workaround to avoid subtle "add_ffpairs" unification exception in Sledgehammer;
to reproduce the old bug, replace the command
by(rule new_Addr_SomeD)
on line 27 of Jinja/J/TypeSafe.thy with
by (metis new_Addr_SomeD)
(* Title: HOL/Import/ROOT.ML
Author: Sebastian Skalberg (TU Muenchen)
*)
use_thys ["HOL4Compat", "HOL4Syntax"];