Hi Matt,

It looks like a bug to me. In addition, VFP doesn't use BINARY index with ISNULL() for query optimization anyway, which is another bug.

CLEAR 
CREATE CURSOR Test (Int1 I NULL, int2 I NOT NULL)
INDEX ON ISNULL(int2) TAG BinTest2 BINARY 
INDEX ON EMPTY(int2) TAG BinTest3 BINARY
INDEX ON DELETED() TAG deleted BINARY

=SYS(3054,11)
? "-- ISNULL ---"
SELECT * FROM Test ;
	WHERE ISNULL(int2) ;
	INTO CURSOR crsTemp

? "-- EMPTY  ---"
SELECT * FROM Test ;
	WHERE EMPTY(int2) ;
	INTO CURSOR crsTemp

=SYS(3054,0)

>
>This seems like a bug to me, but maybe someone else can shed some light.

>*--Create a cursor with 2 fields - one allows NULLs the other does not.
>CREATE CURSOR c_Test (Int1 I NULL, int2 I)
>INDEX ON ISNULL(int1) TAG BinTest1 BINARY  &&-fails with "Invalid index expression for a Binary Index."
>INDEX ON ISNULL(int2) TAG BinTest2 BINARY  &&--Runs fine (it shouldn't)

>The only difference between the two index statements is that the field Int1 allows binary information to be stored, whereas Int2 does not.
>