[committed] Add testcase for already fixed PR c++/84813

[Jakub Jelinek]

Hi!

This PR got fixed in r251433 which I'm afraid is not backportable,
we were trying to register local specialization during dwarf2out_type_decl.

I've committed the testcase as obvious to trunk, so that we don't regress
on it again:

2018-03-12  Jakub Jelinek  <ja...@redhat.com>

        PR c++/84813
        * g++.dg/debug/pr84813.C: New test.

--- gcc/testsuite/g++.dg/debug/pr84813.C.jj     2018-03-12 09:57:50.197029595 
+0100
+++ gcc/testsuite/g++.dg/debug/pr84813.C        2018-03-12 09:57:40.279028562 
+0100
@@ -0,0 +1,33 @@
+// PR c++/84813
+// { dg-do compile }
+// { dg-options "-g -std=c++14" }
+
+template <typename>
+struct P {};
+
+template <int>
+struct F {
+  using type = int;
+};
+
+template <typename T>
+void
+apply ()
+{
+  constexpr int N = T::N;
+  [] (typename F<N>::type)
+  {
+    auto f = [] () {};
+    P<decltype (f)>{};
+  };
+}
+
+struct A {
+  static constexpr int N = 1;
+};
+
+void
+instantiate ()
+{
+  apply<A> ();
+}


        Jakub