Another idiom I wish were gone from phobos/druntime

[Daniel Murphy via Digitalmars-d]

"Zach the Mystic"  wrote in message 
news:qxtyqdeewrjurmwhksbj at forum.dlang.org...

> I don't know how the second assert could men somethign different from the 
> first. If you assert (anything but assert(0)) first thing, you certainly 
> are not checking for bugs *within* the function - you're checking for 
> entry conditions. So the question is whether the practical difference 
> between the two asserts above is sufficient to prevent applying the syntax 
> sugar. I personally can live with it either way (I can handle being told 
> the the function failed when it was really the caller that failed), but 
> it's a judgment call. I mean, this thread was literally called "Another 
> idiom I wish were gone from phobos/druntime." I don't expect it is the 
> last time someone will complain about it.

Here's one:

struct S
{
private:
    static int instanceCount;

...

public:
    void func(int x)
    in
    {
        assert(x >= 0, "can't call func with negative x");
    }
    body
    {
        assert(instanceCount > 0);
    }
}

The first assert checks something the caller has control over, the second 
assert is a sanity check, and if it fails it's not an error in the caller.

Anyway, IMO there is zero chance of this making it into the language and 
you're wasting your energy.