131 lines · cpp
1// RUN: %clang_cc1 -std=c++2a -verify %s2 3template<typename T, typename U>4constexpr static bool is_same_v = false;5 6template<typename T>7constexpr static bool is_same_v<T, T> = true;8 9namespace templates10{11 template<typename T>12 concept AtLeast1 = sizeof(T) >= 1;13 14 template<typename T>15 int foo(T t) requires (sizeof(T) == 4) { // expected-note {{candidate function}}16 return 0;17 }18 19 template<typename T>20 char foo(T t) requires AtLeast1<T> { // expected-note {{candidate function}}21 return 'a';22 }23 24 template<typename T>25 double foo(T t) requires (AtLeast1<T> && sizeof(T) <= 2) {26 return 'a';27 }28 29 static_assert(is_same_v<decltype(foo(10)), int>); // expected-error {{call to 'foo' is ambiguous}}30 static_assert(is_same_v<decltype(foo(short(10))), double>);31 32 template<typename T>33 void bar() requires (sizeof(T) == 1) { }34 // expected-note@-1{{similar constraint expressions not considered equivalent}}35 // expected-note@-2{{candidate function [with T = char]}}36 37 template<typename T>38 void bar() requires (sizeof(T) == 1 && sizeof(T) >= 0) { }39 // expected-note@-1{{candidate function [with T = char]}}40 // expected-note@-2{{similar constraint expression here}}41 42 static_assert(is_same_v<decltype(bar<char>()), void>);43 // expected-error@-1{{call to 'bar' is ambiguous}}44 45 template<typename T>46 constexpr int baz() requires AtLeast1<T> { // expected-note {{candidate function}}47 return 1;48 }49 50 template<typename T> requires AtLeast1<T>51 constexpr int baz() { // expected-note {{candidate function [with T = int]}}52 return 2;53 }54 55 static_assert(baz<int>() == 1); // expected-error {{call to 'baz' is ambiguous}}56}57 58namespace non_template59{60 template<typename T>61 concept AtLeast2 = sizeof(T) >= 2;62 63 template<typename T>64 concept AtMost8 = sizeof(T) <= 8;65 66 template<typename T>67 int foo() requires AtLeast2<long> && AtMost8<long> {68 return 0;69 }70 71 template<typename T>72 double foo() requires AtLeast2<long> {73 return 0.0;74 }75 76 template<typename T>77 double baz() requires AtLeast2<long> && AtMost8<long> { // expected-note {{candidate function}}78 return 0.0;79 }80 81 template<typename T>82 int baz() requires AtMost8<long> && AtLeast2<long> { // expected-note {{candidate function}}83 return 0.0;84 }85 86 template<typename T>87 void bar() requires (sizeof(char[8]) >= 8) { }88 // expected-note@-1 {{candidate function}}89 // expected-note@-2 {{similar constraint expressions not considered equivalent}}90 91 template<typename T>92 void bar() requires (sizeof(char[8]) >= 8 && sizeof(int) <= 30) { }93 // expected-note@-1 {{candidate function}}94 // expected-note@-2 {{similar constraint expression here}}95 96 static_assert(is_same_v<decltype(foo<int>()), int>);97 static_assert(is_same_v<decltype(baz<int>()), int>); // expected-error {{call to 'baz' is ambiguous}}98 static_assert(is_same_v<decltype(bar<int>()), void>); // expected-error {{call to 'bar' is ambiguous}}99 100 // Top-level cv-qualifiers are ignored in template partial ordering per [dcl.fct]/p5.101 // After producing the list of parameter types, any top-level cv-qualifiers modifying102 // a parameter type are deleted when forming the function type.103 template<typename T>104 constexpr int goo(T a) requires AtLeast2<T> && true {105 return 1;106 }107 108 template<typename T>109 constexpr int goo(const T b) requires AtLeast2<T> {110 return 2;111 }112 113 // [temp.func.order] p5114 // Since, in a call context, such type deduction considers only parameters115 // for which there are explicit call arguments, some parameters are ignored116 // (namely, function parameter packs, parameters with default arguments, and117 // ellipsis parameters).118 template<typename T>119 constexpr int doo(int a, ...) requires AtLeast2<int> && true {120 return 1;121 }122 123 template<typename T>124 constexpr int doo(int b) requires AtLeast2<int> {125 return 2;126 }127 128 static_assert(goo<int>(1) == 1);129 static_assert(doo<int>(2) == 1);130}131