I was reading this excellent material about the strict aliasing rule: https://stackoverflow.com/a/51228315/21691539 or https://gist.github.com/shafik/a956a17d00024b32b35634eeba1eb49e

But in the section about std::bit_cast and an alleged limitation of std::bit_cast, I don't understand the need for both a std::memcpy and a std::bit_cast.

The provided example seemed a bit contrived and can be simplified to:

#include 
#include 

struct some_chars {
    unsigned char arr[sizeof(unsigned int)] = {};
};
unsigned int foo(unsigned char *p) {
    some_chars a;
    std::memcpy(a.arr, p, sizeof(unsigned int));
    unsigned int result = std::bit_cast(a);
    return result;
}

(see here)
(Here and in the following, p is assumed to point to a storage of at least sizeof(unsigned int) unsigned char)

I'm finding the purpose of the intermediate struct unclear. What would be wrong with the following?

unsigned int foo(unsigned char *p) {
    unsigned int result;
    std::memcpy(&result, p, sizeof(unsigned int));
    return result;
}

why not std::memcpy directly into an unsigned int as illustrated in cpprefence?

// reinterpreting
double d = 0.1;
//  std::int64_t n = *reinterpret_cast(&d); // aliasing violation
std::int64_t n;
std::memcpy(&n, &d, sizeof d); // OK

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