Confdc compile ietf-ospf fail

When using confdc to compile the standard ietf-ospf@2016-03-20.yang, following error appears. And fxs is not generated.
Actually the area-type is indeed declared in the yang file.
We are using confd 6.1 which is downloaded from the confd web site.
Is it because the confd version is basic version?
ietf-ospf@2016-03-20.yang:2122: error: the node ‘area-type’ from module ‘ietf-ospf’ (in node ‘area’ in module ‘ietf-ospf’ from ‘ietf-ospf’) is not found
ietf-ospf@2016-03-20.yang:2122: error: the node ‘area-type’ from module ‘ietf-ospf’ (in node ‘area’ in module ‘ietf-ospf’ from ‘ietf-ospf’) is not found
ietf-ospf@2016-03-20.yang:2122: error: the node ‘area-type’ from module ‘ietf-ospf’ (in node ‘area’ in module ‘ietf-ospf’ from ‘ietf-ospf’) is not found
ietf-ospf@2016-03-20.yang:2122: error: the node ‘area-type’ from module ‘ietf-ospf’ (in node ‘area’ in module ‘ietf-ospf’ from ‘ietf-ospf’) is not found
ietf-ospf@2016-03-20.yang:2133: error: the node ‘area-type’ from module ‘ietf-ospf’ (in node ‘area’ in module ‘ietf-ospf’ from ‘ietf-ospf’) is not found
ietf-ospf@2016-03-20.yang:2133: error: the node ‘area-type’ from module ‘ietf-ospf’ (in node ‘area’ in module ‘ietf-ospf’ from ‘ietf-ospf’) is not found
ietf-ospf@2016-03-20.yang:2133: error: the node ‘area-type’ from module ‘ietf-ospf’ (in node ‘area’ in module ‘ietf-ospf’ from ‘ietf-ospf’) is not found
ietf-ospf@2016-03-20.yang:2133: error: the node ‘area-type’ from module ‘ietf-ospf’ (in node ‘area’ in module ‘ietf-ospf’ from ‘ietf-ospf’) is not found
ietf-ospf@2016-03-20.yang:2174: error: the node ‘operation-mode’ from module ‘ietf-ospf’ (in node ‘instance’ in module ‘ietf-ospf’ from ‘ietf-ospf’) is not found
ietf-ospf@2016-03-20.yang:2174: error: the node ‘operation-mode’ from module ‘ietf-ospf’ (in node ‘instance’ in module ‘ietf-ospf’ from ‘ietf-ospf’) is not found
ietf-ospf@2016-03-20.yang:2610: error: the node ‘operation-mode’ from module ‘ietf-ospf’ (in node ‘instance’ in module ‘ietf-ospf’ from ‘ietf-ospf’) is not found
ietf-ospf@2016-03-20.yang:2610: error: the node ‘operation-mode’ from module ‘ietf-ospf’ (in node ‘instance’ in module ‘ietf-ospf’ from ‘ietf-ospf’) is not found
ietf-ospf@2016-03-20.yang:2610: error: the node ‘operation-mode’ from module ‘ietf-ospf’ (in node ‘instance’ in module ‘ietf-ospf’ from ‘ietf-ospf’) is not found
ietf-ospf@2016-03-20.yang:2610: error: the node ‘operation-mode’ from module ‘ietf-ospf’ (in node ‘instance’ in module ‘ietf-ospf’ from ‘ietf-ospf’) is not found

It is not a standard module, it is a draft, and not even the current version. It is from draft-ietf-ospf-yang-04, which expires tomorrow - the -05 version was published on July 7, 2016, though the ietf-ospf@2016-07-07.yang therein appears to have the same problem.

This is not sufficient - I believe the relevant part of the module is this, inside the area-common-config grouping (there is at least one other similar expression in the same grouping):

leaf summary {
  when "../area-type = 'ospf:stub' or "
     + "../area-type = 'ospf:nssa'" {
    description
      "Summary advertisement into the stub/NSSA area.";
}

For the paths in the ‘when’ expression to be valid, ‘area-type’ must not only be defined, it must be a sibling of ‘summary’, and this is at least not fulfilled for the grouping per se. The paths could be valid if the grouping is used in a context where an ‘area-type’ sibling exists - the module is rather complex and has several dependencies, so I haven’t attempted to check this - but it is at least a dubious design: a grouping is supposed to “define a reusable block of nodes”, not just save a couple of lines of typing - and it isn’t very reusable if it is usage has such restrictions.

There are no intentional restrictions or limitations for the YANG compiler in ConfD Basic, but of course it may have bugs (in that case the same ones that the corresponding ConfD Premium version has). I don’t think this is the case here, but as I wrote, I haven’t checked it in detail. You can expect the 6.2 version to have fewer bugs than 6.1…

See also http://www.claise.be/IETFYANGPageCompilation.html, where ‘confdc’ is used for validation of standards-track YANG models (the page is maintained by the IETF Area Director for the Operations and Management Area). I suggest that you use the relevant IETF WG mailing list (see Open Shortest Path First IGP (ospf)) to learn more about the status of this draft, such as whether these “complaints” from ‘confdc’ are considered valid, and if so whether they are being addressed (and if not, why not, for both questions).