From 8e43da810d60823d33cee7a863e80c6a5b7f2941 Mon Sep 17 00:00:00 2001
From: Jason Merrill <jason@redhat.com>
Date: Tue, 18 Aug 2015 17:29:01 -0400
Subject: [PATCH] DR 1155

	DR 1155
	* pt.c (convert_nontype_argument): Allow internal linkage in C++11
	and up.

From-SVN: r226992
---
 gcc/cp/ChangeLog                                 | 6 ++++++
 gcc/cp/pt.c                                      | 8 +++++---
 gcc/testsuite/g++.dg/cpp0x/nontype1.C            | 9 +++++++++
 gcc/testsuite/g++.old-deja/g++.oliva/template4.C | 2 +-
 4 files changed, 21 insertions(+), 4 deletions(-)
 create mode 100644 gcc/testsuite/g++.dg/cpp0x/nontype1.C

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 0bf33c8eb6a..2c2cb6d5535 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,9 @@
+2015-08-18  Jason Merrill  <jason@redhat.com>
+
+	DR 1155
+	* pt.c (convert_nontype_argument): Allow internal linkage in C++11
+	and up.
+
 2015-08-17  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	PR c++/67216
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index b84bda47fd1..eaafaeff569 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -6469,16 +6469,18 @@ convert_nontype_argument (tree type, tree expr, tsubst_flags_t complain)
 	{
 	  if (complain & tf_error)
 	    error ("%qE is not a valid template argument for type %qT "
-		   "because it is not an object with external linkage",
+		   "because it is not an object with linkage",
 		   expr, type);
 	  return NULL_TREE;
 	}
 
-      if (!DECL_EXTERNAL_LINKAGE_P (expr))
+      /* DR 1155 allows internal linkage in C++11 and up.  */
+      linkage_kind linkage = decl_linkage (expr);
+      if (linkage < (cxx_dialect >= cxx11 ? lk_internal : lk_external))
 	{
 	  if (complain & tf_error)
 	    error ("%qE is not a valid template argument for type %qT "
-		   "because object %qD has not external linkage",
+		   "because object %qD does not have linkage",
 		   expr, type, expr);
 	  return NULL_TREE;
 	}
diff --git a/gcc/testsuite/g++.dg/cpp0x/nontype1.C b/gcc/testsuite/g++.dg/cpp0x/nontype1.C
new file mode 100644
index 00000000000..29dff363974
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/nontype1.C
@@ -0,0 +1,9 @@
+// { dg-do compile { target c++11 } }
+
+struct L { constexpr operator int() const { return 0; } };
+constexpr L LVar{};
+
+template<const L&> int *f() { return 0; }
+template<int> char *f();
+
+auto r = f<LVar>();		// { dg-error "ambiguous" }
diff --git a/gcc/testsuite/g++.old-deja/g++.oliva/template4.C b/gcc/testsuite/g++.old-deja/g++.oliva/template4.C
index 2268fde400e..ef607f604a2 100644
--- a/gcc/testsuite/g++.old-deja/g++.oliva/template4.C
+++ b/gcc/testsuite/g++.old-deja/g++.oliva/template4.C
@@ -11,7 +11,7 @@ int a = 1;
 X<a> x; // ok, a has external linkage
 
 const int b = 2;
-X<b> y; // { dg-error "" } const b has internal linkage
+X<b> y; // { dg-error "" "" { target c++98_only } } const b has internal linkage
 
 extern const int c;
 X<c> z; // ok, c has external linkage
-- 
2.30.2