[Bug fortran/117070] Procedure target error with parameter structure constructor

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117070

--- Comment #5 from anlauf at gcc dot gnu.org ---
(In reply to Ivan Pribec from comment #4)
> Steve reckons the example is valid, see:
> https://community.intel.com/t5/Intel-Fortran-Compiler/Procedure-target-in-
> structure-constructor/m-p/1681101#M175473

While I still have my doubts on the use of the constructor with a
named constant, I agree that the following reduced code should compile:

module funcs
  implicit none

  abstract interface
     function retchar()
       character(len=1) :: retchar
     end function retchar
  end interface
contains
  function a()
    character(len=1) :: a
    a = 'a'
  end function
end module

module dispatch_table
  use funcs
  implicit none

  ! Procedure container
  type :: pc
     procedure(retchar), pointer, nopass :: rc => null()
  end type pc

  type(pc) :: myfun = pc(rc=a)

end module


Indeed, "7.5.10 Construction of derived‐type values" has:

! For a pointer component, the corresponding component‐data‐source shall be
! an allowable data‐target or proc‐target for such a pointer in a pointer
! assignment statement (10.2.2). If the component data source is a pointer,
! the association of the component is that of the pointer; otherwise, the
! component is pointer associated with the component data source.

But the above is rejected with:

pr117070-1.f90:25:28:

   25 |   type(pc) :: myfun = pc(rc=a)
      |                            1
Error: Parameter 'a' at (1) has not been declared or is a variable, which does
not reduce to a constant expression

Intel ifx 2025.3 gives a similar error.