2018 +0900
@@ -0,0 +1,23 @@
+// PR c++/84906
+// { dg-do compile { target c++14 } }
+
+extern "C" int puts(const char*);
+
+struct aa {
+  operator auto() {
+    puts("auto");
+    return false;
+  }
+  explicit operator bool() {
+    puts("bool");
+    return true;
+  }
+};
+
+int main() {
+  aa x;
+  if (x)			// { dg-error "ambiguous" }
+    puts("here");
+  else
+    puts("there");
+}