CODEWITHSUNDEEP
c++visual-studiovisual-studio-2013visual-studio-2017
Joe
Joe

Reputation: 6816

Warnings not being generated in VS2017

It seems to me that VS2017 fails to catch some fairly obvious compiler warnings which older versions do not. This seems so fundamental to me that I'm guessing the problem has to be something I'm missing (e.g. some new default compiler setting, perhaps?). Has anyone else seen this?

To test this, I create a simple console application in both 2013 and 2017. The only change I made the to the project settings was to set the compiler warning level to 4 and to report warnings as errors. Below is the entirety of the source

In VS2013 this fails. In 2017, it builds just fine...

// TestWarning4127.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include <iostream>


int main()
{
    if (true)   // *** SHOULD generate warning 4127
        std::cout << "Warning";

    return 0;
}

Am I missing something obvious here...?

Upvotes: 3

Views: 74

Answers (1)

Ron
Ron

Reputation: 15521

When used inside an if or while conditions the trivial constants such as 1 or true do not generate warnings in VS 2017 as described in the Compiler Warning (level4) official documentation. Excerpt from the official documentation:

The controlling expression of an if statement or while loop evaluates to a constant. Because of their common idiomatic usage, trivial constants such as 1 or true do not trigger the warning, unless they are the result of an operation in an expression.

That being said it's not a warning in VS 2013 with the default warning levels of W3 either. Only with the elevated W4 settings does the VS 2013 report a warning. It was removed in VS 2017 altogether.

For comparison, the GCC does not generate the warning either: Live example on Coliru.

Upvotes: 7

Related Questions