//Specificity to resolve ambiguity between FList-IEnumerable
public static FList <T> operator+(FList <T> lhs, FList <T> rhs)
{
return(FList.Cast(lhs.collection.Concat(rhs.collection)));
}
public static FList <T> operator+(IEnumerable <T> lhs, FList <T> rhs)
{
return(FList.Cast(FList.Cast(lhs).collection.Concat(rhs)));
}
public static FList <T> operator+(T lhs, FList <T> rhs)
{
return(FList.Cast(Enumerable.Empty <T>().DefaultIfEmpty(lhs).Concat(rhs)));
}