[PATCH] [MSVC2012] Allow 'mutable' references (fix for http://llvm.org/PR22444)

[Bataev, Alexey]

I take this into account, thanks.

Best regards,
Alexey Bataev
=============
Software Engineer
Intel Compiler Team

05.02.2015 1:54, Richard Smith пишет:
> On Tue, Feb 3, 2015 at 6:32 PM, Bataev, Alexey <a.bataev at hotmail.com 
> <mailto:a.bataev at hotmail.com>> wrote:
>
>     Hi Richard,
>     MSVC cl compiler allows mutable references even in user code, not
>     only in system header files. I checked it and both 2012, 2013
>     accepts the code from the test.
>
>
> That's beside the point. We're not trying to accept all the nonsense 
> that MSVC accepts, only the extensions that are needed to get real 
> code to work. Thus we would take patches for bugs/extensions that are 
> used in system headers (and ideally these cases should still give 
> errors if used outside system headers), and for bugs/extensions that 
> are very common in user code.
>
>     I'll add extension warning.
>
>     Best regards,
>     Alexey Bataev
>     =============
>     Software Engineer
>     Intel Compiler Team
>
>     03.02.2015 20:25, Richard Smith пишет:
>>
>>     Please emit a warning when this extension is used. If we're only
>>     doing this to support a system header, you could even make it a
>>     DefaultError ExtWarn. Other than that, this looks fine.
>>
>>     On 3 Feb 2015 02:32, "Alexey Bataev" <a.bataev at hotmail.com
>>     <mailto:a.bataev at hotmail.com>> wrote:
>>
>>         Hi rsmith,
>>
>>         Some standard header files from MSVC2012 use 'mutable' on
>>         references, though it is directly prohibited by the standard.
>>
>>         http://reviews.llvm.org/D7370
>>
>>         Files:
>>           lib/Sema/SemaDecl.cpp
>>           test/SemaCXX/ms_mutable_reference_member.cpp
>>
>>         Index: lib/Sema/SemaDecl.cpp
>>         ===================================================================
>>         --- lib/Sema/SemaDecl.cpp
>>         +++ lib/Sema/SemaDecl.cpp
>>         @@ -12347,7 +12347,7 @@
>>            // Check that 'mutable' is consistent with the type of the
>>         declaration.
>>            if (!InvalidDecl && Mutable) {
>>              unsigned DiagID = 0;
>>         -    if (T->isReferenceType())
>>         +    if (!getLangOpts().MSVCCompat && T->isReferenceType())
>>                DiagID = diag::err_mutable_reference;
>>              else if (T.isConstQualified())
>>                DiagID = diag::err_mutable_const;
>>         Index: test/SemaCXX/ms_mutable_reference_member.cpp
>>         ===================================================================
>>         --- test/SemaCXX/ms_mutable_reference_member.cpp
>>         +++ test/SemaCXX/ms_mutable_reference_member.cpp
>>         @@ -0,0 +1,14 @@
>>         +// RUN: %clang_cc1 %s -fsyntax-only -verify -fms-compatibility
>>         +// expected-no-diagnostics
>>         +
>>         +struct S {
>>         +  mutable int &a;
>>         +  S(int &b) : a(b) {}
>>         +};
>>         +
>>         +int main() {
>>         +  int a = 0;
>>         +  const S s(a);
>>         +  s.a = 10;
>>         +  return s.a + a;
>>         +}
>>
>>         EMAIL PREFERENCES
>>         http://reviews.llvm.org/settings/panel/emailpreferences/
>>
>
>