Re: [PATCH v20 01/40] c++: Sort built-in traits alphabetically

[Ken Matsui <kmatsui@cs.washington.edu>]

On Mon, Oct 16, 2023 at 8:17 AM Patrick Palka <ppalka@redhat.com> wrote:
>
> On Sun, 15 Oct 2023, Ken Matsui wrote:
>
> > This patch sorts built-in traits alphabetically for better code
> > readability.
>
> Hmm, I'm not sure if we still want/need this change with this current
> approach.  IIUC gperf would sort the trait names when generating the
> hash table code, and so we wanted a more consistent mapping from the
> cp-trait.def file to the generated code.  But with this current
> non-gperf approach I'm inclined to leave the existing ordering alone
> for sake of simplicity, and I kind of like that in cp-trait.def we
> currently group all expression-yielding traits together and all
> type-yielding traits together; that seems like a more natural layout
> than plain alphabetical sorting.
>

I see. But this patch is crucial for me to keep all my existing
patches almost conflict-free against rebase, including drop, add, and
edit like you suggested to split integral-related patches. Without
this patch and alphabetical order, I will need to put a new trait in a
random place not close to surrounding commits, as Git relates close
lines when it finds conflicts. When I merged all my patches into one
patch series, I needed to fix conflicts for all my patches almost
every time I rebased. Both thinking of the random place and fixing the
conflicts of all patches would definitely not be desirable. Would you
think we should drop this patch?

> >
> > gcc/cp/ChangeLog:
> >
> >       * constraint.cc (diagnose_trait_expr): Sort built-in traits
> >       alphabetically.
> >       * cp-trait.def: Likewise.
> >       * semantics.cc (trait_expr_value): Likewise.
> >       (finish_trait_expr): Likewise.
> >       (finish_trait_type): Likewise.
> >
> > gcc/testsuite/ChangeLog:
> >
> >       * g++.dg/ext/has-builtin-1.C: Sort built-in traits alphabetically.
> >
> > Signed-off-by: Ken Matsui <kmatsui@gcc.gnu.org>
> > ---
> >  gcc/cp/constraint.cc                     | 68 ++++++++---------
> >  gcc/cp/cp-trait.def                      | 10 +--
> >  gcc/cp/semantics.cc                      | 94 ++++++++++++------------
> >  gcc/testsuite/g++.dg/ext/has-builtin-1.C | 70 +++++++++---------
> >  4 files changed, 121 insertions(+), 121 deletions(-)
> >
> > diff --git a/gcc/cp/constraint.cc b/gcc/cp/constraint.cc
> > index c9e4e7043cd..722fc334e6f 100644
> > --- a/gcc/cp/constraint.cc
> > +++ b/gcc/cp/constraint.cc
> > @@ -3702,18 +3702,36 @@ diagnose_trait_expr (tree expr, tree args)
> >      case CPTK_HAS_TRIVIAL_DESTRUCTOR:
> >        inform (loc, "  %qT is not trivially destructible", t1);
> >        break;
> > +    case CPTK_HAS_UNIQUE_OBJ_REPRESENTATIONS:
> > +      inform (loc, "  %qT does not have unique object representations", t1);
> > +      break;
> >      case CPTK_HAS_VIRTUAL_DESTRUCTOR:
> >        inform (loc, "  %qT does not have a virtual destructor", t1);
> >        break;
> >      case CPTK_IS_ABSTRACT:
> >        inform (loc, "  %qT is not an abstract class", t1);
> >        break;
> > +    case CPTK_IS_AGGREGATE:
> > +      inform (loc, "  %qT is not an aggregate", t1);
> > +      break;
> > +    case CPTK_IS_ASSIGNABLE:
> > +      inform (loc, "  %qT is not assignable from %qT", t1, t2);
> > +      break;
> >      case CPTK_IS_BASE_OF:
> >        inform (loc, "  %qT is not a base of %qT", t1, t2);
> >        break;
> >      case CPTK_IS_CLASS:
> >        inform (loc, "  %qT is not a class", t1);
> >        break;
> > +    case CPTK_IS_CONSTRUCTIBLE:
> > +      if (!t2)
> > +    inform (loc, "  %qT is not default constructible", t1);
> > +      else
> > +    inform (loc, "  %qT is not constructible from %qE", t1, t2);
> > +      break;
> > +    case CPTK_IS_CONVERTIBLE:
> > +      inform (loc, "  %qT is not convertible from %qE", t2, t1);
> > +      break;
> >      case CPTK_IS_EMPTY:
> >        inform (loc, "  %qT is not an empty class", t1);
> >        break;
> > @@ -3729,6 +3747,18 @@ diagnose_trait_expr (tree expr, tree args)
> >      case CPTK_IS_LITERAL_TYPE:
> >        inform (loc, "  %qT is not a literal type", t1);
> >        break;
> > +    case CPTK_IS_NOTHROW_ASSIGNABLE:
> > +      inform (loc, "  %qT is not nothrow assignable from %qT", t1, t2);
> > +      break;
> > +    case CPTK_IS_NOTHROW_CONSTRUCTIBLE:
> > +      if (!t2)
> > +     inform (loc, "  %qT is not nothrow default constructible", t1);
> > +      else
> > +     inform (loc, "  %qT is not nothrow constructible from %qE", t1, t2);
> > +      break;
> > +    case CPTK_IS_NOTHROW_CONVERTIBLE:
> > +       inform (loc, "  %qT is not nothrow convertible from %qE", t2, t1);
> > +      break;
> >      case CPTK_IS_POINTER_INTERCONVERTIBLE_BASE_OF:
> >        inform (loc, "  %qT is not pointer-interconvertible base of %qT",
> >             t1, t2);
> > @@ -3748,50 +3778,20 @@ diagnose_trait_expr (tree expr, tree args)
> >      case CPTK_IS_TRIVIAL:
> >        inform (loc, "  %qT is not a trivial type", t1);
> >        break;
> > -    case CPTK_IS_UNION:
> > -      inform (loc, "  %qT is not a union", t1);
> > -      break;
> > -    case CPTK_IS_AGGREGATE:
> > -      inform (loc, "  %qT is not an aggregate", t1);
> > -      break;
> > -    case CPTK_IS_TRIVIALLY_COPYABLE:
> > -      inform (loc, "  %qT is not trivially copyable", t1);
> > -      break;
> > -    case CPTK_IS_ASSIGNABLE:
> > -      inform (loc, "  %qT is not assignable from %qT", t1, t2);
> > -      break;
> >      case CPTK_IS_TRIVIALLY_ASSIGNABLE:
> >        inform (loc, "  %qT is not trivially assignable from %qT", t1, t2);
> >        break;
> > -    case CPTK_IS_NOTHROW_ASSIGNABLE:
> > -      inform (loc, "  %qT is not nothrow assignable from %qT", t1, t2);
> > -      break;
> > -    case CPTK_IS_CONSTRUCTIBLE:
> > -      if (!t2)
> > -     inform (loc, "  %qT is not default constructible", t1);
> > -      else
> > -     inform (loc, "  %qT is not constructible from %qE", t1, t2);
> > -      break;
> >      case CPTK_IS_TRIVIALLY_CONSTRUCTIBLE:
> >        if (!t2)
> >       inform (loc, "  %qT is not trivially default constructible", t1);
> >        else
> >       inform (loc, "  %qT is not trivially constructible from %qE", t1, t2);
> >        break;
> > -    case CPTK_IS_NOTHROW_CONSTRUCTIBLE:
> > -      if (!t2)
> > -     inform (loc, "  %qT is not nothrow default constructible", t1);
> > -      else
> > -     inform (loc, "  %qT is not nothrow constructible from %qE", t1, t2);
> > -      break;
> > -    case CPTK_HAS_UNIQUE_OBJ_REPRESENTATIONS:
> > -      inform (loc, "  %qT does not have unique object representations", t1);
> > -      break;
> > -    case CPTK_IS_CONVERTIBLE:
> > -      inform (loc, "  %qT is not convertible from %qE", t2, t1);
> > +    case CPTK_IS_TRIVIALLY_COPYABLE:
> > +      inform (loc, "  %qT is not trivially copyable", t1);
> >        break;
> > -    case CPTK_IS_NOTHROW_CONVERTIBLE:
> > -     inform (loc, "  %qT is not nothrow convertible from %qE", t2, t1);
> > +    case CPTK_IS_UNION:
> > +      inform (loc, "  %qT is not a union", t1);
> >        break;
> >      case CPTK_REF_CONSTRUCTS_FROM_TEMPORARY:
> >        inform (loc, "  %qT is not a reference that binds to a temporary "
> > diff --git a/gcc/cp/cp-trait.def b/gcc/cp/cp-trait.def
> > index 8b7fece0cc8..0e48e64b8dd 100644
> > --- a/gcc/cp/cp-trait.def
> > +++ b/gcc/cp/cp-trait.def
> > @@ -84,14 +84,14 @@ DEFTRAIT_EXPR (IS_TRIVIALLY_COPYABLE, "__is_trivially_copyable", 1)
> >  DEFTRAIT_EXPR (IS_UNION, "__is_union", 1)
> >  DEFTRAIT_EXPR (REF_CONSTRUCTS_FROM_TEMPORARY, "__reference_constructs_from_temporary", 2)
> >  DEFTRAIT_EXPR (REF_CONVERTS_FROM_TEMPORARY, "__reference_converts_from_temporary", 2)
> > -/* FIXME Added space to avoid direct usage in GCC 13.  */
> > -DEFTRAIT_EXPR (IS_DEDUCIBLE, "__is_deducible ", 2)
> > -
> >  DEFTRAIT_TYPE (REMOVE_CV, "__remove_cv", 1)
> > -DEFTRAIT_TYPE (REMOVE_REFERENCE, "__remove_reference", 1)
> >  DEFTRAIT_TYPE (REMOVE_CVREF, "__remove_cvref", 1)
> > -DEFTRAIT_TYPE (UNDERLYING_TYPE,  "__underlying_type", 1)
> > +DEFTRAIT_TYPE (REMOVE_REFERENCE, "__remove_reference", 1)
> >  DEFTRAIT_TYPE (TYPE_PACK_ELEMENT, "__type_pack_element", -1)
> > +DEFTRAIT_TYPE (UNDERLYING_TYPE, "__underlying_type", 1)
> > +
> > +/* FIXME Added space to avoid direct usage in GCC 13.  */
> > +DEFTRAIT_EXPR (IS_DEDUCIBLE, "__is_deducible ", 2)
> >
> >  /* These traits yield a type pack, not a type, and are represented by
> >     cp_parser_trait as a special BASES tree instead of a TRAIT_TYPE tree.  */
> > diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc
> > index 80ef1364e33..782aa515da0 100644
> > --- a/gcc/cp/semantics.cc
> > +++ b/gcc/cp/semantics.cc
> > @@ -12090,15 +12090,6 @@ trait_expr_value (cp_trait_kind kind, tree type1, tree type2)
> >                     && classtype_has_nothrow_assign_or_copy_p (type1,
> >                                                                true))));
> >
> > -    case CPTK_HAS_TRIVIAL_ASSIGN:
> > -      /* ??? The standard seems to be missing the "or array of such a class
> > -      type" wording for this trait.  */
> > -      type1 = strip_array_types (type1);
> > -      return (!CP_TYPE_CONST_P (type1) && type_code1 != REFERENCE_TYPE
> > -           && (trivial_type_p (type1)
> > -                 || (CLASS_TYPE_P (type1)
> > -                     && TYPE_HAS_TRIVIAL_COPY_ASSIGN (type1))));
> > -
> >      case CPTK_HAS_NOTHROW_CONSTRUCTOR:
> >        type1 = strip_array_types (type1);
> >        return (trait_expr_value (CPTK_HAS_TRIVIAL_CONSTRUCTOR, type1, type2)
> > @@ -12107,17 +12098,26 @@ trait_expr_value (cp_trait_kind kind, tree type1, tree type2)
> >                 && maybe_instantiate_noexcept (t)
> >                 && TYPE_NOTHROW_P (TREE_TYPE (t))));
> >
> > -    case CPTK_HAS_TRIVIAL_CONSTRUCTOR:
> > -      type1 = strip_array_types (type1);
> > -      return (trivial_type_p (type1)
> > -           || (CLASS_TYPE_P (type1) && TYPE_HAS_TRIVIAL_DFLT (type1)));
> > -
> >      case CPTK_HAS_NOTHROW_COPY:
> >        type1 = strip_array_types (type1);
> >        return (trait_expr_value (CPTK_HAS_TRIVIAL_COPY, type1, type2)
> >             || (CLASS_TYPE_P (type1)
> >                 && classtype_has_nothrow_assign_or_copy_p (type1, false)));
> >
> > +    case CPTK_HAS_TRIVIAL_ASSIGN:
> > +      /* ??? The standard seems to be missing the "or array of such a class
> > +      type" wording for this trait.  */
> > +      type1 = strip_array_types (type1);
> > +      return (!CP_TYPE_CONST_P (type1) && type_code1 != REFERENCE_TYPE
> > +           && (trivial_type_p (type1)
> > +                 || (CLASS_TYPE_P (type1)
> > +                     && TYPE_HAS_TRIVIAL_COPY_ASSIGN (type1))));
> > +
> > +    case CPTK_HAS_TRIVIAL_CONSTRUCTOR:
> > +      type1 = strip_array_types (type1);
> > +      return (trivial_type_p (type1)
> > +           || (CLASS_TYPE_P (type1) && TYPE_HAS_TRIVIAL_DFLT (type1)));
> > +
> >      case CPTK_HAS_TRIVIAL_COPY:
> >        /* ??? The standard seems to be missing the "or array of such a class
> >        type" wording for this trait.  */
> > @@ -12131,18 +12131,21 @@ trait_expr_value (cp_trait_kind kind, tree type1, tree type2)
> >             || (CLASS_TYPE_P (type1)
> >                 && TYPE_HAS_TRIVIAL_DESTRUCTOR (type1)));
> >
> > -    case CPTK_HAS_VIRTUAL_DESTRUCTOR:
> > -      return type_has_virtual_destructor (type1);
> > -
> >      case CPTK_HAS_UNIQUE_OBJ_REPRESENTATIONS:
> >        return type_has_unique_obj_representations (type1);
> >
> > +    case CPTK_HAS_VIRTUAL_DESTRUCTOR:
> > +      return type_has_virtual_destructor (type1);
> > +
> >      case CPTK_IS_ABSTRACT:
> >        return ABSTRACT_CLASS_TYPE_P (type1);
> >
> >      case CPTK_IS_AGGREGATE:
> >        return CP_AGGREGATE_TYPE_P (type1);
> >
> > +    case CPTK_IS_ASSIGNABLE:
> > +      return is_xible (MODIFY_EXPR, type1, type2);
> > +
> >      case CPTK_IS_BASE_OF:
> >        return (NON_UNION_CLASS_TYPE_P (type1) && NON_UNION_CLASS_TYPE_P (type2)
> >             && (same_type_ignoring_top_level_qualifiers_p (type1, type2)
> > @@ -12151,6 +12154,12 @@ trait_expr_value (cp_trait_kind kind, tree type1, tree type2)
> >      case CPTK_IS_CLASS:
> >        return NON_UNION_CLASS_TYPE_P (type1);
> >
> > +    case CPTK_IS_CONSTRUCTIBLE:
> > +      return is_xible (INIT_EXPR, type1, type2);
> > +
> > +    case CPTK_IS_CONVERTIBLE:
> > +      return is_convertible (type1, type2);
> > +
> >      case CPTK_IS_EMPTY:
> >        return NON_UNION_CLASS_TYPE_P (type1) && CLASSTYPE_EMPTY_P (type1);
> >
> > @@ -12166,6 +12175,15 @@ trait_expr_value (cp_trait_kind kind, tree type1, tree type2)
> >      case CPTK_IS_LITERAL_TYPE:
> >        return literal_type_p (type1);
> >
> > +    case CPTK_IS_NOTHROW_ASSIGNABLE:
> > +      return is_nothrow_xible (MODIFY_EXPR, type1, type2);
> > +
> > +    case CPTK_IS_NOTHROW_CONSTRUCTIBLE:
> > +      return is_nothrow_xible (INIT_EXPR, type1, type2);
> > +
> > +    case CPTK_IS_NOTHROW_CONVERTIBLE:
> > +      return is_nothrow_convertible (type1, type2);
> > +
> >      case CPTK_IS_POINTER_INTERCONVERTIBLE_BASE_OF:
> >        return pointer_interconvertible_base_of_p (type1, type2);
> >
> > @@ -12196,24 +12214,6 @@ trait_expr_value (cp_trait_kind kind, tree type1, tree type2)
> >      case CPTK_IS_UNION:
> >        return type_code1 == UNION_TYPE;
> >
> > -    case CPTK_IS_ASSIGNABLE:
> > -      return is_xible (MODIFY_EXPR, type1, type2);
> > -
> > -    case CPTK_IS_CONSTRUCTIBLE:
> > -      return is_xible (INIT_EXPR, type1, type2);
> > -
> > -    case CPTK_IS_NOTHROW_ASSIGNABLE:
> > -      return is_nothrow_xible (MODIFY_EXPR, type1, type2);
> > -
> > -    case CPTK_IS_NOTHROW_CONSTRUCTIBLE:
> > -      return is_nothrow_xible (INIT_EXPR, type1, type2);
> > -
> > -    case CPTK_IS_CONVERTIBLE:
> > -      return is_convertible (type1, type2);
> > -
> > -    case CPTK_IS_NOTHROW_CONVERTIBLE:
> > -      return is_nothrow_convertible (type1, type2);
> > -
> >      case CPTK_REF_CONSTRUCTS_FROM_TEMPORARY:
> >        return ref_xes_from_temporary (type1, type2, /*direct_init=*/true);
> >
> > @@ -12326,9 +12326,9 @@ finish_trait_expr (location_t loc, cp_trait_kind kind, tree type1, tree type2)
> >       return error_mark_node;
> >        break;
> >
> > +    case CPTK_IS_ABSTRACT:
> >      case CPTK_IS_EMPTY:
> >      case CPTK_IS_POLYMORPHIC:
> > -    case CPTK_IS_ABSTRACT:
> >      case CPTK_HAS_VIRTUAL_DESTRUCTOR:
> >        if (!check_trait_type (type1, /* kind = */ 3))
> >       return error_mark_node;
> > @@ -12348,12 +12348,12 @@ finish_trait_expr (location_t loc, cp_trait_kind kind, tree type1, tree type2)
> >       return error_mark_node;
> >        break;
> >
> > -    case CPTK_IS_TRIVIALLY_ASSIGNABLE:
> > -    case CPTK_IS_TRIVIALLY_CONSTRUCTIBLE:
> > +    case CPTK_IS_CONVERTIBLE:
> >      case CPTK_IS_NOTHROW_ASSIGNABLE:
> >      case CPTK_IS_NOTHROW_CONSTRUCTIBLE:
> > -    case CPTK_IS_CONVERTIBLE:
> >      case CPTK_IS_NOTHROW_CONVERTIBLE:
> > +    case CPTK_IS_TRIVIALLY_ASSIGNABLE:
> > +    case CPTK_IS_TRIVIALLY_CONSTRUCTIBLE:
> >      case CPTK_REF_CONSTRUCTS_FROM_TEMPORARY:
> >      case CPTK_REF_CONVERTS_FROM_TEMPORARY:
> >        if (!check_trait_type (type1)
> > @@ -12372,8 +12372,8 @@ finish_trait_expr (location_t loc, cp_trait_kind kind, tree type1, tree type2)
> >
> >      case CPTK_IS_CLASS:
> >      case CPTK_IS_ENUM:
> > -    case CPTK_IS_UNION:
> >      case CPTK_IS_SAME:
> > +    case CPTK_IS_UNION:
> >        break;
> >
> >      case CPTK_IS_LAYOUT_COMPATIBLE:
> > @@ -12436,25 +12436,25 @@ finish_trait_type (cp_trait_kind kind, tree type1, tree type2,
> >
> >    switch (kind)
> >      {
> > -    case CPTK_UNDERLYING_TYPE:
> > -      return finish_underlying_type (type1);
> > -
> >      case CPTK_REMOVE_CV:
> >        return cv_unqualified (type1);
> >
> > -    case CPTK_REMOVE_REFERENCE:
> > +    case CPTK_REMOVE_CVREF:
> >        if (TYPE_REF_P (type1))
> >       type1 = TREE_TYPE (type1);
> > -      return type1;
> > +      return cv_unqualified (type1);
> >
> > -    case CPTK_REMOVE_CVREF:
> > +    case CPTK_REMOVE_REFERENCE:
> >        if (TYPE_REF_P (type1))
> >       type1 = TREE_TYPE (type1);
> > -      return cv_unqualified (type1);
> > +      return type1;
> >
> >      case CPTK_TYPE_PACK_ELEMENT:
> >        return finish_type_pack_element (type1, type2, complain);
> >
> > +    case CPTK_UNDERLYING_TYPE:
> > +      return finish_underlying_type (type1);
> > +
> >  #define DEFTRAIT_EXPR(CODE, NAME, ARITY) \
> >      case CPTK_##CODE:
> >  #include "cp-trait.def"
> > diff --git a/gcc/testsuite/g++.dg/ext/has-builtin-1.C b/gcc/testsuite/g++.dg/ext/has-builtin-1.C
> > index f343e153e56..2223f08a628 100644
> > --- a/gcc/testsuite/g++.dg/ext/has-builtin-1.C
> > +++ b/gcc/testsuite/g++.dg/ext/has-builtin-1.C
> > @@ -8,9 +8,21 @@
> >  #if !__has_builtin (__builtin_bit_cast)
> >  # error "__has_builtin (__builtin_bit_cast) failed"
> >  #endif
> > +#if !__has_builtin (__builtin_is_constant_evaluated)
> > +# error "__has_builtin (__builtin_is_constant_evaluated) failed"
> > +#endif
> > +#if !__has_builtin (__builtin_is_corresponding_member)
> > +# error "__has_builtin (__builtin_is_corresponding_member) failed"
> > +#endif
> > +#if !__has_builtin (__builtin_is_pointer_interconvertible_with_class)
> > +# error "__has_builtin (__builtin_is_pointer_interconvertible_with_class) failed"
> > +#endif
> >  #if !__has_builtin (__builtin_launder)
> >  # error "__has_builtin (__builtin_launder) failed"
> >  #endif
> > +#if !__has_builtin (__builtin_source_location)
> > +# error "__has_builtin (__builtin_source_location) failed"
> > +#endif
> >  #if !__has_builtin (__has_nothrow_assign)
> >  # error "__has_builtin (__has_nothrow_assign) failed"
> >  #endif
> > @@ -44,12 +56,21 @@
> >  #if !__has_builtin (__is_aggregate)
> >  # error "__has_builtin (__is_aggregate) failed"
> >  #endif
> > +#if !__has_builtin (__is_assignable)
> > +# error "__has_builtin (__is_assignable) failed"
> > +#endif
> >  #if !__has_builtin (__is_base_of)
> >  # error "__has_builtin (__is_base_of) failed"
> >  #endif
> >  #if !__has_builtin (__is_class)
> >  # error "__has_builtin (__is_class) failed"
> >  #endif
> > +#if !__has_builtin (__is_constructible)
> > +# error "__has_builtin (__is_constructible) failed"
> > +#endif
> > +#if !__has_builtin (__is_convertible)
> > +# error "__has_builtin (__is_convertible) failed"
> > +#endif
> >  #if !__has_builtin (__is_empty)
> >  # error "__has_builtin (__is_empty) failed"
> >  #endif
> > @@ -65,6 +86,15 @@
> >  #if !__has_builtin (__is_literal_type)
> >  # error "__has_builtin (__is_literal_type) failed"
> >  #endif
> > +#if !__has_builtin (__is_nothrow_assignable)
> > +# error "__has_builtin (__is_nothrow_assignable) failed"
> > +#endif
> > +#if !__has_builtin (__is_nothrow_constructible)
> > +# error "__has_builtin (__is_nothrow_constructible) failed"
> > +#endif
> > +#if !__has_builtin (__is_nothrow_convertible)
> > +# error "__has_builtin (__is_nothrow_convertible) failed"
> > +#endif
> >  #if !__has_builtin (__is_pointer_interconvertible_base_of)
> >  # error "__has_builtin (__is_pointer_interconvertible_base_of) failed"
> >  #endif
> > @@ -98,51 +128,21 @@
> >  #if !__has_builtin (__is_union)
> >  # error "__has_builtin (__is_union) failed"
> >  #endif
> > -#if !__has_builtin (__underlying_type)
> > -# error "__has_builtin (__underlying_type) failed"
> > -#endif
> > -#if !__has_builtin (__is_assignable)
> > -# error "__has_builtin (__is_assignable) failed"
> > -#endif
> > -#if !__has_builtin (__is_constructible)
> > -# error "__has_builtin (__is_constructible) failed"
> > -#endif
> > -#if !__has_builtin (__is_nothrow_assignable)
> > -# error "__has_builtin (__is_nothrow_assignable) failed"
> > -#endif
> > -#if !__has_builtin (__is_nothrow_constructible)
> > -# error "__has_builtin (__is_nothrow_constructible) failed"
> > -#endif
> >  #if !__has_builtin (__reference_constructs_from_temporary)
> >  # error "__has_builtin (__reference_constructs_from_temporary) failed"
> >  #endif
> >  #if !__has_builtin (__reference_converts_from_temporary)
> >  # error "__has_builtin (__reference_converts_from_temporary) failed"
> >  #endif
> > -#if !__has_builtin (__builtin_is_constant_evaluated)
> > -# error "__has_builtin (__builtin_is_constant_evaluated) failed"
> > -#endif
> > -#if !__has_builtin (__builtin_source_location)
> > -# error "__has_builtin (__builtin_source_location) failed"
> > -#endif
> > -#if !__has_builtin (__builtin_is_corresponding_member)
> > -# error "__has_builtin (__builtin_is_corresponding_member) failed"
> > -#endif
> > -#if !__has_builtin (__builtin_is_pointer_interconvertible_with_class)
> > -# error "__has_builtin (__builtin_is_pointer_interconvertible_with_class) failed"
> > -#endif
> > -#if !__has_builtin (__is_convertible)
> > -# error "__has_builtin (__is_convertible) failed"
> > -#endif
> > -#if !__has_builtin (__is_nothrow_convertible)
> > -# error "__has_builtin (__is_nothrow_convertible) failed"
> > -#endif
> >  #if !__has_builtin (__remove_cv)
> >  # error "__has_builtin (__remove_cv) failed"
> >  #endif
> > +#if !__has_builtin (__remove_cvref)
> > +# error "__has_builtin (__remove_cvref) failed"
> > +#endif
> >  #if !__has_builtin (__remove_reference)
> >  # error "__has_builtin (__remove_reference) failed"
> >  #endif
> > -#if !__has_builtin (__remove_cvref)
> > -# error "__has_builtin (__remove_cvref) failed"
> > +#if !__has_builtin (__underlying_type)
> > +# error "__has_builtin (__underlying_type) failed"
> >  #endif
> > --
> > 2.42.0
> >
> >
>