public class FieldFilterTypeFlow
extends TypeFlow<AnalysisField>
The field filter flow is used for unsafe writes to fields. An unsafe write to an object can write
to any of the unsafe accessed fields of that object, however the written values may not be
compatible with all the fields. Thus the written values need to be filtered using the field
FieldFilterTypeFlow type. The FieldFilterTypeFlow is a simplified version of FilterTypeFlow in
that it is 'not-exact', i.e., it allows types of that are sub-types of the field declared type,
it is always 'assignable', i.e., it allows types that are assignable to the field declared type,
and it 'includes-null', i.e., it allows null values to pass through. However it's 'source' is an
AnalysisField and not a ValueNode, thus it's a completely different class.