Re: DMD can implicitly convert class pointer to the bool. Is it bug or terrible feature?

[ilya-stromberg]

On Sunday, 24 November 2013 at 14:12:18 UTC, Maxim Fomin wrote:

void* ptr;
if(ptr)

was a shortcut for 'if(ptr != NULL)' probably since C was created.

Small code change:

import std.stdio;

class Foo
{
}

void main()
{
        Foo f;
        
        if(f == null)
        {
                writeln("f is true");
        }
        
        if(f != null)
        {
                writeln("f is false");
        }
}

DMD output:

Error: use 'is' instead of '==' when comparing with null
Error: use '!is' instead of '!=' when comparing with null

So, C style 'if(ptr != NULL)' isn't allowed in D.