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Date: Tue, 9 Apr 2019 18:05:36 +0200
Cc: Dan Ackroyd <Danack@basereality.com>,
 PHP internals <internals@lists.php.net>
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To: Levi Morrison <levim@php.net>
Subject: Re: [PHP-DEV] [RFC] Always generate fatal error for incompatible
 method signatures
From: gadelat@gmail.com (Gabriel O)


> If you want the reverse to be true, then your code has bugs waiting to
> show themselves

I don=E2=80=99t, I just don=E2=80=99t want fatal errors in production =
when I upgrade library I extend. Let me keep logging such issues and fix =
them later, instead of producing hard crash for customers.


>  The earlier we can catch these bugs, the better.

What prevents somebody to catch warnings? This RFC is about hard crash =
that I disagree with. This type of issue is problematic only when =
expecting parent but injecting child.

> On 9. Apr 2019, at 17:35, Levi Morrison <levim@php.net> wrote:
>=20
> On Tue, Apr 9, 2019 at 9:00 AM Gabriel O <gadelat@gmail.com> wrote:
>>=20
>> I believe rfc deals with reverse situation
>>=20
>> On 9 April 2019 4:47:50 PM Dan Ackroyd <Danack@basereality.com> =
wrote:
>>=20
>>> On Tue, 9 Apr 2019 at 11:58, Gabriel O <gadelat@gmail.com> wrote:
>>>=20
>>>> And this RFC conveniently shows only big LSP violation examples =
like array
>>>> -> int, but not widely used narrowing like mixed/object -> specific =
instance.
>>>=20
>>>=20
>>> Type narrowing or contravariant parameters is properly supported for
>>> PHP 7.4:
>>> =
https://wiki.php.net/rfc/covariant-returns-and-contravariant-parameters
>>> , which is why this RFC doesn't need to cover them.
>>>=20
>>> cheers
>>> Dan
>>> Ack
>=20
> If you want the reverse to be true, then your code has bugs waiting to
> show themselves. The earlier we can catch these bugs, the better.
>=20
> One thing to note is that return type information does permit
> optimizations in some cases. For instance, I believe if a private
> method has a return type constraint of int, then the optimizer can
> rule out certain edge cases, and in some cases use type specialized
> handlers. We can do these sorts of optimizations in more places if the
> LSP issues are always errors, instead of warnings.
>=20
> So for both correctness and performance, I support this change.