ROWDIFF doesn’t currently support rows that child datasets

// The following code syntax checks correctly, however it fails on compile
// Error: UNIMPLEMENTED feature at /var/lib/jenkins/workspace/LN-Candidate-5.0.10-1/LN/centos-5.7-x86_64/HPCC-Platform/ecl/hqlcpp/hqlhtcpp.cpp(7991) (22, 1), -1,

child_rec := record
string1 s;
end;
child1 := dataset([

],child_rec);
parent_rec := record
unsigned1 id := 0;
dataset(child_rec) children := dataset([],child_rec);
end;

parentDataset := DATASET([{1,[

]},
{2,[

]}],
parent_rec);

out_rec := record
string diff;
end;

out_rec rowDiffThem(parent_rec L,parent_rec R) := transform
self.diff := rowdiff(L,R,COUNT);
end;

join(parentDataset,parentDataset,LEFT.id=RIGHT.id,rowDiffThem(LEFT,RIGHT));