Linking error with test-directory submodule and its parent module in separate files

[rouson]

Description

fpm test generates a link-time error when a test-directory submodule exists in a file other than the file containing its parent module.

Expected Behaviour

I expected fpm test to build and run the test(s).

Version of fpm

0.6.0

Platform and Architecture

macOS/Intel

Additional Information

To reproduce the error this issue, execute the following in a Linux or MacOS shell:

% fpm new foo
% cat > foo/test/check.f90 
program check
  use foo_m
  implicit none
  call say_something
end program
<Ctrl-D>
% cat > foo/test/foo_m.f90 
module foo_m
  implicit none
  interface
    module subroutine say_something
    end subroutine
  end interface
end module
<Ctrl-D>
% cat foo/test/foo_s.f90 
submodule(foo_m) foo_s
  implicit none
contains
  module procedure say_something
    print *,"something"
  end procedure
end submodule
<Ctrl-D>
% cd foo
% fpm test
 + mkdir -p build/dependencies
foo_m.f90                              done.
foo.f90                                done.
libfoo.a                               done.
main.f90                               done.
check.f90                              done.
foo_s.f90                              done.
foo                                    done.
check                                  failed.
[ 100%]Compiling...
Undefined symbols for architecture x86_64:
  "___foo_m_MOD_say_something", referenced from:
      _MAIN__ in test_check.f90.o
ld: symbol(s) not found for architecture x86_64
collect2: error: ld returned 1 exit status
<ERROR> Compilation failed for object " check "
<ERROR>stopping due to failed compilation
STOP 1

When using gfortran or the Intel ifort, the following workaround enables successful execution of fpm test:

echo 'include "foo_s.f90"' >> test/foo_m.f90

With the NAG nagfor compiler, the above workaround fails so the submodule must be in the same file as the module.

[LKedward]

Thanks for reporting Damian @rouson. I believe this was fixed in #743 which will be available in our next release. You can try the bleeding edge version of fpm in the meantime.
(Duplicate of #556.)

[rouson]

Thanks, @LKedward. Given that it's a duplicate, I'll close this issue.