109 lines · cpp
1// RUN: %clang_cc1 -std=c++1z -fcxx-exceptions -verify %s2// RUN: %clang_cc1 -std=c++1z -fcxx-exceptions -verify %s -DCLASS3 4#ifdef CLASS5struct Outer {6#endif7 8template<typename> struct A {};9 10// Valid forms.11A(int(&)[1]) -> A<int>;12explicit A(int(&)[2]) -> A<int>;13 14// Declarator pieces are not OK.15*A(int(&)[3]) -> A<int>; // expected-error {{cannot specify any part of a return type in the declaration of a deduction guide}}16&A(int(&)[4]) -> A<int>; // expected-error {{cannot specify any part of a return type in the declaration of a deduction guide}}17A(int(&)[5])[3] -> A<int>;18#ifdef CLASS // FIXME: These diagnostics are both pretty bad.19// expected-error@-2 {{function cannot return array type}} expected-error@-2 {{';'}}20#else21// expected-error@-4 {{expected function body after function declarator}}22#endif23 24(A[3])(int(&)[5][1]) -> A<int>; // expected-error {{'<deduction guide for A>' cannot be the name of a variable}}25#ifndef CLASS26// expected-error@-2 {{declared as array of functions}}27#endif28(*A)(int(&)[5][2]) -> A<int>; // expected-error {{'<deduction guide for A>' cannot be the name of a variable}}29(&A)(int(&)[5][3]) -> A<int>; // expected-error {{'<deduction guide for A>' cannot be the name of a variable}}30(*A(int))(int(&)[5][4]) -> A<int>; // expected-error {{cannot specify any part of a return type in the declaration of a deduction guide}}31 32// (Pending DR) attributes and parens around the declarator-id are OK.33[[deprecated]] A(int(&)[6]) [[]] -> A<int> [[]];34A [[]] (int(&)[7]) -> A<int>;35(A)(int(&)[8]) -> A<int>;36 37// ... but the trailing-return-type is part of the function-declarator as normal38(A(int(&)[9])) -> A<int>;39#ifdef CLASS // FIXME: These diagnostics are both pretty bad.40// expected-error@-2 {{deduction guide declaration without trailing return type}} expected-error@-2 {{';'}}41#else42// expected-error@-4 {{expected function body after function declarator}}43#endif44(A(int(&)[10]) -> A<int>); // expected-error {{trailing return type may not be nested within parentheses}}45 46// A trailing-return-type is mandatory.47A(int(&)[11]); // expected-error {{deduction guide declaration without trailing return type}}48 49// No type specifier is permitted; we don't even parse such cases as a deduction-guide.50int A(int) -> A<int>; // expected-error {{function with trailing return type must specify return type 'auto', not 'int'}}51template<typename T> struct B {}; // expected-note {{here}}52auto B(int) -> B<int>; // expected-error {{redefinition of 'B' as different kind of symbol}}53 54// No storage class specifier, function specifier, ...55friend A(int(&)[20]) -> A<int>;56#ifdef CLASS57// expected-error@-2 {{cannot declare a deduction guide as a friend}}58#else59// expected-error@-4 {{'friend' used outside of class}}60#endif61typedef A(int(&)[21]) -> A<int>; // expected-error {{deduction guide cannot be declared 'typedef'}}62constexpr A(int(&)[22]) -> A<int>; // expected-error {{deduction guide cannot be declared 'constexpr'}}63inline A(int(&)[23]) -> A<int>; // expected-error {{deduction guide cannot be declared 'inline'}}64static A(int(&)[24]) -> A<int>; // expected-error {{deduction guide cannot be declared 'static'}}65thread_local A(int(&)[25]) -> A<int>; // expected-error {{'thread_local' is only allowed on variable declarations}}66extern A(int(&)[26]) -> A<int>;67#ifdef CLASS68// expected-error@-2 {{storage class specified for a member}}69#else70// expected-error@-4 {{deduction guide cannot be declared 'extern'}}71#endif72mutable A(int(&)[27]) -> A<int>; // expected-error-re {{{{'mutable' cannot be applied to|illegal storage class on}} function}}73virtual A(int(&)[28]) -> A<int>; // expected-error {{'virtual' can only appear on non-static member functions}}74const A(int(&)[31]) -> A<int>; // expected-error {{deduction guide cannot be declared 'const'}}75 76const volatile static constexpr inline A(int(&)[29]) -> A<int>; // expected-error {{deduction guide cannot be declared 'static inline constexpr const volatile'}}77 78A(int(&)[30]) const -> A<int>; // expected-error {{deduction guide cannot have 'const' qualifier}}79 80// No definition is allowed.81A(int(&)[40]) -> A<int> {} // expected-error {{deduction guide cannot have a function definition}}82A(int(&)[41]) -> A<int> = default; // expected-error {{deduction guide cannot have a function definition}} expected-error {{only special member functions may be defaulted}}83A(int(&)[42]) -> A<int> = delete; // expected-error {{deduction guide cannot have a function definition}}84A(int(&)[43]) -> A<int> try {} catch (...) {} // expected-error {{deduction guide cannot have a function definition}}85 86#ifdef CLASS87};88#endif89 90namespace ExplicitInst {91 // Explicit instantiation / specialization is not permitted.92 template<typename T> struct B {};93 template<typename T> B(T) -> B<T>;94 template<> B(int) -> B<int>; // expected-error {{deduction guide cannot be explicitly specialized}}95 extern template B(float) -> B<float>; // expected-error {{deduction guide cannot be explicitly instantiated}}96 template B(char) -> B<char>; // expected-error {{deduction guide cannot be explicitly instantiated}}97 98 // An attempt at partial specialization doesn't even parse as a deduction-guide.99 template<typename T> B<T*>(T*) -> B<T*>; // expected-error 1+{{}} expected-note 0+{{}}100 101 struct X {102 template<typename T> struct C {};103 template<typename T> C(T) -> C<T>;104 template<> C(int) -> C<int>; // expected-error {{deduction guide cannot be explicitly specialized}}105 extern template C(float) -> C<float>; // expected-error {{expected member name or ';'}}106 template C(char) -> C<char>; // expected-error {{expected '<' after 'template'}}107 };108}109