A more specific example of why I object is that I want to do things like add a
pointer to the thread an object was created on if ASSERT_DISABLED is false so I
can assert if things are done on invalid threads. If I do this in a class like
RefCounted, this rule would make me add a guarded initializer to every
RefCounted class.
> On Mar 21, 2019, at 1:37 PM, Alex Christensen <achristen...@apple.com> wrote:
>
> I object. I don’t find using { *this } in a header disorienting at all. I
> think it’s better than adding many duplicate lines in each constructor and
> risking forgetting one. I think if we were to remove all the
> m_attributeOwnerProxy initializers in WebKit it would add lots of duplication
> with little benefit. If it were a class with a default constructor we would
> have a high risk of forgetting a constructor somewhere.
>
>> On Mar 20, 2019, at 9:22 AM, Simon Fraser <simon.fra...@apple.com> wrote:
>>
>>> On Mar 14, 2019, at 1:06 PM, Filip Pizlo <fpi...@apple.com> wrote:
>>>
>>> I like to draw this distinction: is the initializer a constant?
>>>
>>> It’s not a constant if it relies on arguments to the constructor. “This” is
>>> an argument to the constructor.
>>>
>>> It’s also not a constant if it involves reading the heap.
>>>
>>> So, like you, I would want to see this code done in the constructor. But
>>> I’m not sure that my general rule is the same as everyone’s.
>>
>> This seems like a reasonable proposal to me: only use initializers when
>> their input is constant data.
>>
>> Any objections?
>>
>> Simon
>>
>>>
>>> -Filip
>>>
>>>> On Mar 14, 2019, at 12:59 PM, Simon Fraser <simon.fra...@apple.com> wrote:
>>>>
>>>> I've seen some code recently that initializes non-POD members via
>>>> initializers. For example, SVGAElement has:
>>>>
>>>> AttributeOwnerProxy m_attributeOwnerProxy { *this };
>>>>
>>>> I find this a little disorientating, and would normally expect to see this
>>>> in the constructor as m_attributeOwnerProxy(*this), as it makes it easier
>>>> to find places to set breakpoints, and the ordering of initialization is
>>>> easier to see.
>>>>
>>>> Are people OK with this pattern, or should we discourage it via the style
>>>> guidelines (and style checker)?
>>>>
>>>> Simon
>>>>
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