[Bug fortran/89366] New: Fails to compile BIND(C) interface with assumed-length character argument

[Bader at lrz dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89366

            Bug ID: 89366
           Summary: Fails to compile BIND(C) interface with assumed-length
                    character argument
           Product: gcc
           Version: 9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: Bader at lrz dot de
  Target Milestone: ---

Created attachment 45736
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=45736&action=edit
test code

The extensions in C interop imply that an assumed-length character dummy
argument can appear in a BIND(C) interface, and is mapped to a C descriptor.
However, the attached test code fails to compile with the following error
message:

assumed_length_01_pos.f90:12:35:

   12 |      subroutine process_string(this, ierr) BIND(C)
      |                                   1
Error: Character argument ?this? at (1) must be length 1 because procedure
?process_string? is BIND(C)