/** Copy the given entry and all entries shadowed by it to table */
 private void copy(Entry e) {
   if (e.sym != null) {
     copy(e.shadowed);
     int hash = e.sym.name.index & hashMask;
     e.shadowed = table[hash];
     table[hash] = e;
   }
 }
 /** Double size of hash table. */
 private void dble() {
   assert shared == 0;
   Entry[] oldtable = table;
   Entry[] newtable = new Entry[oldtable.length * 2];
   for (Scope s = this; s != null; s = s.next) {
     if (s.table == oldtable) {
       assert s == this || s.shared != 0;
       s.table = newtable;
       s.hashMask = newtable.length - 1;
     }
   }
   for (int i = 0; i < newtable.length; i++) newtable[i] = sentinel;
   for (int i = 0; i < oldtable.length; i++) copy(oldtable[i]);
 }