[meta.reflection.traits]

# 21 Metaprogramming library [[meta]](./#meta)

## 21.4 Reflection [[meta.reflection]](meta.reflection#traits)

### 21.4.17 Reflection type traits [meta.reflection.traits]

[1](#1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/meta.tex#L6569)

This subclause specifies consteval functions to
query the properties of types ([[meta.unary]](meta.unary "21.3.6 Unary type traits")),
query the relationships between types ([[meta.rel]](meta.rel "21.3.8 Relationships between types")), or
transform types ([[meta.trans]](meta.trans "21.3.9 Transformations between types")),
during program translation[.](#1.sentence-1)

Each consteval function declared in this class
has an associated class template declared elsewhere in this document[.](#1.sentence-2)

[2](#2)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/meta.tex#L6578)

Every function and function template declared in this subclause
throws an exception of type meta​::​exception unless the following conditions are met:

- [(2.1)](#2.1)

  For every parameter p of type info, is_type(p) is true[.](#2.1.sentence-1)

- [(2.2)](#2.2)

  For every parameter r whose type is constrained on [reflection_range](meta.reflection.substitute#concept:reflection_range "21.4.13 Reflection substitution [meta.reflection.substitute]"), ranges​::​​all_of(​r, is_type) is true[.](#2.2.sentence-1)

// associated with [[meta.unary.cat]](meta.unary.cat "21.3.6.2 Primary type categories"), primary type categoriesconsteval bool [is_void_type](#lib:is_void_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval bool [is_null_pointer_type](#lib:is_null_pointer_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval bool [is_integral_type](#lib:is_integral_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval bool [is_floating_point_type](#lib:is_floating_point_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval bool [is_array_type](#lib:is_array_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval bool [is_pointer_type](#lib:is_pointer_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval bool [is_lvalue_reference_type](#lib:is_lvalue_reference_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval bool [is_rvalue_reference_type](#lib:is_rvalue_reference_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval bool [is_member_object_pointer_type](#lib:is_member_object_pointer_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval bool [is_member_function_pointer_type](#lib:is_member_function_pointer_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval bool [is_enum_type](#lib:is_enum_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval bool [is_union_type](#lib:is_union_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval bool [is_class_type](#lib:is_class_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval bool [is_function_type](#lib:is_function_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval bool [is_reflection_type](#lib:is_reflection_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);

// associated with [[meta.unary.comp]](meta.unary.comp "21.3.6.3 Composite type traits"), composite type categoriesconsteval bool [is_reference_type](#lib:is_reference_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval bool [is_arithmetic_type](#lib:is_arithmetic_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval bool [is_fundamental_type](#lib:is_fundamental_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval bool [is_object_type](#lib:is_object_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval bool [is_scalar_type](#lib:is_scalar_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval bool [is_compound_type](#lib:is_compound_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval bool [is_member_pointer_type](#lib:is_member_pointer_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);

// associated with [[meta.unary.prop]](meta.unary.prop "21.3.6.4 Type properties"), type propertiesconsteval bool [is_const_type](#lib:is_const_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval bool [is_volatile_type](#lib:is_volatile_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval bool [is_trivially_copyable_type](#lib:is_trivially_copyable_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval bool [is_trivially_relocatable_type](#lib:is_trivially_relocatable_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval bool [is_replaceable_type](#lib:is_replaceable_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval bool [is_standard_layout_type](#lib:is_standard_layout_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval bool [is_empty_type](#lib:is_empty_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval bool [is_polymorphic_type](#lib:is_polymorphic_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval bool [is_abstract_type](#lib:is_abstract_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval bool [is_final_type](#lib:is_final_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval bool [is_aggregate_type](#lib:is_aggregate_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval bool [is_consteval_only_type](#lib:is_consteval_only_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval bool [is_signed_type](#lib:is_signed_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval bool [is_unsigned_type](#lib:is_unsigned_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval bool [is_bounded_array_type](#lib:is_bounded_array_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval bool [is_unbounded_array_type](#lib:is_unbounded_array_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval bool [is_scoped_enum_type](#lib:is_scoped_enum_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);

template<[reflection_range](meta.reflection.substitute#concept:reflection_range "21.4.13 Reflection substitution [meta.reflection.substitute]") R = initializer_list<info>>consteval bool [is_constructible_type](#lib:is_constructible_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type, R&& type_args);consteval bool [is_default_constructible_type](#lib:is_default_constructible_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval bool [is_copy_constructible_type](#lib:is_copy_constructible_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval bool [is_move_constructible_type](#lib:is_move_constructible_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);

consteval bool [is_assignable_type](#lib:is_assignable_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type_dst, info type_src);consteval bool [is_copy_assignable_type](#lib:is_copy_assignable_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval bool [is_move_assignable_type](#lib:is_move_assignable_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);

consteval bool [is_swappable_with_type](#lib:is_swappable_with_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type1, info type2);consteval bool [is_swappable_type](#lib:is_swappable_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);

consteval bool [is_destructible_type](#lib:is_destructible_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);

template<[reflection_range](meta.reflection.substitute#concept:reflection_range "21.4.13 Reflection substitution [meta.reflection.substitute]") R = initializer_list<info>>consteval bool [is_trivially_constructible_type](#lib:is_trivially_constructible_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type, R&& type_args);consteval bool [is_trivially_default_constructible_type](#lib:is_trivially_default_constructible_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval bool [is_trivially_copy_constructible_type](#lib:is_trivially_copy_constructible_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval bool [is_trivially_move_constructible_type](#lib:is_trivially_move_constructible_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);

consteval bool [is_trivially_assignable_type](#lib:is_trivially_assignable_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type_dst, info type_src);consteval bool [is_trivially_copy_assignable_type](#lib:is_trivially_copy_assignable_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval bool [is_trivially_move_assignable_type](#lib:is_trivially_move_assignable_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval bool [is_trivially_destructible_type](#lib:is_trivially_destructible_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);

template<[reflection_range](meta.reflection.substitute#concept:reflection_range "21.4.13 Reflection substitution [meta.reflection.substitute]") R = initializer_list<info>>consteval bool [is_nothrow_constructible_type](#lib:is_nothrow_constructible_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type, R&& type_args);consteval bool [is_nothrow_default_constructible_type](#lib:is_nothrow_default_constructible_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval bool [is_nothrow_copy_constructible_type](#lib:is_nothrow_copy_constructible_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval bool [is_nothrow_move_constructible_type](#lib:is_nothrow_move_constructible_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);

consteval bool [is_nothrow_assignable_type](#lib:is_nothrow_assignable_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type_dst, info type_src);consteval bool [is_nothrow_copy_assignable_type](#lib:is_nothrow_copy_assignable_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval bool [is_nothrow_move_assignable_type](#lib:is_nothrow_move_assignable_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);

consteval bool [is_nothrow_swappable_with_type](#lib:is_nothrow_swappable_with_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type1, info type2);consteval bool [is_nothrow_swappable_type](#lib:is_nothrow_swappable_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);

consteval bool [is_nothrow_destructible_type](#lib:is_nothrow_destructible_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval bool [is_nothrow_relocatable_type](#lib:is_nothrow_relocatable_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);

consteval bool [is_implicit_lifetime_type](#lib:is_implicit_lifetime_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);

consteval bool [has_virtual_destructor](#lib:has_virtual_destructor "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);

consteval bool [has_unique_object_representations](#lib:has_unique_object_representations "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);

consteval bool [reference_constructs_from_temporary](#lib:reference_constructs_from_temporary "21.4.17 Reflection type traits [meta.reflection.traits]")(info type_dst, info type_src);consteval bool [reference_converts_from_temporary](#lib:reference_converts_from_temporary "21.4.17 Reflection type traits [meta.reflection.traits]")(info type_dst, info type_src);

// associated with [[meta.rel]](meta.rel "21.3.8 Relationships between types"), type relationsconsteval bool [is_same_type](#lib:is_same_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type1, info type2);consteval bool [is_base_of_type](#lib:is_base_of_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type_base, info type_derived);consteval bool [is_virtual_base_of_type](#lib:is_virtual_base_of_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type_base, info type_derived);consteval bool [is_convertible_type](#lib:is_convertible_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type_src, info type_dst);consteval bool [is_nothrow_convertible_type](#lib:is_nothrow_convertible_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type_src, info type_dst);consteval bool [is_layout_compatible_type](#lib:is_layout_compatible_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type1, info type2);consteval bool [is_pointer_interconvertible_base_of_type](#lib:is_pointer_interconvertible_base_of_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type_base, info type_derived);

template<[reflection_range](meta.reflection.substitute#concept:reflection_range "21.4.13 Reflection substitution [meta.reflection.substitute]") R = initializer_list<info>>consteval bool [is_invocable_type](#lib:is_invocable_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type, R&& type_args);template<[reflection_range](meta.reflection.substitute#concept:reflection_range "21.4.13 Reflection substitution [meta.reflection.substitute]") R = initializer_list<info>>consteval bool [is_invocable_r_type](#lib:is_invocable_r_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type_result, info type, R&& type_args);

template<[reflection_range](meta.reflection.substitute#concept:reflection_range "21.4.13 Reflection substitution [meta.reflection.substitute]") R = initializer_list<info>>consteval bool [is_nothrow_invocable_type](#lib:is_nothrow_invocable_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type, R&& type_args);template<[reflection_range](meta.reflection.substitute#concept:reflection_range "21.4.13 Reflection substitution [meta.reflection.substitute]") R = initializer_list<info>>consteval bool [is_nothrow_invocable_r_type](#lib:is_nothrow_invocable_r_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type_result, info type, R&& type_args);

// associated with [[meta.trans.cv]](meta.trans.cv "21.3.9.2 Const-volatile modifications"), const-volatile modificationsconsteval info [remove_const](#lib:remove_const "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval info [remove_volatile](#lib:remove_volatile "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval info [remove_cv](#lib:remove_cv "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval info [add_const](#lib:add_const "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval info [add_volatile](#lib:add_volatile "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval info [add_cv](#lib:add_cv "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);

// associated with [[meta.trans.ref]](meta.trans.ref "21.3.9.3 Reference modifications"), reference modificationsconsteval info [remove_reference](#lib:remove_reference "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval info [add_lvalue_reference](#lib:add_lvalue_reference "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval info [add_rvalue_reference](#lib:add_rvalue_reference "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);

// associated with [[meta.trans.sign]](meta.trans.sign "21.3.9.4 Sign modifications"), sign modificationsconsteval info [make_signed](#lib:make_signed "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval info [make_unsigned](#lib:make_unsigned "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);

// associated with [[meta.trans.arr]](meta.trans.arr "21.3.9.5 Array modifications"), array modificationsconsteval info [remove_extent](#lib:remove_extent "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval info [remove_all_extents](#lib:remove_all_extents "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);

// associated with [[meta.trans.ptr]](meta.trans.ptr "21.3.9.6 Pointer modifications"), pointer modificationsconsteval info [remove_pointer](#lib:remove_pointer "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval info [add_pointer](#lib:add_pointer "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);

// associated with [[meta.trans.other]](meta.trans.other "21.3.9.7 Other transformations"), other transformationsconsteval info [remove_cvref](#lib:remove_cvref "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval info [decay](#lib:decay "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);template<[reflection_range](meta.reflection.substitute#concept:reflection_range "21.4.13 Reflection substitution [meta.reflection.substitute]") R = initializer_list<info>>consteval info [common_type](time.traits.specializations#lib:common_type "30.4.3 Specializations of common_­type [time.traits.specializations]")(R&& type_args);template<[reflection_range](meta.reflection.substitute#concept:reflection_range "21.4.13 Reflection substitution [meta.reflection.substitute]") R = initializer_list<info>>consteval info [common_reference](#lib:common_reference "21.4.17 Reflection type traits [meta.reflection.traits]")(R&& type_args);consteval info [underlying_type](#lib:underlying_type "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);template<[reflection_range](meta.reflection.substitute#concept:reflection_range "21.4.13 Reflection substitution [meta.reflection.substitute]") R = initializer_list<info>>consteval info [invoke_result](#lib:invoke_result "21.4.17 Reflection type traits [meta.reflection.traits]")(info type, R&& type_args);consteval info [unwrap_reference](#lib:unwrap_reference "21.4.17 Reflection type traits [meta.reflection.traits]")(info type);consteval info [unwrap_ref_decay](functional.syn#lib:unwrap_ref_decay "22.10.2 Header <functional> synopsis [functional.syn]")(info type);

[3](#3)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/meta.tex#L6747)

Each function or function template declared above has the following behavior
based on the signature and return type of that function or function template[.](#3.sentence-1)

[*Note [1](#note-1)*:

The associated class template need not be instantiated[.](#3.sentence-2)

— *end note*]

Table [64](#tab:meta.reflection.traits) — Reflection type traits [[tab:meta.reflection.traits]](./tab:meta.reflection.traits)  

| [🔗](#tab:meta.reflection.traits-row-1)<br>**Signature and Return Type** | ***Returns*** |
| --- | --- |
| [🔗](#tab:meta.reflection.traits-row-2)<br>bool meta​::​*UNARY*(info type);   bool meta​::​*UNARY*_type(info type); | std​::​*UNARY*_v<T>, where T is the type or type alias represented by type |
| [🔗](#tab:meta.reflection.traits-row-3)<br>bool meta​::​*BINARY*(info t1, info t2);   bool meta​::​*BINARY*_type(info t1, info t2); | std​::​*BINARY*_v<T1, T2>, where T1 and T2 are the types or type aliases represented by t1 and t2, respectively |
| [🔗](#tab:meta.reflection.traits-row-4)<br>template<reflection_range R>   bool meta​::​*VARIADIC*_type(info type, R&& args); | std​::​*VARIADIC*_v<T, U...>, where T is the type or type alias represented by type and U... is the pack of types or type aliases whose elements are represented by the corresponding elements of args |
| [🔗](#tab:meta.reflection.traits-row-5)<br>template<reflection_range R>   bool meta​::​*VARIADIC*_type(info t1, info t2, R&& args); | std​::​*VARIADIC*_v<T1, T2, U...>, where T1 and T2 are the types or type aliases represented by t1 and t2, respectively, and U... is the pack of types or type aliases whose elements are represented by the corresponding elements of args |
| [🔗](#tab:meta.reflection.traits-row-6)<br>info meta​::​*UNARY*(info type); | A reflection representing the type denoted by std​::​*UNARY*_t<​T>, where T is the type or type alias represented by type |
| [🔗](#tab:meta.reflection.traits-row-7)<br>template<reflection_range R>   info meta​::​*VARIADIC*(R&& args); | A reflection representing the type denoted by std​::​*VARIADIC*_t<T...>, where T... is the pack of types or type aliases whose elements are represented by the corresponding elements of args |
| [🔗](#tab:meta.reflection.traits-row-8)<br>template<reflection_range R>   info meta​::​*VARIADIC*(info type, R&& args); | A reflection representing the type denoted by std​::​*VARIADIC*_t<T, U...>, where T is the type or type alias represented by type and U... is the pack of types or type aliases whose elements are represented by the corresponding elements of args |

[4](#4)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/meta.tex#L6817)

[*Note [2](#note-2)*:

For those functions or function templates which return a reflection,
that reflection always represents a type and never a type alias[.](#4.sentence-1)

— *end note*]

[5](#5)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/meta.tex#L6823)

[*Note [3](#note-3)*:

If t is a reflection of the type int and u is a reflection of an alias to the type int,
then t == u is false but is_same_type(t, u) is true[.](#5.sentence-1)

Also, t == dealias(u) is true[.](#5.sentence-2)

— *end note*]

[🔗](#lib:rank)

`consteval size_t rank(info type);
`

[6](#6)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/meta.tex#L6838)

*Returns*: rank_v<T>,
where T is the type represented by dealias(type)[.](#6.sentence-1)

[🔗](#lib:extent)

`consteval size_t extent(info type, unsigned i = 0);
`

[7](#7)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/meta.tex#L6850)

*Returns*: extent_v<T, I>,
where T is the type represented by dealias(type) and I is a constant equal to i[.](#7.sentence-1)

[🔗](#lib:tuple_size)

`consteval size_t tuple_size(info type);
`

[8](#8)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/meta.tex#L6863)

*Returns*: tuple_size_v<T>,
where T is the type represented by dealias(type)[.](#8.sentence-1)

[🔗](#lib:tuple_element)

`consteval info tuple_element(size_t index, info type);
`

[9](#9)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/meta.tex#L6875)

*Returns*: A reflection representing
the type denoted by tuple_element_t<I, T>,
where T is the type represented by dealias(type) and I is a constant equal to index[.](#9.sentence-1)

[🔗](#lib:variant_size)

`consteval size_t variant_size(info type);
`

[10](#10)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/meta.tex#L6889)

*Returns*: variant_size_v<T>,
where T is the type represented by dealias(type)[.](#10.sentence-1)

[🔗](#lib:variant_alternative)

`consteval info variant_alternative(size_t index, info type);
`

[11](#11)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/meta.tex#L6901)

*Returns*: A reflection representing the type denoted byvariant_alternative_t<I, T>,
where T is the type represented by dealias(type) and I is a constant equal to index[.](#11.sentence-1)

[🔗](#lib:type_order)

`consteval strong_ordering type_order(info t1, info t2);
`

[12](#12)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/meta.tex#L6915)

*Returns*: type_order_v<T1, T2>,
where T1 and T2 are the types
represented by dealias(t1) and dealias(t2), respectively[.](#12.sentence-1)