[Bug fortran/115072] New: Memory link with unlimited polymorphic function result

[Bug fortran/115072] New: Memory link with unlimited polymorphic function result

[rnhmjoj at eurofusion dot eu]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115072

            Bug ID: 115072
           Summary: Memory link with unlimited polymorphic function result
           Product: gcc
           Version: 13.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: rnhmjoj at eurofusion dot eu
  Target Milestone: ---

The following program works as expected, but the result of the id(x) function
does not appear to be ever deallocated creating a memory leak:

    program test

      print *, transfer(id(7), 1)

    contains

      pure function id(x) result(y)
        class(*), intent(in)  :: x
        class(*), allocatable :: y
        y = x
      end function

    end program test

Specifically, running the program in valgrind memcheck with --leak-check=full
reveals this:

    4 bytes in 1 blocks are definitely lost in loss record 1 of 1
       at 0x484276B: malloc (in vgpreload_memcheck-amd64-linux.so)
       by 0x401338: id.1 (test.f90:10)
       by 0x401243: MAIN__ (test.f90:3)
       by 0x401432: main (test.f90:3)

Replacing the `class(*)` with some other type does not produce a leak.

[Bug fortran/115072] Memory leak with unlimited polymorphic function result

[anlauf at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115072

anlauf at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|Memory link with unlimited  |Memory leak with unlimited
                   |polymorphic function result |polymorphic function result
           Priority|P3                          |P4
     Ever confirmed|0                           |1
             Status|UNCONFIRMED                 |NEW
                 CC|                            |anlauf at gcc dot gnu.org
   Last reconfirmed|                            |2024-05-13

--- Comment #1 from anlauf at gcc dot gnu.org ---
Runtime memleak confirmed, also seen with -fsanitize=address .

Affects all versions up to 15-mainline.