C++ copy elision when returning a function argument

I’m puzzled as to how this code compiles: (https://godbolt.org/z/hjY4ca4rr)

C++ copy elision when returning a function argument

I’m puzzled as to how this code compiles: (https://godbolt.org/z/hjY4ca4rr)

C++ copy elision when returning a function argument

I’m puzzled as to how this code compiles: (https://godbolt.org/z/hjY4ca4rr)

C++ copy elision when returning a function argument

I’m puzzled as to how this code compiles: (https://godbolt.org/z/hjY4ca4rr)