optimized 'bnf_of_typ' further w.r.t. dead variables
optimized 'bnf_of_typ' further w.r.t. dead variables

MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle