Allow using(idisposable) to be used as a boolean in an expression

[wiz0u]

I feel like it would be nice to be allowed to write statement like:

if (using(stream))
{
  stream.CopyTo(destination);
}
else
  Console.WriteLine("stream was null");

What this would mean, is that using is considered as an expression returning true if stream is non-null (i.e. an IDisposable), and false if stream is null.
It also mean that the IDisposable gets dispose at the end of the full statement block (if-else), or at the end of the current statement if that expression is not part of a control-flow statement.
(of course, if stream is null, there is nothing to dispose, just like using(nullValue) is already accepted now and does nothing)

What do you think?

[yaakov-h]

Other than your particular desire to dispose of the object after the last else, the following is already legal C# and achieves pretty much the same thing:

if (stream is not null) using (stream)
{
  stream.CopyTo(destination);
}
else
  Console.WriteLine("stream was null");

[wiz0u]

true, but the automatic indentation gets weird because they are considered as two separate statements.

also it's not a particular desire to dispose after the last else, it's just coherent so you can also write if (!using(stream))

you can consider my proposal as syntactic sugar

[yaakov-h]

automatic formatting is much cheaper to change than the language itself

[huoyaoyuan]

Allowing more things in if downgrades readability very much. An explicit null check is always understandable.

[CyrusNajmabadi]

i tend to agree with this. Every time i see something going on with if statements, i find it to be a but sort of eye-sort. About the only things i've been marginally ok with are allowing if !(...expr...) instead of if (!(...expr)). And:

if (someNullableBool)
{
}
else
{
}
null
{
}

And even those are things i don't feel like there really is enough of a need to do.

[theunrepentantgeek]

I agree - shorter isn't automatically better.