Re: [PATCH] accept all C integer types in function parameters referenced by alloc_align (PR 88363)

[Marek Polacek <polacek@redhat.com>]

On Tue, Dec 11, 2018 at 03:46:37PM -0700, Martin Sebor wrote:
> On 12/11/18 1:47 PM, Jakub Jelinek wrote:
> > On Tue, Dec 11, 2018 at 01:36:58PM -0700, Martin Sebor wrote:
> > > Attached is an updated version of the patch that restores
> > > the original behavior for the positional argument validation
> > > (i.e., prior to r266195) for integral types except bool as
> > > discussed.
> > 
> > I thought Jason wanted to also warn for scoped enums in C++.
> 
> I missed that.  It seems needlessly restrictive to me to reject
> the preferred kind of an enum when ordinary enums are accepted.
> Jason, can you confirm that you really want a warning for B
> below when there is none for A (GCC 8 doesn't complain about
> either, Clang complains about both, ICC about neither when
> using alloc_size -- it doesn't understand alloc_align):
> 
>   enum A { /* ... */ };
>   __attribute__ ((alloc_align (1))) void* f (A);
> 
>   enum class B { /* ... */ };
>   __attribute__ ((alloc_align (1))) void* g (B);
> 
> The only use case I can think of for enums is in APIs that try
> to restrict the available choices of alignment to those of
> the enumerators.  In that use case, I would expect it to make
> no difference whether the enum is ordinary or the scoped kind.

The reason was that C++ scoped enumerations don't implicitly convert to
integral types.

Marek