1 // RUN: %clang_cc1 -fsyntax-only -verify -std=c++2c %s 2 3 template <typename> struct TS; // #template 4 5 struct Errors { 6 friend int, int; 7 friend int, long, char; 8 9 // We simply diagnose and ignore the '...' here. 10 friend float...; // expected-error {{pack expansion does not contain any unexpanded parameter packs}} 11 12 friend short..., unsigned, unsigned short...; // expected-error 2 {{pack expansion does not contain any unexpanded parameter packs}} 13 14 template <typename> 15 friend struct TS, int; // expected-error {{a friend declaration that befriends a template must contain exactly one type-specifier}} 16 17 double friend; // expected-error {{'friend' must appear first in a non-function declaration}} 18 double friend, double; // expected-error {{expected member name or ';' after declaration specifiers}} 19 }; 20 21 template <typename> 22 struct C { template<class T> class Nested; }; 23 24 template <typename, typename> 25 struct D { template<class T> class Nested; }; 26 27 template <bool> 28 struct E { template<class T> class Nested; }; 29 30 template<class... Ts> // expected-note {{template parameter is declared here}} 31 struct VS { 32 friend Ts...; 33 34 friend class Ts...; // expected-error {{declaration of 'Ts' shadows template parameter}} 35 // expected-error@-1 {{pack expansion does not contain any unexpanded parameter packs}} 36 37 // TODO: Fix-it hint to insert '...'. 38 friend Ts; // expected-error {{friend declaration contains unexpanded parameter pack}} 39 40 template<class... Us> 41 friend Us...; // expected-error {{friend type templates must use an elaborated type}} 42 43 template<class... Us> // expected-note {{is declared here}} 44 friend class Us...; // expected-error {{declaration of 'Us' shadows template parameter}} 45 46 template<class U> 47 friend class C<Ts>::template Nested<U>...; // expected-error {{cannot specialize a dependent template}} 48 49 template<class... Us> 50 friend class C<Ts...>::template Nested<Us>...; // expected-error {{cannot specialize a dependent template}} 51 52 // Nonsense (see CWG 2917). 53 template<class... Us> 54 friend class C<Us>::Nested...; // expected-error {{friend declaration expands pack 'Us' that is declared it its own template parameter list}} 55 56 template<bool... Bs> 57 friend class E<Bs>::Nested...; // expected-error {{friend declaration expands pack 'Bs' that is declared it its own template parameter list}} 58 59 // FIXME: Both of these should be valid, but we can't handle these at 60 // the moment because the NNS is dependent. 61 template<class ...T> 62 friend class TS<Ts>::Nested...; // expected-warning {{dependent nested name specifier 'TS<Ts>::' for friend template declaration is not supported; ignoring this friend declaration}} 63 64 template<class T> 65 friend class D<T, Ts>::Nested...; // expected-warning {{dependent nested name specifier 'D<T, Ts>::' for friend class declaration is not supported; turning off access control for 'VS'}} 66 }; 67 68 namespace length_mismatch { 69 struct A { 70 template <typename...> 71 struct Nested { 72 struct Foo{}; 73 }; 74 }; 75 template <typename ...Ts> 76 struct S { 77 template <typename ...Us> 78 struct T { 79 // expected-error@+2 {{pack expansion contains parameter packs 'Ts' and 'Us' that have different lengths (1 vs. 2)}} 80 // expected-error@+1 {{pack expansion contains parameter packs 'Ts' and 'Us' that have different lengths (2 vs. 1)}} 81 friend class Ts::template Nested<Us>::Foo...; 82 }; 83 }; 84 85 void f() { 86 S<A>::T<int> s; 87 S<A, A>::T<int, long> s2; 88 S<A>::T<int, long> s3; // expected-note {{in instantiation of}} 89 S<A, A>::T<int> s4; // expected-note {{in instantiation of}} 90 } 91 } 92