diff -r e460c53c1c9b -r 779af7c58743 src/HOL/MicroJava/BV/StepMono.thy
--- a/src/HOL/MicroJava/BV/StepMono.thy	Wed Dec 06 19:05:50 2000 +0100
+++ b/src/HOL/MicroJava/BV/StepMono.thy	Wed Dec 06 19:09:34 2000 +0100
@@ -174,7 +174,7 @@
                   "is_class G cname" and
               oT: "G\<turnstile> oT\<preceq> (Class cname)" and
               vT: "G\<turnstile> vT\<preceq> b"
-        by simp (elim exE conjE, rule that) 
+        by force
       moreover
       from s1 G
       obtain vT' oT' ST' LT'