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// RUN: %clang_cc1 -std=c++2a -verify %s
template<typename T, typename U>
constexpr static bool is_same_v = false;
template<typename T>
constexpr static bool is_same_v<T, T> = true;
namespace templates
{
template<typename T>
concept AtLeast1 = sizeof(T) >= 1;
template<typename T>
int foo(T t) requires (sizeof(T) == 4) { // expected-note {{candidate function}}
return 0;
}
template<typename T>
char foo(T t) requires AtLeast1<T> { // expected-note {{candidate function}}
return 'a';
}
template<typename T>
double foo(T t) requires (AtLeast1<T> && sizeof(T) <= 2) {
return 'a';
}
static_assert(is_same_v<decltype(foo(10)), int>); // expected-error {{call to 'foo' is ambiguous}}
static_assert(is_same_v<decltype(foo(short(10))), double>);
template<typename T>
void bar() requires (sizeof(T) == 1) { }
// expected-note@-1{{similar constraint expressions not considered equivalent}}
// expected-note@-2{{candidate function [with T = char]}}
template<typename T>
void bar() requires (sizeof(T) == 1 && sizeof(T) >= 0) { }
// expected-note@-1{{candidate function [with T = char]}}
// expected-note@-2{{similar constraint expression here}}
static_assert(is_same_v<decltype(bar<char>()), void>);
// expected-error@-1{{call to 'bar' is ambiguous}}
template<typename T>
constexpr int baz() requires AtLeast1<T> { // expected-note {{candidate function}}
return 1;
}
template<typename T> requires AtLeast1<T>
constexpr int baz() { // expected-note {{candidate function [with T = int]}}
return 2;
}
static_assert(baz<int>() == 1); // expected-error {{call to 'baz' is ambiguous}}
}
namespace non_template
{
template<typename T>
concept AtLeast2 = sizeof(T) >= 2;
template<typename T>
concept AtMost8 = sizeof(T) <= 8;
template<typename T>
int foo() requires AtLeast2<long> && AtMost8<long> {
return 0;
}
template<typename T>
double foo() requires AtLeast2<long> {
return 0.0;
}
template<typename T>
double baz() requires AtLeast2<long> && AtMost8<long> { // expected-note {{candidate function}}
return 0.0;
}
template<typename T>
int baz() requires AtMost8<long> && AtLeast2<long> { // expected-note {{candidate function}}
return 0.0;
}
template<typename T>
void bar() requires (sizeof(char[8]) >= 8) { }
// expected-note@-1 {{candidate function}}
// expected-note@-2 {{similar constraint expressions not considered equivalent}}
template<typename T>
void bar() requires (sizeof(char[8]) >= 8 && sizeof(int) <= 30) { }
// expected-note@-1 {{candidate function}}
// expected-note@-2 {{similar constraint expression here}}
static_assert(is_same_v<decltype(foo<int>()), int>);
static_assert(is_same_v<decltype(baz<int>()), int>); // expected-error {{call to 'baz' is ambiguous}}
static_assert(is_same_v<decltype(bar<int>()), void>); // expected-error {{call to 'bar' is ambiguous}}
template<typename T>
constexpr int goo(int a) requires AtLeast2<int> && true { // expected-note {{candidate function}}
return 1;
}
template<typename T>
constexpr int goo(const int b) requires AtLeast2<int> { // expected-note {{candidate function}}
return 2;
}
// [temp.func.order] p5
// Since, in a call context, such type deduction considers only parameters
// for which there are explicit call arguments, some parameters are ignored
// (namely, function parameter packs, parameters with default arguments, and
// ellipsis parameters).
template<typename T>
constexpr int doo(int a, ...) requires AtLeast2<int> && true {
return 1;
}
template<typename T>
constexpr int doo(int b) requires AtLeast2<int> {
return 2;
}
// By temp.func.order-6.2.2, this is ambiguous because parameter a and b have different types.
static_assert(goo<int>(1) == 1); // expected-error {{call to 'goo' is ambiguous}}
static_assert(doo<int>(2) == 1);
}
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