Length-parameterized passed object to type-bound procedure has gfortran complain

问题

I'm learning Fortran and I'd like to encapsulate an array and a subroutine in a type. The problem appears to be in the type definition of the self-object.

This is the minimal test case I came up with:

module testing
  implicit none

  type test(para)
    integer, len :: para
    real, dimension(para) :: weights

  contains
    procedure :: testing => testing_test
  end type
contains
  subroutine testing_test(self)
    class(test(*)) :: self
  end subroutine
end module

Compiling this with gfortran raises this error:

module_test.f08:9:23:

  procedure :: testing => testing_test
          1
Error: Argument ‘self’ of ‘testing_test’ with PASS(self) at (1) must be of the derived-type ‘test’

It works when the array-length is fixed (so type%para doesn't exist)

Is what I'm trying to do (type with array of variable size and bound procedure) plain impossible or am I missing something regarding dummy argument definition?

回答1:

Thanks to @Rodrigo for the idea, I finally found this bug (and patch): https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82943

To fix the issue, download the source, apply the mentioned patch and compile your own gfortran. (Or wait until it's in the repositories)

回答2:

A previous answer points to a bug report and patch for gfortran. It is worth saying, though, that this is standard Fortran (2003) code.

What we have here is a type-bound procedure with passed-object dummy argument. The main restrictions of such an argument are that it is a:

scalar,
nonallocatable,
nonpointer object,
with all length-type parameters assumed.

Further, as the type is extensible the passed-object dummy argument must be polymorphic.

For the example of the question, all of the conditions are met.

回答3:

This is not really an answer but may provide a solution for some. gfortran-10 still has the same problem. However flang-7 compiles this example and it is available for Ubuntu since 19.10, and maybe other OS:es.

来源：https://stackoverflow.com/questions/52678258/length-parameterized-passed-object-to-type-bound-procedure-has-gfortran-complain

标签

fortran

gfortran

type-definition