paulson [Thu, 16 Dec 1999 17:01:16 +0100] rev 8066
SOUNDNESS BUG FIX for rotate_rule. The original code did not expect
nested parameters such as !!y.
Goal "!!x. x = a ==> (!!y. y ~= a ==> False)";
by (rotate_tac 1 1);
be notE 1;
ba 1;
qed "foo";
val FalseI = standard (True_not_False RS (standard (refl RS foo)));