ifx segmentation fault error with elemental functions

[DataScientist]

Here is my third attempt at posting a potential IFX compiler bug in the hope of not being flagged as s-p-a-m again:

The following code is valid and generates the correct result with ifort and gfortran, but yields a segmentation fault with ifx 2025.2 and most likely the older versions (it has taken me a year to isolate and reproduce this bug from a multimillion-line codebase):

module str_mod

    type :: str_type
        character(:), allocatable :: val
    end type

    interface str_type
        module procedure :: str_maker
    end interface

contains

    pure elemental function endswith(str, suffix) result(itis)
        type(str_type), intent(in) :: str, suffix
        logical :: itis
        itis = str%val(max(1, len(str%val) - len(suffix%val) + 1) : len(str%val)) == suffix%val
    end function

    ! This elemental attribute triggers segfault error in the above function `endswith`.
    pure elemental function str_maker(val) result(str)
        character(*), intent(in) :: val
        type(str_type) :: str
        str%val = trim(val)
    end function

end module str_mod

use str_mod, only: str_type, endswith

implicit none

type(str_type), allocatable :: suffixes(:)

suffixes = [str_type('str1'), str_type('str2')]
!print *, suffixes(1)%val, suffixes(2)%val
print *, endswith(str_type('str1'), suffixes)

end

If one removes the elemental attribute of the constructor str_maker of the str_type derived type, the code compiles and runs successfully. However, this should not be needed because the code is valid; in practice, str_maker is far more complex than this simple bug reproducer above.

The segmentation fault occurs at line 16 inside the elemental function `endswith`. Here is a link to the godbolt website to compile, run, and compare with other compiler outputs (now removed, because I believe this link is what triggers the s-p-a-m detector of  this forum). Visit the website yourself and paste the code there.)

This error is not bound to strings alone. The same segfault error occurs if one uses a container of allocatable scalar other than a string.

Thank you for the impressive compiler and for any help in resolving this bug (or error).

[Arjen_Markus]

FWIW, I have seen all three attempts. I have used Intel Fortran oneAPI 2025.0.0 on Windows and the program fails on line 16. 

If I replace the str_type constructor by a variable that is initialised with the same value, the program works fine.

[DataScientist]

I guess the moderators acted on my pending spam abuse reports.