This has been removed recently.
gdb/ChangeLog:
	* gdb-gdb.py.in (StructMainTypePrettyPrinter) <to_string>: Don't
	print tag_name.
+2018-06-27  Simon Marchi  <simon.marchi@ericsson.com>
+
+       * gdb-gdb.py.in (StructMainTypePrettyPrinter) <to_string>: Don't
+       print tag_name.
+
 2018-06-27  Simon Marchi  <simon.marchi@ericsson.com>
 
        * gdb-gdb.py.in (TypeFlag) <__cmp__>: Remove.
 
         """
         fields = []
         fields.append("name = %s" % self.val['name'])
-        fields.append("tag_name = %s" % self.val['tag_name'])
         fields.append("code = %s" % self.val['code'])
         fields.append("flags = [%s]" % self.flags_to_string())
         fields.append("owner = %s" % self.owner_to_string())