You can edit your prefer type generalize oder typedef boost::mpl::vector::type ordered_number_types; => typedef boost::mpl::vector::type ordered_number_types;

1. Is double guaranteed to be a superset of int? 2. Do you lose the information, which type is contained (int/double)?

Regards, Kris

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I wrote such extension

https://github.com/niitsuma/variant_shrink

float tends not to hold all ints. double usually does, although I'm not sure it is guaranteed.

Such complicated type order can use by defining is_generalizable_to plz see section define is_generalizable_to : in https://github.com/niitsuma/variant_shrink