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Date: Wed, 10 Jun 2009 17:04:00 -0000
Message-ID: <206fcf960906101003y56491009u153ceb13e7f2552e@mail.gmail.com>
Subject: Re: skip_evaluation
From: Gabriel Dos Reis <dosreis@gmail.com>
To: Paolo Bonzini <paolo.bonzini@gmail.com>
Cc: Ian Lance Taylor <iant@google.com>, gcc@gcc.gnu.org
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On Wed, Jun 10, 2009 at 10:51 AM, Paolo Bonzini<paolo.bonzini@gmail.com> wr=
ote:
>
>>> =A0 struct B {};
>>> =A0 struct D : public B {
>>> =A0 =A0 =A0 static const int i =3D sizeof((B*)(D*)0);
>>> =A0 };
>>>
>>> =A0 struct Z {};
>>> =A0 struct A : Z {};
>>> =A0 Z* implicitToZ (Z*);
>>> =A0 struct B : A {
>>> =A0 =A0 =A0 static const int i =3D sizeof(implicitToZ((B*)0));
>>> =A0 };
>>>
>>> =A0 struct B {};
>>> =A0 struct D;
>>> =A0 D* p;
>>> =A0 struct D: public B {
>>> =A0 =A0 =A0 static const int i =3D sizeof ((B*)p);
>>> =A0 };
>>>
>>> (see PR27177). =A0All of these would still be forbidden within (0?x:y).
>>
>> OK, but should they perhaps give an error which would perhaps not be
>> given if skip_evaluation is true?
>
> build_cp_class does not give errors after it tests skip_evaluation. =A0The
> constant-expression errors are given in the parsers.

which arguably is not  a good  place to issue such errors.  Support
for constexpr implies that we refrain from issuing such semantics
error from the parser.  However, constexpr patches will come somewhere in
July, so Ian probably does not want to wait for that now.

-- Gaby