From 0d2e69cb3c08f44a15415fb264bf438bb8c9707c Mon Sep 17 00:00:00 2001
From: Jason Merrill <jason@redhat.com>
Date: Tue, 22 May 2018 23:52:49 -0400
Subject: [PATCH] PR c++/85866 - error with .* in default template arg.

	* pt.c (tsubst_copy_and_build): Handle partial instantiation.

From-SVN: r260562
---
 gcc/cp/ChangeLog                          |  5 ++++
 gcc/cp/pt.c                               |  4 +++-
 gcc/testsuite/g++.dg/cpp0x/fntmpdefarg9.C | 29 +++++++++++++++++++++++
 3 files changed, 37 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/g++.dg/cpp0x/fntmpdefarg9.C

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 6aed157616b..ce22731d63c 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,8 @@
+2018-05-22  Jason Merrill  <jason@redhat.com>
+
+	PR c++/85866 - error with .* in default template arg.
+	* pt.c (tsubst_copy_and_build): Handle partial instantiation.
+
 2018-05-21  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	* parser.c (cp_parser_parameter_declaration_list): Remove
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 81de633b1ee..0b04770e123 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -18433,7 +18433,9 @@ tsubst_copy_and_build (tree t,
 	      /* Unsupported internal function with arguments.  */
 	      gcc_unreachable ();
 	    }
-	else if (TREE_CODE (function) == OFFSET_REF)
+	else if (TREE_CODE (function) == OFFSET_REF
+		 || TREE_CODE (function) == DOTSTAR_EXPR
+		 || TREE_CODE (function) == MEMBER_REF)
 	  ret = build_offset_ref_call_from_tree (function, &call_args,
 						 complain);
 	else if (TREE_CODE (function) == COMPONENT_REF)
diff --git a/gcc/testsuite/g++.dg/cpp0x/fntmpdefarg9.C b/gcc/testsuite/g++.dg/cpp0x/fntmpdefarg9.C
new file mode 100644
index 00000000000..833049c6de3
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/fntmpdefarg9.C
@@ -0,0 +1,29 @@
+// PR c++/85866
+// { dg-do compile { target c++11 } }
+
+template<typename _Tp, typename _Up = _Tp&&>
+_Up
+__declval(int);
+
+template<typename _Tp>
+_Tp
+__declval(long);
+
+template<typename _Tp>
+auto declval() noexcept -> decltype(__declval<_Tp>(0));
+
+template<typename...>
+using void_t = void;
+
+template<typename U, typename V,
+	 void_t<decltype ( (declval<U>().*declval<V>()) () )
+		>* = nullptr>
+void boom(){}
+
+struct Foo {
+  void bar(){}
+};
+
+int main() {
+  boom<Foo, decltype(&Foo::bar)>();
+}