The test suite fails in a seemingly harmless way:
### Failure in: All:0
expected: "(MyDataType Int,(DataType {tycon = \"MyDataType\", datarep = AlgRep [MyDataType]},(\"\",(\"MyDataType\",(\"\",\"MyDataType\")))))"
but got: "(MyDataType Int,(DataType {tycon = \"Datatype.MyDataType\", datarep = AlgRep [MyDataType]},(\"\",(\"MyDataType\",(\"Datatype\",\"MyDataType\")))))"