re PR c++/53856 (Default argument allowed on member defined outside of class template)

/cp
2015-10-05  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/53856
	* pt.c (check_default_tmpl_args): Per [temp.param]/9, do not
	reject default template arguments in out of class definitions
	of members of non-template classes.

/testsuite
2015-10-05  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/53856
	* g++.dg/template/defarg19.C: New.
	* g++.dg/template/defarg20.C: Likewise.

From-SVN: r228501

gcc/cp/ChangeLog

+2015-10-05  Paolo Carlini  <paolo.carlini@oracle.com>
+
+	PR c++/53856
+	* pt.c (check_default_tmpl_args): Per [temp.param]/9, do not
+	reject default template arguments in out of class definitions
+	of members of non-template classes.
+
 2015-10-05  Richard Sandiford  <richard.sandiford@arm.com>
 
 	* tree.c (cp_tree_equal): Use real_equal instead of

gcc/cp/pt.c

@@ -4940,8 +4940,15 @@ check_default_tmpl_args (tree decl, tree parms, bool is_primary,
   else if (is_partial)
     msg = G_("default template arguments may not be used in "
 	     "partial specializations");
-  else
+  else if (current_class_type && CLASSTYPE_IS_TEMPLATE (current_class_type))
     msg = G_("default argument for template parameter for class enclosing %qD");
+  else
+    /* Per [temp.param]/9, "A default template-argument shall not be
+       specified in the template-parameter-lists of the definition of
+       a member of a class template that appears outside of the member's
+       class.", thus if we aren't handling a member of a class template
+       there is no need to examine the parameters.  */
+    return true;
 
   if (current_class_type && TYPE_BEING_DEFINED (current_class_type))
     /* If we're inside a class definition, there's no need to

gcc/testsuite/ChangeLog

+2015-10-05  Paolo Carlini  <paolo.carlini@oracle.com>
+
+	PR c++/53856
+	* g++.dg/template/defarg19.C: New.
+	* g++.dg/template/defarg20.C: Likewise.
+
 2015-10-05  Aditya Kumar  <aditya.k7@samsung.com>
 	    Sebastian Pop  <s.pop@samsung.com>
 

gcc/testsuite/g++.dg/template/defarg19.C

+// PR c++/53856
+
+template<typename T>
+struct A
+{
+  struct B;
+};
+
+template<typename T = int>
+struct A<T>::B  // { dg-error "default argument" }
+{
+  int i;
+};
+
+A<int>::B b = { };

gcc/testsuite/g++.dg/template/defarg20.C

+// PR c++/53856
+
+struct A
+{
+  template<typename T>
+  struct B;
+};
+
+template<typename T = int>
+struct A::B
+{
+  int i;
+};
+
+A::B<int> b = { };