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145
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1 // { dg-do compile { target c++2a } }
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2 // { dg-additional-options "-fconcepts-ts" }
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3
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4 template<typename T, int N, typename... Xs> concept bool C1 = true;
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5
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6 template<template<typename> class X> concept bool C2 = true;
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7
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8 template<typename... Ts> concept bool C3 = true;
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9
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10 C1{A, B, ...C} struct S1 { };
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11
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12 C2{T} void f();
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13
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14 C2{...Ts} void g(); // { dg-error "cannot be introduced" }
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15
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16 C3{...Ts} struct S2 { };
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17 C3{T, U, V} struct S3 { };
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18 C3{...Ts, U} struct S4 { }; // { dg-error "cannot deduce template parameters" }
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19
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20 template<typename> struct X { };
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21
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22 void driver1() {
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23 S1<int, 0, char, bool, float> s1a;
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24 S1<0, 0, char, bool, float> s1b; // { dg-error "type/value mismatch" }
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25
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26 f<X>();
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27 f<int>(); // { dg-error "no matching function for call" }
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28
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29 S2<int> s2a;
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30 S2<char, signed char, unsigned char> s2b;
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31 S2<0> s2c; // { dg-error "type/value mismatch" }
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32
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33 S3<int, int, int> s3a;
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34 S3<int, int> s3b; // { dg-error "wrong number of template arguments" }
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35 }
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36
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37 template<typename... Args>
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38 struct all_same;
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39
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40 template<typename T, typename U, typename... Args>
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41 struct all_same<T, U, Args...>
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42 {
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43 static constexpr bool value = __is_same_as(T, U) && all_same<U, Args...>::value;
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44 };
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45
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46 template<typename T>
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47 struct all_same<T>
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48 {
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49 static constexpr bool value = true;
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50 };
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51
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52 template<>
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53 struct all_same<>
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54 {
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55 static constexpr bool value = true;
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56 };
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57
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58 template<typename... Ts>
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59 concept AllSame = all_same<Ts...>::value;
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60
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61 AllSame{...Ts} struct S5 { };
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62 AllSame{T, U} struct S6 { };
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63
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64 void driver2()
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65 {
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66 S5<int, int> s5a;
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67 S5<int, int, int, int> s5b;
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68 S5<int, int, int, char> s5c; // { dg-error "template constraint failure" }
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69 S6<void, void> s6a;
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70 S6<void, int> s6c; // { dg-error "template constraint failure" }
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71 S6<void, void, void> s6b; // { dg-error "wrong number of template arguments" }
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72 } |
