Bug 77358 - [F08] deferred-length character function returns zero-length string

[Damian Rouson]

I just submitted the following text in the above referenced bug report.

As shown below with gfotran 7.0, a deferred-length character function 
returns a zero-length string when the function is implemented inside a 
submodule. Either of the following eliminates the bug: 

(1) moving the function from the submodule to the module or 
(2) changing the deferred-length character declarations to fixed-length 
declarations with or without the allocatable attribute.

It would be great if the fix could be backported to the 6 branch.

$ cat alloc-char-func-in-submodule.f90 
module hello_interface
  character(len=13) :: string="Hello, world!"
  interface
    module function get() result(result_string)
      character(:), allocatable :: result_string
    end function
  end interface
end module

submodule(hello_interface) hello_implementation
contains
  module function get() result(result_string)
    character(:), allocatable :: result_string
    result_string = string
  end function
end submodule

  use hello_interface
  print *,len(get())
end
$ gfortran alloc-char-func-in-submodule.f90 
$ ./a.out
           0
$ gfortran --version
GNU Fortran (MacPorts gcc7 7-20160814_0) 7.0.0 20160814 (experimental)

Damian