C++: Add support for default member initializers.

[sashabu]

No description provided.

[jbj]

The new consistency errors are expected, but they're real enough. We'll have to come back and fix them later.

How do the data-flow libraries of other languages assign an enclosing callable to field initializers like these? @hvitved, you probably know.

[hvitved]

How do the data-flow libraries of other languages assign an enclosing callable to field initializers like these? @hvitved, you probably know.

For C#, we inline field initializers into the relevant contstructor(s) in the CFG. So, if we have something like

class C
{
    int Field = 0;

    public C()
    {
        Console.WriteLine("C");
    }
}

then the CFG for the constructor will be based on this rewrite

class C
{
    int Field;

    public C()
    {
        Field = 0;
        Console.WriteLine("C");
    }
}

[jbj]

We can merge this PR together with the internal PR when that's approved.

[sashabu]

@jbj Could you please have another look since I've pulled changes from main?

[jbj]

LGTM. We can merge this when the internal PR is ready.