diff --git a/src/Attr.cc b/src/Attr.cc
index b0d2947a00..22e1ef35d8 100644
--- a/src/Attr.cc
+++ b/src/Attr.cc
@@ -192,6 +192,9 @@ void Attributes::AddAttr(AttrPtr attr, bool is_redef)
 	{
 	auto acceptable_duplicate_attr = [](const AttrPtr& attr, const AttrPtr& existing) -> bool
 	{
+		if ( attr == existing )
+			return true;
+
 		AttrTag new_tag = attr->Tag();
 
 		if ( new_tag == ATTR_DEPRECATED )