If <code>list</code> pointed to a cyclic list,
then the original program would never access <code>*p</code> or <code>*q</code>,
but the rewritten program would.
(Moving `*p` ahead would be safe if the compiler can prove `*p` will not panic;
moving `*q` ahead would also require the compiler proving that no other
goroutine can access `*q`.)
</p>

<p>
Not introducing data races also means not assuming that called functions

Otherwise, the local stack frame must not contain pointers,
and the assembly must confirm this fact by executing the
pseudo-instruction <code>NO_LOCAL_POINTERS</code>.
Because stack resizing is implemented by moving the stack,
the stack pointer may change during any function call:
even pointers to stack data must not be kept in local variables.
</p>

<p>
Assembly functions should always be given Go prototypes,