message: Work around some kythe indexer issues found in [sv-tests](https://chipsalliance.github.io/sv-tests-results/)
  These are mere stop-gap 'fixes' and logging while we debug the
  underlying root-causes.
  TODO: drill down to the particular code-snippete triggering it,
  and fix properly.
diff: @@ -943,6 +943,14 @@ void KytheFactsExtractor::ReferenceMacroCall(
  VName KytheFactsExtractor::DeclareFunctionOrTask(
  const IndexingFactNode& function_fact_node) {
  + // TODO(hzeller): null check added. Underlying issue
  + // needs more investigation; was encountered at
  + // https://chipsalliance.github.io/sv-tests-results/?v=veribleextractor+ivtest+regress-vlg_pr1628300_iv
  + if (function_fact_node.Value().Anchors().empty()) {
  + LOG(ERROR) << FilePath() << ": encountered empty function name";
  + return VName();
  + }
  +
  const auto& function_name = function_fact_node.Value().Anchors()[0];
  const VName function_vname = {
  @@ -1130,8 +1138,18 @@ void KytheFactsExtractor::ReferencePackageImport(
  const VName current_anchor = CreateAnchor(package_name_anchor);
  CreateEdge(current_anchor, kEdgeRefImports, *definition_vnames[0].first);
  - scope_resolver_->AddDefinitionToCurrentScope(*definition_vnames[0].first);
  - scope_resolver_->AppendScopeToCurrentScope(*definition_vnames[0].second);
  + // TODO(hzeller): null check added. Underlying issue of nullptr
  + // scope needs more investigation; was encountered at
  + // https://chipsalliance.github.io/sv-tests-results/?v=veribleextractor+hdlconv_std2017+hdlconvertor_std2017_p600
  + if (const VName* vname = definition_vnames[0].first; vname)
  + scope_resolver_->AddDefinitionToCurrentScope(*vname);
  + else
  + LOG(ERROR) << FilePath() << ": ReferencePackageImport: NULL vname";
  +
  + if (const Scope* scope = definition_vnames[0].second; scope)
  + scope_resolver_->AppendScopeToCurrentScope(*scope);
  + else
  + LOG(ERROR) << FilePath() << ": ReferencePackageImport: NULL scope";
  }
  }
  