From 8f712b76904c9e495d16817fa93f8edde4c1f0cd Mon Sep 17 00:00:00 2001
From: Jason Merrill <jason@redhat.com>
Date: Mon, 20 Feb 2017 01:06:39 -0500
Subject: [PATCH] PR c++/78282 - auto template and pack expansion

	* pt.c (find_parameter_packs_r): Don't walk into the type of
	templates other than template template-parameters.

From-SVN: r245594
---
 gcc/cp/ChangeLog                       |  4 ++++
 gcc/cp/pt.c                            |  6 +++++-
 gcc/testsuite/g++.dg/cpp1y/auto-fn36.C | 26 ++++++++++++++++++++++++++
 3 files changed, 35 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/g++.dg/cpp1y/auto-fn36.C

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 7258348ec9e..b5def8cbb53 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,5 +1,9 @@
 2017-02-19  Jason Merrill  <jason@redhat.com>
 
+	PR c++/78282 - auto template and pack expansion
+	* pt.c (find_parameter_packs_r): Don't walk into the type of
+	templates other than template template-parameters.
+
 	PR c++/79606 - ICE with this->base_member in NSDMI
 	* class.c (build_base_path): Check processing_template_decl.
 
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 0a9f5d518d3..2cac24f0714 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -3576,8 +3576,12 @@ find_parameter_packs_r (tree *tp, int *walk_subtrees, void* data)
       *walk_subtrees = 0;
       return NULL_TREE;
 
-    case CONSTRUCTOR:
     case TEMPLATE_DECL:
+      if (!DECL_TEMPLATE_TEMPLATE_PARM_P (t))
+	return NULL_TREE;
+      gcc_fallthrough();
+
+    case CONSTRUCTOR:
       cp_walk_tree (&TREE_TYPE (t),
 		    &find_parameter_packs_r, ppd, ppd->visited);
       return NULL_TREE;
diff --git a/gcc/testsuite/g++.dg/cpp1y/auto-fn36.C b/gcc/testsuite/g++.dg/cpp1y/auto-fn36.C
new file mode 100644
index 00000000000..f89c0928f11
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1y/auto-fn36.C
@@ -0,0 +1,26 @@
+// PR c++/78282
+// { dg-do compile { target c++14 } }
+
+struct null_node
+{
+  null_node(const null_node&);
+};
+
+extern null_node null;
+
+template <typename T>
+auto get() { return null; }
+
+template <typename... Ts>
+struct inheritor: Ts...
+{
+  inheritor(const inheritor& outer)
+    : Ts(get<Ts...>())...
+    { }
+};
+
+void test()
+{
+  extern inheritor<null_node> example;
+  inheritor<null_node> result(example);
+}
-- 
2.30.2