public override IExpression Specialize(IEnumerable <Type> allowedTypes)
{
var unified = Types.SpecializeTo(allowedTypes);
if (unified == null)
{
return(null);
}
var isFormAb = formAB.UnifyAll(unified) != null;
var isFormCd = formCD.UnifyAll(unified) != null;
if (isFormAb && isFormCd)
{
return(new EitherFunc(unified)); // Can't make a decision yet
}
if (isFormAb)
{
return(Funcs.Const.Specialize(unified));
}
if (isFormCd)
{
return(Funcs.ConstRight.Specialize(unified));
}
return(null);
}