r_symbol
if (reporter->r_symbol)
reporter->r_symbol(fix_mode(ret, mode), &expr->pos, sym);
if (reporter->r_symbol)
reporter->r_symbol(U_W_VAL, &sym->pos, sym);
void (*r_symbol)(unsigned, struct position *, struct symbol *);
r_symbol(-1, &sym->pos, sym);
.r_symbol = r_symbol,