PR c++/71738 - nested template friend

	* pt.c (lookup_template_class_1): Handle getting template from tsubst.

From-SVN: r238685

gcc/cp/ChangeLog

 2016-07-23  Jason Merrill  <jason@redhat.com>
 
+	PR c++/71738
+	* pt.c (lookup_template_class_1): Handle getting template from tsubst.
+
 	PR c++/71350
 	* decl.c (reshape_init_r): Check complain for missing braces warning.
 

gcc/cp/pt.c

@@ -8601,7 +8601,9 @@ lookup_template_class_1 (tree d1, tree arglist, tree in_decl, tree context,
 	     for parameters in the TYPE_DECL of the alias template
 	     done earlier.  So be careful while getting the template
 	     of FOUND.  */
-	  found = TREE_CODE (found) == TYPE_DECL
+	  found = TREE_CODE (found) == TEMPLATE_DECL
+	    ? found
+	    : TREE_CODE (found) == TYPE_DECL
 	    ? TYPE_TI_TEMPLATE (TREE_TYPE (found))
 	    : CLASSTYPE_TI_TEMPLATE (found);
 	}

gcc/testsuite/g++.dg/template/friend63.C

+// PR c++/71738
+
+template < class > struct S
+{
+  template < class > struct A
+  { 
+    template < class > struct B
+    {
+      template <class Z>
+      void operator=(Z) { S::i = 0; }
+    };
+  };
+
+  // Note that this friend declaration is useless, since nested classes are
+  // already friends of their enclosing class.
+  template < class X >
+  template < class Y >
+  template < class Z >
+  friend void A < X >::B < Y >::operator= (Z);
+
+private:
+  static int i;
+};
+
+int main()
+{
+  S<int>::A<int>::B<int> b;
+  b = 0;
+}