Set<Object> (final PropertyReferenceBase propertyReference) { final Set<Object> variants = new ObjectOpenCustomHashSet<>(new Hash.Strategy<>() { @Override public int hashCode(@Nullable Object object) { if (object instanceof IProperty) { String key = ((IProperty)object).getKey(); return key == null ? 0 : key.hashCode(); } else { return 0; } } @Override public boolean equals(@Nullable Object o1, @Nullable Object o2) { if (o1 == o2) { return true; } return o1 instanceof IProperty && o2 instanceof IProperty && Objects.equals(((IProperty)o1).getKey(), ((IProperty)o2).getKey()); } }); List<PropertiesFile> propertiesFileList = propertyReference.getPropertiesFiles(); if (propertiesFileList == null) { PropertiesReferenceManager .getInstance(propertyReference.getElement().getProject()).processAllPropertiesFiles((baseName, propertiesFile) -> { addVariantsFromFile(propertyReference, propertiesFile, variants); return true; }); } else { for (PropertiesFile propFile : propertiesFileList) { addVariantsFromFile(propertyReference, propFile, variants); } } return variants; }