1 // RUN: %clang_cc1 -std=c++11 -fsyntax-only -fexceptions -fcxx-exceptions -verify=expected,pre20 %s
2 // RUN: %clang_cc1 -std=c++2a -fsyntax-only -fexceptions -fcxx-exceptions -verify=expected,post20 %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 {
fPR11850::S28 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 {
Foo(int)62 void Foo(int) {}
63 void Foo(int, int) = delete;
64 template<typename ...Args> struct Var {
VarPR12096::Var65 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>
initializer_list_expansion()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 { };
f(Args...args)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 { }; // pre20-note{{candidate constructor (the implicit copy constructor) not viable: no known conversion from 'int' to 'const A' for 1st argument}} \
103 // pre20-note{{candidate constructor (the implicit move constructor) not viable: no known conversion from 'int' to 'A' for 1st argument}} \
104 // pre20-note{{candidate constructor (the implicit default constructor) not viable: requires 0 arguments, but 1 was provided}}
105 struct B { }; // pre20-note{{candidate constructor (the implicit copy constructor) not viable: no known conversion from 'int' to 'const B' for 1st argument}} \
106 // pre20-note{{candidate constructor (the implicit move constructor) not viable: no known conversion from 'int' to 'B' for 1st argument}} \
107 // pre20-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>
HasMixins()122 HasMixins<Mixins...>::HasMixins(): Mixins()... { }
123
124 template<typename ...Mixins>
HasMixins(const HasMixins & other)125 HasMixins<Mixins...>::HasMixins(const HasMixins &other): Mixins(other)... { }
126
127 template<typename ...Mixins>
HasMixins(int i)128 HasMixins<Mixins...>::HasMixins(int i): Mixins(i)... { }
129 // pre20-error@-1 {{no matching constructor for initialization of 'A'}}
130 // pre20-error@-2 {{no matching constructor for initialization of 'B'}}
131 // post20-error@-3 {{excess elements in struct initializer}}
132 // post20-error@-4 {{excess elements in struct initializer}}
133
test_has_mixins()134 void test_has_mixins() {
135 HasMixins<A, B> ab;
136 HasMixins<A, B> ab2 = ab;
137 HasMixins<A, B> ab3(17); // expected-note{{in instantiation of member function 'HasMixins<A, B>::HasMixins' requested here}}
138 }
139
140 template<typename T>
141 struct X {
142 T member;
143
XX144 X() : member()... { } // expected-error{{pack expansion for initialization of member 'member'}}
145 };
146
147 // There was a bug in the delayed parsing code for the
148 // following case.
149 template<typename ...T>
150 struct DelayedParseTest : T...
151 {
152 int a;
DelayedParseTestDelayedParseTest153 DelayedParseTest(T... i) : T{i}..., a{10} {}
154 };
155
156
157 // In a template-argument-list (14.3); the pattern is a template-argument.
158 template<typename ...Types>
159 struct tuple_of_refs {
160 typedef tuple<Types& ...> types;
161 };
162
163 tuple<int&, float&> *t_int_ref_float_ref;
164 tuple_of_refs<int&, float&>::types *t_int_ref_float_ref_2 = t_int_ref_float_ref;
165
166 template<typename ...Types>
167 struct extract_nested_types {
168 typedef tuple<typename Types::type...> types;
169 };
170
171 tuple<int, float> *t_int_float;
172 extract_nested_types<identity<int>, identity<float> >::types *t_int_float_2
173 = t_int_float;
174
175 template<int ...N>
176 struct tuple_of_ints {
177 typedef tuple<int_c<N>...> type;
178 };
179
180 int check_temp_arg_1[is_same<tuple_of_ints<1, 2, 3, 4, 5>::type,
181 tuple<int_c<1>, int_c<2>, int_c<3>, int_c<4>,
182 int_c<5>>>::value? 1 : -1];
183
184 #if __cplusplus < 201703L
185 // In a dynamic-exception-specification (15.4); the pattern is a type-id.
186 template<typename ...Types>
187 struct f_with_except {
188 virtual void f() throw(Types...); // expected-note{{overridden virtual function is here}}
189 };
190
191 struct check_f_with_except_1 : f_with_except<int, float> {
192 virtual void f() throw(int, float);
193 };
194
195 struct check_f_with_except_2 : f_with_except<int, float> {
196 virtual void f() throw(int);
197 };
198
199 struct check_f_with_except_3 : f_with_except<int, float> {
200 virtual void f() throw(int, float, double); // expected-error{{exception specification of overriding function is more lax than base version}}
201 };
202 #endif
203
204 namespace PackExpansionWithinLambda {
205 void swallow(...);
f(U...u)206 template<typename ...T, typename ...U> void f(U ...u) {
207 swallow([=] {
208 // C++17 [temp.variadic]p4:
209 // Pack expansions can occur in the following contexts:
210
211 // - in a function parameter pack
212 void g(T...);
213
214 #if __cplusplus >= 201703L
215 struct A : T... {
216 // - in a using-declaration
217 using T::x...;
218 using typename T::U...;
219 };
220 #endif
221
222 #if __cplusplus > 201703L
223 // - in a template parameter pack that is a pack expansion
224 swallow([]<T *...v, template<T *> typename ...W>(W<v> ...wv) { });
225 #endif
226
227 // - in an initializer-list
228 int arr[] = {T().x...};
229
230 // - in a base-specifier-list
231 struct B : T... {
232 // - in a mem-initializer-list
233 B() : T{0}... {}
234 };
235
236 // - in a template-argument-list
237 f<T...>();
238
239 // - in an attribute-list
240 // FIXME: We do not support any such attributes yet.
241
242 // - in an alignment-specifier
243 alignas(T...) int y;
244
245 // - in a capture-list
246 [](T ...t) { [t...]{}(); } (T()...);
247
248 // - in a sizeof... expression
249 const int k1 = sizeof...(T);
250
251 #if __cplusplus >= 201703L
252 // - in a fold-expression
253 const int k2 = ((sizeof(T)/sizeof(T)) + ...);
254
255 static_assert(k1 == k2);
256 #endif
257
258 // Trigger clang to look in here for unexpanded packs.
259 U u;
260 } ...);
261 }
262
nested()263 template<typename ...T> void nested() {
264 swallow([=] {
265 [](T ...t) { [t]{}(); } (T()...); // expected-error {{unexpanded parameter pack 't'}}
266 }...); // expected-error {{does not contain any unexpanded}}
267 }
268
g()269 template <typename ...T> void g() {
270 // Check that we do detect the above cases when the pack is not expanded.
271 swallow([=] { void h(T); }); // expected-error {{unexpanded parameter pack 'T'}}
272 swallow([=] { struct A : T {}; }); // expected-error {{unexpanded parameter pack 'T'}}
273 #if __cplusplus >= 201703L
274 swallow([=] { struct A : T... { using T::x; }; }); // expected-error {{unexpanded parameter pack 'T'}}
275 swallow([=] { struct A : T... { using typename T::U; }; }); // expected-error {{unexpanded parameter pack 'T'}}
276 #endif
277
278 swallow([=] { int arr[] = {T().x}; }); // expected-error {{unexpanded parameter pack 'T'}}
279 swallow([=] { struct B : T... { B() : T{0} {} }; }); // expected-error {{unexpanded parameter pack 'T'}}
280 swallow([=] { f<T>(); }); // expected-error {{unexpanded parameter pack 'T'}}
281 swallow([=] { alignas(T) int y; }); // expected-error {{unexpanded parameter pack 'T'}}
282 swallow([=] { [](T ...t) {
283 [t]{}(); // expected-error {{unexpanded parameter pack 't'}}
284 } (T()...); });
285 }
286
287 struct T { int x; using U = int; };
g()288 void g() { f<T>(1, 2, 3); }
289
pack_expand_attr()290 template<typename ...T> void pack_expand_attr() {
291 // FIXME: Move this test into 'f' above once we support this.
292 [[gnu::aligned(alignof(T))...]] int x; // expected-error {{cannot be used as an attribute pack}} expected-error {{unexpanded}}
293 }
294 }
295