Ok, now the next step would be the following. Carefully check that all
modules, that you're using in libraries are included in `Modules` or
`InternalModules`. It is the case
that sometimes when you forgot to include a module, oasis (actually
`ocamlbuild`), may produce a strange, and on a first glance, irrelevant
error message.

If it doesn't help then the `_build/_log` file might help us to debug the
issue.

On Thu, Oct 27, 2016 at 10:59 AM, Jonathan DiLorenzo <
dilorenzo@cs.cornell.edu> wrote:

> Hey Ivan,
>
> Thanks for your response.
>
> The first one is that you didn't run `oasis setup` after you made the
>> changes, so I would suggest cleaning current state
>> and starting from scratch. (I usually just do `git clean -idx` just to be
>> sure that I got rid of any generated files, like setup.data, et alas, but
>> be careful,
>> don't delete something that you need).
>>
>
> I tried cleaning up all the generated files. Same error unfortunately
>
>
>> Another idea is that you're using oasis 0.4.7 with ocaml-4.03.0+flambda,
>> they are currently incompatible, and can produce weird bugs. If that so,
>> then consider switching
>> either a compiler or oasis to different versions.
>>
>
> I am using oasis 0.4.7 and ocaml-4.03.0, but I don't appear to be using
> flambda. I tried passing in -config and it said that flambda was false at
> least, but I admit, I'm not especially familiar with it, so if there's some
> other way I should be checking for this please let me know. Hopefully,
> they're compatible sans flambda?
>
>
> On Thu, Oct 27, 2016 at 1:01 AM, Jonathan DiLorenzo <
>> dilorenzo@cs.cornell.edu> wrote:
>>
>>> Hey all,
>>>
>>> I'm trying to build my system using Oasis and OCamlbuild. I have 3
>>> different libraries and for some reason I seem to only be able to refer
>>> from one to the other in seemingly random files. For example, I want my
>>> 'ppx' library to be able to use functions from my 'parser' library. One
>>> file (ppx_forest.ml) can use functions from it, while another in the
>>> same library (skins.ml) cannot, giving me this error:
>>>
>>> File "_none_", line 1:
>>> Error: No implementations provided for the following modules:
>>>          Forest_parser_helper referenced from ppx/ppx.cmxa(Skins)
>>> Command exited with code 2.
>>>
>>> They can all refer to types I've defined therein though.
>>>
>>> I'm not fantastic at Oasis so maybe I'm just missing something basic?
>>> Any ideas? Any more information I can gather to give more context otherwise?
>>>
>>> Thanks in advance,
>>> Jonathan
>>>
>>> Excerpt of my Oasis file that may possibly be relevant:
>>>
>>> Library forest
>>>   Path:          lib
>>>   BuildTools:    ocamlbuild
>>>   BuildDepends:   pads, str, re, re.glob, core, threads, ppx_let
>>>   CompiledObject: best
>>>   Modules:       Forest, PadsInterface
>>>
>>> Library parser
>>>   Path:           parsing
>>>   BuildTools:     ocamlbuild, menhir, ocamllex
>>>   Findlibparent:  forest
>>>   Findlibname:    parser
>>>   BuildDepends:   forest, ppx_deriving.show, compiler-libs.common
>>>   CompiledObject: best
>>>   Modules:  Forest_parser_helper
>>>   InternalModules: Forest_lexer, Forest_parser, Forest_types
>>>
>>> Library ppx
>>>   Path:           ppx
>>>   BuildTools:     ocamlbuild
>>>   Findlibparent:  forest
>>>   Findlibname:    ppx
>>>   BuildDepends:   re, re.str, forest.parser, forest, ppx_tools.metaquot
>>>   CompiledObject: best
>>>   Modules:        Ppx_forest
>>>   InternalModules: Ppx_forest_lib, Utility, Skins
>>>   XMETAEnable:    true
>>>   XMETARequires:   str re core threads ppx_tools.metaquot
>>>   XMETAExtraLines:  ppx = "ppx_forest"
>>>
>>> Executable ppx_forest
>>>   Path:           ppx
>>>   MainIs:         ppx_forest.ml
>>>   BuildDepends:   forest, forest.parser, forest.ppx, pads.ppx,
>>> ppx_tools.metaquot
>>>   CompiledObject: best
>>>
>>>
>>
>