Wireshark-dev: [Wireshark-dev] proto_field_is_referenced
Date: Sat, 23 Nov 2013 14:23:54 -0500 (EST)
Is proto_field_is_references still a valid function?

In looking at the intent, it either looks completely useless or should be used on almost all dissectors.  I was leaning more towards useless because I can't think of a scenario where tree (is already) != NULL, yet a dissector would be called without having its proto field referenced.