Implement shift operators

gcc/elna-tree.cc

@@ -195,7 +195,7 @@ namespace gcc
         else
         {
             error_at(expression_location,
-                    "invalid operands of type %s and %s for operator %s",
+                    "invalid operands of type '%s' and '%s' for operator %s",
                     print_type(left_type).c_str(), print_type(right_type).c_str(),
                     elna::boot::print_binary_operator(expression->operation()));
             return error_mark_node;