private @NotNull List<StubFileElementType<?>> determinePreviousFileElementType(int fileId, @NotNull StubUpdatingIndexStorage index) {
    String storedVersion = index.getStoredSubIndexerVersion(fileId);
    if (storedVersion == null) return Collections.emptyList();
    return myFileElementTypesCache.compute(storedVersion, (__, value) -> {
      if (value != null) return value;
      List<StubFileElementType<?>> types = StubBuilderType.getStubFileElementTypeFromVersion(storedVersion);
      if (types.size() > 1) {
        reportStubFileElementTypeVersionConflict(types, storedVersion);
      }
      return types;
    });
  }
private @NotNull List<StubFileElementType<?>> determinePreviousFileElementType(int fileId, @NotNull StubUpdatingIndexStorage index)