contexpr lambdaが一行で表現できないconstexpr variable templateの定義に使えそうとういうアレ

type_find_if.cpp

template<template <class> class Pred, typename ...Types>
constexpr inline std::size_t type_find_if = []
{
    size_t result{};
    for(bool b: {Pred<Types>::value...}) if(b) return result; else ++result;
    return sizeof...(Types);
}();

int main() {
    static_assert(type_find_if<std::is_unsigned, int, char, short, int, unsigned,long> == 4);
}