anchor.diff:  	register struct sdef *sd;
   	register struct e_stack *p = p_stack;
   
  -	if (gen_error) return p->s_tpp;
  +	if (gen_error) if (p) return p->s_tpp; else return 0;
   again:
   	tp = *(p->s_tpp);
   	switch(tp->tp_fund) {
  
positive.code: static int gen_error;
  struct type **gen_tphead(), **gen_tpmiddle();
  struct sdef *gen_align_to_next();
  }
  
  /*	initial_value recursively guides the initialisation expression.
  
negative.code: 	struct type **tpp;
  {
  	register struct type *tp = *tpp;
  	register struct e_stack *p;
  	register struct sdef *sd;
  
  	if (gen_error) return tpp;
  	p = new_e_stack();
  	p->next = p_stack;
  	p_stack = p;
  	p->s_nested = nest;
  