1 // RUN: %clang_cc1 -std=c++1z -verify %s
2
3 // Test that we cope with failure to expand a pack.
4 template<typename ...T> struct Unexpanded : T... {
5 using T::f; // expected-error {{unexpanded}}
6 using typename T::type; // expected-error {{unexpanded}}
gUnexpanded7 template<typename ...U> void g(U ...u) { f(u...); } // expected-error {{undeclared identifier 'f'}}
hUnexpanded8 void h() {
9 Unexpanded<type...> *p; // expected-error {{undeclared identifier 'type'}}
10 }
11 };
test_Unexpanded()12 void test_Unexpanded() {
13 struct A { void f(); }; // expected-note {{must qualify}}
14 struct B { void f(int); }; // expected-note {{must qualify}}
15 Unexpanded<A, B>().g(0); // expected-note {{instantiation of}}
16 }
17
18 // Test using non-type members from pack of base classes.
19 template<typename ...T> struct A : T... {
20 using T::T ...; // expected-note 2{{inherited here}}
21 using T::operator() ...;
22 using T::operator T* ...;
23 using T::h ...;
24
fA25 void f(int n) { h(n); } // expected-error {{ambiguous}}
fA26 void f(int n, int m) { h(n, m); } // expected-error {{member using declaration 'h' instantiates to an empty pack}}
gA27 void g(int n) { (*this)(n); } // expected-error {{ambiguous}}
gA28 void g(int n, int m) { (*this)(n, m); } // expected-error {{does not provide a call operator}}
29 };
30
31 namespace test_A {
32 struct X {
33 X();
34 X(int); // expected-note {{candidate}}
35 void operator()(int); // expected-note 2{{candidate}}
36 operator X *();
37 void h(int); // expected-note {{candidate}}
38 };
39 struct Y {
40 Y();
41 Y(int, int);
42 void operator()(int, int);
43 operator Y *();
44 void h(int, int);
45 };
46 struct Z {
47 Z();
48 Z(int); // expected-note {{candidate}}
49 void operator()(int); // expected-note 2{{candidate}}
50 operator Z *();
51 void h(int); // expected-note {{candidate}}
52 };
53
f()54 void f() {
55 A<> a;
56 a.f(0, 0); // expected-note {{instantiation of}}
57 a.g(0, 0); // expected-note {{instantiation of}}
58
59 A<X, Y> axy(0);
60 A<X, Y>(0, 0);
61 axy.f(0);
62 axy.f(0, 0);
63 axy.g(0);
64 axy.g(0, 0);
65 axy(0);
66 axy(0, 0);
67
68 A<X, Y, Z>(0); // expected-error {{ambiguous}}
69 A<X, Y, Z> axyz(0, 0);
70 axyz.f(0); // expected-note {{instantiation of}}
71 axyz.f(0, 0);
72 axyz.g(0); // expected-note {{instantiation of}}
73 axyz.g(0, 0);
74 axyz(0); // expected-error {{ambiguous}}
75 axyz(0, 0);
76
77 X *x;
78 x = a; // expected-error {{incompatible}}
79 x = axy;
80 x = axyz;
81 x = a.operator X*(); // expected-error {{no member}}
82 x = axy.operator X*();
83 x = axyz.operator X*();
84
85 Z *z;
86 z = axyz;
87 z = axyz.operator Z*();
88 }
89 }
90
91 // Test using pack of non-type members from single base class.
92 template<typename X, typename Y, typename ...T> struct B : X, Y {
93 using X::operator T* ...;
94 };
95
96 namespace test_B {
97 struct X { operator int*(); operator float*(); operator char*(); }; // expected-note {{candidate}}
98 struct Y { operator int*(); operator float*(); operator char*(); }; // expected-note {{candidate}}
99 B<X, Y, int, float> bif;
100 int *pi = bif;
101 float *pf = bif;
102 char *pc = bif; // expected-error {{ambiguous}}
103 }
104
105 // Test using type member from pack of base classes.
106 template<typename ...T> struct C : T... {
107 using typename T::type ...; // expected-error {{target of using declaration conflicts}}
fC108 void f() { type value; } // expected-error {{member using declaration 'type' instantiates to an empty pack}}
109 };
110
111 namespace test_C {
112 struct X { typedef int type; };
113 struct Y { typedef int type; }; // expected-note {{conflicting}}
114 struct Z { typedef float type; }; // expected-note {{target}}
115
f()116 void f() {
117 C<> c;
118 c.f(); // expected-note {{instantiation of}}
119
120 C<X, Y> cxy;
121 cxy.f();
122
123 C<X, Y, Z> cxyz; // expected-note {{instantiation of}}
124 cxyz.f();
125 }
126 }
127
128 // Test using pack of non-types at block scope.
fn1()129 template<typename ...T> int fn1() {
130 using T::e ...; // expected-error 2{{class member}} expected-note 2{{instead}}
131 // expected-error@-1 2{{produces multiple values}}
132 return e; // expected-error {{using declaration 'e' instantiates to an empty pack}}
133 }
134
135 namespace test_fn1 {
136 struct X { static int e; };
137 struct Y { typedef int e; };
138 inline namespace P { enum E { e }; }
139 inline namespace Q { enum F { e }; }
f()140 void f() {
141 fn1<>(); // expected-note {{instantiation of}}
142 fn1<X>(); // expected-note {{instantiation of}}
143 fn1<Y>(); // expected-note {{instantiation of}}
144 fn1<E>();
145 fn1<E, F>(); // expected-note {{instantiation of}}
146 fn1<E, X>(); // expected-note {{instantiation of}}
147 }
148 }
149
150 // Test using pack of types at block scope.
fn2()151 template<typename ...T> void fn2() {
152 // This cannot ever be valid: in order for T::type to be a type, T must be a
153 // class, and a class member cannot be named by a block-scope using declaration.
154 using typename T::type ...; // expected-error {{class member}}
155 type x; // expected-error {{unknown type name 'type'}}
156 }
157
158 // Test partial substitution into class-scope pack.
lambda1()159 template<typename ...T> auto lambda1() {
160 return [](auto x) {
161 struct A : T::template X<decltype(x)>... { // expected-note 1+{{instantiation of}}
162 using T::template X<decltype(x)>::f ...;
163 using typename T::template X<decltype(x)>::type ...;
164 void g(int n) { f(n); } // expected-error {{empty pack}} expected-error {{expected 2, have 1}} expected-error {{ambiguous}}
165 void h() { type value; } // expected-error {{empty pack}}
166 };
167 return A();
168 };
169 }
170
171 namespace test_lambda1 {
172 struct A {
173 template<typename> struct X {
174 void f(int); // expected-note {{candidate}}
175 using type = int;
176 };
177 };
178 struct B {
179 template<typename> struct X {
180 void f(int, int); // expected-note {{declared here}}
181 using type = int;
182 };
183 };
184 struct C {
185 template<typename> struct X {
186 void f(int); // expected-note {{candidate}}
187 void f(int, int);
188 using type = int;
189 };
190 };
191
f()192 void f() {
193 lambda1<>() // expected-note 2{{instantiation of}}
194 (0)
195 // FIXME: This is poor error recovery
196 .g(0); // expected-error {{no member named 'g'}}
197 lambda1<A>()
198 (0)
199 .g(0);
200 lambda1<B>()
201 (0) // expected-note {{instantiation of}}
202 .g(0);
203 lambda1<A, B, C>()
204 (0) // expected-note {{instantiation of}}
205 .g(0);
206 }
207 }
208
209 namespace p0195r2_example {
210 template<typename ...Ts>
211 struct Overloader : Ts... {
212 using Ts::operator() ...;
213 };
214
215 template<typename ...Ts>
make_overloader(Ts &&...ts)216 constexpr auto make_overloader(Ts &&...ts) {
217 return Overloader<Ts...>{static_cast<Ts&&>(ts)...};
218 }
219
test()220 void test() {
221 auto o = make_overloader(
222 [&](int &r) -> int & { return r; }, // expected-note {{candidate function}}
223 [&](float &r) -> float & { return r; } // expected-note {{candidate function}}
224 );
225 int a; float f; double d;
226 int &ra = o(a);
227 float &rf = o(f);
228 double &rd = o(d); // expected-error {{no matching function}}
229 }
230 }
231