message: Fix querydb corruption/invalid references accumulating over time.
  Hopefully this catches all of the issues. We will see in time.
  This resolves issue
diff: @@ -511,7 +511,6 @@ IndexUpdate::IndexUpdate(const IdMap& previous_id_map,
  [this, &previous_id_map](IndexType* type) {
  if (type->def.spell)
  types_removed.push_back(type->usr);
  - else {
  if (!type->derived.empty())
  types_derived.push_back(QueryType::DerivedUpdate(
  previous_id_map.ToQuery(type->id), {},
  @@ -524,7 +523,6 @@ IndexUpdate::IndexUpdate(const IdMap& previous_id_map,
  types_uses.push_back(
  QueryType::UsesUpdate(previous_id_map.ToQuery(type->id), {},
  previous_id_map.ToQuery(type->uses)));
  - }
  },
  /*onAdded:*/
  [this, &current_id_map](IndexType* type) {
  @@ -571,9 +569,8 @@ IndexUpdate::IndexUpdate(const IdMap& previous_id_map,
  previous_file.funcs, current_file.funcs,
  /*onRemoved:*/
  [this, &previous_id_map](IndexFunc* func) {
  - if (func->def.spell) {
  + if (func->def.spell)
  funcs_removed.push_back(func->usr);
  - } else {
  if (!func->declarations.empty())
  funcs_declarations.push_back(QueryFunc::DeclarationsUpdate(
  previous_id_map.ToQuery(func->id), {},
  @@ -586,7 +583,6 @@ IndexUpdate::IndexUpdate(const IdMap& previous_id_map,
  funcs_uses.push_back(QueryFunc::UsesUpdate(
  previous_id_map.ToQuery(func->id), {},
  previous_id_map.ToQuery(func->uses)));
  - }
  },
  /*onAdded:*/
  [this, &current_id_map](IndexFunc* func) {
  @@ -633,9 +629,8 @@ IndexUpdate::IndexUpdate(const IdMap& previous_id_map,
  previous_file.vars, current_file.vars,
  /*onRemoved:*/
  [this, &previous_id_map](IndexVar* var) {
  - if (var->def.spell) {
  + if (var->def.spell)
  vars_removed.push_back(var->usr);
  - } else {
  if (!var->declarations.empty())
  vars_declarations.push_back(QueryVar::DeclarationsUpdate(
  previous_id_map.ToQuery(var->id), {},
  @@ -644,7 +639,6 @@ IndexUpdate::IndexUpdate(const IdMap& previous_id_map,
  vars_uses.push_back(
  QueryVar::UsesUpdate(previous_id_map.ToQuery(var->id), {},
  previous_id_map.ToQuery(var->uses)));
  - }
  },
  /*onAdded:*/
  [this, &current_id_map](IndexVar* var) {
  @@ -1225,7 +1219,6 @@ TEST_SUITE("query") {
  db.ApplyIndexUpdate(&delta_update);
  }
  REQUIRE(db.vars.size() == 1);
  - // FIXME/TODO: See https://github.com/cquery-project/cquery/issues/443.
  - // REQUIRE(db.vars[0].uses.size() == 0);
  + REQUIRE(db.vars[0].uses.size() == 0);
  }
  }
  