STATIC void
S_invlist_replace_list_destroys_src(pTHX_ SV * dest, SV * src)
{
    /* Replaces the inversion list in 'dest' with the one from 'src'.  It
     * steals the list from 'src', so 'src' is made to have a NULL list.  This
     * is similar to what SvSetMagicSV() would do, if it were implemented on
     * inversion lists, though this routine avoids a copy */

    const UV src_len          = _invlist_len(src);
    const bool src_offset     = *get_invlist_offset_addr(src);
    const STRLEN src_byte_len = SvLEN(src);
    char * array              = SvPVX(src);

    const int oldtainted = TAINT_get;

    PERL_ARGS_ASSERT_INVLIST_REPLACE_LIST_DESTROYS_SRC;

    assert(is_invlist(src));
    assert(is_invlist(dest));
    assert(! invlist_is_iterating(src));
    assert(SvCUR(src) == 0 || SvCUR(src) < SvLEN(src));

    /* Make sure it ends in the right place with a NUL, as our inversion list
     * manipulations aren't careful to keep this true, but sv_usepvn_flags()
     * asserts it */
    array[src_byte_len - 1] = '\0';

    TAINT_NOT;      /* Otherwise it breaks */
    sv_usepvn_flags(dest,
                    (char *) array,
                    src_byte_len - 1,

                    /* This flag is documented to cause a copy to be avoided */
                    SV_HAS_TRAILING_NUL);
    TAINT_set(oldtainted);
    SvPV_set(src, 0);
    SvLEN_set(src, 0);
    SvCUR_set(src, 0);

    /* Finish up copying over the other fields in an inversion list */
    *get_invlist_offset_addr(dest) = src_offset;
    invlist_set_len(dest, src_len, src_offset);
    *get_invlist_previous_index_addr(dest) = 0;
    invlist_iterfinish(dest);
STATIC void
S_invlist_replace_list_destroys_src(pTHX_ SV * dest, SV * src)
{
     

    const UV src_len          = _invlist_len(src);
    const bool src_offset     = *get_invlist_offset_addr(src);
    const STRLEN src_byte_len = SvLEN(src);
    char * array              = SvPVX(src);

    const int oldtainted = TAINT_get;

    PERL_ARGS_ASSERT_INVLIST_REPLACE_LIST_DESTROYS_SRC;

    assert(is_invlist(src));
    assert(is_invlist(dest));
    assert(! invlist_is_iterating(src));
    assert(SvCUR(src) == 0 || SvCUR(src) < SvLEN(src));

     
    array[src_byte_len - 1] = '\0';

    TAINT_NOT;       
    sv_usepvn_flags(dest,
                    (char *) array,
                    src_byte_len - 1,

                     
                    SV_HAS_TRAILING_NUL);
    TAINT_set(oldtainted);
    SvPV_set(src, 0);
    SvLEN_set(src, 0);
    SvCUR_set(src, 0);

     
    *get_invlist_offset_addr(dest) = src_offset;
    invlist_set_len(dest, src_len, src_offset);
    *get_invlist_previous_index_addr(dest) = 0;
    invlist_iterfinish(dest);