From 0bcd172dbf4f3d9168d4436e5f34730b8987762a Mon Sep 17 00:00:00 2001
From: Jason Merrill <jason@redhat.com>
Date: Wed, 21 Dec 2016 14:10:23 -0500
Subject: [PATCH] PR c++/78767 - ICE with inherited constructor default
 argument

	* method.c (strip_inheriting_ctors): Strip template as appropriate.

From-SVN: r243864
---
 gcc/cp/ChangeLog                        |  3 +++
 gcc/cp/method.c                         |  6 +++++-
 gcc/testsuite/g++.dg/cpp0x/inh-ctor24.C | 15 +++++++++++++++
 3 files changed, 23 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/g++.dg/cpp0x/inh-ctor24.C

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index c4c51719374..1b14e1980c8 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,5 +1,8 @@
 2016-12-21  Jason Merrill  <jason@redhat.com>
 
+	PR c++/78767 - ICE with inherited constructor default argument
+	* method.c (strip_inheriting_ctors): Strip template as appropriate.
+
 	PR c++/78749 - friend in anonymous namespace
 	* decl.c (wrapup_globals_for_namespace): Don't complain about friend
 	pseudo-template instantiations.
diff --git a/gcc/cp/method.c b/gcc/cp/method.c
index 73d42b19d55..a5271a443cf 100644
--- a/gcc/cp/method.c
+++ b/gcc/cp/method.c
@@ -496,14 +496,18 @@ forward_parm (tree parm)
    constructor from a (possibly indirect) base class.  */
 
 tree
-strip_inheriting_ctors (tree fn)
+strip_inheriting_ctors (tree dfn)
 {
   gcc_assert (flag_new_inheriting_ctors);
+  tree fn = dfn;
   while (tree inh = DECL_INHERITED_CTOR (fn))
     {
       inh = OVL_CURRENT (inh);
       fn = inh;
     }
+  if (TREE_CODE (fn) == TEMPLATE_DECL
+      && TREE_CODE (dfn) == FUNCTION_DECL)
+    fn = DECL_TEMPLATE_RESULT (fn);
   return fn;
 }
 
diff --git a/gcc/testsuite/g++.dg/cpp0x/inh-ctor24.C b/gcc/testsuite/g++.dg/cpp0x/inh-ctor24.C
new file mode 100644
index 00000000000..7c1fae0cfc7
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/inh-ctor24.C
@@ -0,0 +1,15 @@
+// PR c++/78767
+// { dg-do compile { target c++11 } }
+
+template <class T> struct A
+{
+  template <class U>
+  A(U, U = 42);
+};
+
+struct B: A<int>
+{
+  using A::A;
+};
+
+B b(24);