std::bit_cast is one of the standard functions working with binary representation. Together with other bit-level functions, it is
defined in the <bit> header introduced by C++20.
std::bit_cast standardizes the diverse and sub-optimal approaches of reinterpreting a value as being of a different type of the same
length, preserving its binary representation.
Before C++20, the correct way to reinterpret a value was a call to std::memcpy, copying the exact binary representation from a
variable of one type into a variable of another. Although canonical, the use of std::memcpy might still be confusing; it is verbose, and
it might introduce performance overhead if the compiler does not recognize the idiom and does not remove the function call.
In contrast, std::bit_cast clearly states the intent and is guaranteed to map to an optimal implementation.
This rule reports the uses of std::memcpy that can be replaced by std::bit_cast.
Noncompliant code example
static_assert(sizeof(float) == sizeof(uint32_t));
float src = 1.0f;
uint32_t dst;
std::memcpy(&dst, &src, sizeof(float)); // Noncompliant: verbose and might incur performance hit
Compliant solution
float src = 1.0f;
auto dst = std::bit_cast<uint32_t>(src); // Compliant
