instantiate-requires-clause.cpp
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// RUN: %clang_cc1 -std=c++2a -x c++ %s -verify
template <typename... Args> requires ((sizeof(Args) == 1), ...)
// expected-note@-1 {{because '(sizeof(int) == 1) , (sizeof(char) == 1) , (sizeof(int) == 1)' evaluated to false}}
void f1(Args&&... args) { }
// expected-note@-1 {{candidate template ignored: constraints not satisfied [with Args = <int, char, int>]}}
using f11 = decltype(f1('a'));
using f12 = decltype(f1(1, 'b'));
using f13 = decltype(f1(1, 'b', 2));
// expected-error@-1 {{no matching function for call to 'f1'}}
template <typename... Args>
void f2(Args&&... args) requires ((sizeof(args) == 1), ...) { }
// expected-note@-1 {{candidate template ignored: constraints not satisfied [with Args = <int, char, int>]}}
// expected-note@-2 {{because '(sizeof (args) == 1) , (sizeof (args) == 1) , (sizeof (args) == 1)' evaluated to false}}
using f21 = decltype(f2('a'));
using f22 = decltype(f2(1, 'b'));
using f23 = decltype(f2(1, 'b', 2));
// expected-error@-1 {{no matching function for call to 'f2'}}
template <typename... Args> requires ((sizeof(Args) == 1), ...)
// expected-note@-1 {{because '(sizeof(int) == 1) , (sizeof(char) == 1) , (sizeof(int) == 1)' evaluated to false}}
void f3(Args&&... args) requires ((sizeof(args) == 1), ...) { }
// expected-note@-1 {{candidate template ignored: constraints not satisfied [with Args = <int, char, int>]}}
using f31 = decltype(f3('a'));
using f32 = decltype(f3(1, 'b'));
using f33 = decltype(f3(1, 'b', 2));
// expected-error@-1 {{no matching function for call to 'f3'}}
template<typename T>
struct S {
template<typename U>
static constexpr auto f(U const index) requires(index, true) {
return true;
}
};
static_assert(S<void>::f(1));
constexpr auto value = 0;
template<typename T>
struct S2 {
template<typename = void> requires(value, true)
static constexpr auto f() requires(value, true) {
}
};
static_assert((S2<int>::f(), true));
template<typename T>
struct S3 {
template<typename... Args> requires true
static constexpr void f(Args...) { }
};
static_assert((S3<int>::f(), true));
template<typename T>
struct S4 {
template<typename>
constexpr void foo() requires (*this, true) { }
constexpr void goo() requires (*this, true) { }
};
static_assert((S4<int>{}.foo<int>(), S4<int>{}.goo(), true));