constexpr is often difficult to get right. For example, we use a wide_integer type for 128 and 256-bit integers: https://github.com/ClickHouse/ClickHouse/blob/

constexpr is often difficult to get right. For example, we use a wide_integer type for 128 and 256-bit integers: https://github.com/ClickHouse/ClickHouse/blob/master/base/base/wide_integer_impl.h https://github.com/ClickHouse/ClickHouse/blob/master/base/ba... It was developed by a C++ expert to fit into the C++ standard, so it has constexpr everywhere. But for this reason, we cannot use memcpy inside its methods and have to wait for a new standard with constexpr memcpy. Note: memcpy is to satisfy strict aliasing - we can use std::bit_cast instead, but there was some trouble.