1 // RUN: %clang_cc1 -std=c++11 -fsyntax-only -fexceptions -fcxx-exceptions -verify %s
2 // RUN: %clang_cc1 -std=c++2a -fsyntax-only -fexceptions -fcxx-exceptions -verify %s
3 
4 template<typename... Types> struct tuple;
5 template<int I> struct int_c;
6 
7 template<typename T>
8 struct identity {
9   typedef T type;
10 };
11 
12 template<typename T, typename U>
13 struct is_same {
14   static const bool value = false;
15 };
16 
17 template<typename T>
18 struct is_same<T, T> {
19   static const bool value = true;
20 };
21 
22 // FIXME: Several more bullets to go
23 
24 // In a function parameter pack, the pattern is the parameter-declaration
25 // without the ellipsis.
26 namespace PR11850 {
27   template<typename ...T> struct S {
28     int f(T...a, int b) { return b; }
29   };
30   S<> s;
31   S<int*, char, const double&> t;
32   int k = s.f(0);
33   int l = t.f(&k, 'x', 5.9, 4);
34 
35   template<typename ...As> struct A {
36     template<typename ...Bs> struct B {
37       template<typename ...Cs> struct C {
38         C(As..., Bs..., int &k, Cs...);
39       };
40     };
41   };
42   A<>::B<>::C<> c000(k);
43   A<int>::B<>::C<int> c101(1, k, 3);
44   A<>::B<int>::C<int> c011(1, k, 3);
45   A<int>::B<int>::C<> c110(1, 2, k);
46   A<int, int>::B<int, int>::C<int, int> c222(1, 2, 3, 4, k, 5, 6);
47   A<int, int, int>::B<>::C<> c300(1, 2, 3, k);
48 
49   int &f();
50   char &f(void*);
51   template<typename ...A> struct U {
52     template<typename ...B> struct V {
53       auto g(A...a, B...b) -> decltype(f(a...));
54     };
55   };
56   U<>::V<int*> v0;
57   U<int*>::V<> v1;
58   int &v0f = v0.g(0);
59   char &v1f = v1.g(0);
60 }
61 namespace PR12096 {
62   void Foo(int) {}
63   void Foo(int, int) = delete;
64   template<typename ...Args> struct Var {
65     Var(const Args &...args, int *) { Foo(args...); }
66   };
67   Var<int> var(1, 0);
68 }
69 
70 // In an initializer-list (8.5); the pattern is an initializer-clause.
71 // Note: this also covers expression-lists, since expression-list is
72 // just defined as initializer-list.
73 void five_args(int, int, int, int, int); // expected-note{{candidate function not viable: requires 5 arguments, but 6 were provided}}
74 
75 template<int ...Values>
76 void initializer_list_expansion() {
77   int values[5] = { Values... }; // expected-error{{excess elements in array initializer}}
78   five_args(Values...); // expected-error{{no matching function for call to 'five_args'}}
79 }
80 
81 template void initializer_list_expansion<1, 2, 3, 4, 5>();
82 template void initializer_list_expansion<1, 2, 3, 4, 5, 6>(); // expected-note{{in instantiation of function template specialization 'initializer_list_expansion<1, 2, 3, 4, 5, 6>' requested here}}
83 
84 namespace PR8977 {
85   struct A { };
86   template<typename T, typename... Args> void f(Args... args) {
87     // An empty expression-list performs value initialization.
88     constexpr T t(args...);
89   };
90 
91   template void f<A>();
92 }
93 
94 // In a base-specifier-list (Clause 10); the pattern is a base-specifier.
95 template<typename ...Mixins>
96 struct HasMixins : public Mixins... {
97   HasMixins();
98   HasMixins(const HasMixins&);
99   HasMixins(int i);
100 };
101 
102 struct A { }; // expected-note{{candidate constructor (the implicit copy constructor) not viable: no known conversion from 'int' to 'const A' for 1st argument}} \
103 // expected-note{{candidate constructor (the implicit move constructor) not viable: no known conversion from 'int' to 'A' for 1st argument}} \
104 // expected-note{{candidate constructor (the implicit default constructor) not viable: requires 0 arguments, but 1 was provided}}
105 struct B { }; // expected-note{{candidate constructor (the implicit copy constructor) not viable: no known conversion from 'int' to 'const B' for 1st argument}} \
106 // expected-note{{candidate constructor (the implicit move constructor) not viable: no known conversion from 'int' to 'B' for 1st argument}} \
107 // expected-note{{candidate constructor (the implicit default constructor) not viable: requires 0 arguments, but 1 was provided}}
108 struct C { };
109 struct D { };
110 
111 A *checkA = new HasMixins<A, B, C, D>;
112 B *checkB = new HasMixins<A, B, C, D>;
113 D *checkD = new HasMixins<A, B, C, D>;
114 C *checkC = new HasMixins<A, B, D>; // expected-error{{cannot initialize a variable of type 'C *' with an rvalue of type 'HasMixins<A, B, D> *'}}
115 HasMixins<> *checkNone = new HasMixins<>;
116 
117 template<typename Mixins>
118 struct BrokenMixins : public Mixins... { }; // expected-error{{pack expansion does not contain any unexpanded parameter packs}}
119 
120 // In a mem-initializer-list (12.6.2); the pattern is a mem-initializer.
121 template<typename ...Mixins>
122 HasMixins<Mixins...>::HasMixins(): Mixins()... { }
123 
124 template<typename ...Mixins>
125 HasMixins<Mixins...>::HasMixins(const HasMixins &other): Mixins(other)... { }
126 
127 template<typename ...Mixins>
128 HasMixins<Mixins...>::HasMixins(int i): Mixins(i)... { }
129 // expected-error@-1 {{no matching constructor for initialization of 'A'}}
130 // expected-error@-2 {{no matching constructor for initialization of 'B'}}
131 
132 void test_has_mixins() {
133   HasMixins<A, B> ab;
134   HasMixins<A, B> ab2 = ab;
135   HasMixins<A, B> ab3(17); // expected-note{{in instantiation of member function 'HasMixins<A, B>::HasMixins' requested here}}
136 }
137 
138 template<typename T>
139 struct X {
140   T member;
141 
142   X() : member()... { } // expected-error{{pack expansion for initialization of member 'member'}}
143 };
144 
145 // There was a bug in the delayed parsing code for the
146 // following case.
147 template<typename ...T>
148 struct DelayedParseTest : T...
149 {
150   int a;
151   DelayedParseTest(T... i) : T{i}..., a{10} {}
152 };
153 
154 
155 // In a template-argument-list (14.3); the pattern is a template-argument.
156 template<typename ...Types>
157 struct tuple_of_refs {
158   typedef tuple<Types& ...> types;
159 };
160 
161 tuple<int&, float&> *t_int_ref_float_ref;
162 tuple_of_refs<int&, float&>::types *t_int_ref_float_ref_2 =  t_int_ref_float_ref;
163 
164 template<typename ...Types>
165 struct extract_nested_types {
166   typedef tuple<typename Types::type...> types;
167 };
168 
169 tuple<int, float> *t_int_float;
170 extract_nested_types<identity<int>, identity<float> >::types *t_int_float_2
171   = t_int_float;
172 
173 template<int ...N>
174 struct tuple_of_ints {
175   typedef tuple<int_c<N>...> type;
176 };
177 
178 int check_temp_arg_1[is_same<tuple_of_ints<1, 2, 3, 4, 5>::type,
179                              tuple<int_c<1>, int_c<2>, int_c<3>, int_c<4>,
180                                    int_c<5>>>::value? 1 : -1];
181 
182 #if __cplusplus < 201703L
183 // In a dynamic-exception-specification (15.4); the pattern is a type-id.
184 template<typename ...Types>
185 struct f_with_except {
186   virtual void f() throw(Types...); // expected-note{{overridden virtual function is here}}
187 };
188 
189 struct check_f_with_except_1 : f_with_except<int, float> {
190   virtual void f() throw(int, float);
191 };
192 
193 struct check_f_with_except_2 : f_with_except<int, float> {
194   virtual void f() throw(int);
195 };
196 
197 struct check_f_with_except_3 : f_with_except<int, float> {
198   virtual void f() throw(int, float, double); // expected-error{{exception specification of overriding function is more lax than base version}}
199 };
200 #endif
201 
202 namespace PackExpansionWithinLambda {
203   void swallow(...);
204   template<typename ...T, typename ...U> void f(U ...u) {
205     swallow([=] {
206       // C++17 [temp.variadic]p4:
207       //   Pack expansions can occur in the following contexts:
208 
209       //    - in a function parameter pack
210       void g(T...);
211 
212 #if __cplusplus >= 201703L
213       struct A : T... {
214         //  - in a using-declaration
215         using T::x...;
216         using typename T::U...;
217       };
218 #endif
219 
220 #if __cplusplus > 201703L
221       //    - in a template parameter pack that is a pack expansion
222       swallow([]<T *...v, template<T *> typename ...W>(W<v> ...wv) { });
223 #endif
224 
225       //    - in an initializer-list
226       int arr[] = {T().x...};
227 
228       //    - in a base-specifier-list
229       struct B : T... {
230         //  - in a mem-initializer-list
231         B() : T{0}... {}
232       };
233 
234       //    - in a template-argument-list
235       f<T...>();
236 
237       //    - in an attribute-list
238       // FIXME: We do not support any such attributes yet.
239 
240       //    - in an alignment-specifier
241       alignas(T...) int y;
242 
243       //    - in a capture-list
244       [](T ...t) { [t...]{}(); } (T()...);
245 
246       //    - in a sizeof... expression
247       const int k1 = sizeof...(T);
248 
249 #if __cplusplus >= 201703L
250       //    - in a fold-expression
251       const int k2 = ((sizeof(T)/sizeof(T)) + ...);
252 
253       static_assert(k1 == k2);
254 #endif
255 
256       // Trigger clang to look in here for unexpanded packs.
257       U u;
258     } ...);
259   }
260 
261   template<typename ...T> void nested() {
262     swallow([=] {
263       [](T ...t) { [t]{}(); } (T()...); // expected-error {{unexpanded parameter pack 't'}}
264     }...); // expected-error {{does not contain any unexpanded}}
265   }
266 
267   template <typename ...T> void g() {
268     // Check that we do detect the above cases when the pack is not expanded.
269     swallow([=] { void h(T); }); // expected-error {{unexpanded parameter pack 'T'}}
270     swallow([=] { struct A : T {}; }); // expected-error {{unexpanded parameter pack 'T'}}
271 #if __cplusplus >= 201703L
272     swallow([=] { struct A : T... { using T::x; }; }); // expected-error {{unexpanded parameter pack 'T'}}
273     swallow([=] { struct A : T... { using typename T::U; }; }); // expected-error {{unexpanded parameter pack 'T'}}
274 #endif
275 
276     swallow([=] { int arr[] = {T().x}; }); // expected-error {{unexpanded parameter pack 'T'}}
277     swallow([=] { struct B : T... { B() : T{0} {} }; }); // expected-error {{unexpanded parameter pack 'T'}}
278     swallow([=] { f<T>(); }); // expected-error {{unexpanded parameter pack 'T'}}
279     swallow([=] { alignas(T) int y; }); // expected-error {{unexpanded parameter pack 'T'}}
280     swallow([=] { [](T ...t) {
281           [t]{}(); // expected-error {{unexpanded parameter pack 't'}}
282         } (T()...); });
283   }
284 
285   struct T { int x; using U = int; };
286   void g() { f<T>(1, 2, 3); }
287 
288   template<typename ...T> void pack_expand_attr() {
289     // FIXME: Move this test into 'f' above once we support this.
290     [[gnu::aligned(alignof(T))...]] int x; // expected-error {{cannot be used as an attribute pack}} expected-error {{unexpanded}}
291   }
292 }
293