Strange WHERE predicate begin generated when check for NULL

Hello.

I have met strange SQL generated when adding null-check in WHERE clause:

var veh = con.Vehicles.FirstOrDefault(x => x.StyleId != null && x.StyleId != -1000);

I get this SQL:

--  SqlServer.2008
SELECT TOP (1)
        [x].[VehicleId],
        [x].[LV_autoStyleId]
FROM
        [Vehicle] [x]
WHERE
        [x].[LV_autoStyleId] IS NOT NULL AND ([x].[LV_autoStyleId] IS NULL OR [x].[LV_autoStyleId] <> -1000)

LV_autoStyleId is checked against NULL and NOT NULL simultaneously. Is it by design or I am doing something wrong?

This doesn’t bother me much, just curious if it is normal.

I saw it in 2.6.4 and still see this in 2.7.4 (had to update just to check this is bug and was fixed).

[sdanyliv]

@jods4, try to set this global configuration setting. I hope it works, we have plans to review this in near future https://github.com/linq2db/linq2db/blob/master/Source/LinqToDB/Common/Configuration.cs#L148

[jods4]

@sdanyliv Great, thanks!