IllegalStateException in SpanTermQuery

[Yonghui Zhao]

One of my UT is passed In lucene 3.5, but it is failed in lucene4.3.
The exception is:

IllegalStateException("field \"" + term.field() + "\" was indexed without
position data; cannot run SpanTermQuery (term=" + term.text() + ")");


After I change index option of the field from DOCS_ONLY to
DOCS_AND_FREQS_AND_POSITIONS, the test is passed.

I am wondering what's the reason of this limit in lucene 4.3.

Thanks