If you pass a pointer into a function, the Go compiler can (and sometimes does) allocate it on the heap. Go has no allocation/ownership semantics, tragically, so the best we can do is depend on undefined behavior regarding the escape analyzer and hope the Go team doesn’t break it (which is a relatively safe assumption, considering that it’s unlikely that the Go team would start allocating things on the heap that were previously allocated on the stack—Go rarely regresses performance like this).