[Bug fortran/95947] PACK intrinsic returns blank strings when an allocatable character array with allocatable length is used

[anlauf at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95947

--- Comment #5 from anlauf at gcc dot gnu.org ---
The dump tree shows near the pack intrinsic:

- for character(len=10):

    atmp.4.dtype = {.elem_len=10, .rank=1, .type=6};
    atmp.4.span = 10;
    atmp.4.data = 0B;
    atmp.4.offset = 0;
    _gfortran_pack_char (&atmp.4, 10, D.4308, D.4328, 0B, 10, 0);

- for character(len=:):

    atmp.5.dtype = {.elem_len=(unsigned long) slen.4, .rank=1, .type=6};
    atmp.5.span = (integer(kind=8)) SAVE_EXPR <(sizetype) NON_LVALUE_EXPR
<slen.4>>;
    atmp.5.data = 0B;
    atmp.5.offset = 0;
    slen.4 = 0;
    _gfortran_pack_char (&atmp.5, &slen.4, D.4314, D.4334, 0B, .n, 0);

So we seem to clobber the string length before calling pack.