clang/AST/DeclBase.h

1203   NamedDecl *Single = nullptr;
1211   DeclContextLookupResult(NamedDecl *Single)
1212       : Result(SingleElementDummyList), Single(Single) {}
1225     explicit iterator(pointer Pos, value_type Single = nullptr)
1226         : IteratorBase(Pos), SingleElement(Single) {}
1237   iterator begin() const { return iterator(Result.begin(), Single); }
1238   iterator end() const { return iterator(Result.end(), Single); }
1241   pointer data() const { return Single ? &Single : Result.data(); }
1242   size_t size() const { return Single ? 1 : Result.size(); }
1243   reference front() const { return Single ? Single : Result.front(); }
1244   reference back() const { return Single ? Single : Result.back(); }
1245   reference operator[](size_t N) const { return Single ? Single : Result[N]; }
1250     Sliced.Single = Single;