DR 1155

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

From-SVN: r226992

gcc/cp/ChangeLog

+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

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;
 	}

gcc/testsuite/g++.dg/cpp0x/nontype1.C

+// { 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" }

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