[PATCH v23 03/33] c++: Accept the use of built-in trait identifiers

[Ken Matsui]

On Mon, Oct 23, 2023 at 1:36 PM Jason Merrill <jason@redhat.com> wrote:
>
> On 10/20/23 09:53, Ken Matsui wrote:
> > This patch accepts the use of built-in trait identifiers when they are
> > actually not used as traits.  Specifically, we check if the subsequent token
> > is '(' for ordinary built-in traits or is '<' only for the special
> > __type_pack_element built-in trait.  If those identifiers are used
> > differently, the parser treats them as normal identifiers.  This allows
> > us to accept code like: struct __is_pointer {};.
> >
> > +/* Peeks the corresponding built-in trait if a given token is
> >      a built-in trait.  Otherwise, returns nullptr.  */
> >
> >   static const cp_trait *
> > +cp_lexer_peek_trait (cp_lexer *lexer, const cp_token *token1)
>
> Passing in both the lexer and the peeked token seems awkward, let's just
> pass in the lexer.  Looking up the peeked token again is fast.
>
> >   {
> > +  if (token1->type == CPP_NAME && IDENTIFIER_TRAIT_P (token1->u.value))
> > +    {
> > +      const cp_trait &trait = cp_traits[IDENTIFIER_CP_INDEX (token1->u.value)];
> > +      const bool is_pack_element = (trait.kind == CPTK_TYPE_PACK_ELEMENT);
> > +
> > +      /* Check if the subsequent token is a `<' token to
> > +         __type_pack_element or is a `(' token to everything else.  */
>
> git complains about indentation with spaces instead of a tab on this line.
>

Thank you!

> Jason
>