--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/g++.dg/torture/pr51737.C	Fri Oct 27 22:46:09 2017 +0900
@@ -0,0 +1,30 @@
+// { dg-do compile }
+template<class T> class intrusive_ptr {
+public:
+    ~intrusive_ptr() { intrusive_ptr_release( px ); }
+    T * px;
+};
+template <typename T>     struct intrusive_base     {
+    friend void intrusive_ptr_release(T* ptr) { delete ptr; }
+};
+struct section_info;
+struct file_info : intrusive_base<file_info> {
+    intrusive_ptr<file_info> parent;
+    intrusive_ptr<section_info> switched_section;
+};
+struct section_info : intrusive_base<section_info> {
+    intrusive_ptr<section_info> parent;
+};
+struct id_state {
+    void * start_file(void);
+};
+void * id_state::start_file(void) {
+    intrusive_ptr<file_info> parent;
+}
+struct id_generation_data : intrusive_base<id_generation_data> {
+    void child_length() const {}
+};
+void generate_id(id_generation_data& generation_data)
+{
+  generation_data.child_length();
+}