Represents a conditional postcondition that must be verified by BaseTypeVisitor or
one of its subclasses. Automatically extracted from annotations with meta-annotation
@ConditionalPostconditionAnnotation, such as EnsuresNonNullIf.
The return value for the annotated method that ensures that the conditional postcondition
holds. For example, given @EnsuresNonNullIf(expression="foo", result=false) boolean method() foo is guaranteed to be @NonNull after a call to method() if that
call returns false.