#92 Executability of existential quantifiers in jmlc

[Yoonsik Cheon]

The jmlc can execute the first quantifier, but not the
second one;

//@ requires (\exists Object e; s.contains(e) && e !=
null);

//@ requires (\exists Object e; s.contains(e));

Perhaps, it is looking for patterns like "R && P" when
determining the domains of existential quantifiers, where
R is a predicate constraining the quantified variables.