LookupElementBuilder (@NotNull Collection<String> another) { Set<String> set = new HashSet<>(myAllLookupStrings.size() + another.size()); set.addAll(myAllLookupStrings); set.addAll(another); return cloneWithUserData(myLookupString, myObject, myInsertHandler, myRenderer, myExpensiveRenderer, myHardcodedPresentation, myPsiElement, Collections.unmodifiableSet(set), myCaseSensitive); }