Our website uses cookies to enhance your browsing experience.
Accept
to the top
close form

Fill out the form in 2 simple steps below:

Your contact information:

Step 1
Congratulations! This is your promo code!

Desired license type:

Step 2
Team license
Enterprise license
** By clicking this button you agree to our Privacy Policy statement
close form
Request our prices
New License
License Renewal
--Select currency--
USD
EUR
* By clicking this button you agree to our Privacy Policy statement

close form
Free PVS‑Studio license for Microsoft MVP specialists
* By clicking this button you agree to our Privacy Policy statement

close form
To get the licence for your open-source project, please fill out this form
* By clicking this button you agree to our Privacy Policy statement

close form
I am interested to try it on the platforms:
* By clicking this button you agree to our Privacy Policy statement

close form
check circle
Message submitted.

Your message has been sent. We will email you at


If you haven't received our response, please do the following:
check your Spam/Junk folder and click the "Not Spam" button for our message.
This way, you won't miss messages from our team in the future.

>
>
>
V3019. It is possible that an incorrect…
menu mobile close menu
Analyzer diagnostics
General Analysis (C++)
General Analysis (C#)
General Analysis (Java)
Micro-Optimizations (C++)
Diagnosis of 64-bit errors (Viva64, C++)
Customer specific requests (C++)
MISRA errors
AUTOSAR errors
OWASP errors (C#)
Problems related to code analyzer
Additional information
toggle menu Contents

V3019. It is possible that an incorrect variable is compared with null after type conversion using 'as' keyword.

Oct 30 2015

The analyzer has detected a potential error that may lead to memory access by a null reference.

The situation that the analyzer detected deals with the following algorithm. An object of the base class is first cast to a derived class by using the 'as' operator. Then the same object is checked for a null value, though it is the object of the derived class that this check should have been applied to.

Here's an example. In this code, the baseObj object may not be an instance of the Derived class, in which case, when calling the Func function, the program will crash, raising the NullReferenceException. The analyzer will output a warning pointing out two lines. The first line is the spot where the object of the base class is checked for null; the second is where it is cast to an object of the derived class.

Base baseObj;
Derived derivedObj = baseObj as Derived;
if (baseObj != null)
{
    derivedObj.Func();
}

It is most likely the object of the derived class that the programmer intended to check for null before using it. This is the fixed version of the code:

Base baseObj;
Derived derivedObj = baseObj as Derived;
if (derivedObj != null)
{
    derivedObj.Func();
}

This diagnostic is classified as:

You can look at examples of errors detected by the V3019 diagnostic.