To get a trial key
fill out the form below
Team license
Enterprise license
** By clicking this button you agree to our Privacy Policy statement

Request our prices
New License
License Renewal
--Select currency--
USD
EUR
RUB
* By clicking this button you agree to our Privacy Policy statement

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

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

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

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.

>
>
>
V3180. The 'HasFlag' method always retu…
Analyzer diagnostics
General Analysis (C++)
General Analysis (C#)
General Analysis (Java)
Diagnosis of 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
Contents

V3180. The 'HasFlag' method always returns 'true' because the value '0' is passed as its argument.

Sep 07 2022

The analyzer has detected the call of the 'HasFlag' method, that always returns 'true' because the argument value is '0'.

Let's look at the following example:

public enum RuntimeEvent
{
  Initialize = 1,
  BeginRequest = 2,
  BeginSessionAccess = 4,
  ExecuteResource = 8,
  EndSessionAccess = 16,
  EndRequest = 32
}

public void FlagsTest()
{
  ....
  RuntimeEvent support = GetSupportEvent();
  ....
  Assert.True(support.HasFlag(  RuntimeEvent.EndRequest
                              & RuntimeEvent.BeginRequest),
              "End|Begin in End|SessionEnd");
  ....
}

'support' is an enumeration instance of the 'RuntimeEvent' type. The variable gets the value after the 'GetSupportEvent' method is called. After initialization, 'support' is checked for the flag with a bitwise 'AND' value for 'EndRequest' and 'BeginRequest'.

A check like this makes no sense, because the expression '32 & 2' is zero. If the 'HasFlag' argument is zero, the result of the method call is always 'true'. Therefore, the test passes regardless of the 'support' value. Such code looks suspicious.

The correct version of the check might look as follows:

public void FlagsTest()
{
  ....
  RuntimeEvent support = GetSupportEvent();
  ....
  Assert.True(support.HasFlag(  RuntimeEvent.EndRequest 
                              | RuntimeEvent.BeginRequest),
              "End|Begin in End|SessionEnd");
  ....
}
Unicorn with delicious cookie
Our website uses cookies to enhance your browsing experience. Would you like to learn more?
Accept